ISSN:0144-557X    

DOI:10.1039/AP98522FX013

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANPRDI 22(4) 93-1 24 (1 985) Analytical Proceedings Proceedings of the Analytical Division of The Royal Society of Chemistry CONTENTS 93 James Fowler Tocher (1846-1945) 95 95 Summaries of Papers 'Quality and Acceptance Testing of Packaging-With Beverages, P ha rmaceut ica Is and Cosmetics' 'The Analysis of Drugs and Their Metabolites' 'Laser Applications' is a monthly current awareness bulletin providing worldwide coverage of recent literature on hazards safe working practice those working in the and allied industries, CHI 110 115 120 Equipment News 123 Publications Received 124 Conferences and Meetings 124 Courses iii Analytical Division Diary \ / CHI issues contain over 200 items drawn from the world's current scientific and technical literature - keeping you up to date in your area of interest! references include titles, bibliographic details and FULL ABSTRACTS! CHI is divided into sections to give you quick and easy access to relevant topics! CHI is indexed by Chemical and Subject (cumulated annually) to aid location of specific items - making it the perfect tool for both current awareness and retrospective searching! 7 Electronically typeset and printed by Heffers Printers Ltd, Cambridge, England \ HAZARDS IN THE CHEMICAL LABORATORY deals with safety measures,; practice and toxic effects:- I 0 Health & Safety at Work Act '74 0 Safety Planning & Management i 0 Fire protection 0 Reactive Chemical Hazards i 0 Health Care 6. First Aid 0 Hazardous Chemicals 0 Precautions against RadiationsEm 0 Chemical Hazards 8 Toxicology Regarded by many as the most authoritative, comprehensive source of chemical laboratory safety information.For prices, further details and a FREE SAMPLE of CHI contact:- The Royal Society of Chemistry The University Nottinaham NG7 2RD Tel: 0602 50741 1 Telex: 37488 ENGLAND April 1985 Reference t o Foods,

ISSN:0144-557X    

DOI:10.1039/AP98522BX015

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

93 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 James Fowler Tocher (18661945) Dr. J. F. Tocher would have been 70 when the first moves to form the Scottish Section of the Society of Public Analysts and Other Analytical Chemists were made. He was a member of Council at the time, as he had been previously in 1918- 19. He had already had an amazingly full and varied life and career. He was born in Fyvie on October 24th, 1864, the son of a police constable, and educated at Alford and Lumsden schools. He became apprenticed to Mr. William Troup, the pharmacist at Rhynie, and then acted as an assistant in Glasgow. He then served in the pharmacy of Dr. Robertson, Castle Street, Aberdeen, and at the same time studied chemistry at Aberdeen Univer- sity. On passing the relevant examination, he became registered as a chemist and druggist, and set up a business in Peter- head.In 1888-9 he attended Mason Col- lege, Birmingham, to complete the train- ing necessary to become an Associate of the Institute of Chemistry. In 1890 he became registered as a pharmaceutical chemist, and in 1894 became a Fellow of the Institute of Chemistry. In 1905-8 he again studied at Aberdeen University, and graduated with special distinction in chemistry in March 1908. At the same time, however, he was doing the work that was to earn him the degree of DSc in 1911, for a thesis entitled “Studies in Applied Statistics from Scottish Popu- lations.” He was appointed Lecturer in Statistics (part-time) at Aberdeen University in 1911, a post that he held until 1941. In 1912, he sold his Peterhead pharmacy on accepting appointments in Aberdeen as Public Analyst and Official Agricultural Analyst, and as Consulting Chemist to the Highland and Agricultural Society of Scotland.He held these posts until his death on November 8th, 1945. This brief account of Tocher’s career gives only a glimpse of the wide range of his scientific and other interests, which included pharmacy, analytical chemistry, ethnology, anthropometrics, biometrics, agriculture, history and prehistory, archaeology, poetry, etc., etc. His earliest publication, “The Springs and Wells of Peterhead,” describing his analytical investigation on, and drawing conclusions about, the waters of Peterhead, was published in the Transactions of the Buchan Field Club, 1889. Tocher was a founder member of the Buchan Field Club, and he was its Secretary and Editor of the Transactions, from 1891 until 1938.The Club produced, with Tocher as Ed- itor, two separate volumes entitled “The Book of Buchan,” one of which is referred to as the “Majority” volume, because it was produced to celebrate 21 years of existence of the Buchan Field Club, and the other as the “Jubilee” volume. Both of these volumes contain articles by a number of authors (29 in the first and 16 in the second) covering a wide range of topics. As would probably be expected from the titles, there are many historical, geographical and literary items. However, there are also many articles that are more of a scientific nature, including pieces on the geology, archaeology, botany and zoology of Buchan, and on the role of science.The two Books of Buchan are generally re- garded as classics of North-East Scottish literature. Tocher’s analytical publications included papers on the detection of sesame oil (1891), determination of red lead (1900), determination of phenol (1901), determination of uric acid and urates (1902), detection of citrates and tartrates (1906), criteria for purity of water (1913), variations in the composi- tion of milk (1925), errors of judgement in chemical analysis (1926) and the nature of probable error (1931). His work on the composition of milk is most impressive: the report extends to almost 200 pages. It involved the analysis of a large series of samples of the whole milk of individual cows for butter-fats, other solids, total nitrogen, casein, albumen, lactose, fat and mineral matter, and also determination of the specific gravity, refractive index and freezing- point.This analytical work was done in Tocher’s laboratory and at the Rowett Institute. The samples were obtained from cows selected at random throughout the whole of Scotland: 785 were obtained, but only 676 were in a fit state for analysis. The results obtained were subjected to an extensive statistical analysis, first with regard to the nature of the distribution for each constituent, then subsequently cor- relation coefficients and regression curves were calculated for each pair of constitu- ents (and other attributes of samples, such as age of cow, period of lactation, etc.). The amount of statistical analysis done was enormous, particularly when it is remembered that there were no com- puters at that time.Tocher’s staff must have been diligent and dedicated work- ers. A major purpose of the survey was to ascertain whether the legally prescribed standards for milk, minimum 3% of butter fat and 8.5% solids-not-fat, were fair. It was shown that 12% of all samples from individual cows fell below the butter-fat standard, and 24% below that for solids-not-fat, although the mean val- ues for both were well above the limits. This tended to suggest that poor quality milk need not necessarily arise from watering by the farmer. Tocher therefore protested strongly against the injustice of the legal presumption that low values for these parameters implied that milk had been adulterated.He proposed that poor milk should perhaps not be allowed to be marketed, but that the farmer, instead of being blamed, should be helped to improve his milk quality by selection of cows with good milk records, and by ensuring that they were adequately fed. Closely related to Tocher’s analytical work is his work concerned with agricul- tural problems. He published a number of papers on topics such as the citric acid solubility of mineral phosphates (1922), food values and costs in relation to milk production (1918), mortality among live- stock (1939) and the bracken problem (1941). He was not infallible, however; apparently his paper on grass sickness in horses (1923) contains a quite spurious suggestion as to the cause. Tocher had many other publications reflecting his interests in anthropometry and related subjects.He spent a great deal of time measuring people’s heads, looking into their eyes and observing the colour of their hair. He collected data on the hair and eye colours of 502155 Scottish school children, by enlisting the co-operation of teachers. The statistical analysis showed that the distribution of these colours was not uniform throughout Scotland; maps were drawn to show regional variations. The amount of labour involved in the analysis must have been enormous (Tocher has been said to have had “a hypnotic power of making other people do things for which they had neither time, desire nor ability”). Appar- ently, enquiries were made very recently to AU Statistics Department about the data collected in this survey.94 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 He also made extensive studies of the inmates of Scottish asylums, the aim being to find out whether “the insane” differed in any way from the normal population, particularly with regard to head size However, these measurements were of limited value when collected, without a similar series for the normal population for comparison purposes.Tocher there- fore followed up this work in later years by similar studies of the civil population of Aberdeenshire, Kincardineshire and Banffshire, and of the Scottish soldiers. Nowadays, this work would probably be considered to be concerned with the testing of outmoded, perhaps rather naive, theories of inheritance. Neverthe- less, it was of fundamental importance in the advancement to more sophisticated theories.Besides his own work, Tocher took a great deal of interest in education, and in the scientific institutes in Aberdeen. He campaigned for the introduction of uni- versity degrees in pharmacy, and was successful in persuading the Universities of Manchester , Glasgow , London and Wales to introduce such degrees. He served on the Chemistry and Pharmacy Board of Robert Gordon’s Technical College (now RGIT), which had set up a school of pharmacy. (My own father, who studied pharmacy there, can remember his class being visited by Tocher, to be told off for some communal misdeed.) In recognition of his great interest in phar- maceutical education, a medal called the J. F. Tocher Medal and Scholarship, and bearing his portrait, was inaugurated there in 1936.This medal is still awarded annually to the most outstanding student completing the BSc Honours degree in pharmacy at RGIT. Tocher also devoted much energy to the Rowett Institute, to the North of Scotland College of Agricul- ture and to the Macaulay Institute. With such a busy professional life it is rather difficult to imagine Tocher having much time for his personal life , yet he had married while still a young man and had a son, James Williamson Tocher, born in 1884, and a daughter, Julia (Dickie). The son graduated MB, ChB at Aberdeen University in 1911; after serving in the RAMC during the war, he worked as a bacteriologist with his father for some 15 years, before taking over a General Prac- tice in Arbroath. Several of his grand- children and great-grandchildren also entered the medical profession, but none seems to have become a chemist or statistician.His daughter does, however, seem to have shared his interest in the Buchan Field Club. It has been said that Tocher had an infinite capacity for making friends, a “genius for friendship.” This is perhaps best illustrated by the fact that, after he had been awarded the honorary degree of LLD by Aberdeen University in spring 1937, some of his friends held a meeting which appointed a committee to raise funds to pay some public tribute. The tribute took the form of a portrait painted in oils by Mr. Alexander Christie. There were over 500 subscribers, and so much money was collected that three portraits were actually done.Among the sub- scribers were the then Prime Minister, Neville Chamberlain, with whom Tocher had worked in Manchester. Many mem- bers of the Scottish Section were also among the subscribers. I would like to express my gratitude to the very many people who have most kindly provided material that was of assistance in the preparation of this article and of the history of the Scottish Region published in the March issue. I would welcome any additions or corrections to the informa- tion presented. MARY R. MASSON Department of Chemistry, Aberdeen University ROYAL SOCIETY OF CHEMISTRY ANALYTICAL DIVISION: AUTOMATIC METHODS GROUP A Meeting on CHEMICAL SENSORS will be held at The Health and Safety Executive Laboratories, Sheffield June ZOth, 1985, 10.30 a.m. This meeting will consider the application of chemical sensors to a range of analytical requirements both in the laboratory and in the field. The speakers have been drawn both from within the Health and Safety Executive and from various industrial and university analytical laboratories. They include Drs. L. Guest, S. Gentry and B. Bott from HSE, Sheffield, together with Mr. B. J. Birch from Unilever Research at Port Sunlight, Messrs. P. R. Fielden and A. J. Guthrie from the Department of Instrumentation and Analytical Sciences at UMIST, Mr. V. P. Y. Gadzekpo from UWIST and Dr. H.Thompsonfrom Kent Industrial Measurements, Chertsey. An opportunity to tour and reviewthefacilitiesand work of the Health and Safety Executive Laboratories in Sheffield will be provided. The registration fee, which will cover lunch, abstracts and transport from Sheffield (Midland) station, is f 15 for RSC members, f22 for non-members and f7 for retired members or students. Further information can be obtained from Dr. Clive Jackson, Health and Safety Executive, 403 Edgware Road, London NW2 6LN. Tel: 01 -450-891 1, EX. 227.

ISSN:0144-557X    

DOI:10.1039/AP9852200093

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 95 Quality and Acceptance Testing of Packaging-With Reference to Foods, Beverages, Pharmaceuticals and Cosmetics The following are summaries of eight of the papers presented at a Joint Meeting of the Scottish Region and the Automatic Methods Group, held on June 21st and 22nd, 1984, in the University of St. Andrews. Packaging Materials Quality Control in the Pharmaceutical Industry K. Harburn Quality Controller, Glaxo Pharmaceuticals Ltd., Harmire Road, Barnard Castle, Co. Durham DL 12 8DT The Company for which I work generally produces liquid and dry powder sterile injections, creams, ointments, lotions and tablet preparations. These are packaged into a variety of primary containers, e.g., ampoules, vials, collapsible tubes, securitainers, etc.There are many secondary items associated with the final pack, e.g., labels, leaflets, cartons etc., totalling several thousand items. This paper briefly covers some of the basic requirements for the control of packaging materials and discusses the means by which quality is to be improved. Component Specification Before a component can be obtained, the following specifica- tion details need to be provided and agreed with the component supplier (Scheme 1). Component specification Detailed drawing Dimensional limits based on component manufacturers capability and packaging - filling machine usabi I ity I Quality I I Clz;! I standards Primary materials, e.g., vials, ampoules, seals T- from v7i + 1 of the number of containers and assessed using BS6001-inspection by attributes (single sampling plan) Appearance, general inspection level II, usually used with AQLs set for major and minor defectives Scheme 1 materials, e.g., labels, leaflets and cartons / Dimensions, equipment used and measuring technique must be included Scheme 2 Quality Monitoring System At present all deliveries of primary and printed secondary materials received are monitored by Quality Control (Scheme Dimensions and perfor ma nce checks generally special inspection level L Immediate rejection for incorrect material of construction, rogue items (at any level) In addition to the above, special testing may be required in order to ensure that the components comply with certain market requirements.The method of packaging, labelling, transporting and palletising must also be detailed in the specification.If all of the above parameters are not clearly understood and agreed with the supplier, problems will arise. It is important to ensure that all checking carried out on components is worthwhile and that maximum information is obtained with minimum effort, e . g . , with reference to the dimensional checks, only the critical dimensions are monitored routinely (those relevant to ensure pack integrity and machine usability). These checks are carried out using computerised equipment, giving rapid recording and interpretation of results, including a detailed printout (Scheme 3). Component Problems The sort of problems that can be encountered and the potential risks are as shown in Scheme 4.96 Clean and tidy storage areas, with segregation ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 - Ca I i pe rs u Micrometer Computer m Printer f Rogue or incorrectly printed items Thickness gauge Scheme 3 Misinterpretation of potential riskto patient m contents-hence Incorrect material of construction * 1 I 1 1 Possible non-compatibility with prod uct-prod uct degradation-risk to patient with other components, Incorrect critical e.g.,vial and seal-potential dimensions non-sterile pack and product leakage.Machine Poor company image, potential hazard to patient Poor appearance and contaminated materials, e.g., insects, dirt, etc. I I I 1 Scheme 4 Disadvantages of Current Testing System Quality Control can only monitor the quality of items received. The quality (whether good or bad) is built in at the time of manufacture.With the statistical sampling system used, there is a risk that unacceptable material might be passed. The consequences of this are: potential filling - packaging area rejection, with loss of product and lost output; a greater risk of defective material getting on to the market; low production line output, especially with dimensional problems; extra cost and delay in despatching an order, owing to the introduction of an extra inspection stage; and possible component stock shortages, putting extra strain on the supplier. A rushed order can suffer with respect to quality. The above five points indicate that component quality does play a significant part in the total filling - packaging operation. From the commercial point of view the quality affects the cost of production and can adversely affect the lead time in the despatch of goods to a customer.In other words, good quality control is always cost effective. How Can Quality Be Improved? It is obvious that quality must be controlled at the time of manufacture. At present we operate a quality auditing system for assessing and helping the suppliers to produce the required quality. This involves examining their premises from the incoming stores area, through production to the final despatch of components. Comments are made concerning the GMP aspects, e . g . , cleanliness, security, manufacturing controls, etc. I Building of good construction and finish (leak proof, vermin proof, etc.) Effective clean- down of machines between batches of different components to prevent rogues Staff trained adequately and appreciative of GMP requirements considerations Good quality raw materials- Well spaced supplier machinery to help assessment. prevent cross- Obtaining conta m i na ti on certificate of between lines conformance with each batch I I / Y Secure formulation mixing system for rubber - polymeric components Effective in-process system control Y I 1 Scheme 5 In some instances suppliers do not appreciate what actual GMP standards are required during the manufacture of components for the pharmaceutical industry.It is necessary to collaborate with them in establishing the appropriate under- standing of the quality standard required. The main GMP considerations are as follows (Scheme 5): Good records of in-process checks done including details of problems and actions taken ~~ ~ Ensure that it is appreciated that production staff are responsible for quality, not quality control.Quality control monitor quality and set the standards 1 In-process Regular checking of critical parameters during manufacturing level and frequency to be decided by process capability I '/ I Quality control monitoring of quality and final authorisation for release of batch ~ Defective material must be immediately quarantined for later assessment and machine problem corrected before production continues I Certain parameters, e.g., appearance, may require more frequent checks Quarantined material can be assessed by sampling and statistical assessment before final decision on its fate Scheme 6ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 97 Considering the in-process control aspect of the GMP considerations, this is thought to be the most effective method of controlling quality during manufacture. In-process Control (IPC) Some of the main requirements for effective IPC are as shown in Scheme 6.The ultimate aim is to cease testing of components on receipt when confidence has been gained on the quality of the components supplied. The supplier will be asked to send a copy of the in-process control results for each batch in a delivery. This system is to be operated in conjunction with regular audits of the supplier’s premises in collaboration with the supplier. Quality and Acceptance Testing of Glass Packaging in the Pharmaceutical Industry P.A. Rhodes Beecham Pharmaceuticals plc, Clarendon Road, Worthing, West Sussex BN 74 8QH The Need for Pharmaceutical Grade Quality Quality can be defined as “fitness for intended use,” or “the capacity of a commodity to satisfy a need.” For pharmaceutical products the requirements for quality are very high. A product’s condition (e.g., sterility, potency, taste, etc.) is maintained by its container and closure. If the container fails to perform its function then in the most serious situation the possibility exists that a medicinal product may have deterior- ated to the extent of being ineffective. Product shelf life, production efficiency and customer acceptance all place high demands upon packaging material quality. It is therefore easy to understand why the pharmaceutical industry expects materials of the highest quality from its suppliers.Good quality cannot be added by the user after component manufacture. The user can, however, attempt to screen out bad quality, but this is costly, inconvenient and inefficient. Therefore, the objective should always be to design quality into the packaging material at the development and manufacturing st ages. User expectations of material quality may be somewhat higher than the realities of component mass production in a non-pharmaceutical environment. Therefore to avoid misun- derstandings, disappointment and dissatisfaction, the user and manufacturer of packaging materials should seek to under- stand the requirements and limitations that apply, so that the right quality is produced to the satisfaction of all.This understanding is best established by discussion between the two parties at an early stage. The user should make known his intended method and speed of filling and handling, also performance expections with regard to the product and the market place. The manufacturer should then be able to provide technical comment on the packaging material application. He will also be more aware of what is expected of the material and what needs to be achieved in terms of quality. This discussion should lead to a quality audit and then to the establishment of an agreed specification. Let us first consider the quality audit. Quality Audit This should be undertaken by the user, at the invitation or agreement of the manufacturer, in order to assess the manufacturer’s potential capability for producing packaging material at a consistent level of quality.Observations are made of the process, methods and procedures of control, batch identity, tests on raw materials and finished components, recording and analysis of results, etc. All of these will contribute to an assessment of whether the quality level required by the user can be realistically achieved by the manufacturer . Similarly, the opportunity should be extended to the manufacturer to view the user’s facilities for filling and handling packaging materials supplied. From such an exchange, positive benefits invariably arise in the form of improved understanding in the areas of Good Manufacturing Practice (GMP), which applies to the UK pharmaceutical industry, and quality awareness at all stages of the manufactur- ing (the filling - packaging - marketing chain).Whereas the quality audit identifies the manufacturer’s level of quality consciousness, a specification is required to identify and define the performance characteristics and properties expected of the packaging material. Our attention should now turn to the specification document. Specifications The Specification should be based upon material performance with regard to firstly, the pharmaceutical product, secondly, production filling/packaging and thirdly, the market place. For glass packaging the specification document must iden- tify: product requirements, e.g., glass colour for light sensitive products or glass alkalinity in relation to the type of product to be contained; legal requirements, e.g., with regard to glass colour or bottle design features for listed poisons; production requirements, e.g., conformity of dimensions, mass, capacity, strength and surface lubricity; and customer requirements, e.g., glass clarity and general appearance.The document should also include instructions for delivery packaging and identification labelling of material consignments for storage purposes by the user. A further and vital section is that relating to the definition of intolerable, critical, major and minor defects and the “Accept- able Quality Levels” (AQLs) which should be realistically assigned to each. Defect definitions and AQLs need to be agreed between manufacturer and user, depending upon the packaging material, its intended use and the speed of filling.The following illustrates the distinction. Intolerable Defects-a defect which would be potentially (AQL OYo) hazardous to a customer, e.g., introduc- ing glass fragments into the product. Critical Defects -a defect which would adversely affect the (AQL 0.65%) product or its acceptance by the cus- tomer, e.g., excessive light transmission for sensitive products. Major Defect -a defect which would reduce filling (AQL 1.0%) efficiency, e.g., restricted bore. Minor Defect -a defect which may affect the appearance (AQL 4.0%) of the finished pack, e.g., air bubbles in glass. Acceptance Testing Principles Having conducted a quality audit with satisfactory results and agreed a specification, the user could leave the question of meeting quality requirements to the manufacturer.Alterna- tively a request could be made for a “Certificate of Analysis” from the manufacturer confirming the test results obtained, or implement a sampling scheme and acceptance testing schedule to verify the quality of stock before production takes place. A combination of the second and third options would generally seem to be the best approach. This gives the user greater confidence in the stock released for production, an opportunity to identify defectives not detected by the manufacturer, an98 Glass container tolerances Quality control in the glass container industry ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Glass Manufacturers Federation (GMF), 19 Portland Place, London W1N 4BH indication of trends in quality and performance and an incentive for the manufacturer to maintain optimal control of his processes.As glass containers are frequently supplied in shrink wrapped and palletised units, which make it difficult to obtain random samples, a manufacturer’s sample could be requested to accompany each consignment. Examination of this sample and of the user’s own representative sample would soon indicate, over several consignments, whether the manufac- turer’s sample is a reliable indicator of quality. If the user elects to conduct acceptance testing, the important principle is to concentrate upon assessing those features of the glass container which, if defective, would be of greatest concern. Acceptance Testing Practice This assessment can be considered under the three categories of visual, mechanical and chemical testing.Visual testing Cleanliness -absence of extraneous matter, insects, carbon deposits, loose glass fragments, etc. Inclusions -absence of “stones” and metallic debris in the glass. Defective moulding-absence of deformed features, cracks etc. Strain -using a polarised light source to identify residual strain and quantifying by com- parison with Standard Strain Discs. Mechanical testing Dimensions Verticality Wall thickness Strength Light resistance Surface lubricity Capacity -by gauging or direct measurement verifying comformity of those features vital to the efficiency of product filling and container sealing. -by gauging, measurement or optical projection. -by sectioning, optical projection or ultrasonics.-by impact, compression or internal pres- sure testing. -by sectioned sample in a spectropho- tometer for light sensitive products in amber glass. -by incline plane testing unit to assess surface friction for smooth running on filling lines. -to filling height or brim full, based upon standard deviation or mean range from random sample. Mass -mean mass and range determined from random sample. Chemical testing A1 kalini ty -for verification of Type I, I1 or 111 glass using whole or crushed container method published in European Phar- macopoeia. Achieving the Required Quality If good working relations are established between the user and manufacturer of glass containers, and if specifications are agreed and appropriate test procedures adopted, it is possible to achieve the required quality not by luck but by design. Also, the mechanism will have been established to identify quickly and effectively and to deal with sub-standard containers so that, should these occur, the chance of disruption to produc- tion, and product sales, is minimised.Selection of Surface Coating Materials for Food and Drinks Cans R. J. Kitchingman Holden Surface Coatings Ltd., Bordesley Green Road, Birmingham B9 47Q Aluminium and steel could not be used for making food cans, without suitable surface coatings. The cost of the coating is Internal Lacquers for Beer and Beverage Cans drink cans, tubes Or Choice of Raw Materials to be Used in the Lacquer Composition only a small percentage of the cost of the container and contents but it is a vital part of the package.The contents will be ruined if the inside lacquer does not provide protection properties during the expected life of the product. In this paper I will consider firstly internal can lacquers for beer, beverage and food, and secondly external coatings. All materials in contact with foodstuffs must be non-toxic and I will explain some of the guidelines used to determine sub- stances that may be used in the lacquer composition. The American Code of Federal Regulations for food and drugs contains a white list, which is used as a basic reference. Title 21, Part 175, Section 300,' provides a list of substancesANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 99 permitted for use in polymeric coatings, which, in the finished form, are in contact with food and drinks.Also permitted are substances recognised as safe in food. Therefore, by reference to this approved list the lacquer formulator will know which substances may form the lacquer. Certain countries, for example Germany, have their own white list, but those who do not have their own explicit gvidelines usually follow the regulations contained in the FDA regulations. In the UK guidelines are contained in Statutory Instruments Food and Drugs 1978 No. 1927, amended in 1980 and 1982.2 These are administered by the Minister of Agriculture, Fisheries and Food. Section 4 concerns materials in their finished state, which come into contact with food. It is required that the applied film should not transfer its constituents to any food with which it comes into contact.It must not cause the food to become contaminated or unacceptable for taste. Lacquer Application Two-piece beer and beverage cans are made from tinplate or aluminium at speeds of up to 1000 cans min-1 on one line. The inside lacquer is applied by spray from fixed heads outside the spinning can. The lacquer must perfectly cover all the internal surface of the can. If one small pinhole remains uncovered or only thinly covered then this is a site for potential corrosion and can perforation. The adjustment of solid content, viscosity and solvent balance, which determine the rheological properties of the lacquer, are critical. The type of substrate and the size of the can will determine how much lacquer is to be applied. It has been found that tinplate two-piece beverage cans require higher lacquer masses than aluminium beverage cans.Applied Film Performance During handling, cans are knocked together. The inside lacquer must be flexible and not too brittle to withstand minor distortions without rupturing during handling and trans- portation. The cured film must be resistant to the chemicals in the beverage; for example, sulphur dioxide, phosphoric acid and citric acid. Many products are pasteurised in the container and the lacquer must withstand the pasteurisation processing. Beer is a product in which trace amounts of certain contami- nants can cause haziness and off flavour. The maximum level of iron normally acceptable is 0.2p.p.m. The barrier that the lacquer film must provide on the inside of a steel beer can must therefore be perfect to prevent trace amounts of iron being absorbed into the beer.Internal Lacquer for Food Cans The choice of lacquer is dependent on the food to be packed. Most of the human food cans in the UK are made from pre-lacquered sheets and the lacquer is applied by roller coating on to the sheets. The solvent balance of these lacquers will be different from the spray lacquers in order to facilitate good flow and film formation properties under different application and stoving conditions. Highly coloured fruits, such as cherries and strawberries, must be packed in lacquered cans because contact with tin or iron causes discoloration and very small traces of iron in the pack will cause this deterioration. Acid resistant lacquers are used for this application.Certain foods, like meat and peas, will release sulphur when the food is processed in the can. This will cause sulphur staining or blackening of the tinplate surface owing to sulphide formation on an unlacquered can. A surface coating must be chosen which forms a barrier betwen the foodstuff and the tin surface. Sometimes, to avoid the smell of sulphides when the can is opened, a coating is applied which absorbs the sulphur, but the sulphide formed is white and discoloration of the container is therefore prevented. External Can Coatings Can making and can filling lines run at high speed. The outside of the two-piece Coca Cola can is coated with a white base coat. This must dry in about 6 s stoving and have sufficient hardness, slip and mobility to pass through the lines.The base coat selected must be highly lubricated but printing inks applied over it must have good adhesion. The coating on the outside of two-piece drawn and wall ironed tin plate pet food cans is applied by curtain coating. The inverted cans pass through a falling curtain of lacquer, which is constantly re-cycled. A water-based lacquer is chosen for the outside, which must be flexible to withstand the beading that is required to give the can strength. A feature of this lacquer is that it must wet the metal surface but not drain down the wall of the can too rapidly, or it will leave insufficient film thickness on the can. The filled cans are sterilised and the lacquer must withstand this process. Cans that contain pat6 or fish products can be manufactured by tooling of flat coated sheet.The exterior of the sheets may be decorated with a size coat, white coating, printing inks and clear varnish. The overprint varnish is applied wet on wet over the inks and the solvent balance of this varnish must be carefully adjusted so that the inks do not wash into each other, but have sharp definition and good colour after varnish stoving. The varnish must be non-yellowing, flexible, hard and glossy. When the flat coated sheets are stacked there is considerable pressure exerted on the sheets. They must separate well when being fed to the presses and there should be no plucking of the external decoration on to the inside coating of the sheet. When the lacquers and coatings have been manufactured they are tested before being supplied to the can maker.The viscosity, solid content and specific gravity of the liquid are measured. The values must fall within the specified range. The lacquer is applied in the laboratory using the same technique and conditions as far as possible as those which it will receive in the can making plant. The appropriate metal substrate is always used. Tests are made on the film which are appropriate for its intended use. For example, the test on an inside lacquer for meat cans will include tooling the laboratory coated metal into a can end, filling the can with meat, seaming the end on to a can and processing in steam or water. The can is opened and the end examined for corrosion and lacquer detachment. There are many tests to examine the film properties of can coating lacquers.These include: the assessment of the application, i.e., the flow and plate wetting properties; the ability to cure under the specific conditions; the colour of the film, also after re-stoving and processing; the adhesion to the metal substrate and intercoat adhesion between base coats, inks and varnishes; the hardness, scratch and scuff resistance; the flexibility of the film; the assessment of stain and blush resistance and metal protection properties; the need to impart no off flavour to the foodstuffs; and the lubricity to pass through can making and filling lines. A sample of each batch of lacquer is retained for 1 year and applied specimens retained for reference. I have explained the factors which govern the selection of surface coatings for metal packaging of food and drinks.I hope that it will have been appreciated that the lacquers are highly specialised. Technical support is an essential part of the lacquer supplier’s commitment to the can manufacturer and an important property of the coatings must be that they provide consistent and reliable performance. Only the use of high quality surface coatings will enable this to be achieved and the correct choice of lacquer for each specific application is essential. References 1. 2. Code of Federal Regulations, Title 21, Part 175.300. Statutory Instruments: “The Materials and Articles in Contact with Food Regulations 1978, No. 1927”; “The Materials and Articles in Contact with Food (Amendment) Regulations 1982, No. 1701.100 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 The Development and Acceptance Testing of the Wine Box Patricia Matthews Saccone and Speed Ltd., 17 Cumberland Avenue, London NWIO 7RN When the wine box, or bag-in-box to be more precise, was first launched in Great Britain in June, 1981, it was hailed as a new concept in packaging.This was not so. Bag-in-box packaging had been used for milk since the 1950s in Australia. Many unsuccessful attempts to find a bag with suitable barrier properties for wine had been made. Continuing research led to the development of the metal- lised bag and real opportunities for improved shelf-life. The Wynfoil metallised bag was available in Australia in the mid-1970s and announced to the UK trade in 1977. It was not until January 1980 that one particular Australian company investigated the UK market potential for a complete system of filler and bag.In mid-1981 Stowells of Chelsea launched their first 3-1 wine boxes, followed closely by Saccone and Speed with Cloberg, a branded Yugoslav Riesling. Impact on Market Although it is my intention to confine what follows to technical matters, I am deliberately going to stray briefly into the marketeer’s realm to put the importance of this pack to the UK wine trade into perspective. The UK table wipe market was estimated at 77 million gallons in 1983. Bag-in-box sales already represent 6.2 million gallons, or 11% of the off-licence market alone. It is forecast that this sector will grow to over 7 million gallons by 1986. It is therefore easy to see why the Trade has paid such close technical attention to this form of packaging since its introduc- tion.The Production Environment For those who are unfamiliar with a wine bottling hall, I shall sketch an outline of some of its mysteries. Wine destined for bag-in-box arrives in bulk by road, rail or even ship. When transferred to the receiving vat it may well contain spoilage micro-organisms, few or many depending on how tight is the Quality Control Manager’s grip on the supplier. Simultaneously, one hopes, the selected bags arrive already fitted with taps. The wine is then suitably filtered and treated with preservatives (sulphur dioxide and/or sorbic acid within legally prescribed limits). The sterile wine is led into a sterilised filler, which automatically removes the tap from each bag presented and fills a metered volume through the tap gland.The tap is then automatically replaced. The bag is boxed, etc. The Bag Now let us consider the requirements against which a bag is selected. The bag must be the right size for the box. It needs to be durable and inert. It must be flexible, leak free, reasonably robust, impart no taint to aroma or palate of wine and comply with legislation concerning plastic materials in contact with food. Furthermore, it must provide an adequate barrier to the ingress of air and arrive for filling free from spoilage organisms. It must be fitted with a suitable tap, which itself does not taint or permit air ingress. All of these demanding criteria must be met in one bag capable of being filled under sterile conditions. Both clear and metallised bags are available.All materials used are approved for food use and comply with USA FDA legislation. The materials commonly used are: ethyl vinyl acetate copolymer (EVA) (usually inner layer) ; low density polyethylene (LDPE) ; extruded biaxially orientated nylon; metallised polyester. The most usual format is a three-layer laminate with a loose inner bag of EVA or LDPE to absorb the shock of moving liquid during transportation. The bags are made by heat sealing the laminate and single layers into place on all four sides-two by two-the upper pair of layers already having been punched and fitted with the tap gland (collar). Alternatively it is possible to seam bags by means of an impulse seal, described as using radiofrequency energy; this method used generally to be considered too slow for automatic production but is now gaining favour.Heat sealing, which is a function of temperature, pressure and contact time, is prefer- able. Individual bags are made in a continuous strip and slit apart at the final stage in the process. Bags for web feeding are left in strip form but perforated. Taps are inserted into the desired position by a hand controlled pneumatic machine at the bag manufacturers. The angle of the tap is an important considera- tion if the tap is to be correctly aligned when the pack is ultimately opened by the consumer. Barrier Properties Oxidation is the enemy of wine. Combination of oxygen with free sulphur dioxide negates its preservative properties. White wines turn yellow, red wines brown and the flavour of both is seriously impaired.In “average” terms clear or non-metallised materials permit oxygen ingress at the rate of up to 7 ml m-2 in 24 h at standard pressure, with a temperature of 20°C and an RH value of 65-90%. Metallised polyester permits oxygen ingress at around 1 M . 5 ml m-2. These data, however, apply to the materials as manufac- tured. Flexing of the material during transportation of the filled boxes, caused by liquid movement or inadequate support of the bag from the box, has a detrimental affect on the oxygen barrier. The passage of oxygen can be doubled or even quadrupled if the material is severely creased. Nevertheless, metallised bags are used almost exclusively for domestic 3-1 packs because of their better barrier properties.They do have one inherent disadvantage. One cannot see the contents of a metallised bag. Some of the oxygen entering a bag after filling does so through the tap. The tap most generally used is the press tap made exclusively by one manufacturer. It is moulded from high and medium density polyethylene with the press cap made from EVA (oxygen ingress 0.20-4.35 ml m-2) to minimise oxygen ingress. The accurate fit of the tap into the gland is a vital factor in reducing oxygen intake. Bag Manufacturers Quality Control Procedures A 3-1 bag-in-box retails from around f7.00. Not unnaturally, any purchaser who suffers loss of wine through leakage is disconsolate. Manufacturer’s quality control tests are stringent. These involve visual examination for pinholes, delamination, incomplete metallisation and dimensional checks, coupled with tests designed to ensure weld strength, tap orientation, tap depth and flex resistance.Strictly speaking it is the bag manufacturer who purchases the taps, but the wine packer has a vested interest. The taps in most frequent use are assembled automatically. Each and every tap is then subjected to automatic testing by applied air pressure. Tap failure after such precautions is very rare but can occur; 3 1 of wine spreads over a large area of carpet if the tap spigot fails to reposition after the first use! Even more importantly, disproportionate losses are caused by leaker damage in the warehouse. Saccone and Speed have solved that problem by the introduction of bulk shrink wrapping.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 101 Manufacturers use batch coding systems, which enable production problems to be traced back to their original inspection records.Filling Considerations It is not possible to divorce the pack from the filling procedure. The vulnerability of wine to the effects of air cannot be overstressed. Leaving aside the ingress of air that occurs after filling, air is present in the headspace of every bag because the tap traps 17-22ml as it is replaced into the bag. Ways of eliminating air in headspace will be discussed later. As a bag-in-box cannot be considered a “sealed unit” in the same way as a corked bottle there is a risk of proliferation of spoilage organisms from even the lowest level of infection. Firstly, and obviously, sterility must be achieved.We rely upon final filtration from bright-wine vats through 0.65 vm mem- brane cartridges, combined with cold chemical (hypochlorite) cleaning of filler and associated pipe work and brief steaming. The empty bag and tap are presented to the filler and the tap is automatically removed. Residual air is drawn from the bag by applied vacuum. Wine is then “metered” in by an adjustable pre-set turbine and the tap automatically replaced. The free SO2 content of the wine at filling must be compatible with adequate shelf-life. We have found it suffi- cient to maintain free SO2 levels at the upper end of the bracket normally used for bottled wines, say 50 p.p.m. for white wine. Certainly our experience echoes that of Australian packers, where a rapid fall in free SO2 over the first few weeks after filling is followed by a steady state.Initially the dissolved oxygen contents of the wine were closely monitored but experience has taught us that much greater attention should be paid to the air in the headspace. In my opinion, this is one of the greatest single factors affecting shelf-life. Filling Development In the early days of bag-in-box, wine traders were cautious. Semi-automatic lines were installed. Consistent filling relied to a large extent on the skills of the machine operator, who was responsible for presenting the single bags individually to the filling nozzle at an angle compatible with minimum headspace air. Nitrogen injection was possible but ineffective, not surprising when you consider the air trapped within the tap as previously mentioned. Now that the bag-in-box market share is assured major companies have invested heavily in automatic fillers.We boast the most modern in Europe, filling 7-8 web-fed bags per minute on each of four heads. Filled bags are boxed automatic- ally, check weighed, shrink wrapped and palletised. The first semi-automatic fillers were discontinuous. Wine splashing ensured that the cabinet contained a wine aerosol, creating conditions in which the possibility of yeast infection was an ever present threat. Automatic filling has largely eliminated this problem. Single-head semi-automatic fillers with sterile filling chambers have also been developed. Routine Quality Control For the most part bag users rely upon the quality control procedures of the manufacturers and do little in the way of acceptance QC except in the event of particular production difficulties. All of the usual parameters checked against pre-agreed specifications when wine is bottled apply to boxed wines, i .e . , free and total S02, volatile and total acidity, alcohol, etc. Headspace air is monitored by the use of a hypodermic syringe inserted through a tap adapter carrying a rubber septum. Dissolved oxygen in wine is measured by means of an oxygen meter. So far one important facet of wine quality control has been ignored, that of tasting. Suffice to say that we do plenty of that and have carried out extensive shelf-life testing. The most difficult aspect of bag-in-box quality assurance has been left until last, that of microbiological monitoring.Imagine a large, dark pond containing a single goldfish. A small child stands nearby with a fishing net. How many times will he need to dip in the net before he catches the goldfish? There is a clear analogy. The level of micro-organism infection in a bag will be zero or very low indeed given that adequate hygiene proce- dures are followed. However, the release of faulty stock can have a disastrous effect on consumer confidence and it must be prevented. One bag contains 3-1 of wine. How much does one filter to ensure detection of low levels of infection? There is a school of thought that dictates that all 3-1 should be filtered, which is extremely unwieldly in routine terms. Even more important, what sampling rate does one adopt? Wine is expensive and Customs and Excise regulations permitting one duty free sample per production run are rigorously enforced.The duty on a 3-1 pack alone is currently almost f3.00. One unsatisfactory microbiological result from a sample of 20 boxes drawn from a production run of 1000 (2%) means that there will be, with 90% certainty, between 1 and 130 faulty boxes in the 1000. If one increases the sample rate five fold to 10 per 100 the presence of one “failure” will mean that between 1 and 26% of the whole batch will be unsaleable. We are capable of producing 8500 boxes in a single working day. Statistically valid sampling schemes are prohibited by cost considerations alone. Packers rely upon rigorously enforced hygiene procedures combined with sampling schedules based on experience to ensure that goods reach the customer in the best possible condition.Shelf-life and Bag Development Shelf-life is influenced by the choice of bag, wine preparation, filling technique, storage conditions and not least by the actual selection of the wine itself. Currently, shelf-lives of 6-8 months are being achieved. As no wine trader can predict what will happen to a wine box once it has left his control ways of extending this shelf-life are constantly being pursued. This is taking place mainly through the auspices of the bag manufac- turers, who frequently offer alternative bags for trial. These include alternative materials, such as aluminium foil laminates (polyolefin - foil - polyolefin), co-extruded materials and double metallised layers. Alternative taps are also becoming available in an attempt to reduce the air trapped within.One of the most advanced types is inserted with a membrane behind the tap gland. The membrane is not broached until the customer opens the pack for the first time. Any steps that can reduce oxygen contact should improve shelf-life. The area that is still undergoing investigation is that of nitrogen sparging (removal of dissolved oxygen by nitrogen) and displacement of air by nitrogen purging. Pack Development It was inevitable that the potential of bag-in-box as a catering pack should be exploited. Wine by the glass in hotels, restaurants and wine bars is dispensed via cooler and pump from 10-1 and even 20-1 containers, usually concealed in an attractive fascia.Conclusion The packaging of wine in plastic bags was a major departure from tradition. Consumer acceptance of this pack as an alternative to the glass bottle and cork is assured. Wine consumption in the UK is rising steadily and bag-in-box packaging will continue to play an important role. What I have outlined has been the development of bag-in- box and quality control procedures applicable today. I will conclude by confidently predicting continued technical investi- gation into the product, the pack and the associated filling systems.102 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Physical and Regulatory Testing of Paper and Board Packaging Products J. M. Chamberlin Thames Board Limited, Siddick, Workington, Cum bria Food, beverages and cosmetics are packed in order to assist in preservation of the product, to assist transportation and to identify the product.Each type of packaging material has its advantages and its disadvantages. For example, glass is brittle, cans rust and plastics are made from oil, a non-renewable source. Paper and board are made from a renewable source, cellulose. Recently, the trends of health and consumerism have led to the setting up of regulatory systems for food packaging. Most systems consider food packaging as an adjunct to food additive legislation. The first systematic examination of food packaging in relation to health was carried out by Frawley.1 He concluded that, apart from heavy metals and pesticides, a level of 0.2% by mass of a packaging ingredient would not contribute more than 0.1 mg kg-1 to the diet.The USA has had an ad-hoc approach to food packaging,2 but this is now being rationalised.3-5 The lack of a unified system has led to a problem of trade between countries and this has been discussed elsewhere.6.7 The EC Commission, with the co-operation of other bodies, is proposing a control system for the EC. This will replace the UK system relying upon the Food and Drugs Act 1955.8 Migration of substances from packages into food can occur by several mechanisms and these are covered extensively by Katan.9 The extent of migration is governed partly by the foodstuff that is packed. Foods can be classified according to whether they are aqueous, oily or fatty (or both), contain more than 5% of alcohol or are dry and non-fatty.10 The majority of food packed in paper and board is dry and non-fatty.Because of the difficulty in measuring migration actually into food, substitutes or “food simulating solvents” have been proposed. These are distilled water, acetic acid, ethanol and olive oil. Where olive oil is not appropriate, a synthetic triglycenate mixture is proposed. 11-13 Control It is necessary to ensure that paper and board are satisfactory, both from the physical and the chemical standpoint. The major physical properties measured are as follows. Stiffness. This is the force (or moment of the force) required to bend a standard sized sample through a given angle.14-17 Thickness. This is measured by a micrometer, applying a standard pressure. 18 Grammage. This is the mass per unit area.19 Printing characteristics.Ink absorption20 and surface strength during printing are important .21 Gluabilify. The ability of the board to form a strong bond with itself is measured. Water absorption.22 The absorption of water in g of water per m2 of board in a given time is important in offset litho printing. Moisture content. Paper and board are hygroscopic and strength properties vary with moisture content. All measure- ments are made under standard atmospheric conditions (23 “C, 50% RH). The moisture content can be determined by drying to constant mass (at 105 OC),23 by drying under vacuum, by the Dean and Stark method and by microwave absorption. Surface pH is measured by indicator smear,24 a surface electrode25 or an extract .26 Odour and tainting tendency can be assessed by the British Standard test27 o r German Standard test.28 The British Standard is superior as it only requires discrimination between paired samples and not evaluation on a hedonic scale, as in the German method.Waste paper is used for the manufacture of packaging materials. However, it is normally suitable only for packages for dry, non-fatty foods. The polychlorinated biphenyl content must be kept below 10mg kg-1 to minimise vapour phase migration to the food. For other foodstuffs, it is preferable to use paper and board made from virgin fibre. Chemicals used should be those approved by the appropriate regulating body. The German BGA has issued a list of chemicals that are permitted in Germany, together with an analytical control procedure.29 Qualitative detection of nitrogen, chloride, bromine, fluorine, chromium, phosphorus and sulphur, for example, is carried out after sodium fusion of the sample; starch, dextrine and polyvinyl alcohol are detected from the reaction with iodine - potassium iodide solution.Quantitative methods of analysis are also laid down. For example, alkyl ketene dimer is determined by hydrolysis and HPLC. PCBs are extracted and determined by gas - liquid chromatography using an electron-capture detector. It should be noted that the majority of PCB present in a board is PCB40.30 Metals are frequently determined by atomic- absorption spectrometry (AAS) in the ashed sample or on an acid digest. Mercury is usually determined by flameless AAS and arsenic and antimony hydrides are determined by the use of the nitrogen - hydrogen entrained air flame. Chromium can be determined by using the acetylene flame on the point of luminosity; under these conditions, the sensitivities for Cr(II1) and Cr(V1) are similar.31 Starch can also be determined by the colour produced by reaction with iodine - potassium iodide solution32; the colour depends on the amylopectin : amylose ratio and on the degree of modification of the starch.33J4 A summary of analytical procedures to be applied to paper and board has been prepared by Browning.35 1.2. 3. 4. 5. 6 . 7. 8. 9. 10. 11. References Frawley, J. P., Food Cosmet. Toxicol., 1967, 5,293. Code of Federal Regulations, Title 21, Parts 100-199. Till, D. E., “4th International Symposium on Migration, 24-25 November 1983, Hamburg,” Unileverforschungs- gesellschaft MBH, Hamburg, 1983, pp. 83-105.Reid, R. C., Schwope, A. D., and Sidman, K. R., “4th International Symposium on Migration, 24-25 November 1983, Hamburg,” Unileverforschungsgesellschaft MBH, Ham- burg, 1983, pp. 106-156. Schwarz, P. S., “4th International Symposium on Migration, 24-25 November 1983, Hamburg,” Unileverforschungs- gesellschaft MBH, Hamburg, 1983, pp. 157-171. Chamberlin, J. M., and Kingsnorth, S. W., “EUCEPA XVI Conference, 22-25 March 1976, Grenoble,” EUCEPA, Grenoble, 1976. Chamberlin, J . M., “BPBIF Conference, ‘Coating for the Eighties,’ 19-20 November, 1980, Slough, BPBIF, London, 1980.” Food and Drugs Act, 1955, Sections 1 and 2, HM Stationery Office, London. Katan, L. L., in “Food Packaging and Health; Migration and Legislation,” Institute of Packaging, London, 1971.EC Working Document, “Draft Proposal for a Council Direc- tive Establishing the List of Simulants to be Used for Testing Migration of the Constituents of Plastic Materials and Articles Intended to Come into Contact with Foodstuffs,” Commission of the EC, Brussels, 1984. vom Bruck, C. G., Figge, K., and Wolf, V., Dtsch. Lebensm. Rundsch., 1970, 66, 253.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 103 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. Figge, K., Eder, S. R., and Piater, H., Dtsch. Lebensm. Rundsch., 1972, 68, 359. Figge, K., Cmelka, D., and Koch, J . , Food Cosmet. Toxicol., 1978, 16, 165. British Standard 3748. DIN 53 121, Deutscher Normenausschuss, Berlin. Casey, J.P., in “Pulp and Paper Chemistry and Chemical Technology,” Second Edition, Volume 3, Interscience, New York, 1961, p. 1312. Ranger, A. E., Pap. Technol., 1967, 8, 51. British Standard 3983. British Standard 3432. British Standard 4754. British Standard 4885: Part 2. British Standard 2644. British Standard 3433. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. RTM3: 1972, BPBIF, London. RTM4: 1972, BPBIF, London. British Standard 2924. British Standard 3755. DIN 20 955, Deutscher Normenausschuss, Berlin. “Untersuchung von Papieren, Karton und Pappen fur Lebens- mittelverpackungen,” Verlag Erich Goltze KG , Gottingen, 1977 (plus amendments). Robinson-Mand, L., and Piringer, O., Papier, 1984,38, 1. Thompson, K. C., Analyst, 1978, 103, 643. TAPPI Standard T419, TAPPI, Atlanta, GA, USA. Richter, M., Nuhrung, 1964, 8, 106.Simerl, L. E., and Browning, B. L., Znd. Eng. Chem., Anal. Ed., 1939, 11, 125. Browning, B. L. , “Analysis of Paper,” Second Edition, Marcel Dekker, New York, 1975. The Identification of Plastic Films J. L. Sham Imperial Chemical Industries PLC, Petrochemicals and Plastics Division, Wilton, Middlesbrough, Cleveland, TS6 8JE Inspection of the average dustbin reveals a lot of polymeric items. The discarding of cellulosic material, such as news- papers, advertising pamphlets and potato peelings, leaves a considerable plastic fraction. This fraction is made up of materials which range from the black plastic dustbin liner itself, composed of a single polymer, to much more complicated convenience food wrappings.The latter are often composed of many layers, designed to keep the contents fresh rather longer than it takes the average purchaser to prise open the package. Such mutli-layer films are manufactured by co-extrusion of two or three polymers, the use of adhesives to stick various films together or combinations of both of these techniques. Barrier layers may be incorporated to reduce the ingress of air and water and to retain flavorants. Other layers are added or treatments carried out to make the pack attractive to look at and improve processing. This paper describes the identification of these plastic films. Infrared spectroscopy is the major identification tool employed, but both visual examination and solvent treatment are important aspects of the characterisation of multi-layer wrappers.Preliminary Examination Sometimes it is all too obvious that the film one is examining is a laminate, either because visible metal or printed layers are present or because the two surfaces are not equally shiny or slippery. A laminate may often be revealed by making a small cut in the film and then carefully watching the way in which the tear develops as the film is stretched. For example, in a laminate of polyethylene and polyethylene terephthalate, the tear will be propagated in the latter layer, with the poly- ethylene layer stretching considerably before this also tears. Sometimes the edges of such a tear can be prised apart to separate the layers, using adhesive tape if necessary to grip one of the layers. Before commencing the identification one should remove any traces of the contents which would interfere with the subsequent examination, e .g . , vegetable oil from crisp bags, fat and water residues from meat packs, by wiping with absorbent tissue. It is preferable to begin with clear unprinted material away from sealed areas, marking each surface with a scribe for reference purposes. On many occasions, however, the printing has to be considered as just another polymer layer but with a high pigment loading. Infrared Spectroscopic Examination In order to obtain an infrared spectrum of a polymer one needs it in the form of a uniform film of the order of 0.03mm thickness. Most packaging films are near enough to this thickness to be directly amenable to infrared examination. The advantages of infrared spectroscopy for this work are that most polymers have characteristic spectra, the instrumentation can be relatively cheap, it is easily operated and adequate reference spectra are available. In practice the comparison of spectra may be hindered with shiny films by interference fringes and with cellulosic or polyester films by very intense spectra. The first problem can be partially overcome by gently scuffing the film surfaces with steel wool.The second problem is overcome by comparison of the weaker bands in the spectrum and the use of internal reflection spectroscopy. This form of spectroscopy is most useful for the examination of surface layers. By this technique, abbreviated variously as ATR, MIR, FIR, informa- tion on the outer 0.01 mm is obtained, although this figure will vary considerably according to the refractive indices of the prism and the surface, the angle of incidence and the wavelength of the incident beam.Solvent Separation Here the objective is either to wash coatings off the surface selectively or to dissolve or soften an interior layer so that one ply can be floated away or physically separated from another. Then the separated layer or layers and any soluble material are dried and identified by use of the infrared techniques men- tioned above. The most useful solvents are chloroform, toluene, dimethylformamide and, more rarely, hexa- fluoropropan-2-01. Appropriate safety precautions should be taken to avoid vapour inhalation and skin contact with these solvents. In the instance of toluene work away from sources of ignition.The solvent treatment is most conveniently carried out in a Petri dish, with pieces of material about 7 X 15mm, first in the cold for a few hours. If this is unsuccessful boiling solvent can be tried. Very Thin Coatings Coatings that are too thin to be identified successfully by direct infrared examination can normally be detected by X-ray photoelectron spectroscopy. The elements present, together with some information on their bonding and relative propor-104 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 tions, in the outer 1 nm (10 A) can be obtained by using this technique. Solvent washing can sometimes be employed to identify these very thin coatings, provided that great care is taken to avoid contamination from impurities in solvents, dust on the film surface and soluble impurities from the substrate.On packagings obtained from the market place, the level of contamination often precludes a satisfactory identification so I do not propose to deal with these coatings in more detail. Concluding Examples As an example of the application of these techniques the polyethylene - polyethylene terephthalate laminate referred to earlier will be considered further. From the “tearing and stretching” treatment it was obviously a laminate and this would be confirmed by obtaining the appropriate two reflec- tion spectra. Careful examination of the transmission spectrum may well reveal a weak band at 6.5 pm (1540 cm-I), in addition to the polyethylene and polyester bands. This can be exposed by boiling the laminate with toluene to dissolve the poly- ethylene and obtaining the reflection spectrum of a poly- urethane adhesive left on the polyester surface.If the laminate contains an aluminium layer, how will this affect the identifica- tion? It certainly increases the number of possibilities. Either the polyester or the polyethylene could be vacuum metallised and the other layer attached with adhesive. Alternatively, both layers might be attached with adhesives to the metal. In order to discover the precise structure solvent treatment is carried out but this time with 10% aqueous sodium hydroxide solution to dissolve away the aluminium. The two layers are separated, washed well with water and dried. Internal reflection spectro- scopy carried out on the two exposed surfaces will then reveal what adhesive or adhesives are used and to which layers they are attached.In this way these techniques can be applied to ascertain the structure of a wide range of plastic wrapping films. Recent Developments in Blister Packaging R. Webb Packaging Development, Beecham Pharmaceuticals, Clarendon Road, Worthing, West Sussex BN 14 8QH Pharmaceutical blister packs offer a simple method for presenting a company’s products individually packed in a clean, separate cell in a convenient, ready to use pack. The method of manufacture involves impressing into a continuous sheet of, usually, a plastic film a shape into which, for example, the tablet may be fed. The pack is closed by sealing a lid, usually aluminium foil, by compression under a heated metal plate.The packs are punched out of the continuous web. The “blisters” can be formed by application of vacuum or com- pressed air and the distribution of plastic may be improved by plug assist, in which the softened plastic is pushed most of the way into the mould by a plug, prior to final application of the compressed air to complete the formation of the blister. Blister Materials The following materials have been commonly used. Poly(viny1 chloride) (PVC) PVC film, available in a wide range of thicknesses, is commonly used at 250p.m. The film is usually transparent so that the product can be seen. It is also available opaque, or tinted to provide child resistance or some protection of the product from light. Poly(viny1idene chloride) (PVDC) coated PVC This is available in a wide range of thicknesses of PVC with coatings of PVDC up to about 80 g m-2.The moisture barrier improves with increased coating mass. PVDC - polythene (PE) - PVC A laminate of PVC and PE coated with PVDC has been claimed to have improved barrier properties. PVC - PVDC - PE - PVDC - PVC A Japanese sandwich, which was claimed to provide a high moisture barrier. It has not been made in Europe. Polymonochlorotri’uoroethylene - PVC Aclar, a close relative to Teflon, is claimed to provide a barrier ten times better than PVC at ten times the price. Extended shelf lives are possible but cost is usually prohibitive. Polypropylene (PP) The physical properties of PP necessitate the use of specialised blister manufacturing techniques (heated plug assist), but several machines are now producing blister packs from this film, which is cheaper or the same price as PVC, but which has barrier properties as good as PVDC coated PVC.A special lid foil, not yet available in the UK, is required. Saranex - PVC laminate Saranex (PVDC) film has recently been laminated to PVC and offered as an alternative to PVDC coated PVC. Cold form aluminium blisters The ultimate moisture barrier is obtained (at the expense of transparency and visibility of product) by the use of aluminium. Laminated between PVC and PP or polyamide, the aluminium can be formed, at ambient temperatures, by specially designed, high-pressure forming tools, into blisters. The blisters can be lidded with aluminium foil in the usual way. The specialised laminate for cold forming is expensive but the finished pack is very elegant and virtually impermeable to moisture.CAM Partena have recently introduced a ne6 all-aluminium pack based on a thinner (cheaper) soft foil in which corrugated foil is pressed into a die and subsequently lidded convention- ally. Steeper wall profiles are possible, the over-all blister tray size is smaller and costs are only 30% of the earlier type described previously. Quality Control It is necessary to ensure that every pack contains its full complement of correct unbroken tablets. Methods of ensuring this have increased in sophistication. Visual inspection Reliance on the human eye has proved to be not entirely satisfactory. Pin detector An array of moveable pins is lowered on to the filled tablets, momentarily held stationary.If a tablet is present, the descending pin is stopped in its tracks. An absent tablet is detected by an unimpeded pin and the partially filled tray of tablets is removed from the stream.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 105 Infrared beam scanner Photodiode and photodetector. Infrared light emitted by a diode is shone on to the passing tablets. The shape and size of the reflected light is assessed by a phototransistor. Any variation from the memorised standard, caused by chipped, thin or absent tablets is detected and used to actuate a rejection mechanism. Each format of tablets requires a different set of diodes and detectors. Optical fibre detector. Infrared light is focused on the passing web and detected by an array of optical fibres beneath. The shadow of an acceptable set of tablets can be recorded and stored electronically. An aberrant shadow can lead to rejection of faulty packs.Pack changes can be made without affecting the detection mechanism, as several formats can be called up from the memory. Colour sensitive detector. Light reflected from passing tablets can be analysed by passage through prisms. Three detectors are used to evaluate the proportion of primary colours. Split laser beams. An experimental system is claimed to be less expensive. Video camera. One video camera can record and memorise any passing format of tablets. Any deviation from standard can lead to pack rejection. The above detectors allow for the movement of tablets occasioned by the moving web.Their accuracy is affected to a varying degree by this movement, the size of tablet and the web speed. Each manufacturer has used his own preferred system. Video camera and flash exposure. Three days after the Symposium, Hiltcroft Ltd. introduced Polyphem at Interphex 84: this was a video camera system which included an electronic flashlight. The whole tray is observed in the fraction of a second of exposure, effectively eliminating the effect of movement. Not only can tablets be checked for size, shape, position and colour, but fragments of tablets straying on to surfaces to be sealed, likely to lead to sealing faults, can be detected and appropriate action taken. The system is designed to enable it to be used in almost any new or existing blister pack equipment.Up to 40 reference images of various packs can be stored and recalled. Properties and Physical Testing of Polyethylenes J. P. Watson* 8x1 Plastics Limited, Inch yra Road, Grangemouth, Stirlingshire Polyethylene is the most widely used packaging material. Applications range from bread bags to 40 gallon drums, from roll-on deodorants to pallet hoods, from reticular fruit bags to mailing envelopes; the list is virtually endless. In 1983 some 380000 t of low density and 142000 t of high density polyethylene were used in packaging in the UK.1 This total represents 3.7% by weight of total packaging. However, bare tonnage does not reflect the range of use nor the number of packages. In almost all instances significant weight reductions are achieved over traditional materials (Table 1).Table 1. Weights of packages Product Package Weight 1 pint milk Glass bottle 350 HDPE (non-returnable) 15 LDPE bag 8 LDPE bag 6 1 loaf bread Wax coated paper 11 5 Ib potatoes Paper bag 45 Properties of Polyethylene The major properties of polyethylene in packaging applica- tions can be defined as: processability ; chemical resistance; barrier properties; strength; optical properties; properties relating to additives. It is not intended, in the space available, to discuss all properties in detail but rather to give a brief overview and then to cover in more detail three aspects of particular relevance to polyethylene: firstly, environmental stress cracking; secondly, the effect of processing conditions on film strength and opticals; and lastly, puncture resistance testing.Processability The ease of processing polyethylene is a significant factor in its success as a packaging material. It is readily extruded and moulded over a wide range of conditions, does not decompose readily and can be reprocessed into non-critical applications. High-pressure polyethylene film can be drawn down to 12 pm; linear polyethylene can be drawn down to below 4 pm. The ease of sealing makes polyethylene a preferred product, not only by itself but also as the sealing layer in coatings and laminates. * Present address: BP Chemicals Ltd., Boness Road. Grangemouth, Stirlingshire. Chemical Resistance Polyethylene is chemically resistant to all except very strong oxidising agents and halogens and will swell in hydrocarbon and halogenated solvents.It can be affected by non-solvents, which may cause the polymer to crack. Environmental stress cracking will be discussed later. Barrier Properties Polyethylene has excellent barrier properties to water and water vapour, but is relatively permeable to oxygen and carbon dioxide. A comparison with other plastic films is shown in Table 2.2 Its low water transmission makes polyethylene an ideal packaging medium in many food, cosmetic and pharmaceutical areas. In some packaging areas, e . g . , cooked meats, the oxygen permeability prevents the use of polyethylene alone though it may be used as the sealing layer in a laminate. Oxygen permeability falls sharply with temperature so it is used for packaging frozen chickens, etc.Indeed frozen foods is one of the largest markets for polyethylene and its related co- polymers. Table 2. Barrier properties of plastic films Permeability/ mlmm-1cm-3~-1cm-*Hg x 101° Plastic Low density polyethylene High density polyethylene Nylon PET Polystyrene Plasticised PVC Cellulose Water (25 "C) 300 150 8 000 1300 12 000 6 000 400 Oxygen (30 "C) 60 10 0.1 0.2 50 40 0.1 Carbon dioxide 350 35 0.4 1.5 250 120 0.2 Strength No single test adequately defines the toughness of poly- ethylene. Tensile, impact, tear, puncture and rigidity are standard tests but high values in one do not necessarily imply corresponding increases in the others. It is important to identify which characteristics are most critical for a given application.106 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 The strength properties of polyethylene are highly depen- dent on the method of testing, especially testing speed and temperature.This is a consequence of its long-chain structure. Lowering the temperature and increasing the testing speed raise the elastic modulus, as is shown in Fig. 1. Decreasing temperature Increasing test rate PE film in cross-section z I Total / -2- Surface Strain Fig. 1. Effect of temperature and test rate on elastic modulus Density Fig. 2. Haze of polyethylene film An equally important factor affecting strength is polymer morphology, which is process dependent. Chain alignment and degree of crystallinity are affected by the orientation induced during fabrication and the rate of cooling of the polymer. The relevance to polyethylene film production is discussed later.Optical Properties Polyethylene is a translucent material and for thick or opaque sections the only optical property of importance is gloss. This is the amount of light reflected from the surface and is wholly dependent on surface smoothness. Good flow, achieved by suitable grade choice or high temperature, will improve gloss. The gloss of mouldings is also dependent on the smoothness of the mould and good venting. Clarity, which is narrow angle scattering or the ability to see distant objects through film, is not relevant for most packaging applications where the packaged product is close to the polymer. On the other hand, wide angle scattering or haze is important as it is haze that causes polyethylene film to appear milky.Haze is a product of both film surface (rough surface, more light scatter) and polymer crystallinity. Large crystallites known as spherulites differ slightly in refractive index from amorphous polymer, thus causing scatter (Fig. 2). The effect of film extrusion conditions on optical properties is discussed later. Additives Additives are incorporated into polyethylene to impart specific properties, such as slip, anti-static, opacity, etc. Except for pigments, additives are normally present in very small amounts (less than 1000 p.p.m.). Fillers are seldom used as they have a detrimental effect on properties even at low additions. Although additive levels can be controlled by chemical analysis, actual performance testing is more relevant. Slip properties are measured by coefficient of friction tests, anti-block by openability tests similar to peel strength and anti-static performance by surface resistivity, half charge decay time or a subjective dust pick-up test.These additives have their effect on the polyethylene surface so it is important that they do not affect other surface properties, such as sealing or ink adhesion. As polyethylene is inert it is essential to oxidise the surface in order to allow ink to key. This is carried out by corona discharge treatment on film and flame treatment on mouldings. The level of treatment is measured by determining the wettability of the surface to mixtures of varying surface tension (cellosolve - formamide) . Testing Table 3 below gives the common tests applied to polyethylene articles used for packaging.~~ ~ ~ Table 3. Tests applied to polyethylene articles Film Moulding Tensile - elongation Tensile - elongation Dart drop impact Various impact tests Elmendorf tear Coefficient of friction Gloss Haze Wetting tension (treatment level) Surface resistivity Compression Cold temperature embrittlement Environmental stress crack resistance Environmental Stress Cracking Although inert to most chemicals polyethylene can crack in the presence of certain polar solvents. This phenomenon, known as environmental stress cracking (ESC), can usually be overcome by suitable choice of grade or by reducing stress in the polymer, which is often inbuilt during fabrication. In general, the following factors influence ESC. 1. Stress-reduction in stresses created in fabrication or service improve ESC resistance. 2.Environment-polar products with low surface tension and low viscosity are more prone to cause cracking. Thus, dilute solutions are often worse. 3. Polymer-generally high relative molecular mass polymers are more resistant, especially if accompanied by a reduction in low relative molecular mass species. The latter have a significant influence on ESC. Density (which is related to polymer crystallinity) is a more complex effect as, in practice, it can influence stress level. At constant stress more crystallineANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 107 products tend to be more resistant but the actual size of the crystallites also has a marked effect. Theory The cause of ESC is not fully understood.Evidence points to the environment entering the polymer through the amorphous regions or through voids. The cracks run across the boundaries between the crystalline and amorphous areas. Several theories have been proposed to suggest that the presence of the environment loosens intercrystalline links (Fig. 3) . 3 The intercrystalline link theory may explain the improved ESC resistance caused by the presence of long chains (high relative molecular mass) and the loss of resistance if the polymer has been degraded. The excellent ESC resistance of linear LDPE may be due to both structural differences in branch distribution and narrower relative molecular mass distribution than its high pressure counterpart. t t n These tests not only evaluate the polymer but also the article design.Cracks will occur in areas of high stress. A typical test on polyethylene bottles is shown in Fig. 4(b). (a) Micro-switch to timers Bell bent strip test Pin Shot can A o i n t s Side view Pressure n 7der s1 :ress rupture test Solenoid 11 Fig. 3. Loosening of intercrystalline links Testing Environmental stress crack resistance of polymers is usually tested by using a constant strain test (Bell Telephone Bent Strip test) or a constant stress test (Lander test) (Fig. 4). Because of the different stress factors the tests do not give the same rating, especially where the polyethylenes differ in density. In many areas the Bell test is preferred as it relates more closely to practical experience. More relevant tests on fabricated articles involve exposing the article itself to the environment under a stress condition.BP Test Electrode Detergent Water Fig. 4. Methods for testing crack resistance The Effect of Processing on Film Properties Most polyethylene film is made by tubular extrusion. Molten polymer from an annular die is blown into a bubble, which is pulled through nip rolls to give a collapsed tube. Typically, film is drawn down from one fifth to one fiftieth of the die gap. This drawing produces chain alignment, mainly in the machine direction. Tubular film is therefore highly anisotropic. Increas- ing the bubble size increases transverse orientation, giving a more balanced film. Changes in bubble shape induced by varying the cooling conditions or an increase in melt tempera- ture will also influence the chain alignment.Bubbles on long stalks induce greater transverse orientation (Fig. 5 ) . The factors which improve transverse orientation, however, tend to lead to greater bubble instability.108 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 - - _ _ - - - - I \ I I I Frost line . - - - - Transverse direction -+ Fig. 5. Effect of bubble shape on chain alignment Strength Orientation induced by processing has a marked effect on strength properties. The effect of blow ratio (bubble diameter to die diameter) and frost line height (height when bubble reaches its maximum diameter) on tensile strength, elongation and dart impact is shown in Tables 4 and 5. by slow cooling. Film haze will depend on which factor has the most influence. This, of course, is thickness dependent. Puncture Resistance Testing The advent of linear LDPE with excellent puncture perfor- mance has stimulated interest in puncture measurement.Unfortunately, existing tests have proved extremely unreli- able. Two of the major factors affecting testing are probe shape and the presence of grease, etc., on the probe. A test developed at BXL4 involves the use of a spherical probe tip of 1.65 cm diameter, replacing the standard conical tips in other tests. A simple mechanical clamp is used to hold the sample (15cm diameter) immediately beloa the crosshead of a tensometer, to which the probe is attached. In order to achieve consistent results it is necessary to condition samples at 23 "C, to use unexposed film surfaces and to de-grease the probe after each test.Fig. 6 shows the test rig. Typical force - extension curves are indicated in Fig. 7. Load a Table 4. Effect of blow ratio and frost line height on properties of film. Low density film DFDG 4262,38 pm Blow ratio (frost line heightkm) 50 1.5:l 3 : 1 Dart impact/g 75 170 Tensile MD/MPa 26.3 20.9 strength { TD/MPa 15.5 20.4 Elongation MD , 'Xo Gloss, PU 69 67.5 (30) (30) 170 260 495 450 { TD, yo Haze, Yo 6.5 4.5 ~ ~~ 2: 1 135 (15) 24.6 18.1 150 490 61 6.5 - 2: 1 140 (70) 20.5 18.6 190 470 62 5.5 Table 5. Impact strength of film. High density film H 090-56F, 10 pm. Blow ratio, 4: 1 Neck height above die/mm Impact strength/g 500 50 750 90 lo00 120 The chain orientation is also responsible for the shrink characteristics of polyethylene. Re-heating will allow the chains to relax to their pre-orientated state.When allowed to shrink freely polyethylene film may shrink by as much as 80% in the machine direction. Balanced shrinkage can be achieved by increasing transverse orientation. Optical Properties As stated earlier gloss depends on surface smoothness so that higher melt temperatures and longer cooling time will tend to improve gloss. Increase in the frost line height and blow ratio give a longer cooling path. Thicker film, which cools slower, will also be glossier than thin film made under the same conditions. Haze due to the film surface is affected in the same way as gloss. However, polymer haze depends on the formation of large crwtallites known as mherulites and these are increased U a 'tension Fig. 6. Equipment for puncture resistance measurement The slip properties of the film have a profound influence on The puncture results generated by the test relate closely to results (Table 6).other strength tests and to field experience. Extension/cm Fig. 7. Typical force versus extension graphs. A, Original test; B, modified test Conclusion The properties of polyethylene are related to molecular parameters such as relative molecular mass, relative molecular mass distribution and chain branching (crystallinity). Physical testing must take into account the effects of testing speed and temperature on strength properties. Sample preparation is of the utmost importance in any test where Dolvmer morpholoev OJANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 109 for the same polymer grade.Where possible, testing should be on the final article. Table 6. Effect of slip properties on puncture resistance Melt Puncture index1 Density/ resistance/ “C m-1 gcm-3 Ncmu - I References HPPE low slip 1 0.920 7.4 HPPE high slip 1 0.920 3.5 HPPE low slip 0.3 0.921 10.8 LLDPE low slip 0.8 0.920 23.7 LLDPE high slip 0.8 0.920 14.5 1 . “UK Polyethylene General Packaging Film Market,” Corpor- ate Development Consultants, July, 1983 (1982 figures updated). 2. S. H. Pinner. Editor. “Modern Packaging Films,” Butter- worths, London, 1967. 3. Lustieer. A . . and Markham. R. L.. Polvmer. 1983. 24. 1647. is involved. Fabrication conditions affect chain orientation and inbuilt stress. Significant changes in properties can be obtained 4. Camiron, R . , and Edmiston. G . . BXL internal communica- tion. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY ( J A W An International Journal on the Development and Application of Spectrometric Techniques ANNOUNCEMENT AND CALL FOR PAPERS AIMS AND SCOPE JournalofAnalytical Atomic Spectrometry (JAAS) is a new international journal, to begin publication in February 1986, which will contain original research papers, short papers, communications and letters concerned with the development and analytical application of atomic spectrometric techniques. JAAS, which will be published bimonthly, will also include comprehensive reviews on specific topics, general information and news of interest to analytical atomic spectroscopists, including information on forthcoming conferences and book reviews. Special issues of JAAS will be published, devoted to subjects highlighted by particular symposia. Also included will be the literature reviews which were previously published in Annual Reports on Analytical Atomic Spectroscopy. JAAS will have a style and format similar to that of the well-established journal The Analyst. JAAS will provide an improved publication service to support the growing research effort in, and applications of, atomic spectrometric techniques. Manuscripts intended for publication as papers or communications must describe original work related to atomic spectrometric analysis. Papers on all aspects of the subject will be accepted, including fundamental studies, novel instrument developments and practical analytical applications. As well as atomic absorption, atomic emission and atomic fluorescencespectrometry, paperswill be welcomed on atomic mass spectrometry and X-ray fluorescence/ emission spectrometry. Papers describing the measurement of molecular species where these relate to the characterisation of sources normally used for the production of atoms, or are concerned for example, with indirect methods of analyses, will also be acceptable for publication. Papers on the development and applications of hybrid techniques involving atomicspectrometry (eg. GCcoupled AAS, HPLC-ICP, etc.) will be particularly welcome. Manuscripts on other subjects of direct interest to atomic spectroscopists including sample preparation and dissolution and analyte preconcentration procedures, as well as the statistical interpretation and use of spectrometric data, will also be within the scope of the journal. EDITORIAL ADVISOKY BOARD Afull international advisory board is being established under the chairmanship of Professor J.M. Ottaway. SUBMISSION OF PAPERS Papers on all aspects of Analytical Atomic Spectrometry, as described above, are invited and should be sent to the Editor, Mrs Judith Brew, The Royal Society of Chemistry, Burlington House, London W1V OBN. PUBLICATION DETAIIS Frequency: 1st Issue: February 1986 Subscription: Further details from: Sales and Promotion Dept, The Royal Society of Chemistry, Burlington House, London WIV OBN Six issues per annum (bimonthly) Price to be announced July 1985. The Royal Society of Chermstry Burlington House Piccadilly London W 1V OBN

ISSN:0144-557X    

DOI:10.1039/AP9852200095

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

110 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 The Analysis of Drugs and Their Metabolites The following are summaries of three of the papers presented at the Analytical Division’s Symposium at the RSC Autumn Meeting, held on September 18th-20th, 1984, in the University of Hull. Metabolites are Important Too! 1. R. Marten ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK 10 4TG The purpose of this summary is to explain why I believe that it is important to measure levels of metabolites in biological fluids in addition to, or instead of, the administered drug substance. I will also cover the most commonly observed pathways of drug metabolism and indicate how easily analytical methods can be modified to allow assay of both drugs and their metabolites. Drug metabolism can be defined as the chemical alteration of foreign compound by a living system, i .e . , what the body does to the drug. Radioisotopically labelled compounds are usually used to follow the fate of a new drug in a living system and a comparison of radioactivity levels with those of the drug often reveals a discrepancy, an unknown but necessarily drug-related material. Isolation and identification of this material will lead to the structure of the metabolites. There are a number of reasons why these metabolites should be characterised and measured. Firstly, correlation of the pharmacodynamic response with the blood level. The effect that administering a drug to a system has on that system may not be mediated by the drug and trying to correlate the time course of the drug’s action with the pharmacokinetics of the drug may therefore fail.This is often because metabolites have pharmacological activity additional to or different from the administered compound. Propranolol is a @blocker which is metabolised to a variety of products and one of these, 4-hydroxypropranolol, has P-blocking activity. Measurement of the circulating levels of both the drug and its active metabolite leads to a better correlation of the time course of the pharmacological activity with the presence of active chemicals. Similarly, the drug’s metabolites may have undesirable effects; if these are only apparent at high or overdose levels and can be shown, by monitoring, to be absent at lower doses, the safe use of the drug at therapeutic doses can be recommended and controlled.Secondly, pro-drugs are chemical variants of a drug which, when administered to a living system, are converted by metabolism to the active drug. Thus, it is important to monitor for systemic levels of the active drug, and not the dosed pro-drug, in order to ensure that the required metabolic step has taken place. This is particularly important when looking at various species, as differences in metabolism are often species dependent. Pivampicillin is an example of a pro-drug. Ampicillin is a penicillin antibiotic, which is poorly absorbed from the gut when given orally. By making the pivaloyloxymethyl ester of the carboxyl group, the lipophilicity of the compound is increased and it is better absorbed. During its passage to the circulation from the GI-tract the ester is hydrolysed and the active drug released.Monitoring for its presence ensured that this occurred and that it happened in both the species used for toxicity testing as well as in humans. Thirdly, the identification of a metabolite and its subsequent testing for pharmacological activity may lead to the identifica- tion of a new drug. By correlating the presence of the metabolite with the time course of the pharmacological activity this activity may become apparent. Not identifying this activity can lead to loss of revenue from a potentially useful drug. The major metabolite of diazepam, oxazepam, is an example of a compound that showed a useful profile of pharmacologically desirable activity and is now marketed in its own right.Fourthly, drugs may not only be metabolised differently between species but may also be metabolised differently within a species. Although there are a number of reasons why this may occur, one well defined cause is that there are genetically determined metabolic pathways. An individual with a defic- iency in a particular pathway will not be able to metabolise some compounds and may, therefore, end up with much more of the drug in the circulation. This, in turn, may lead to undesirable prolongation of the drug’s action or side effects. Debrisoquine is a compound which is metabolised, and excreted, as its inactive 4-hydroxy metabolite. The inability of 10% of the population to carry out this reaction efficiently leads to a variability in response to the drug which can only be successfully controlled by monitoring for the drug and its metabolite.This is usually done by assaying the urine for the two components and adjusting the dose of debrisoquine accordingly. Fifthly, as was mentioned above, there are a number of variables that govern the rates and routes of metabolism in different individuals. One example is age. Drug metabolism efficiency seems to be decreased at either end of the age spectrum; old and young are less well able to catalyse reactions that alter exogenous compounds. This can, therefore, lead to overdose of an active drug if the recipient is not carefully monitored. In particular, benoxaprofen (Opren) suffered from the inability of old patients to metabolise the compound efficiently. This, in turn, led to increased amounts of the drug in the system and subsequently to unacceptable side effects.Careful monitoring of the drug and its glucuronide metabolite in these subjects might well have retained a useful drug on the market. Now to turn to the products to which drugs are metabolised. The liver, which is the principal organ for performing drug metabolism, is capable of much elegant chemistry, but reactions to which drugs are subjected are mainly of an oxidative nature. The most commonly observed pathways are hydroxylation of either aliphatic or aromatic carbon atoms, dealkylation of ethers and amines (initially by hydroxylation of the alkyl group), oxidation of sulphur or nitrogen atoms (to sulphoxides or sulphones and to N-oxides) and hydrolyses of esters and amides.There are reductive reactions, which are less common, such as reduction of carbonyl and nitro double bonds. Reductions of carbon - carbon double bonds are less common and these reductive reactions are sometimes found to be mediated by the intestinal bacteria rather than the liver. Another series of reactions that are commonly found are the so-called conjugation reactions. Endogenous molecules, such as glucuronic acid or sulphate, are added on to a drugANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 111 molecule. Hydroxy groups or carboxyl groups are particularly prone to this form of metabolism. Carboxylic acids may also form peptide links with the N-terminus of amino acids or even with oligopeptides. Why do all of these reactions take place? The principal reason for the body to metabolise drugs is to increase their water solubility, so that they are more soluble in biological fluids and hence more readily excreted.The body recognises them as being unusable as building blocks and so uses an appropriate mechanism to excrete them. Having stated why this takes place I shall now provide some general rules about the implications of drug metabolism for the analyst who wants to measure metabolites in biological fluids. Firstly, metabolites are more polar than the parent mole- cule. As a consequence metabolites will elute before the parent molecule on reversed-phase chromatographic systems and after it on normal-phase systems. In order to ensure that the metabolites are detected, chromatographic systems should be designed to allow for this; for example, a reversed-phase HPLC system should always include an internal standard that elutes after the parent compound and a suitable gap between the solvent front and the parent drug’s retention time should be allowed so that potential metabolites are separated from both.Secondly, the introduction of polarity into the molecule may necessitate derivatisation of the metabolite in order to decrease the polarity to analytically manageable proportions or to increase the volatility of the chemical for gas - liquid chromatography. Thirdly, metabolites generally have the same core structure as the parent molecule. There are often only minor changes to the nature of a chromophore used for ultraviolet detection and so changes in wavelength are often unnecessary for the detection of both drug and metabolites. Similarly, the mass spectrum of a metabolite usually bears a considerable resem- blance to that of the parent molecule, and often shows a characteristic change, such as an increase in the base peak by 16 units as a result of the introduction of an oxygen atom.Thus, use of GC - MS or LC - MS can readily accommodate measurement of both drugs and their metabolites. In summary, minor modifications to assay methods for compounds can often be accomplished so that levels of their metabolites in biological samples can also be measured. The information that this gives the pharmacokineticist, toxicologist or clinician can often be invaluable and can help to understand the action or duration of a drug more completely.A Stability-indicating Assay of Nystatin A. G. Coutts May and Baker Ltd., Dagenham, Essex RMlO 7XS Nystatin is an anti-fungal antibiotic produced as a natural product by strains of S. noursei. It is not a single substance but consists principally of nystatin Al (I). Various other substances are also present, differing from nystatin Al mainly in the nature, number and location of the sugar units attached to the ring. The conventional method of assay, required by the British Pharmacopoeia and other compendia, is microbiological. Several organisms have been used for this purpose1 with varying results because of the differing potency of the various components of nystatin towards the different organisms. OH OH OH OH C02H OH Me OH Me I It is clear that no practica1,method (chemical or biological) of assay can precisely predict the potency of a sample of nystatin in use against pathogenic organisms.All that can be obtained is a figure representing a total content of the various components weighted in various ways according to their chemical properties or their potencies towards chosen non-pathogenic test organ- isms. The potency of nystatin is associated with the tetraene element in the molecule and it is the destruction of this by atmospheric oxidation that is the main reason for the instability of the drug. The tetraene element also gives rise to a very distinctive ultraviolet absorption spectrum consisting of three sharp (less than 10-nm width at half height) bands between 290 and 320 nm. Oxidative degradation results in the loss of these bands, leaving a residual absorbance of about 10% of the original but lacking the sharp bands.As the sharpness of the bands implies a large first derivative, a determination of total tetraene is possible by measurement of the first derivative of the spectrum. Experimental Samples of nystatin (approximately 50 mg) were dissolved in 50ml of dimethylformamide and diluted to 100ml with methanol. A 2-ml volume of this solution was further diluted to 100ml with methanol and the spectrum of a 10-mm layer recorded between 240 and 360nm. The first derivative was obtained both digitally (using a simple algorithm involving fitting the absorbance at five successive 1-nm intervals to a 4th degree polynomial) or by means of a commercially available analog system. The amplitude of the first derivative measured between the maximum at 317 nm and the minimum at 324 nm was used for determination of the nystatin content of the sample.By using this method numerous samples were examined by several operators, including samples deliberately degraded by heating (at 60°C) in air for periods of several weeks and samples of material kept at room temperature for several years. Results The analog and digital methods for obtaining the derivative gave similar results, with the digital method being slightly more precise (relative standard deviations 0.74% with 50 degrees of freedom for the digital method and 1.06% with 24 degrees of freedom for the analog method). The potency of material degraded by heating in air, expressed as a percentage of the potency of undegraded material, when determined by the method decribed agrees with the same quantity determined microbiologically to within 5% for loss of up to 50% of the original potency.In the assay of mixtures of degraded and undegraded material the response varies linearly with the amounts mixed.112 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 The examination of samples of five different batches kept at room temperature for periods of up to 5 years showed agreement with the microbiological assay (using Saccharo- myces cerevisiae NCYC 87 as test organism) to within &5% for samples varying in potency between 2000 and 5000 units mg-1. The method can also be applied to simple formulations containing nystatin and, for instance, lactose.In such instances it is desirable to use a mixture of dimethylformamide and water (rather than dimethylformamide alone) in the initial dissolu- tion step. For such formulations, recoveries of 100 k 1.5% were obtained from mixtures of excipients and nystatin containing between 50 and 150% of the nominal nystatin content of the formulation. Conclusions The precision of the method is clearly greatly superior to that of the microbiological assay. A single determination gives 95% fiducial limits of error of better than 98-102. At least four 4 x 4 assay plates are usually required to obtain equivalent precision microbiologically. For the control of formulations, where comparison may be made with a sample of the same batch of drug substance, there is no evidence of inaccuracy.With assay by comparison with a standard prepared from a different batch of drug, a difference of up to 5% from the result by microbiological assay may be introduced. However, this error is no greater than that which results from the use of a different test organism in the microbiological assay and can be explained in the same way by the heterogeneous composition of the drug. There is no evidence as to which of these differing results gives the best estimate of the potency of nystatin in actual use. Reference 1. Thomas, A. H., Newland, P., and Sharma, N. R., Analyst, 1982, 107, 849. Analysis of Primidone and its Metabolites Phenobarbitone and Phenylethylmalanomide (PEMA) in Body Fluids J. M. Streete and D. J. Berry Poisons Unit, New Cross Hospital, Avonley Road, London SE14 5ER Primidone was introduced in 1952, and has become a valuable drug for the treatment of generalised and some types of partial epileptic seizures.Therapy is started at a low dose and gradually increased to a maximum of 1.25 g daily in divided doses, in order to develop tolerance to the side effects. In order to suppress fits it is necessary to choose a drug that is known to be effective against the type of seizure involved and to maintain an adequate concentration of this drug in the bloodstream and hence in the brain tissue. At the same time, one attempts to minimise side effects by controlling the patient at the lowest effective blood level. Primidone is metabolised to phenobarbitone and to phenyl- ethylmalonamide (PEMA) (see Fig.1). Phenobarbitone is an antiepileptic drug in its own right and can cause toxicity at elevated plasma levels. As the rates of metabolism, disposition and excretion of anticonvulsant drugs vary widely from one Table 1. Details of analytical methods Method of Phenobarbitone, GLC with primidone N2 specific detection Drug analysis Phenobarbitone HPLC with UV detection PEMA GLC with FID Sample Internal size standard 50 pl 50 mg dm-3 methyl primidone in ethanol 200 p1 50 mg dm - methoxy- carbamazepine in ethanol 200 p1 30 mg dm3 e t hyl-p- malonamide tolyl- Column 2 mm x 0.77 m FFAPKDMS on Chromosorb WHP lO(L-120 mesh Guard column 10 cm Whatman ODS. Analytical column 25 cm Hypersil5 MOS (C8) 2mm x 1.5m CDMS/WG11 on Chromosorb WHP 100-120 mesh Conditions Injector and detector temperature = 275 "C Column temperature = 250 "C Carrier gas flow-rate Bead (H2) Gases (air) = 130kNm-2 Wavelength 220 nm Solvent pH 5.4 acetate buffer - acetonitrile 1000 + 580 cm3 + 100 cm3 distilled H20 Flow-rate 1.8 cm3 min-* Column temperature = 220 "C Carrier gas flow-rate H2 Air } = 50-60 cm3 min- 1 = 70 kN m-2 = 50-60cm3 min-I = 1.4 kg cm-2 Table 2.Details of standard and quality control preparation; standards (and QCs where appropriate) are prepared by spiking blank plasma or water with stock solutions of the drug dissolved in ethanol or water Drug Medium Standard rangelmg dm-3 Phenobarbitone, Expired 40 (20), 20 (lo), 10 (9, primidone human 5(2.5) GLC method blood bank plasma Phenobarbitone, Equine 40 (20), 30 (15), 20 (lo), HPLC method plasma 10 ( 5 ) , 5 (2.5) PEMA Distilled 20,15,10,5,2.5 water Other drugs Phenytoin, carbamazepine (concentration in brackets) Phenytoin, carbamazepine (concentration in brackets) No Quality controls/mg dm-3 External QC Pheno., phenyt.Prim. Carb. Red 5.0 3.0 White 15.0 9.0 6.0 Blue 45.0 18.0 12.0 Yes, 2.0 oncea month Yes, once a month Red, White and Blue as above Low 7.0 Made in No Medium 12.0 equine plasma High 25 .OANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 113 person to another, the measurement of blood levels can help the clinician to optimise treatment in the most efficient way. A recommended concentration range in plasma has been established for phenobarbitone (5-30 mg 1-1) and primidone (<12mg 1-I) within which the drugs have maximum anticon- vulsant effect and above which toxicity often develops.The value of measuring PEMA has not yet been established, although it may be useful in cases of unexplained toxicity. A variety of analytical methods have been used to measure phenobarbitone, primidone and PEMA: spectrophotometry,' thin-layer chromatography (TLC) ,2 gas - liquid chromato- graphy (GLC)2 and high-performance liquid chromatography (HPLC) .3-5 Experimental The preferred method for the analysis of these compounds employs either gas or liquid chromatography to examine an extract of the biological sample. The general extraction scheme that we have developed for the three methods is summarised below. Sta nda rd/sa rn ple/q u a I ity control Sodium dihydrogen orthophosphate, 250 pl, 0.5 rnol drn-3 Internal standard, 50 pI Dichloroethane, 6 rnl t Whirlirnix 1 rnin Allow layers to separate 1 4 Remove aqueous layer Filter solvent through a Whatrnan No.1 filter-paper Evaporate to dryness 1 Reconstitute in solvent Inject on to chrornatrograph The sample volume and internal standard are listed in Table 1, together with details of the equipment and the conditions under which they are operated. Table 2 summarises the quality control concentrations used in the various assays and gives details of their preparation where appropriate. GLC (Nz Detector Method) Four calibration standards and three quality controls are extracted together with each batch of samples. The extracts are reconstituted in 50pl of butyl acetate prior to 5 pl being injected on to the gas chromatograph.The correlation coeffi- cient for the calibration graphs using the range of standards in Table 1 for both phenobarbitone and primidone is 0.96. The between-batch coefficient of variation (CV) calculated from quality control (QC) data on 67 successive runs is 2.6-4.7% for phenobarbitone and 2.1-2.7% for primidone. 0 H Prirnidone H Phenobarbitone 1 p-OH phenobarbitone 1 G I u cu ro n i de conjugate PEMA (phenylethyl- rnalonarnide 1 Excreted unchanged in the urine Excreted in the urine Fig. 1. Metabolism of primidone HPLC Method Five standards and three quality controls are extracted together with the samples. The extract residue is reconstituted in 50 p1 of eluent prior to injecting 15 vl on to the HPLC. The within-batch CV calculated from replicate assays of 10 samples for each of the quality controls for phenobarbitone was 2.4-4.7%, and the correlation coefficient for the calibration graph was 0.96.PEMA Method Five standards and three quality controls are extracted together with the samples. The extract residue is reconstituted in 50 pl of chloroform and 5 pl are injected on to the GC. The between-batch CV calculated from QC data on 80 successive runs was 2.7-4.4% and the correlation coefficient for the calibration graph was 0.96. Fig. 2 gives examples of sample traces for all three methods. Discussion The gas-chromatographic method for phenobarbitone and primidone is also able simultaneously to detect and measure both phenytoin and carbamazepine, when they are present. This screening capacity makes the method particularly valu- able if a clinician is unaware that one or more of these drugs are being ingested.The HPLC method for phenobarbitone is used by us largely as a back-up procedure, in particular to confirm the presence of non-prescribed drugs. Also, it is used to measure drugs in the presence of compounds that interfere with the nitrogen detector method. The assay for PEMA was developed in order to study the pharmacokinetics of administered PEMA in normal, epileptic9 and elderly volunteers. Little was known about the significance of PEMA concentrations in the plasma of epileptics and there had been reports in the literature of this metabolite accumulat- ing to elevated plasma levels and causing toxicity, particularly in patients with poor renal function.10.11 In an attempt to investigate these claims we are surveying PEMA levels in the majority of patient samples submitted to our laboratory for primidone analysis; we are also in the process of collating our blood level data for PEMA with the clinical information114 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 0 10 J 1 I 0 10 20 Ti me/m i n Fig.2. Examples of sample traces. ( a ) , GLC nitrogen-detector trace; ( b ) , HPLC trace; ( c ) , PEMA sample trace supplied on our routjne anticonvulsant request form. To date we have measured over 1000levels and we hope that eventually we will be able to assess the value of PEMA determination in patients who are maintained on primidone. 4. Wad, N., 1. Chromatogr. Biomed. Appl., 1984,305, 127. 5. Neals, H. M., Totte, J. A., Verkerk, R.M., Vlietinck, A. J., and Scharpe, S. L., J. Clin. Chem. Clin. Biochem., 1983, 21, 295. Kupferberg. H. J . , in Pippenger, C. E., Penry, J. K., and Kutt, H., Editors, “Antiepileptic Drugs: Quantitative Analysis and Interpretation,” Raven Press, New York, 1978, p. 14. Standefer, J., Am. Ass. Clin. Chem., 1982, July issue. Blecka, L. J., Am. Ass. Clin. Chem., 1983, March issue. Cottrell, P. R., Streete, J. M., Berry, D. J., Schafer, H., Pisani, F., Perucca, E., and Richens, A., Epilepsia, 1982, 23, 307. Heipertz, R., Guthoff, A., and Bernhardt, W., J . Neurol., 1979, 221,101. Stern, E. L., Ann. Neurol., 1977, 2 , 356. 6. References 1. Gallagher, B. B., and Baumell, I. P., in Woodbury, D. M., Penryl, J. K., and Schmidt, R. P., Editors, “Antiepileptic Drugs,” Raven Press, New York, 1972, pp.353-354. Kupferberg, H. J . , in Pippenger, C. E., Penryl, J. K., and Kutt, H., Editors, “Antiepileptic Drugs: Quantitative Analysis and Gerson, G., Bell, F., and Chan, S., Clin. Chem., 1984,30,105. 7. 8. 9. 10. 11. 2. Interpretation,” Raven Press, New York, 1978, pp. 10-13. 3. Environmental Chemistry Vol. 3 Senior Reporter H. J. M. Bowen A review of the literature published up to the end of 1982. Disposal and Utilization of Sewage Sludge Possible Consequences of Sewage Sludge Disposal and Utilization and the Need for Monitoring Brief Contents: Tropospheric Ozone Ozone Sources in the Unpolluted Troposphere Photochemistry of the Clean Troposphere Ozone Distribution in the Troposphere Sinks of Ozone in the Unpolluted Troposphere Tropospheric Ozone Budget Ozone Formation and Destruction in Polluted Air Elevated Ozone Levels Biological Effects of Ozone Analytical Techniques The Environmental Chemistry of Organotin Compounds Toxicological Patterns of Organotins Analysis of Organotins at Environmental Levels Modes of Entry into the Environment Aqueous Chemistry Transformations in the Environment Degradation of Organotin Compounds Determination of Heavy Metals in Sewage Sludge Analysis of Sewage Slud e Selected Procedures for gludge Analysis Inorganic Deposits in Invertebrate Tissues Metal Deposits Ligand Binding Silica Deposition Urates Specialist Periodical Report ( I 984) Hardcover 153pp 0 85186 775 8 Price f41 .OO ($74.00) RSC Members f27.00 RSC Members should send their orders to: The Royal Society of Chemistry, Membership Officer, 30 Russell Square, London WCl5 5DT. Non-RSC Members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1 HN, England. The Royal Society of Chemistry Burlington House Piccadilly London W I V OBN

ISSN:0144-557X    

DOI:10.1039/AP9852200110

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年代:1985

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ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 115 Laser Applications The following are summaries of three of the papers presented at a Meeting of the Analytical Division in conjunction with the Special Techniques Group held on October 24th, 1984, in the Scientific Societies’ Lecture Theatre, London W.1. The Use of Lasers in Raman Spectroscopy D. L. Gerrard BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex Tw16 7LN The Raman effect was first demonstrated as long ago as 1928, at which time it appeared to have great potential as an analytical technique for structural and kinetic studies and for the identification and quantification of unknown materials. The main problem with the effect, and one which for many years proved to be insurmountable, is its very weak nature.Only 1 in 106 to 1 in 108 of the incident photons exhibit Raman scattering, and before the advent of lasers no suitably intense light source was available to obtain Raman spectra for more than a small number of strongly scattering compounds. It was the development of reliable continuous wave gas lasers, notably the helium - neon, argon and krypton ion lasers, in the late 1960s, which provided the necessary high intensity, coherent, monochromatic light sources that led to the revival of Raman spectroscopy as an analytical technique. By this time it was too late for it to become established as an alternative to other spectroscopic techniques, notably infrared and NMR spectroscopy and mass spectrometry. Hence, the Raman spectroscopist today has to look for applications to those areas where the Raman effect and the properties of lasers offer some distinct advantages over the other techniques; some of these areas are considered below.Advantages of Lasers and the Raman Effect Light Scattering Unlike infrared spectroscopy, with which the Raman tech- nique is closely associated, the Raman effect is the result of a scattering rather than an absorption process. Because of this opaque samples of any size or shape can be studied without any particular difficulty. Furthermore, as the laser excitation wavelength used is normally in the visible region of the spectrum (typically between 400 and 800 nm), the Raman signal can be easily detected using photomultiplier tubes or intensified diode arrays. Samples require no pre-treatment, and this is particularly valuable in the case of solid samples which can be examined as powders, lumps, films, or even as fabricated articles.This can be a considerable advantage in the study of polymers, where pressing, freeze grinding or dissolu- tion of the sample can alter the structure. A great deal of structural information is available in the Raman spectra of polymers. For example, the spectrum of polyethylene can yield information on chain-branching,’ lamellar thickness,2 crystal- linity3 and relative molecular mass, and in most instances this information is readily available from spectra obtained directly from fabricated articles in only a few seconds. Use of Water and Glass Both water and glass exhibit only very weak Raman scattering, but each is highly transparent to laser radiation at the wavelengths normally used for Raman spectroscopy.Also, the laser remains essentially coherent after passing through water or glass, and so can still be used as an excitation source for Raman studies. Water is therefore a very good solvent for Raman work and glass the ideal material for containing the sample. Liquids can readily be examined in glass bottles and air- or water-sensitive liquids in sealed glass ampoules. Similarly, air- or water-sensitive solids or highly toxic or pathogenic materials can be studied in sealed glass containers. Also, a complete glass reaction apparatus containing, for example, a catalyst - reactant system can be accommodated in the sample compartment of the spectrometer, and reactions followed under a wide range of conditions. Hydrolysis reactions can readily be studied in situ as can emulsion polymerisation reactions.The action of water, even sea water, on iron and steel can also be monitored, and the effect of corrosion inhibitors can be studied without the need to remove the sample from its corrosion environment. Raman spectroscopy is also widely applicable to biological systems where water is normally present as a major component. Strong Scatter of Non-polar Groups The Raman effect is exhibited most strongly by non-polar groupings, especially homoatomic groupings such as C-C, C=C, N-N, S-S, 0-0, etc. Hence, information in the Raman spectrum is often very different from that available from other spectroscopic techniques, particularly infrared spectroscopy.Spectral features due to carbon - carbon bonding are often of great value in the study of polymer backbones. For example, the relative concentration of cis-, trans-, and 1,2-groupings in polybutadiene can be readily determined from the intensities of their characteristic C=C stretching modes. Stretching modes due to C-C bonds have proved to be of value in determining the amorphous and graphitic contents of a wide range of carbon samples,4 including coals, carbon fibres and catalysts. Similarly Si-Si modes can be used to determine the amorphous and microcrystalline contents of silicon semi- conductors. Other strongly Raman active vibrations are produced by metal - metal bonding, and these can prove to be valuable in structural studies of inorganic and organometallic compounds.Low Frequency Modes Because Raman spectra are always the result of frequency shifts, and are expressed in terms of Acm-1, there is, in principle, no difficulty in studying very low frequency vibra- tions that are not normally available in infrared spectra unless special accessories or instruments are used. Such modes often occur in inorganic and organometallic compounds and have proved to be of value in structural studies, especially of catalysts. But the best example of such vibrations occurs with polyethylene, which exhibits low frequency modes in the range 5-50 cm-l, the so-called longitudinal acoustic modes (LAMS). These modes are related to the thickness of the polymer lamellae, and although the exact nature of this relationship is still not completely understood they can be used to characterise different types and grades of polyethylene.116 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 The Resonance Effect-Use of Dye Lasers When the wavelength of the laser line being used to obtain the Raman spectrum lies within the electronic absorption profile of a particular chromophore within the molecule being irradiated, the Raman spectrum of that chromophore can be enhanced by several orders of magnitude.This is known as the resonance Raman effect, and where it occurs the sensitivity of the technique is increased dramatically. One of the best examples of a grouping which exhibits resonance enhancement is a conjugated polyene, (-CH=CH-),. Such polyenes can be formed by the dehydrochlorination of poly(viny1 chloride) and resonance Raman spectroscopy has been extensively used to study the thermal, chemical and photochemical degradation of PVC and other vinyl polymers under a range of conditions at extremely low levels.w3 Another material containing polyenes and which is currently attracting a great deal of attention, both academic and commercial, because of its unusual electrical properties, is polyacetylene. This is a highly air-sensitive material and so is conveniently examined in a sealed glass tube. In theory, the polyacetylene molecule consists of a long chain of alternating single and double bonds, and so should exhibit resonance enhancement. It does indeed give the two anticipated bands near 1100 cm-1 (C-C stretch) and 1500 cm-1 (C=C stretch), but more important from the structural point of view is that the positions of these bands change depending on the laser wavelength being used to obtain the spectrum.The only satisfactory explanation for this is that the polyacetylene contains a wide range of individual conjugated polyene sequences, and by varying the laser wavelength these are brought into resonance one by one, each having its own characteristic C-C and C=C stretching modes. In this way a picture can be built up of the distribution of these polyenes in the polymer, and such studies have been widely used in structural studies of polyacetylene made by different routes. 9-11 Because only a limited number of wavelengths is available from conventional continuous wave gas ion lasers, studies of the above type have benefited considerably from develop- ments in dye lasers. It is a relatively simple procedure to attach a standing wave dye laser to an argon ion laser, and by passing the output from the argon laser through a narrow jet of a solution of a suitable dye a broad band output can be obtained, which is due to the fluorescence of the dye.This output can be finely tuned with an optical wedge. By use of a range of dyes complete tunability can be achieved over the whole range of the visible spectrum. The use of resonance Raman spectroscopy is potentially one of the most important areas of application of the technique as for many compounds it will give a sensitivity in the parts per billion range. At the present time it is only routinely applicable to the study of compounds that exhibit absorption in the range 400-800 nm.However, recent developments in the area of tunable pulsed systems, based on neodymium - YAG and excimer lasers have shown great promise for the study of aromatic hydrocarbons12 at extremely low levels. The potential of such lasers, which are now continuously tunable from about 190 nm to 4 pm, is considerable and will extend resonance Raman studies into areas of great interest. Spatial Resolution - Raman Microscopy The principal advantage of lasers from the point of view of the Raman spectroscopist is that they provide an intense source of coherent monochromatic visible radiation. A second major advantage, however, is that they offer a very high degree of spatial resolution. It is a relatively simple procedure to focus a laser beam down to a diameter of about 1 ym, and this opens up the possibility of obtaining spectra from very small samples or parts of samples. This can be achieved by attaching an optical microscope to a conventional Raman spectrometer ,13 and the technique of Raman microscopy is being increasingly used both academically and industrially.This technique of Raman microscopy has proved extremely valuable for the identification of inclusions in polymers and other solids, catalyst studies, the identification of small particles isolated on to micromesh filters and biological systems. Use of Fibre Optics The small beam diameters of lasers, and the fact that most of the lines used in Raman studies are in the visible region of the spectrum, means that the laser beam can conveniently be passed down a fibre optic or liquid light guide to the sample.The Raman signal, which is also visible radiation, can be collected in a similar way, and this makes it possible to obtain spectra of samples situated remotely from the spectrometer. In this way spectra can be obtained, for example of high temperature - high pressure systems, which are often more conveniently located in a different room from the Raman spectrometer. The use of fibre optics is also potentially useful for studying samples in toxic or corrosive environments or for investigating reactions on or near electrode surfaces. 14 Conclusions The development of continuous wave gas ion lasers led to the revival of Raman spectroscopy as an analytical technique in the late 1960s, and it is now well established as a valuable, broad-based analytical tool in its own right.The subsequent developments in standing wave dye lasers extended the areas of application considerably by giving an increase in sensitivity to the analysis of many compounds. This will be extended in the near future with the use of tunable ultraviolet sources, which will open up the study at very low concentrations of a very wide range of organic and inorganic compounds and will also enable Raman spectrometers to be coupled to separation techniques, such as high-performance liquid chromatography. The advan- tages of spatial resolution in terms of Raman microscopy and the use of fibre optics are already established and hold considerable promise for the future.The development of Raman spectroscopy to date has been closely linked with developments in laser technology and this relationship will undoubtedly continue in the future. Permission to publish this manuscript has been given by the British Petroleum plc. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. References Gerrard, D. L., Maddams, W. F., and Williams, K. P. J., Polym. Commun., 1984, 25, 182. Glotin, M., and Mandelkern, L., J. Polym. Sci., Polym. Phys. E d . , 1983, 21, 29. Strobl, G. R., and Hagedorn, W., J. Polym. Sci., Polym. Phys. E d . , 1978, 16, 1181. Nakamizo, M., Kammereck, R., and Walker, P. L., Carbon, 1974, 12,259. Martinez, G., Mijangos, C., Millan, J. L., Gerrard, D. L., and Maddams, W. F., Makromol. Chem., 1979, 180, 2937. Gerrard, D. L., and Maddams, W.F., Macromolecules, 1975, 8, 54. Gerrard, D. L., and Maddams, W. F., Macromolecules, 1977, 10, 1221. Biggin, I. S., Gerrard, D. L., and Williams, G. E., J. Vinyl Technol., 1982, 4, 150. Shirakawa, H., Ito, T., and Ikeda, S., Polym. J., 1973,4460. Lichtmann, L. S., Sarkangi, A., and Fitchen, D. B., Chem. Scr., 1981, 17, 149. Schugerl, F. B., and Kuzmany, H., J. Chem. Phys., 1981, 74, 953. Asher, S. A., Appl. Spectrosc., 1984, 38, 276. Cook, B. W., and Louden, J. D., J. Raman Spectrosc., 1979,8, 249. McCreery, R. L., Fleischmann, M., and Hendra, P., Anal. Chem., 1983, 55, 146.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 117 Low Angle Laser Light Scattering Used in the Measurement of Polymer Relative Molecular Masses S. R. Holding Polymer Supply and Characterisation Centre, Rubber and Plastics Research Association, Shawbury, Shropshire SY4 4NR Along with chemical type, relative molecular mass is one of the fundamental properties of a polymer determining, amongst other features, the ease of processing and the physical strength of the final products.Low angle laser light scattering (LALLS) has been applied in both the static (or “stand alone”) mode and combined with gel permeation chromatography (GPC) to determine polymer relative molecular masses. Static Mode The static mode use of LALLS can be contrasted with conventional light scattering. The high incident light intensity of a laser enables the technique to be applied using a single low solid angle and a small cell volume; the former considerably simplifies light scattering, removing the need for Zimm plots, and the latter reduces the need for rigorous sample clarifica- tion. However, when limited to a single angle, light scattering does not furnish any information on the size or shape of the polymer molecule.Static LALLS Practice Important variables, other than relative molecular mass, that influence the amount of light scattering include: the solvent’s refractive index (this is easily determined); the polymer - solvent differential refractive index, dn/dc (this parameter is difficult to measure, and all too often questionable literature values are employed, which can introduce serious errors); or, the concentration of the sample (it must be accurate). The Rayleigh scatter is measured as the ratio of the incident intensity (measured as the unscattered beam) and the scattered light intensity.The incident, or straight through beam, is attenuated to bring its intensity to a similar value to that of the scattered light. The solvent and a series of 4-6 different sample solution concentrations are run and the mass-average relative molecular mass (arn) of the polymer is determined by an extrapolation to zero concentration. Applicability of Static LALLS Static LALLS has been applied to a wide range of polymer types. The ease of application is determined by the solvent (toluene is easier to use than tetrahydrofuran) and the solvent will often be dictated by the need to obtain a reasonable polymer - solvent differential refractive index. This laboratory has applied LALLS to a particularly wide range of relative molecular masses.Relative molecular masses in excess of 106 and as low as 2000 have been measured. At high relative molecular masses there are problems with solution clarification; the polymer molecules are of the same order of size as dust particles. Also, it can be difficult to handle precisely the very dilute solutions that may be required for high Mrn values. High concentration solutions are a problem for low M , polymers a_nd we have observed some anomalous plots for some low M , - high sample concentration samples. Reproducibility of Static LALLS Collaborative work has shown static LALLS to give very good intra- and inter-laboratory reproducibility. 1 Combined GPC - LALLS GPC is a chromatographic technique in which molecules are separated according to size.It is a rapid technique, which can be applied to a wide range of polymers to provide a great deal of information about the whole relative molecular mass distribution (MMD) of a polymer. However, GPC is a secondary technique and only a small range of polymers can be covered by suitable calibrants. A mathematical correction (universal calibration), for chemical type, can be applied to the GPC calibration; this involves extra assumptions and often utilises questionable literature data. The small cell size and the generally low sample concentra- tions used in LALLS make it suitable for use as a chromato- graphic detector. The LALLS response is basically a function of the relative molecular mass and the concentration; if the signal from the LALLS is used in conjunction with a concentration detector signal, then relative molecular mass can be calculated.With the combined GPC - LALLS the MMD of a polymer can be determined without the need for calibration. Combined GPC - LALLS has the advantages of GPC in that it is fast and widely applicable. In addition an “absolute” MMD is determined and the technique has some special applications, which will be mentioned later. However, there- are some problems with interpretation. In reality, it is the M , at each elution volume point that is being calculated, consequently the apparent MMD by GPC - LALLS is considerably narrower than that measured by GPC alone. Also, at the extremes of the MMD there is an imbalance in the detector responses which can cause large errors; frequently it is the extremes of this distribution that are of most interest.L_arge errors have been apparent when measuring very high M , values and this is probably caused by some of the high relative molecular mass material being retained in the GPC part of the system. Applications GPC - LALLS has been applied considerably in three general areas: firstly, to study branching; secondly, in characterising copolymers; and thirdly, in determining the relative molecular mass of novel polymers. Branching Basically some qualitative data on branching in polymers can be obtained by comparing the “absolute” relative molecular mass determined by GPC - LALLS, and the relative molecular mass indicated by GPC alone. The GPC system is calibrated with the linear polymer. When a branched polymer is run, the molecules are more compact and appear to have a lower relative molecular mass than the equivalent linear polymer.The ratio of the “absolute” to “apparent” relative molecular mass values can be studied across the relative molecular mass range to given an indication as to how the branching varies. Copolymers A considerable amount of work has been carried out by this laboratory and is reported elsewhere.2 If a copolymer’s composition varies across the relative molec_ular mass range, then generally LALLS will not give a true M,. For such heterogeneous copolymers, static LALLS must be carried out in three different solvents in order to allow calculation of the true M,. In a manner similar to that described for branching, GPC - LALLS can be used to determine “apparent” relative molecular mass values, which can be compared with “true” relative molecular masses from118 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 GPC used on its own.A heterogeneity parameter has been defined and how this varies with relative molecular mass can be very informative. Most copolymers so examined have been found to include significant amounts of homopolymer. Novel polymers Clearly an absolute relative molecular mass technique is very useful when considering new polymer types, where GPC is limited by the lack of suitable calibrants and parameters for the universal calibration procedure are not available. There have been many such applications reported in the literature. However, because of the problems which can be encountered in GPC - LALLS, such work should be supported by some static LALLS work. References 1.Dumelow, T . , Holding, S. R., and Maisey, L. J . , Polym. Commun., 1983, 24, 307. 2. Dumelow, T., PhD Thesis, Loughborough University of Technology, 1984. Laser Source Solid State Mass Spectrometry T. K. Sanderson Analytical Techniques Group, Instrumentation and Applied Physics Division, AERE, Harwell, Oxfordshire OX1 1 ORA Spark source mass spectrometry is a well established technique for the semi-quantitative determination of trace elements in a wide variety of solid samples. The method is capable of measuring all of the elements from lithium to uranium, at sensitivities of 10 p.p.b. or lower, subject to possible interfer- ence from other elements present in the matrix.The electrodes prepared from ultra-pure semiconductor materials and glasses are not, however, sufficiently conducting to enable an RF discharge to take place using a conventional spark-source mechanism. The normal solution to this problem is to mix the powdered sample with an equal amount of high-purity graphite, but this procedure increases the risk of contamination. In addition, molecular and combination ions formed by the graphite lead to increased interference problems. The use of a laser source seemed the best way of avoiding the need for conducting electrodes. 1~ The original samples could then be directly mounted in the source, and the resulting ions analysed in the conventional manner on the double-focusing mass spectrometer. Thus, the handling of the samples was reduced to a minimum and contamination problems avoided.Laser Source Mass Spectrometer (LSMS) The most important laser characteristic for direct laser - solid interaction is the power density. Q-switched lasers with short pulse lengths produce higher power densities compared with normal pulsed lasers.’ The resultant ionised particles are caused by explosive vaporisation with the former type. The normal working range for the power density is 109-1011 W cm-2, and for a focused beam spot of 20 ym diameter the power density is 2 x 1011 W cm-2. As the beam is defocused, the power density falls off rapidly. When a Q-switched neodymium - YAG laser is fired repetitively (up to 50 Hz), a large “crater” is formed, which increases the working distance and soon causes the beam to become defocused.Ion Source A diagram of the laser source arrangements is shown in Fig. 1. The insulated lens holder was fitted with a tantalum disc, which was connected to the HT accelerating potential. The tantalum disc had a 5 mm hole at the centre in order to allow transmission of the laser beam. A thin cover glass was positioned in front of the lens, to protect it from sputtered material. Experimental The laser could be fired manually to provide a series of single shots, or repetitively. Exposures were normally collected in the range from 10-4 to 100 nC on Ilford Q2 photoplates. For exposures of more than 10-2 nC, it was necessary to raster the target across the laser beam because of the defocusing effect. Mass analyser Beam focusing apertures at 0 V I Laser beam Ta shield I ,:a+c;;ekv \ \ at t-20 kV Viewing telescope Focusing lens Glass window on in ceramic front of source lens holder Schematic diagram of laser source arrangement Fig.1. At the higher repetition rates, the laser beam does not remain precisely focused for each shot, compared with individually fired single shots. Consequently, the charge collected per shot for an exposure run at a frequency of 50 Hz can be substantially less than the charge collected for a single manually triggered shot. However, it was found that at optimum settings, exposures of 100 nC could be collected in 30-60 min, depending on the nature of the sample. This rate of collection compares favourably with the spark-source mode. A wide variety of samples have been analysed to assess both the performance of the laser source technique and the validity of the results obtained. These include glasses, metals, rock samples and several types of semiconductors. Suitable samples were analysed directly by cleaning their surfaces with appro- priate etchants, mounting the samples in the source, and running a series of exposures using a photoplate detector.Examples of the results are given below. Results and Discussion NBS Glass, SRM 612 This standard sample consists of a 3 mm thick glass wafer, about 1 cm in diameter, containing a number of trace elements at a nominal 50 p.p.m. level. A series of 15 x 10 nC exposures were accumulated on a photoplate, and the optical densities of 16 trace elements measured by using microdensitometry.Both silver and iron were used as the internal standards, in order to calculate the elemental concentrations of the remaining trace elements. By using these results the mean relative sensitivity coefficients (RSC) were calculated, and the results obtained are shown in Table 1.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 119 Table 1. Relative sensitivity coefficients as measured on NBS Glass, SRM 612 Element Isotope S,(Ag) S,(Fe) K 39 0.96 0.72 Ti 48 0.71 0.55 Fe 56 1.33 1 .oo c o 59 1.46 1.1 Ni 58 1.43 1.08 c u 63 1.33 1 .oo Rb 85 2.38 1.79 Ag 107 1 .oo 0.75 Ba 138 1.02 0.77 La 139 1.03 0.77 Ce 140 0.94 0.71 Nd 144 0.96 0.72 Eu 15 1 0.97 0.73 Pb 208 0.58 0.44 Th 232 0.56 0.42 U 238 0.56 0.42 The calculated RSC’s show reasonable uniformity across the broad spectrum of trace elements determined.The over-all spread was within a factor of x5, which is a considerable improvement in the range observed for the spark-source technique. Surface Analysis In order to assess the potential use of the laser source for the analysis of “surfaces,” samples of silicon wafers and steel were mounted in the source chamber. The craters formed were then examined by scanning electron microscopy, and their depths measured. These results showed that single shots of the laser can sample a layer of a few microns or less. Such a shot would have an estimated elemental sensitivity of about 1000 p.p.m. (0.1%) by mass, and ten shots would enable levels of 100 p.p.m. to be reached, for most elements. However, the estimated depth of the latter firing would be of the order of approximately 20 pm, depending on the sample.Conclusion The present work has demonstrated that a high-power Q-switched neodymium - YAG laser can be used as an alternative to the RF spark-discharge mechanism in the analysis of solid inorganic samples by mass spectrometry. High purity semiconductor materials, ceramics and glasses, which are non-conducting, can be analysed directly with minimum sample preparation, thus avoiding the problem of sample contamination. As in conventional SSMS, the range of elements which can be determined simultaneously is also higher than in any other comparable analytical method, with a sensitivity for bulk analyses at the parts per billion level. The laser source produced photoplates that are subject to reduced background fogging, resulting in improved mass line definition with less interference from multiple C,+ and (C,X)+ mass lines.The photoplates were, therefore, easier to interpret than those obtained from the spark-source technique. The laser technique also offers the possibility of microanaly- sis or surface analysis. Suitable modifications to the laser optics and sample positioning and viewing mechanisms could clearly increase this capability. A detailed account of the LSMS system has now been published, together with a complete discussion of the method as reported above.3 References 1. Bingham, R. A. and Salter, P. L., Anal. Chem., 1976,48,1735. 2. Jansen, J. A. J . , and Witmer, A. W., Spectrochim. Acta, Part B , 1982, 37, 483. 3. Sanderson, T. K., Mapper, D., and Farren, J . , “The Determi- nation of Trace Elements in Solid Samples by Laser Source Mass Spectrometry,” AERE Harwell Report No. AERE- R11113, 1984. Health and Safety in the Chemical Laboratory - Where do we go from here? This publication provides an overview of health and safety developments in the chemical laboratory and workplace, and will provide essential reading for anyone involved in these areas. Brief Contents : Accident and Dangerous Occurrence Statistics in the United Kingdom; Morbidity and Mortality Studies; Economics of Health and Safety Measures; Procedures and Statistics in France; Professional Negligence, Liability and Indemnity; The System in the United States of America; The System in the United Kingdom; The System in the Federal Republic of Germany; Hazards of Handling Chemicals; Hazards of Apparatus, Equipment and Services; Managing People; What Standards Should We Use? Conflict of Safety Interests with Legislation; The Protection of Workers Exposed to Chemicals: the European Community Approach; Recommendations Arising from the Symposium. Special Publication No. 57 Softcover 206pp 0 85186 945 9 Price f 16.50 ($30.00). RSC Members f 12.00 Ordering: Non-RSC Members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1 HN, England. RSC Members should send their orders to: The Royal Society of Chemistry, Membership Officer, 30 Russell Square, London WClB 5DT. The Royal Society of Chemistry Burlington House, Piccadilly London WlV OBN

ISSN:0144-557X    

DOI:10.1039/AP9852200115

出版商:RSC    

年代:1985

数据来源: RSC

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ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 120 Equipment News Portable X-ray Analyser The X-MET 840, developed by Outo- kumpu Oy of Finland, can be used both for identifying alloys and for element analysis. The composition of known alloys can be measured and the results stored in the analyser's memory. When an unknown alloy is analysed its composition is compared with those compositions which are stored; if it corresponds to one of them the analyser presents its name on the display. If the correspondence is not close enough, the analyser gives the names of one or two alloys that are similar. Alternatively, the composition can be given in percentages for up to six elements at a time. Clandon Scientific Ltd., Lysons Ave- nue, Ash Vale, Aldershot, Hampshire GU 12 5QR. Fourier Transform Spectrometers A new generation of instruments is avail- able from Bomen Inc.A standard spec- trometer with suitable detectors can pro- duce spectra from 50000 cm-1 to 4 cm-1. In addition to an ultraviolet to far infrared capability the new instruments feature a five-port sample compartment and an automatic optical alignment system, and the spectrometers can be fully evacuated in order to eliminate water vapour. A range of sample handling accessories is available. Anaspec International Ltd., Anaspec House, Faraday Road, Newbury, Berk- shire RG13 2AD. Ultraviolet - Visible Spectrophotometers The Response range of instruments has been expanded to encompass three sepa- rate models. The basic model is supplied complete with a single cell holder and programs for wavelength scanning, kinet- ics, time scanning, multi-wavelength analysis, standard curves and sample read.The second unit has an automatic six-position cell holder and the capability for adding gel scanning, rapid sampling and a six-position thermoset cuvette hol- der for electronic control of sample tem- perature. The most advanced unit has two disk drives for archival data storage and recall, together with extended software applications. All three have an autorang- ing photometer, transverse sample com- partment, high resolution graphics, data storage facilities and a 16-bit computer. Corning Medical and Scientific, Corn- ing Ltd., Halstead, Essex C 0 9 2DX. Spectrofluorophotometer Accessories The Shimadzu RF 540 incorporates a microcomputer and parallel line plotter and features an off-plane monochromator and automatic wavelength shift correc- tion.New optional accessories include a choice of flow-through cells made of fused silica, two test-tubes holders that accept preparing samples from minerals such as iron agglomerates, calcites and dolomites and furnace and mill cinders, slags and sludges. The composite crucible does not have to be cleaned between successive samples because of the absence of wetting of the carbon liner. EDT Research, 14 Trading Estate Road, London NWlO 7LU. HPLC Modules Three new modules have been added to the HP1090 family of integrated modules. The first is the local user interface, or LUSI, which allows the HP1090 to be controlled from its own keyboard for those applications which do not require the computing power of the HP85 con- troller.Up to 10 liquid chromatographic methods can be stored in a battery protec- Analytical Instrumentation Group HPLC modules tubes of 8 mm 0.d. and 45-100 mm length or 12 mm 0.d. and 60-100 mm length, and a bottom rinse sample stage which reduces the minimum measurable volume to 1.5 ml. A thermostated cell is also available; used in conjunction with a thermocirculator or a heater - chiller it allows temperature control of the sample. The recorder stand now available allows the DR-3 data recorder to be placed above the spectrofluorophotometer. V. A. Howe and Co. Ltd., 12-14 St. Ann's Crescent. London SW18 2LS. Solution Preparation System Plasmasol is a system made by Jobin - Yvon of France for the preparation of solutions from intractable materials such as blast furnace slag, prior to analysis by atomic-absorption or optical-emission spectroscopy or related techniques.Con- trolled by a fully programmable micro- processor, the system has been used for ted memory. The second module is the PV5 ternary solvent delivery module, which can be used with standard, high speed and microbore columns. The third is the DPU multi-channel integrator, which quantifies up to eight signals from the HP1090 diode-array detector simul- taneously. Analytical Instrumentation Group, Hewlett-Packard Ltd., Miller House, The Ring, Bracknell, Berkshire RG12 1XN. HPLC Column Packing PLRP-S, a styrene based rigid macro- porous adsorbent makes possible the per- formance of reversed-phase separations over a wide range of operating conditions.Individual columns are computer tested and issued with a test certificate. Polymer Laboratories Ltd., The Tech- nology Centre, Epinal Way, Lough- borough LE11 OQE.ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 121 Radioactive Flow Detector for HPLC A new range of flow detectors in the IC range is available. In addition to their high sensitivity detection cells the makers offer a wide range of quick change cells, both liquid and solid, built-in electronic splitter and a computerised data acquisi- tion and processing package. Radiomatic Instruments and Chemicals Ltd., 11 Lincoln Park Business Centre, Lincoln Road, High Wycombe, Bucking- hamshire HP12 3RD. Computing Integrator System for Chromatography Chemputer 10 is based on the Apricot microcomputer and works in conjunction with any GC or LC detector through a specially designed “plug-in-and-run” interface module.The software allows both area and height to be reported as % arealheight together with normalisation, internal or external standards,with linear or non-linear multi-level calibration - analysis sequencing and bracketing. Screen chromatograms are displayed using a split-screen format which shows the whole run plus current peaks at whatever size may be required. Storage of both raw and bunched data allows either true re-integration with different parameters or simply base-line realloca- tion. Quadrant Scientific, 36 Brunswick Road, Gloucester GL1 1JJ. Bioseparation System The Ultrochrom GTi purification system offers multi-mode separation of macro- molecules.Designed for work with proteins, peptides, nucleic acids and even carbohydrates, GTi provides fast separa- tion, high resolution and increased bio- logical activity (results range from 91 to 99%). Complete purification schemes can be integrated on one system. Using gel filtration, ion-exchange and hydrophobic- interaction chromatography, the most appropriate chromatography can be exploited for any particular problem. In addition, the total separation capability provided by the system enables it to be used for mainstream reversed-phase chromatography, including microbore and fast LC. LKB-Produkter AB, Box 305, S-16126 Bromma, Sweden. Gas Detectors The Enterra CHLOR-GUARD detects hazardous chlorine gas leaks, giving an alarm.‘It uses a gas diffusion electrode and is calibrated for a range of 0-10 p.p.m. with two adjustable alarms, one latching and one automatic re-set. The sensor requires no reagents or other periodic recharging and it can be located up to 200ft from the electronics. The Tox-ALARM uses an electrochemical gas diffusion sensor to detect hazardous con- centrations of sulphur dioxide. Two adjustable alarm levels are provided, factory set at 5 and 10p.p.m. Alarm settings may be adjusted by the user from 1 to 25 p.p.m. Visual alarm lights and an audible horn are provided in the NEMA 4X alarm package. Quantitech Ltd., 75 Garamonde Drive, Wymbush, Milton Keynes, Buckingham- shire MK8 8DD. pH - Ion Meter The ECM220 is designed especially for use with ion-selective electrodes and it features simple calibration for their use and direct readout of concentrations in a choice of three different units: molar decimal, molar exponential and p.p.m.It measures pH, pX, mV, relative mV and temperature. Standard buffer values are programmed into its memory and the instrument features an optional IEEE488 computer interface. EDT Research, 14 Trading Estate Road, London NWlO 7LU. pH and Ion Meters The Radiometer ION83 ion meter is designed for precision measurement and routine work with pH and ion-selective electrodes. Ion concentration is deter- mined by direct potentiometry. Multi- point calibration with up to 5 standards including a blank measure ensures accu- racy and use of the full working range of the electrodes. There is capacity for stor- ing the calibration data for up to 3 different electrode pairs. The PHM85 pH meter is intended for research and preci- sion measurement of pH, pX and mV.Resolution is 0.001 pH, 0.001 pX, 0.1 mV and 0.1 “C. Buffer values can be selected as desired and stored in the microproces- sor’s memory. Sensitivity, zero point and ISO-pH point are automatically calcu- lated and displayed during calibration. Both instruments can be connected to a sample changer and each has an RS232C output for connection to computer or printer. V. A. Howe and Co. Ltd., 12-14 St. Ann’s Crecent, London SW18 2LS. Thermal Analysis System Several new features have been added to the TA3000. These include a new measur- ing sensor for differential-scanning cal- orimetry and an adaptation of the evalua- tion programs.The new control and evaluation unit of the system, the TClOA TA processor, has a bidirectional RS232C interface that allows connection to a personal computer for storage of data, which can be transferred back to the TClOA for evaluation and printout. Mettler Instrumente AG, CH-8606 Greifensee, Switzerland. Balance The ABA180 analytical electronic balance is a top-loading instrument with a capacity of 180g and a resolution of 0.1 mg. An internal reference weight and a computer with a non-volatile memory make daily calibrations simple. The balance has RS232C and current loop and parallel BCD output interface options. Salter Industrial Measurement Ltd., George Street, West Bromwich, Birming- ham B70 6AD. Balances The Shimadzu ED-K Series of top- loading balances are microprocessor con- trolled and have dual range facilities, for example from 0.5 to 56 g or from 0.1 g to 28 kg.Features include data averaging and piece counting plus automatic zero- ing, memory and stability detection. Serial data output is standard and all units will link to a digital printer. Statistical calculations functions are useful in appli- cations such as sample inspection, weight control, incorporation into production lines and animal weighing. V. A. Howe and Co. Ltd., 12-14 St. Ann’s Crescent, London SW18 2LS. Scales The PE22 Deltarange scales feature a ten times more accurate fine range of 2kg, which can be recalled as often as neces- sary within the over-all 24kg weighing range; instead of reading to l g , weight indications are displayed with a 0 .l g accuracy. If this fine range is exceeded while material is being weighed in, the scales automatically revert to indicating to an accuracy of l g . There is an overload protection device, and a single control bar allows the scales to be switched on or off, re-set to zero or tared with a single touch. Mettler Instrumente AG, CH-8606 Greifensee, Switzerland. Particle Sizer The TSI differential mobility particle sizer offers a method of obtaining high- resolution particle size data in the 0.01-1 .O pm range, distributing particle sizes over a total of 39 mobility channels which span this range. Components of the system include the electrostatic classifier, which selects a narrow predictable size fraction of the particles and passes the selected airborne particles to an aerosol concentration detector.For this classifica- tion the system uses either a condensation nucleus counter, which measures the122 number concentration of the selected particles from less than 0.01 to 107 par- ticles cm-', or an aerosol electrometer, which measures the electric current from particles as they collect on a high effi- ciency filter. An Apple I1 microcomputer controls the specific size of particles selec- ted by the electrostatic classifier and reads the particle concentration data from the condensation nucleus counter or aerosol electrometer. Data provided include number, surface and volume concentra- tion versus diameter, cumulative per cent. of these data and calculations of mean and geometric standard deviation for number, surface and volume distribution.Biral, P.O. Box 2, Portishead, Bristol BS20 9JB. Microscope Accessory Wild Heerbrugg have introduced a stereoscopic attachment for their M600 series of surgical operating microscopes. It allows a second observer to follow the progress of a microsurgical operation and to participate. It can be rotated through 360". The new accessory can also be used with a beam splitter on the makers' M3, M7A, M7S and M8 sfereomicroscopes. E. Leitz (Instruments) Ltd., 48 Park Street, Luton LU1 3HP. Centrifuge Rotors Three new rotors are available for the J2-21 centrifuge. The JA-18.1 fixed angle rotor allows microcentrifuge-sized tubes to be spun in a refrigerated centrifuge at three times the g-force of a microcentri- fuge.The ten-place JA-18 fixed-angle rotor holds 100-ml tubes and generates forces to 47 900 g; it is suitable for harvest- ing bacteria, viruses, cell membranes and subcellular particles, processing tissue homogenates and separating cell particu- lates. The JS-13.1 swinging bucket rotor holds 50-ml tubes and has six buckets. Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire. pH - Blood Gas Control When used with the maker's real time quality control system, Pathway provides a quality assurance system for all blood gas analysers. It monitors blood gas ana- lyser measurements in order to detect instrument malfunctions and ensure oper- ator accuracy. There are four levels: acidosis, normal, alkalosis and elevated oxygen. The 5-ml ampoule is shaken for 10s and then used on the blood gas analyser.The control value is entered in the real time quality control system to obtain an instant report of its acceptability and a comparison with other data. The control is foam-free after shaking and there is no waste because it is not neces- sary to tap the ampoule. Stable for 18 months from the date of manufacture, Pathway can be stored at room tempera- ture; when the ampoule is opened the control is stable for 60 s. ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire. Centrifugal Evaporator The GyroVap is a centrifuge with high vacuum and temperature control facili- ties; it meets the safety standards of BS4402. Solutions are concentrated or solidified by evaporating off the solvent under vacuum at ambient temperature, below ambient or up to 70 "C. Samples are spun at a moderate g force, which prevents the bumping and foaming nor- mally encountered in heat - vacuum con- centration.For reproducible runs the timer, which operates between 30 min and 4h, can be switched in. Accessories include refrigerated traps for solvent col- lection, isolation valves and chemical traps in a range of sizes, and a water jet vacuum pump for the removal of organic solvents too difficult to handle with a standard vacuum pump. V. A. Howe and Co. Ltd., 12-14 St. Ann's Crescent, London SW18 2LS. Temperature Control Equipment Neslab Coolflow refrigerated recircula- tors provide a continuous flow of clean cooling water at constant temperature and pressure.The RTE series of refriger- ated bath - circulators are designed for smaller benchtop cooling and precise temperature control applications; tem- perature control to +O.Ol"C over the range -80 to 250 "C is available. Neslab Cryocool immersion probe coolers offer temperatures down to - 100 "C. Two temperature controllers are also available. The EPT3 performs linear heating or cooling programs over a span of 130°C for an adjustable period of 10-10 000 min. The MTP 5 has a memory capable of storing 10 separate programs, each with 95 steps of 0.1 to 999.9 min. Jencons (Scientific) Ltd., Cherrycourt Way Industrial Estate, Stanbridge Road, Leighton Buzzard, Bedfordshire LU7 8UA. Digital Storage Oscilloscope The 1421 incorporates a sequential Sam- pling technique which enables it to store both repetitive waveforms up to 20MHz and single-shot transients.It includes a single push-button trace-hold facility, which enables sorted and real-time traces to be viewed simultaneously. It offers dual-channel operation up to its full 20MHz band width and it includes facili- ties for pre-trigger viewing, post-storage expansion and the ability to copy auto- matically the displayed waveform to a pen recorder. Design and Test Systems Division, Gould Instruments Ltd., Roebuck Road, Hainault, Essex IG6 3UE. Laboratory Automation and Data Management CALS (Computer Automated Labora- tory System) can be interfaced with a variety of analytical instruments. It offers complete software packages for data acquisition, data reduction, data manage- ment and data storage and retrieval.Data can be acquired in analogue or digital form from instruments such as chromato- graphs and spectrophotometers, or they can be entered manually via a keyboard. The laboratory management package provides complete sample tracking facili- ties including log-on, label printing, work list generation, scheduling of analytical tests, test validation and approval and reporting of data. The system is based on Hewlett-Packard 1000 Series computers and optional software and a full support service are available. Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire . Literature A leaflet introduces the Sirius 100 and Cygnus 25 Fourier transform infrared spectrometers from Mattson Instruments Inc.They offer resolution capabilities of 0.125 and 0.5 wavenumbers, respectively, over the mid-infrared spectral range 4400-400 wavenumbers with optional extensions to 25 000 and 10 wavenumbers. Reference is also made to the Starlab data system, which is Unix-based, and the Cryolect GC - IR. Glen Creston Instruments Ltd., 16 Dalston Gardens, Stanmore, Middlesex HA7 1DA. A detailed report gives information on the use of Jobin - Yvon inductively coupled plasma systems for the determination of wear metals at very low levels in oils. The undiluted oils were nebulised direct into the plasma source. EDT Research, 14 Trading Estate Road, London NWlO 7LU. A catalogue gives details of instruments for infrared, ultraviolet - visible, fluores- cence and atomic spectroscopy, gas and liquid chromatography, thermal andANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 123 elemental analysis and surface chemical analysis.Details are also given of labora- tory computers, data stations and applica- tions software. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. A catalogue, “Products for Chromato- graphy,” lists a wide range of products. Major topics covered include sample pre- paration, HPLC, thin-layer chromato- graphy and preparative-column chromat- ography. J. T. Baker Chemicals B. V., P.O. Box 1, 7400 Deventer, The Netherlands. A catalogue gives details of a wide range of products for chromatography, includ- ing: HPLC instruments, columns, sor- bents and reagents; thin-layer - HPTLC instruments, pre-coated plates, sorbents and reagents; preparative-column chro- matography; GLC reagents and analytical standards for chromatography.BDH Chemicals Ltd., Broom Road, Poole, Dorset. A catalogue gives information on vials, caps and seals for over 50 chromato- graphy autosamplers. Among the new products decribed are two vials for the Waters 96-vial carousel and a seal which reduces coring problems in GC and HPLC autosamplers. Chromacol Ltd., Glen Ross House, Summers Row, London N12 OLD. Two “GC Application News Bulletins” are available. One describes the char- acterisation of beeswax using the capillary liquid on-column injection technique and a de-activated fused silica retention gap with single ferrule column connection. The other describes the analysis of various trade preparations of pyrethroid insecti- cides using the capillary liquid on-column injection technique and an electron cap- ture detector.Both give all relevant experimental conditions, and the resul- tant chromatograms are illustrated. Packard Instruments Ltd., 13-17 Church Road, Caversham, Reading, Berkshire RG4 7AA. Application notes are available on poly- meric columns for the determination of organic acids and carbohydrates; the col- umns are based on microporous sulpho- nated polystyrene divinylbenzene resins. The notes include “Organic Acids” (oxalic, maleic, citric, uric, butyric, etc., acids), “Aromatic Acids” (benzoic, gallic, protocatechuic, salicylic, etc., acids) and “Carbohydrates” (DP2, DP3, DP4, mal- totriose, glucose, fructose, arabitol, sor- bitol, etc.).Chrompack UK Ltd., Unit 4, Indescon Court, Millharbour, London El4 9TN. A brochure describes the Series 450 Cross Duct range of analysers, which are de- signed for direct in-situ monitoring of combustion processes and emissions with- out extraction sampling. Analysers now available include the CO analyser, used for combustion efficiency monitoring, and the SOz analyser for pollution emis- sions monitoring. Analysis Automation Ltd., Southfield House, Eynsham, Oxford OX8 1JD. A brochure describes the Mark 3 range of flow microcalorimeters, which are espe- cially suited to the evaluation of surfaces and their properties. They allow the measurement of heats of adsorption and desorption and they can be used with a wide variety of media including both liquids and gases.With appropriate acces- sories heats of mixing between fluids, heats of evacuation and heats of wetting may be measured. Microscal Ltd., 79 Southern Row, Lon- don W10 5AL. A leaflet describes the PHM85 precision pH meter. This instrument measures pH and pX to a resolution of 0.001, mV to 0.1 and temperature to 0.1 “C. Buffer values can be selected as desired and stored in the microprocessor’s memory. There is an RS232C output for connection to a com- puter or printer. Radiometer A/S, Emdrupvej 72, DK- 2400, Copenhagen NV, Denmark. A brochure gives information on a range of light meters. These include the Chroma Meter I1 reflectance meter for measuring reflected subject colour. Using silicon photo-cells filtered to match the CIE standard observer response, it makes precise readings, which are processed by a built-in microcomputer and displayed on a liquid crystal display.Reference colours and calibration standards can be put into the memory and recalled at any time. Minolta (UK) Ltd., 1-3 Tanners Drive, Blakelands North, Milton Keynes MK14 5BU. Details of the Coulter Counter S-Plus VI haematology analyser are given in a bro- chure. It describes a complete haemato- logical workstation with automatic sam- ple handling, advanced data handling and differential screening. Up to 32 specimens per tray can be loaded with a further 32 undergoing simultaneous premixing. Urgent one-off samples can be processed at any time without interrupting through- put. Coulter Electronics Ltd., Northwell Drive, Luton, Bedfordshire LU3 3RH. A brochure describes the K85 micro- processor development system, which consists of the K85 computer, a keyboard, umbilical cable and MTB-1 micro-target board. Also available are a video moni- tor, a printer, additional MTB-1 target boards and expansion facilities. The target board is designed to be used as the controller element within a user system. It has 22 input/output lines, a programm- able timer, 5 interrupts and up to 4.25k of ROM/RAM. It can be interfaced to the user’s environment via one of many avail- able interface modules. Kimberry, 29 Thorney Hedge Road, Chiswick, London W4 5SB. A catalogue gives detailed specifications of a full range of laboratory ware, from complete distillation apparatus to beak- ers, bottles, stoppers and coolers, all supplied in fluoro-plastics (PTFE, FEP and PFA). Safelab Systems Ltd., PO Box 275, Bristol BS99 7EX.

ISSN:0144-557X    

DOI:10.1039/AP9852200120

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 123 ~ ~ ~- ~ ~ _ _ _ _ Publications Received Vibrational Spectroscopy at High Exter- nal Pressures. The Diamond Anvil Cell. John R. Ferraro. Pp. xiv + 264. Academic Press. 1984. Price f41.50; $59. ISBN 0 12 254160 X. Laser Dyes. Properties of Organic Com- pounds for Dye Lasers. Mitsuo Maeda. Pp. x + 335. Academic Press. 1984. Price f33; $46.50. ISBN 0 12 464980 7. Nuclear Analytical Chemistry. Dag Brune, Bengt Forkman and Bertil Person. Pp. 557. Studentlitteratur (Lund, Sweden) and Chartwell-Bratt (Bromley, UK). 1984. Price f24.60. ISBN 91 44 19561 3 (Student-litteratur); 0 86238 047 2 (Chartwell-Bratt). Employing Staff. Norman Ellis. Pp. x + 121. British Medi- cal Association. 1984. Price f5; f 7 (Over- seas); $10.50 (USA). ISBN 0 7279 0107 9.Water Analysis. Volume 111. Organic Species. Edited by Roger A. Minear and Law- rence H. Keith. Pp. xiv + 456. Academic Press. 1984. Price S48.50; $69.00. Chapter titles are as follows: “Waste Strength and Water Pollution Para- meters,” by J. C. Young; “Chemical124 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Nonspecific Organics Analysis , ” by Wil- liam J. Copper and James C. Young; “Concentration, Partitioning, and Isola- tion Techniques,” by Jerry A. Leenheer; “Gas Chromatography,” by R. P. Schwarzenbach, W. Giger and K. Grob; “Organic Mass Spectrometry ,” by J. Ronald Hass and Daniel L. Norwood; “The Use of HPLC for Water Analysis,” by Karl J. Bombaugh; and “Infrared Spectrophotometry of Pollutants in Water Systems,” by Fred Katsumi Kawa- hara. Spectroscopy of Biological Molecules. Theory and Applica t i o n o C hemis t r y , Physics, Biology and Medicine. Edited by Camille Sandorfy and Theo- phile Theophanides. NATO AS1 Series. Pp. x + 646. D. Reidel. 1984. Price Z58.50; Dfl 230; $89. ISBN 90 277 1849 0. Thirty-two chapters are arranged in six sections: Theoretical Overview; Raman and IR Studies of the Structure and Dynamics of Nucleic Acids and Proteins; NMR Spectroscopy and its Applications; Mechanism of Vision Plant Pigments; Spectroscopy of Membranes; Recent Advances in Spectroscopic Techniques.

ISSN:0144-557X    

DOI:10.1039/AP9852200123

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

124 ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Electrochemistry in Your Laboratory May, 1985 EDT Research will be holding a series of free seminars in mid-May. The format will be a series of talks, followed by working demonstrations of the full range of EDT's electrochemistry instrumentation, includ- ing ion-selective electrodes, pHlion con- ductivity and oxygen meters, HPLC elec- trochemical detection, polarography and voltammetry, and a blood sodium/ potassium monitor. The venues are: May 13, Basingstoke; May 14, London; May 15, Cardiff; May 16, Stevenage; May 17, Rochester; May 20, Aberdeen; May 21, Falkirk; May 22, Altrincham; May 23, Selby Fork; May 24, Coventry. Pre-registration is essential. Contact EDT Research, 14 Trading Estate Road, London, NW10 7LU. Workshop in Liquid Scintillation Counting July 15-19, 1985, Loughborough The Radiochemical Methods Group of the Analytical Division of the Royal Society of Chemistry is to organise the above workshop at the University of Technology. It will include lectures, prac- tical work and discussion periods and will cost %325, inclusive of meals and accom- modation. The Workshop Organisers are Dr. P. ' Warwick and Dr. J. R. Thornback, Nuclear Chemistry Laboratories, Lough- ~ borough University of Technology, Loughborough, Leicestershire, LE11

ISSN:0144-557X    

DOI:10.1039/AP985220124b

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, APRIL 1985, VOL 22 Analytical Division Diary APRIL Friday, 26th, 3 p.m.: Poole Western Region, jointly with the Mid-Southern Counties Section of the RSC. Quality Control in the Chemical Laboratory-The National Testing Laboratory Accreditation Scheme. Speaker: E. Broderick. BDH Ltd., Broom Road, Poole. There are no registration formalities for this meeting. Contact: Mr. F. W. Sweeting, Wessex Water Authority, Bristol Avon Division, P.O. Box 95, The Ambury, Bath BA1 2YP. (Tel. 0225-313500, Ex. 278). MAY Wednesday, lst, 10.30 a.m.: Nottingham Midlands Region. Microprocessors and Microcomputers in an Analytical Laboratory. Trent Polytechnic, Clifton, Nottingham. Contact: Mr. H. E. Brookes, 35 Dunster Road, West Bridgford, Nottingham NG2 6JE.(Tel. 0602-231769). Tuesday, 14th: London Joint Pharmaceutical Analysis Group. FDA and DHSS Guidelines for the Registration of Medicines. Pharmaceutical Society of GB, 1 Lambeth High Street, London, S.E. 1. Contact: Room 413, Pharmaceutical Society of GB, 1 Lambeth High Street, London SE1 7JN. (Tel. 01-735- 9141). Wednesday, 15th: London Education and Training and Automatic Methods Groups. Training Requirements for the New Technologies in Analy- tical Chemistry. Laboratory of the Government Chemist, Cornwall House. Waterloo Road, London, S.E.l. Contact: Dr. L. A. Gifford, Department of Pharmacy, University of Manchester, Oxford Road, Manchester M13 9PL. (Tel. 061-273-7121, Ex. 5178). Wednesday, 15th: Bedford Midlands and East Anglia Regions.Luminescence. Unilever Research, Sharnbrook, Bedford. Contact: Mr. R. P. Munden, Analytical Department, Glaxo Group Research, Ware, Hertfordshire SG12 ODJ. (Tel. 0902-3993). Wednesday, 22nd, 10 a.m.: London Particle Size Analysis Group, jointly with the Combustion Physics Group of the Institute of Physics. 111 Particle Sizing by Light Scattering. “Light Scattering from Fly Ash,” By S. A. Boothroyd. “Dynamic Size Analysis by Light Scattering of an Agglomerating Crystalline Adsorbent in Aqueous Solution,” by U. Tuzun. “Mapping Spray Structure by Using Light Scattering Techniques,” by A. Yule. “Multiple Scattering Effects on Droplet Sizing by Laser Diffraction With Particular Reference to Diesel Engines,” by P.G. Felton and A. A. Hamidi. “Particle Size Analysis of Powders in Civil Engineering,’‘ by J . Cabrera and C. Hopkins. “Industrial Use of the Microtrac.” by R. Guy. “Particle Size Distribution Measurement by Automated Dual- wavelength Turbidirnetry,” by s. Haselar. “Particle Size Measurement by Auto-correlation Spectroscopy of Scattered Light,” by R. W. Lines. A demonstration of equipment will be held during the meeting. Lecture Theatre 1, Department of Chemical Engineering and Chemical Technology, Imperial College, South Kensington, London, S.W.7. Registration is necessary. Cost El5 to members of RSC and IOP, f25 to non-members and f l l to students. Contact: Dr. A. R. Jones, Department of Chemical Engin- eering and Chemical Technology, Imperial College, London SW7 2BY.(Tel. 01-589-5111). Thursday, 23rd, 1.45 p.m.: London Microchemical Methods Group. Standardisation and Certification of Reference Materials. The production of reference materials. whether interna- tionai or “in-house ,” is becoming increasingly important. The meeting will cover four aspects of the subject. “LGC, BCR and Standard Reference Materials,” by T. G. Alliston. “Testing, Certification and Distribution of Reference Samples Within the Wellcome Foundation,” by Miss J. E. Rutty. “Reference Materials for Pesticide Analysis,” by A. J . Head. “Standardisation and Certification, as Applied to the Metal Industry,” by J . E. Page-Gibson. Laboratory of the Government Chemist, Cornwall House, Waterloo Road, London, S.E.l.Registration is necessary. Cost f4 to RSC members and 26 to non-members; no charge to students and retired mem- bers. Contact: Mr. P. R. W. Baker, 55 Braemar Gardens, West Wickham, Kent BR4 OJN. (Tel. 01-777-1225). Wednesday, 29th: Loughborough Midlands Region and Chromatography and Electrophoresis Group. Research Topics in Chromatography. “A Procedure for Testing the Robustness of an HPLC Assay,” by K. Truman. “Study of the HPLC Separation of the Local Anaesthetics,” by T. G. Hurdley and R. M. Smith. “Relationships between Temperature Programmed and Isothermal Kovats Retention Indices in GLC,” by E. E. Akporhonor. “Hydrophobic Chromatography with Dynamically Coated Station- ary Phases,” by Y. Ghaemi. “The Use of Porous Graphitic Carbon in HPLC,” by B. Kaur. Registration is necessary, but there is no charge. University of Technology, Loughborough. Contact: Dr . D. Simpson, Analysis For Industry, Factories 2/3, Bosworth House, High Street, Thorpe-le-Soken, Essex C016 OEA. (Tel. 0255-861714).

ISSN:0144-557X    

DOI:10.1039/AP985220iiia

出版商:RSC    

年代:1985

数据来源: RSC