摘要:

Proceedingsof the Analytical Division ofThe Chemical Society1231241251261271271361391431441 44145147148CONTENTSAnnual General Meeting of theAnalytical DivisionReports of MeetingsAnalytical Division DistinguishedRank Hilger Spectroscopy PrizeSummaries of PapersBristol Area'Service Award1978'Use of Microchemistry in the'Windows on Chromatography'Equipment NewsNew British StandardsWater Research Centre TechnicalPublications ReceivedConferences and MeetingsCourseAnalytical Division DiaryReportVolume 16 No 4 Pages 123-148 April 197PADSDZ 16(3) 89-122(1979)ISSN 0306-1396PROCEEDINGSMarch 1979OF THEANALYTICAL DIVISION OF THE CHEMICAL SOCIETYOfficers of the Analytical Divisionof The Chemical SocietyPresidentR.BelcherHon. SecretaryP. G. W. CobbHon. Treasurer Hon. Assistant SecretariesJ. K. Foreman D. I. Coomber, O.B.E.; D. C. M. Squirrel1S e cretar yMiss P. E. HutchinsonHOR. Publicity and Public Relations OfficerDr. A. Townshend, Department of Chemistry,University of Birmingham, Birmingham, B15 2TTEditor, ProceedingsP. C. WestonProceedings is published by The Chemical Society.Editorial: The Director of Publications, The Chemical Society, Burlington House, London, W1 V OBN.Telephone 01 -734 9864. Telex 268001.Subscriptions (non-members): The Chemical Society, Distribution Centre, Blackhorse Road,Letchwonh, Herts., SG6 1 HN.Non-members can only be supplied with Proceedings as part of a combined subscription with The Analystand Andytical Abstracts.@ The Chemical Society 1979CHEMICAL SOClETY/ROYAL INSTITUTE OF CHEMISTRYANNUAL CONGRESSatThe University of Bristol, April 3rd-5th, 1979The Analytical Division will arrange two symposia.At the first, "lmmuno andCoupled Enzyme Assays," the speakers will be Professor Vincent Marks,Dr. Alister Voller, Dr. David Goldie, Dr. John Whicher, Mr. 6. Joyce, Dr. J. N.Miller, Dr. D. I. Chapman and Dr. A. C. Moffat.The second Symposium will be on the subject "The Influence of SpaceExploration on Analytical Instrumentation" and those speaking will be Dr. JamesMartin, Dr. Benton C. Clark, Professor Klaus Biemann, Dr. C. T. Pillinger andMr. R. J. Granger.In addition, the eighth Theophilus Redwood Lecture, entitled "Analysis in Non-segmented Flowing Systems," will be given by Professor E. Pungor.For further information contact Dr. J. F. Gibson, The Chemical Society,Burlington House, Piccadilly, London, W1 V OBN

ISSN:0306-1396    

DOI:10.1039/AD97916FX014

出版商:RSC    

年代:1979

数据来源: RSC

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Analytical Division DiaryAPRIL and work, including a tour of theLaboratory.Home Office Forensic Science Laboratory, Tuesday, 24th, 11 a.m. : BirminghamSandbeck Way, Audby Lane, Wetherby,West Yorkshire.Midlands Region on “Flow Injection Tech-Speakers to include: J. RiiEiCka and D. Numbers are limited to 40.niques. ”Betteridge.Tuesday, 24th, 4 p.m.: BelfastNorthevn Ireland Sub-Comnittee.“Luminescence Spectroscopy in the Analysisof Drugs,” by J. N. Miller.Chemistry Department, The Queen’s Univer-sity, Belfast.Wecinesday, 25th, 10.30 a.m.: SouthendEast A nglia Region and Chronzatography andElectrophovesis Group, jointly with theEssex Section of CS on “Chromatographyin Pharmaceutical and Forensic Analysis. ”“Enantiomers, Diastereoisomers and Chroma-tography,” by D.W. Selby and B. Stephen-son.“Quantitative Analysis of Drugs in BiologicalFluids by HPLC,” by J. Chamberlain.“Chromatographic Systems in Screening Pro-cedures for Doping,” by M. s. Moss.“Chromatography and Pharmaceutical Prob-lems in a Public Analyst’s Laboratory,”by G. J. Dickes.College of Technology, Caernarvon Road,Southend.Thursday, 26th, 2.30 p.m.: LondonMicrochemical Methods Group.Discussion on “Recent Developments inElectrobalances,” introduced by M. R.Cottrell.School of Navigation, City of London Poly-technic, 100 Minories, London, E.C.3.Please note change of date, time and venue.“Analysis and the Brewing Industry,” byP. A. Martin.“The Examination of Wines and Spirits forExcise Purposes,” by G.C. Hands.Reception Centre, Allied Breweries (Produc-tion) Ltd., The Brewery, Station Street,Burton-on-Trent .(Meeting postponed from January 25th).Thursday, 10th: LondonJoint Phavmaceutical Analysis Group, for thepresentation of short original papersconcerned with pharmaceutical analysis.Pharmaceutical Society of Great Britain,1 Lambeth High Street, London, SE1 7JN.Monday, 14th, 10.30 a.m.: LondonRadiochemical Methods Group on “ScienceSpeakers to include M. J. Aitken and invitcdBritish Museum Lecture Theatre, London,in Art and Archaeology.”lectures from Research Students.W.C. 1.Thursday, 17th, 10.30 a.m. : StevenagePavticle Size Analysis Group on “The Rele-vance of Particle Size and Shape onMaterials Handling.”“Measurement of the Dustability of Powders,”by C.Schofield.“The Effect of Particle Properties on thePneumatic Conveying of Powders, ” by13. J. Flain.“Applications of Charged Particles in ElectricFields,” by S. Singh. Friday, 27th,4 p.m. : Poole “The Effect of Particle Size and Shape on the Western Region.“Application of D.C. Argon Plasma Emission Of a Powder,” J.Williams.Followed by a tour of the Materials HandlingDivision, Warren Spring Laboratory.Warren Spring Laboratory, Stevenage.in the Water Industry,” by C. J. Triner.Please note change of subject and speaker.BDH Staff Club, Poole, Dorset.Thursday, 31st, 6.30 p.m. : NottinghamMAY Midlands Region.Wednesday, 9th, 2 p.m.: Wetherby “Luminescence Analysis of Drugs,” byNorth East Region on “Forensic Science.” J. N. Miller.Introductory remarks and talks by Staff Lecture Theatre, The Boots Co. Ltd.,Pennyfoot Street, Nottingham.Printed by Heffers Printers Ltd Cambridge Englandof the Laboratory, illustrating its function

ISSN:0306-1396    

DOI:10.1039/AD97916BX016

出版商:RSC    

年代:1979

数据来源: RSC

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Vol. 16 No. 4 April 1979 Proceedings of the Analytical Division of the Chemical Society Annual General Meeting of the Analytical Division The seventh Annual General Meeting of the Analytical Division of the Chemical Society was held at 2 p.m. on Friday, March 16th, 1979, a t the Old Ship Hotel, Hrighton. The Chair was occupied by the President, Professor R. Belcher, PhD, DSc, CChem, FRIC, SFInstF, FInstFT.The Report of the Council for the pear ending March, 1979, was presented by the Honorary Secretary and adopted. The Scrutators, Dr. A. H. Andrews and Dr. E. Reid, reported that no ballot had been required for the Officers of the Division and the following had therefore been elected for the coming year- Pvesident-R. Helcher, PhD, DSc, CChem, FRIC, SFInstF, FInstFT.Past Presidents serving on the Council- G. W. C. Milner, T. s. West, C. Whalley and D. W. Wilson. Vice-Pvesidents-L. S . Bark, D. Betteridge and S. Greenfield. Honorary Treasurev- J. K. Foreman. Honoravy Secretary-P. G. W. Cobb. Honorary Assistant Secretaries-D. I, Cooniber (Programmes Secretary) and D. C. M. Squirrell. Other Afembers of Council-The Scrutators further reported that 569 valid ballot papers had been received and that votes had been cast in the election of Ordinary Members of Council as follows: E.Bishop, 369; H. Egan, 375; G. F. Kirkbright, 360; J. N. Miller, 343; J . W. Ogleby, 366; T. B. Pierce, 344; D. Simpson, 391; A. M. Ure, 353. The President declared the following to have been elected Ordinary Members of Council for the ensuing 2 years: E.Bishop, H. Egan, G. F. Kirkbright, J . IT. Ogleby, 11. Simpson and A. At. Ure. H. E. Brookes, D. T. Burns, G. J. Dicltes, J . M. Skinner, A. A. Smales and A. Townshend, having been elected members of the Council in 1978, will, by the Rules of the Division, remain members of the Council for 1979. H. J . Cluley (Chairman of Analytical Abstracts Editorial Committee), J. M.Ottaway (Chairman of The Analyst Publications Committee), 1%'. H. C. Shaw (Chairman of SAC 80 Steering Cow- mittee), J . D. R. Thomas (Chairman of Progvam- mes Committee), D. R. Williams (Chairman of the Analytical Methods committee), G. C. Cochrane (Chairman of the Scottish Region), A. G. Croft (Chairman of the East Anglia Region), G. B. Crump (Chairman of the North West Region), M.C. Finniear (Chairman of the Western Region), R. Goulden (Chairman of the South East Region), D. F. Griffiths (Chairman of the North East Region) and D. h4. Peake (Chaivman of the iwidlands Region) will be ex oficio members of the Council for 1979. , Presentation of the fourth?@ Analytical Division Distinguished Service Award, by the _President to LWr. K . L. Smith. 123 MY. S. Greenfield (L) receiving the fourteenth SAC Gold Medal f r o m the President.124 REPORTS OF MEETINGS Proc. Analyt. Div. Chem SOC. At the Informal Dinner held a t the Old Ship Hotel, Hrighton, in the evening, the President presented the fourteenth Society for Analytical Chemistry Gold Medal to Mr. S. Greenfield and the fourth CS L4nalytical Division Distinguished Service Award to Mr. I(. L. Smith. Biographies of the two recipients were published in the January issue of Proceedimgs, p. 1, and this issue of Proceedings, p. 125, respectively.

ISSN:0306-1396    

DOI:10.1039/AD9791600123

出版商:RSC    

年代:1979

数据来源: RSC

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124 REPORTS OF MEETINGS Proc. Analyt. Div. Chem. Soc. Reports of Meetings North West Region The fifty-fourth Annual General Meeting of the Region was held a t 6.30 p.m. on Friday, January 19th, 1979, in the Training Centre, Laporte Industries Ltd., Warrington. The Chair was taken by the Chairman of the Region, Mr. J . W. Ogleby. The following office bearers were elected for the forthcoming year : Chair- man-Mr.G. B. Crump. Vice-chairman- Mr. G. F. Hooke. Honorary Secretary-Mr. G. Davison, Kodak Ltd., Research Ilepartment, Acornfield Road, Kirkby, Merseyside, L33 7UF. Honorary Treasurer-Mr. T. Hodson. Members of Cowzmittee-Mr. E. C. Conchie, Mr. J. Cottam, Dr. A. Dyer, Mr. J. B. Faulder, Mr. W. I?. Heyes, Dr. A. Mathias, Mr. P. Morries, Mr. J. W. Ogleby (ex oflcio) and Mr.P. Platt. Mr. G. W. Earnshaw and Mr. M. Green were appointed as Honorary Auditors. Scottish Region The forty-fourth Annual General Meeting of the Region was held a t 5 p.m. on Friday, November 3rd, 1978, a t Heriot-Watt University, Chambers Street, Edinburgh. The Chair was taken by the Chairman of the Region, Dr. A. M. Ure. The following office bearers were elected for the forthcoming year : Chairman-Dr.G. C. Cochrane. Vice-Chairman-Dr. J . E. Whitley. Honorary Secvetavy-Mr. A. F. Fell, Department of Pharmacy, Heriot-Watt University, 79 Grassmarket, Edinburgh, EH 1 2H J . Honovary Treasurer-Dr. Mary Masson. Honorary Assis- tant Secretary-Dr. D. E. Wells. Members of Committee-Dr. G. A. Best, Dr. J . M. Ottaway, Dr. M. J. Stewart, Dr. A. M. Ure, Dr.J. W. Wells and Dr. P. R. Wood. Dr. R. A. Chalmers and Dr. B. W. East were appointed as Honorary Auditors. Western Region The twenty-fourth Annual General Meeting of the Region was held a t 5.30 p.m. on Friday, December lst, 1978, a t UWIST, Cardiff. The Chair was taken by the Chairman of the I<egion, Mr. M. C. Finniear. The following office bearers were elected for the forthcoming year: Chairman--Mr. M.C. Finniear. Vice-Chair- man-Dr. G. Nickless. Honorary Secvetavy--- Mr. J. Garetli Jones, Wessex Water *4uthority, The Ambury, P.O. Box 95, Bath, BA1 2YP. Honorary Treasurer-Dr. 11. Betteridge. iV!em- bevs of Committee-Mr. D. B. Adams, Dr. E. G. Bradfield, Mr. D. Casey, Mr. G. J . Llickes ( e x oficio), h'fr. E. W. Sweeting, Dr. J . D. I<. Thomas and Dr.'Llr. J. Williams. Mr. E. ,2. Hontoir and Mr. E. Minshall were re-appointed as Honorary Auditors. South East Region The fourth Annual General Meeting of the Rcgion was held a t 6 p.m. on Tuesday, January ISth, 1979, in the Linnean Society rooms, Bur- lington House, London, W.l. The Chair was taken by the Chairman of the Region, Mr. R. Goulden. The following office bearers were elected for the forthcoming year: Chairnzan- Mr.R. Goulden. Vice-Chaivman-Mr. R. Sawyer. Honorary Secretary-Dr.-4. H. Andrews, Beecham Pharmaceuticals, Clarendon Road, Worthing, Sussex, BN14 8QH. Honorary Treasurer-Mr. I>. Mi. Houghton. Membevs of Conamittee-Dr. H. J. M. Bowen, Dr. S. J . Lyle, Dr. E. I. Reid and Mr. A. I>. Urquhart. Dr. J . E. Page and Mr. D. C. M. Squirrel1 were re-appointed as Honorary Auditors. Electroanalytical Group The ninth Annual General Meeting of the Group was held a t 2 p.m.on Friday, December 8th, 1978, in the Holiday Inn, Birmingham. The Chair was taken by the Chairman of the Group, Dr. W. F. Smyth. The following office bearers were elected for the forthcoming year : Chaivman -Dr. B. J . Birch. Vice-Chairman-Dr.J . D. R. Thomas. Honoravy Secretary-Dr. H. Thomp- son, Electronic Instruments Ltd., Hanworth Lane, Chertsey, Surrey. Honorary Treasurer- Dr. A. G. Fogg. Honorary Assistant Secretary- Mr. I. Davidson. Members of Committee- Mr. A. E. Bottom, Dr. J. P. Hart, Dr. 1'. 0.April, 1979 AD DISTINGUISHED SERVICE AWARD 125 Kane, Dr. T. H. Ryan, Dr. W. F. Smyth (ex oficio) and Dr. M. Smyth.Dr. J. A. W. Dalziel and Mr. J. H. Glover were re-appointed as Honorary Auditors. Joint Pharmaceutical Analysis Group The ninth Annual General Meeting of the Group was held a t noon on Thursday, January lSth, 1979, at the Pharmaceutical Society of Great Britain, 1 Lambeth High Street, London, SE1 7JN. The Chair was taken by Mr. E. Addison, Chairman of the Group, who reported a number of apologies for absence including an apology from Professor Belcher, President of the Chemical Society, Analytical IXvision.The Chairman thanked those members who had managed t o attend the AGM on the day of a national rail strike despite the difficulties in travelling. The Chairman reported briefly on Group finances and thanked the sponsoring bodies for their support ; he also expressed gratitude for the enthusiastic support of the Committee of Management.The Annual Report for 1978 was presented by the Honorary Secretary, Miss I. Ladden. The Chairman reported that three ordinary members were retiring from the Committee of Management, Mr. J. F. Chissell, Mr. D. R. Crudgington and Mr. J . C. Deavin. He thanked the retiring members for their services to the Group and, in particular, Mr.Deavin who had been Honorary Secretary to the Group for seven years and an ordinary member of the Com- mittee for the past two years. Three nomina- tions had been received to fill the three vacancies arising; no election had therefore been necessary and Dr. A. H. Andrews, Dr. L. E. Coles and Mr. F. W. Webb were appointed to the Com- mittee.He then reported that the composition of the Committee of Management for 1979 would be : Chairman-Mr. E. Addison. Honor- ary Secretary-Miss I. Ladden. Immediate Past Chairman-Mr. S. C. Jolly. Ordinary Members-Dr. ,4. H. Andrews, Dr. L. E. Coles, Miss M. C. Cone, Mr. G. F. Phillips, Dr. L. R. Rowe and Mr. F. W. Webb. Members nomin- ated by sponsoring bodies-Dr. D. C. Garratt (Pharmaceutical Society of Great Britain), Mr. W. H. C. Shaw (Chemical Society, Analyt- ical Division) and Mr. H. E. Brookes (Royal Institute of Chemistry). The Annual General Meeting was followed by lunch. In the afternoon a Discussion Meeting was held on “Analytical Problems Associated with Specialised Dosage Forms” a t which the speakers were Dr. G. Hallworth (Glaxo- Allenburys Research Laboratories) and Mr. M. Ogden (Warner-Lambert UK Limited) ; the third speaker, Dr. K. Gilding (Liverpool University) was unfortunately unable to be present due to the national rail strike.

ISSN:0306-1396    

DOI:10.1039/AD9791600124

出版商:RSC    

年代:1979

数据来源: RSC

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April, 1979 AD DISTINGUISHED SERVICE AWARD 125 Analytical Division Distinguished Service Award As announced in the February issue of Proceedings (p. 85) and reported earlier in this issue (p. 123), the fourth Analytical Division Distinguished Service Award has been conferred on Mr. K. L. Smith. Kenneth L. Smith was educated a t the Grammar School, March, and then served an apprenticeship at the Pharmacy of Mr.P. H. Davies. When the business was acquired by Boots the Chemists, Mr. Smith moved to Nottingham, gained a Boots’ Scholarship Award and attended the University College Nottingham to study for the Chemist and Druggist Qualifying Diploma. On qualifying, he joined the Pharmacological Department of Boots Pure Drug Co. Ltd. under Mr. W. A. Broom and continued in the Pharmacy and Physiology Division of the Research Depart- ment on the arrival of Sir Jack Drummond.When Dr. D. C. Garratt was appointed Chief Analyst in 1950, Mr. Smith joined the Standards Department as Head of the Bio-Assay Division and held that position until 1970 when he accepted an early retirement and returned to retail pharmacy. He considers himself fortunate to have had the encouragement of Mr.E. C. Fieller to apply statistical methods to routine biological assays and produced assay designs for insulin and pyrogene that were accepted as standard pharmacopoeia1 methods. He served on the Biological Assays Committee of the British Pharmacopoeia Commission, contributed the chapter on The Assay of Insulin to “Methods in Hormone Research,” published by Academic Press, and assisted Dr.D. C. Garratt in the preparation of his text-book on the Quantitative Analysis of Drugs. He presented papers at meetings of the Biological Methods Group, a t the126 Pharmaceutical Conference and a t the Bio- metrics Conference. In 1966 lie was designated a Fellow of the Pharmaceutical Society. Mr. Smith joined the Society of Public Analysts and other Analytical Chemists in 1949, was elected to the Biological Methods Group Committee in 1961 and served continuously until 1969 (two years as Committee Member, two years as Vice-chairman, one year as Chair- man and 13 years as Secretary and Treasurer). He acted as Treasurer a t tlie first two SA4C Conferences held in Nottingham in 1965 and 1968, and with Mrs.Smith hosted at these conferences as well as a t tlie Centenary Confer- ence in London in 1974 and the 4th SAC Conference in Birmingham in 1977.Mr. Smith recalls that whilst a t the University College the Head referred to him as the “ubiqui- tous Mr. Smith” and he feels this may still apply, for in addition to being Treasurer of the local branch of the Pharmaceutical Society he is Treasurer of the Newark Music Club and tlie Sewark Community Music Association but claims his interest is more monetary than musical. He is Secretary of the local branch of the Royal Scottish Country Dance Society, serves on the local committees of tlie Holiday Fellowship, takes frequent holidays with that organisation, occasionally acting as host, and RANK HILGER SPECTROSCOPY PRIZE 1978 Proc. Analyt. Dzv. Chem. SOC. accepts emergency calls for a locum from liis friends in general pharmacy practice.

ISSN:0306-1396    

DOI:10.1039/AD9791600125

出版商:RSC    

年代:1979

数据来源: RSC

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126 RANK HILGER SPECTROSCOPY PRIZE 1978 Proc. Analyt. Div. Chem. SOC. Rank Hilger Spectroscopy Prize 1978 The Rank Hilger prize for 1978 has becn awarded to Dr. David Littlejohn for his work on carbon furnace atomic-emission spectrometry. The prize, which has a value of k75, was pre- sented to Dr. Littlejohn by Mr. C. P. Cole, the retiring Chairman of the Atomic Spectroscopy Group, a t the Group’s AGM on December 7th, 1978.Dr. Littlejohn, who is now employed by ICI Pctrochernicals at Wilton as an Analytical Research Chemist, graduated at the University of Stratbclyde in 1976 and subsequently obtained a scholarship from the Salters’ Institute to work with Dr. John Ottaway at the same University. He has published a number ol papers on his work on carbon furnace atomisa- PhD for his research in this field. Dv. D. Littlejohn (R) veceiving the R a n k Hilgcv Gvoztp, MY. C. P. Cole. tion and excitation and in 1978 was awarded a pyize fYom the Chaivl.nalz of tlL2e Spectvoscopy

ISSN:0306-1396    

DOI:10.1039/AD9791600126

出版商:RSC    

年代:1979

数据来源: RSC

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April, 1979 CSE OF MICROCHEMISTRY IK THE BRISTOL AREA 127 Use of Microchemistry in the Bristol The following are summaries of five of the papers presented at a meeting of the Western Region and the Microchemical Methods Group held on September 21st and ZZnd, 1978, at Bristol University. M icrochemistry-Past, Present and Future L. S. Bark Uiaivevsity of Salfard, Snlfovd, Lancnshive, AT5 4Tt7T Microchemistry cannot be restricted to either the organic or inorganic branches of analysis although there is no doubt that over various periods of time there has been emphasis on one or other of the branches.This is simply because microchemistry has generally been used to solve a once current problem, which was insoluble by other means, and not used, as are many other techniques, as the basis for which problems are found or invented.Terms such as micro and semi-micro have always required re-definition as chemistry has progressed and as techniques of investigation and determination have altered. Apparatus design and manufacture has also caused the meaning to change; for example, in the field of organic quantitative microchemistry for the elements carbon and hydrogen, up to the 1950s the sample size was 5-10 mg, even though balance design had radically altered over the pre- vious two or three decades and baiances weighing to *2 pg, by direct reading of a graticule, were available.Modern instruments use much smaller samples (now masses of 20pg are accept able) and the process is still called niicrochemistry. For inorganic materials a similar situation has existed; for example, in the 1950s Belcher and Wilson gave a convenient, if somewhat arbitrary, classification based on size of sample, such that samples of 2.0-0.1 mg (0.5 ml-20 p1) were classed as micro-samples and 10-0.1 pg (20-0.2 p1) as ultra-micro samples.About this time it proved to be especially easy to employ amounts in the border regions between centigram and milligram for the teaching of small scale methods of analysis, which could be used with advantage when the worker transferred from the semi-micro scale to the micro-scale using classical techniques.However, classical techniques are generally no longer used as the basis of training and the developments in the detection and determination of small amounts of material have done much to change the type of chemistry that can best be classified as micro.Just as elemental macrochemistry played an important part in the development of organic chemistry, so micro-elemental analysis played an important role in the development of physiology, biology and biochemistry. In these fields it was common to isolate only very small amounts of a substance and so the development of quantitative methods depended upon the availability of a sufficiently sensitive balance.However, chemistry is not merely con- cerned with quantitative elemental analysis ; other areas, including functional group analysis, molecular-species analysis, radical analysis and the determination of some physical or chemi- cal parameter have helped in the elucidation of problems.All of these areas have macro- analysis equivalents, but there are areas of microchemistry that have no macro-equivalent . These are catalytic analysis, spot-test analysis, surface analysis and, of course, analysis involving microscopes of all types. The optical microscope, discovered in 1685 by Leuwenhoek, proved to be an important piece of apparatus both for the identification of crystalline samples and for the study of reactions on a small scale.The application of the microscope to identification analysis is probably due to Marggraf who established, in 1747, that beet sugar and cane sugar are the same; in 1756 he used the microscope for tests on platinum salts and throughout the period up to 1900 various workers used the microscope both for reactions on microscope slides and for crystal identification. During the period 1930-1940 much work was done in the field of ultra-micro analysis involving micro-manipulation and it is of interest to note that inorganic ultra-micro analysis has been used to solve several important problems, including the establishment of the chem-128 Proc.Analyt. DiV. Ckzel.12. SOC.istry of the trans-uranic elements. Inclusions in meteorites, corrosion products, etc., have been analysed using related techniques. The field of spot-test analysis, systematically studied and reported by Feigl, and the ring- oven technique, developed by Weisz, are examples of ultra-micro analysis. The analytical application of catalytic processes was first reported in 1876 when it was used to identify vanadium by means of its catalytic effect on the formation of aniline black.Since then much work has been published and continues to be published in this area. How- ever, the main impact on micro-chemistry has been that of instrumentation, and one must remember that in many instances of gas - liquid chromatography, high-performance liquid chromatography, neutron-activation analysis and electron microscopy of various kinds, the sample size of the analyte qualifies the technique to be considered as one used in ultra-micro- chemistry.For all the techniques the same fundamental problems apply, i.e., those of obtaining a representative sample and an accurate and precise measurement of the analyte, in the amount and chemical form required to answer the problem posed before analysis.Regarding future trends, it will be necessary to go towards samples of molecular order, both in biology and in fields such as the semiconductor industry. It may be necessary to obtain a result in minutes or seconds, or even microseconds, in order that we might solve the problems that still arise from the demands for a greater knowledge of the eco- and biospheres in which we live.USE OF MICROCHEMISTRY IN THE BRISTOL AREA Microchemistry and Meat R. L. S. Patterson and C. A. Voyle Agricultural Research Council, Meat Research Institute, Laqagford, Bristol, RS18 7 0 1’ Histochemistry The methods used at the Meat Research Institute today embody either simple physical principles or highly complex chemical reactions.For example, the location of fat in muscle tissue can be shown by staining with dyes which have a greater solubility in the fat than in the solvent in which they are presented to the tissue. In contrast to that simple technique, the demonstration of a microscopically detectable end-product of a chemical reaction may identify the site of enzyme activity or the presence of a hormone or mineral substance.Quan- titative analysis of the final reaction product can be carried out by measuring the absorption at a wavelength corresponding to a suitable absorption maximum. A technique that is becoming increasingly important for the location of macromolecules of proteins is the fluorescent antibody technique. Specific antibodies are prepared and labelled with fluorescein, and these are reacted with thin tissue sections in which the protein of interest acts as an antigen.The site of the antigen - antibody reaction is indicated by the location of the fluorescence which is emitted when the section is examined microscopically under ultraviolet illumination. In bovine muscle, three genetically distinct types of collagen are known to exist and it is possible to differentiate these by immunofluorescence using specific antibodies.The incorporation of different substances into the chemical structure of cells and tissues by the metabolic process can be studied by the use of radioactive isotopes. Amino acids labelleck with I4C may be found incorporated into liver cells and white blood cells; 32P is incorporated into newly formed nucleic acids, as is 3H-labelled thymidine.The sites where such labels are incorporated can be identified by the preparation of autoradiographs from thin sections of labelled tissue. This method can be used effectively in studies of the sites of hormone activity, such as the adrenal medulla, or in following the uptake of metal ions e.g., calcium in teeth and bone. A highly sophisticated and extremely valuable technique in cytochemistry is analytical electron microscopy.The measurement of the wavelength, or alternatively, the energy of the X-rays emitted from an area of tissue irradiated with electrons, produces a spectrum that is characteristic of the elements present in the tissue. Elements from sodium to uraniumApril, 1979 USE OF MICROCHEMISTRY I N THE BRISTOL AREA 129 can be detected and, with the aid of a mini-computer, which usually forms an integral part of the instrument, the concentration of each element present in the cell or tissue can be ascertained. The method is particularly useful for identifying foreign substances, e g ., cadmium, lead or mercury, which accumulate as a result of pollution. Flavour Analysis The aroma and flavour of a food depend upon the presence of volatile compounds (or their precursors) in the bulk matrix.The main volatile compound, water, may constitute up to 90% of the product, while most organic volatiles are present only in very small amounts, e.g., lo-' mg 1-l. Such low concentrations might be thought to be unimportant in aroma formation and not to arouse any sensory impression, but odour threshold values as low as Aroma research should be carried out by analysing the vapour phase because it contains the volatiles that are responsible for the odour in the same concentration and ratios that impinge upon the nasal epithelium.Normally, in order to obtain sufficient material for analysis, large volumes of vapour have to be sampled and either cryogenic, adsorptiveor absorptive trapping methods are used to concentrate the volatiles.In flavour or off-flavour studies of solid or liquid foods the choice of the method is often determined by the physical state and composition of the product, for example, whether it is the fat or lean of meat or whether it has been cooked or uncooked, and also the purpose of the analysis.Vacuum distillation procedures have been applied successfully to the fat of meat and early work on the identification of 5~-androst-16-en-3-one, a steroidal compound found sometimes in the fat of meat from the male pig, was based upon this technique. The isolation of aroma volatiles from cooked lean meat has been achieved in the past by classical steam-distillation procedures followed by suitable batchwise solvent extraction.Recently, steam distillation has been combined with simultaneous extraction by an organic solvent in an elegant apparatus designed by Likens and Nickerson. Two flasks containing, respectively, an aqueous slurry of the product and an immiscible organic solvent, attached to the central condenser unit, are heated separately; the steam and solvent vapour rise and condense simultaneously on the cooled central section, thereby mixing intimately and effecting extraction of the volatiles.They then separate into phases in the lower U-section of the apparatus and flow back through side-arms into their respective flasks. This provides a continuous, simultaneous distillation and extraction process, which requires only a small volume of solvent for the extraction of a large amount of food.This technique has been applied recently to the elucidation of a disinfectant-like off- flavour affecting pork meat. Simple taste and odour tests on rejected meat confirmed the presence of an off-flavour and odour in all samples of lean and fat, and tasters' reactions varied from slight dislike to immediate rejection of the sample; the conclusion was that the tainting was a more extreme form of that experienced on previous occasions when the com- pound 2-methyl-6-chlorophenol had been involved.Samples of both lean and fat, cooked and uncooked, were analysed by means of the proce- dures outlined above; normal pork lean and fat from two sources were also put through the extraction procedures to act as controls.All extracts of cooked and uncooked fat (3) and lean (2) were clearly positive, although the odour intensity from the lean was considerably weaker. All extracts were then analysed by use of gas chromatography - mass spectrometry, using a computerised data system : mass chromatograms were reconstructed over the major part of the gas-chromatographic run for the first eight major ions of the spectrum of 2-methyl- 6-chlorophenol.All eight ions were found in two fat extracts and six in the third (but none in the controls), and all reached a maximum simultaneously at the retention time of authentic 2-methy1-6-ch1oropheno1, thus providing conclusive proof of the presence of 2-methyl-6- chlorophenol in the tainted fats. Five major ions of 2-methyl-6-chlorophenol were also recorded in one extract of lean but none in the other; although this meant that the confirma- tion in the lean was less than absolute, this was not unexpected because organic compounds are usually more readily absorbed by fatty tissue than by the essentially aqueous muscle.The source of the 2-methyl-6-chlorophenol was a disinfectant, which had been used un- advisedly and rather liberally in the meat processing plant ; its presence in the disinfectant was readily confirmed by use of the same techniques.mg 1-1 for vanillin or trichloroanisoles have been recorded. The controls (lean and fat) were completely free of foreign odour.130 USE OF MICROCHEMISTRY IN THE BRISTOL AREA R o c . Analyt. Div. Ckzem. SOC. Determination of Residual Solvents in Flexible Packaging Materials W.J. Carpenter Cadbuvy Schweppes Ltd., P.O. B o x 1, Somerdale, Keynsham, Bvistol, BS18 2A U By using a 100-cm2 template three samples from representative areas of the wrapper are placed in three separate 140-ml, gas-tight bottles, each fitted with a PTFE washer and a metal cap with a septum holder and septum. Two standard solvent mixtures are used for compari- son and calculation purposes; 1 p1 of each standard is transferred to a separate gas-tight bottle .The bottles are incubated sequentially at 115 "C for 15 min in the order standard solvent mixture 1, the three wrapper samples and finally standard solvent mixture 2. A 500-pl volume of headspace gas from the incubated bottles is injected on to the column of a gas - liquid chromatograph.By comparison of the retention times of unknown peaks with those from standard solvent mixtures the unknown peaks are identified. The amounts of residual solvents in the wrapper are determined by measuring the peak heights of sample and standards. The result, the mean of the sample in triplicate, is reported as mg m-2. Gas - Liquid Chromatography A Perkin-Elmer F11 instrument, fitted with analyser unit No.3 (flame-ionisation detectors), is used, adjusted to the following conditions: oven temperature, 90 "C; injection block tem- perature, 135 "C; gas pressure of hydrogen, 15 lb in-2, of air, 20 lb in-2, and of nitrogen, 55 lb in-2 (column flow-rate 20 ml min-1). Columns The columns were 2 m x 3.2 mm stainless-steel columns packed with the following phases: phase A, 15Yh diisodecyl phthalate and 374 polytliene on Chroniosorb W (80-100 mesh); and phase B, 8% Carbowax 1540 on HMDS Chromosorb W (80-100 mesh).Recorder The recorder was a Hitachi Perkin-Elmer 159, operating at a chart speed of 240 cm kl. Standard solvent mixtures These were as follows: Mixture 1 2-E thoxyethanol Propyl acetate Isopropyl acetate Ethyl methyl ketone Isopropanol Ethanol Total volume Volu me/ml 0.86 0.95 0.92 0.99 1.02 1.00 5.74 ___ - Mixture 2 Toluene Butanol Propyl acetate Te trahydrof uran Ethyl acetate A4cetone Total volume Volume/ 1111 0.92 0.99 0.95 0.90 0.89 1.01 .5.66 __ From preliminary work done on incubation time, with temperaturesranging from 85 to 150 "C, it was clear that at the lower temperatures the higher boiling solvents were not readily vola- tilised.It was desirable to have an incubation temperature above the boiling-point of the solvents to be determined, if possible. The temperature must not be excessive or there is a risk of thermal degradation of some laminates. The condition finally chosen was 115 "C for 15 min. Injection of standard solvent mixtures into bottles incubated at 115 "C for 15 min showed that recovery of solvents in satisfactory ratios took place at solvent levels up to 10 pl.At higher levels of solvent mixtures the recovery was less satisfactory. The results also showed that the detector responses were in agreement with the ratios of solvents used. The efficiency of recovery was also compared with that obtained by directApvil, 1979 USE OF MICROCHEMISTRY IN THE BRISTOL AREA 131 injection of the solvent mixtures in the same amounts on to the column.An over-all recovery of 927& was obtained on solvents volatilised in a bottle following the method described, compared with direct injection of solvent mixture on to the column. When this recovery test was repeated using odourless tissue in order to simulate a wrapper the recovery of solvents ranged from 90 to 99%, with the exception of 2-ethoxyethanol, which was 55%.Because of the low recovery of 2-ethoxyethanol the use of an internal standard was not recommended. Use is also made of panels of trained people to assess the odour level of wrapping materials and the potential of these materials for causing tainting of chocolate was described.The headspace method does not determine the total residual solvent level of wrapping materials because there is the possibility of an equilibrium between solvent retained in the wrapper and that free in the headspace of the incubated bottle. The method described has not replaced odour panels for the reason that there is no close correlation between the results obtained, This is not surprising as the gas - liquid chromato- graphic method is only measuring those solvents and any other materials which are readily volatilised under the test conditions used.The odour panel judges wrappers as they would be used, that is, at room temperature. The nose has a different order of sensitivity and wrappers will be rejected by odour panels for odours which are not necessarily due to residual solvents. The two systems will continue to be used but the gas-chromatographic method has added a new dimension to testing in that the residual solvent levels in wrappers have been quantified.Microchemistry at Imperial Tobacco Ltd. D. Spincer Imperial Tobacco Ltd., Raleigh Road, Bristol, BS3 1 QX For many years Imperial Tobacco has used a wide range of microchemical techniques in the analysis of tobacco and cigarette smoke.This has been necessary to ensure consistency of products in spite of variations in materials and processes, and to gain information for product development, e.g., the effect of new filters, papers, etc. Unlike many other areas of trace analysis much of our work has been on the analysis of organic, rather than inorganic, compounds.The techniques used include all forms of chroma- tography, absorption spectrophotometry (ultraviolet, visible and infrared), nephelometry, fluorimetry, chemiluminescence, mass spectrometry, radiochemistry, ion-selective electrodes, etc. I shall, therefore, confine myself to some examples of the problems and our solutions in the analysis of smoke and also outline our work on metals in tobacco and smoke.It is impossible to cover'all of these topics in this paper. Smoke Analysis Problems Smoke is an aerosol, which contains a very large number of compounds that have a wide range of chemical and physical properties and concentrations. About 2 500 compounds have been identified in smoke and most of these make up approximately 1 yo by mass of smoke.The quantification of most compounds obviously requires microchemical methods ! Before an analysis can be performed three sampling problems must be overcome: smoke must be generated; the compounds of interest must be trapped; and reactive compounds must be stabilised. The first problem is overcome by using automatic smoking machines, which smoke cigarettes in a standard way.The machines have pistons that draw air through lit cigarettes, taking one puff, of 35 ml volume and 2 s duration, once every minute until the cigarette is burnt to a standard butt length. The method of sample collection and stabilisation of reactive compounds depends on both the physical and chemical properties of the compounds to be analysed.The physical proper- ties (boiling-point, etc.) dictate whether a compound can be collected in the particulate or vapour phase of smoke or whether all of the smoke (whole smoke) must be trapped. Vapour phase is that part of smoke that passes through a particulate filter. The chemical properties dictate whether vapour phase or whole smoke samples can be collected at low temperatures or132 Proc.Analyt. Div. Chenz. SOC. by absorption in specific liquids to stabilise the compound. Thus, in general, stable com- pounds that exist entirely in the particulate phase are collected on a glass-fibre filter, stable compounds that exist entirely in the vapour phase or whole smoke are collected a t -80 "C and unstable compounds are collected in liquid traps containing solutions that stabilise them rapidly. Unstable compounds can also be measured directly on each puff immediately after i t emerges from the cigarette.At present the only example of this is the determination of nitrogen oxide. Examples of compounds necessitating the use of these trapping systems are benzo(a)pyrene on a filter, acrolein and hydrogen sulphide in specific liquid traps and formaldehyde and acetonitrile in cold traps. After trapping and stabilising the compounds, where necessary, we can then consider the methods of detection.It is useful at this point to indicate that the samples have three sources of variability: from cigarettes, from smoking and from trapping. The final results will also contain the variability associated with the method of detection.USE OF MICROCHEMISTRY I N THE BRISTOL AREA Methods of Smoke Analysis Examples of methods covering a range of compounds and techniques are outlined below. The massive area of interferences will be mentioned only in passing. Colorimetric Analysis Formaldehyde1 Whole smoke is trapped at -80 "C, extracted with tetrachloromercurate and reacted with bisulphite and p-rosaniline.Any interference from nitrogen oxide is overcome by the addition of sulphamic acid prior to the colour reaction. Typical UK cigarettes deliver approximately 50 pg per cigarette. As full colour development takes nearly 2 h we have automated the method. The colour developed is read at 570 nm. Hydrogen sulphide2 smoke. re-trapping prior to carrying out the well known methylene blue reaction.660 nm. compounds. Typical UK cigarettes deliver about 40 pg per cigarette. automated in order to minimise distillation variations. This is a reactive compound which exists in both the particulate and vapour phases of Whole smoke is trapped in alkaline zinc acetate and subjected to acid distillation and Detection is at The distillation stage is to overcome interference from unidentified alkaline reducing The method is A crolein3 The vapour phase of smoke is trapped and stabilised in metabisulphite.The sample is reacted with hexylresorcinol, mercury(I1) chloride and trichloroacetic acid at 60 "C and the colour read at 610 nm. This method is automated as the reaction is so time dependent that manual results are unreliable. Typical UK cigarettes deliver about 60 pg per cigarette.It should be noted that gas chromtography cannot be used for this determination unless acrolein is first stabilised and converted into a derivative. Gas chromatography can cause some smoke components to decompose to acrolein. This is a very reactive component of smoke vapour phase. ChemiEuminescence3 This last com- pound is very reactive and exists in the vapour phase; however, it is extremely difficult to trap and stabilise.The vapour phase portion of smoke is, therefore, detected by chemi- luminescence immediately after each puff leaves the cigarette. UK cigarettes deliver, typical- ly, about 50 pg per cigarette. FEuorimetry3 jected to column and thin-layer chromatography. metry. graphic stages are required to remove other polycyclic aromatic hydrocarbons.radiotracer is used to determine the recovery of benzo(a)pyrene. This technique is used for the determination of nitrogen oxide in smoke. Benzo(a)pyrene in smoke is trapped on a glass-fibre filter, extracted with hexane and sub- The extract is then detected by fluori- The chromato- Carbon-14 Typical UK cigarettes deliver between 10 and 25 ng per cigarette.April, 1979 USE OF MICROCHEMISTRY I N THE BRISTOL AREA 133 Gas chr om at ography3 The acetonitrile in whole smoke is trapped at -80 "C and extracted in methanol containing pyridine as an internal standard.The sample is subjected to gas chromatography and the acetonitrile detected with a nitrogen-selective detector. The use of chromatography and a selective detector minimises the possibility of interference from other smoke compounds.The typical delivery from a UK cigarette is of the order of 150 pg per cigarette. Ion-selective electrodes Although there are several published methods for the analysis of compounds in smoke using this technique, we have been unable to produce satisfactory methods using ion-selective electrodes.It seems likely that this is because our understanding of the complexities of smoke chemistry is insufficient for us to apply these techniques. Metal Determinations Recently we have used electrothermal atomisation and hydricie generation atomic-absorp- tion spectrophotometry for the determination of a number of metals in tobacco and smoke. Determination of Cadmium, Cobalt, Lead and Nickel3 Tobacco samples (1 g) are digested with gentle heating in nitric acid and the solutions diluted before analytical detection by atomic absorption with a carbon rod atomisation system.Non-specific background absorption is detected by means of a deuterium lamp. The maximum levels found in tobacco samples were 3 pg 8-1 for cadmium, 3 pg g-l for cobalt and 2.5 pg g-l for lead and nickel.The metal content of whole smoke (10 cigarettes) was trapped at -80 "C and extracted with nitric acid. The extract was digested and analysed in the same way as for the tobacco samples. Typical UK cigarettes delivered less than 200 ng of cadmium per cigarette and less than 100 ng of lead per cigarette. Approximately 10% of lead and cadmium contained in the burnt portion of a cigarette is found in the smoke.No cobalt or nickel could be detected in smoke samples. Determination of Antimony, Arsenic, Bismuth, Selenium and Tellurium4 These metals are detected by atomic-absorption spectrophotometry following hydride generation. Tobacco samples (5 g) are digested in nitric acid with gentle heating and the solutions diluted with EDTA. Aliquots (1 ml) of sample are injected into the hydride genera- tion apparatus, which contains l ml of 4% sodium borohydride.The evolved hydride is decomposed to the metal in a heated silica tube and the metal detected. Under the test condi- tions EDTA overcomes interference from other metals and there is no evidence of selenium or tellurium existing in the hexavalent state, which is not detectable. In the tobacco samples examined the maximum levels observed were 500 ng g-l for arsenic, 50 ng g-l for antimony, bismuth and tellurium and 90 ng g-l for selenium. The metal content of whole smoke (40 cigarettes) is trapped at -80 "C and extracted with nitric acid.The extract is digested and analysed in the same way as the tobacco samples. The maximum levels of metals delivered from typical UK cigarettes were found to be 50 ng per cigarette for arsenic, 20 ng per cigarette for selenium, 10 ng per cigarette for antimony and bis- muth and 6 ng per cigarette for tellurium.Approximately 10% of the metal content of the burnt portion of a cigarette is found in smoke. Conclusion I t is hoped that this paper has given some idea of the problems of microchemistry at Imper- ial Tobacco Ltd., and the low levels of some compounds present in smoke.The author thanks the Directors of Imperial Tobacco Limited for permission to publish this paper,134 USE OF MICROCHEMISTRY IN THE BRISTOL AREA Proc. Analyt. Div. Chem. SOC. References 1. Spincer, D., and Lewis, P. J., “Proceedings of 5th International Tobacco Scientific Congress, Hamburg, Germany, September 1970,” Wissenschaftliche Forschungsstelle im Verband der Cigarettenindustrie, Hamburg, 1971.2 . Spincer, D., and Lewis, P. J., “Technicon International Symposium, Madrid, Spain, 15-16th Novem- ber, 1973,” Technicon Espaiia, Madrid, 1973. 3. “Standard Methods for the Analysis of Tobacco Smoke,” Second Edition, Tobacco Research Council KP11, London. 4. Spincer, D., “30th Tobacco Chemists Research Conference, Nashville, Tenne<see, USA, 18-20th October, 1976.” Microchemistry and the Local Authority A.J. Harrison Cozt+zty LabovatoZry, 7 Redcvoss Street, BZristol, BS2 OB-4 This paper briefly traces the history of the development of the Public Analyst service and the importance of microchemical techniques from the outset. The law, in its broad generalisations for the protection of the consumer, from the outset forbade the addition of injurious ingredients to food and drugs and the sophistication by non- nutritional materials and therefore the level of enforcement was restricted only by the analyst’s ability to detect the adulteration.Since the 1920s, there has been a steadily increasing demand for the use of microchemical techniques to detect, determine and identify a wide range of additives, contaminants and trace constituents in food for the purpose of enforcing legislation.Although it has always been UK policy to keep the use of food additives to a minimum, the complexity of modern food technology now demands a wide range of materials to meet specific needs, all of which are controlled by permissive legislation.This means that all foods sold today are covered by some aspect of food additive or contaminant legislation. A parallel development exists with the progress of animal feed technoIogy to keep pace with the demands of intensive farming techniques, which rely on control of the health and nutritional aspects of the animal environment. The control of land, air and water pollution, and the Trade Descriptions and Consumer Protection Acts, have also added to the demands made on modern local authority laboratories, creating a diversification of function and in- terest resulting in broad based scientific-services departments built around the nucleus of the Public Analyst.Microchemistry in local authority laboratories encompasses the examination of small amounts of material and their detection in a larger mass.The former technique relies on a forensic approach based essentially on analytical microscopy, especially in the instance of foreign matter in food, where it is desirable to use non-destructive methods to preserve the material as evidence in court proceedings, and in air pollution studies. In addition to microscopy, determination of particle size, determination of refractive index, atomic-absorption spectrophotometry, infrared spectroscopy and spectrofluorimetric tech- niques are used to determine trace amounts of metals and organic characteristics.By far the greatest use of microchemistry is for the determination of small amounts of material in a sample. In theory, using modern analytical instrumentation, this presents little difficulty.I n practice, however, there are limitations inherent in the available instru- mentation and, in particular, the clean-up procedure. In view of the wide range of interests and the constantly changing emphasis, the choice of analytical instrumentation, within a fixed budget, must be carefully controlled to provide the maximum flexibility and use of resources available.It would be possible to justify the use of every technique. As it is, we have to use every technique we can afford and maximise, as far as possible, its application to the problems we have. Undoubtedly, the clean-up process is the key to successful microchemistry. I t is also the most time consuming and possibly the most expensive part of the analysis. It follows, therefore, that in many instances a breakthrough in clean-up processes is potentially a greater step than the introduction of a new technique with limited application.April, 1979 USE OF MICROCHEMISTRY I N THE BRISTOL AREA 135 The techniques currently in use in the Avon Laboratory include atomic-absorption spectro- photometry and chromatography.Atomic-absorption spectrophotometry is used for a wide range of metals that are controlled by legislation and are of environmental significance, using aqueous digests, and for the determination of mercury in fish and urine from occupationally exposed personnel in industry, in the vapour phase, the mercury being determined at the sub-parts per million level.However, the most exacting exercise is the determination of lead in blood from non-occupationally exposed children, carried out on a sub-sample from a single drop of blood by the carbon rod technique.The amount of lead determined in the sub-sample, in this instance, is of the order of 200 pg. Thin-layer chromatography, gas - liquid chromatography and high-performance liquid chromatography are all used to detect low concentrations of material in the parent sample.Examples are aflatoxins by thin-layer chromatography, solvent and pesticide residues by gas - liquid chromatography in the nanogram region and the development of headspace techniques for flavour volatiles and volatiles derived from packaging materials. High-performance liquid chromatography is the most rapid growth area at present.Whilst, generally, more material is required for analysis, this is non-destructive and eluted peaks can be examined further by infrared spectro- scopy using microdiscs or by ultraviolet spectroscopy and spectrofluorimetry using suitable links and microcells. In addition to these techniques, pre-concentration and separation of small amounts of the materials sought continues to be of interest, and in recent months we have had considerable success with the use of trace-enrichment techniques, involving the use of polar or non-polar cartridges packed with chromatographic separation materials based on silica.Using this technique, large volumes of sample, such as water, for pesticide residues, or trace amounts of hydrocarbons, can be passed rapidly through an appropriate cartridge that will retain the appropriate polarity.We are investigating the use of this technique for the concentration and isolation of vitamins added to animal feeds that are normally extracted into hexane, which is then passed through a silica (or high polarity) cartridge retaining the vitamins. Stepwise elution, with increasing concentrations of ethyl acetate in hexane, successively liberates the vitamins. The technique offers considerable potential savings in time in certain types of analysis and has been particularly useful when searching for pesticides or herbicide residues either on the surface of plants, in soil, or in water courses. The need for and the use of microchemistry in modern local authority laboratories, with their wide range of interest, which is no longer confined to food and drugs and basic agricul- tural materials but extends across the spectrum of local authority activity and responsi- bility, is clear. Looking to the future, there is no doubt that the demand for our services will continue to grow as a direct consequence of the steady flow of new legislation, which, if it is to be enforced effectively, must be matched by an increase in resources if we are to avoid being swamped and the value of the legislation lost. The benefits to be gained by high technology are often offset by the generation of new problems, such as the carryover of medicinal residues from animal feeds into the human food chain or the concentration of trace amounts of constituents, not otherwise a recognised pro- blem, in industrial food isolates used as precursors for compound foods, which in turn pro- duce a new crop of regulations to control them. The future development of microchemistry in the local authority laboratory can therefore be best summarised as the detection of more and more materials in smaller and smaller concentration. Indeed, the expertise of the analytical chemist is now such that in some instances his ability embarrasses the legislation. This is noticeable in some instances where nil tolerances have been specified in the past, only to be confounded by some development that improves the method by an order of magnitude. I can see in the future a need to spccily what we mean by not detectable. ’

ISSN:0306-1396    

DOI:10.1039/AD9791600127

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

136 WINDOWS ON CHROMATOGRAPHY Proc. Analyt. Dia. Chern. SOC. Windows on Chromatography The following is a summary of the paper presented at a Meeting of the Analytical Division held on October 25tI-1, 1978, at Imperial College, London. Strategy for Chromatography J. H. Purnel! Departuncnt of Cheniistvj: University College of SwanAea, Singletox Pavk, Swansen, SA 2 8PP Twenty-five years ago, with the advent of gas - liquid chromatography, there was widespread anticipation of virtually unlimited sample selectivity.Despite the phenomenal success of the technique, and the remarkable range and number of problems that it has solved, we have been forced to recognise that the attainable selectivity, with single liquid substrates, is to some extent limited. This fact was recognised at least 15 years ago by the few pioneers who initiated the use of mixed substrates in order to enhance separation.The literature in the field of multi-substrate gas chromatography has, however, remained sparse. The reasons are two-fold. First, detailed experimental study of retention variation with substrate composition is very tedious and study of any given system is not guaranteed to provide a solution.Secondly, where this has been done, interpretation of the numerous chromato- grams and the subsequent location of an optimum composition have proved debilitatingly difficult. In practice, as will be shown, the foregoing difficulties can readily be overcome, indeed the first would never have presented a difficulty a t all had it been more widely realised that the liquids comprising a multi-substrate system need not be intimately mixed.The argu- ment is as follows. The retention volume of a solute eluted from a gas - liquid chromato- graphic column composed of two mechanically mixed packings, A+ support and B + support, is defined1-4 by . . * . (1) VE w A v E 4 + wBvg’B .. .. * . where w represents a mass of solvent (A or B) and VT represents a solute specific retention volume at the column temperature, T .Thus, the column temperature specific retention volume for the solute with respect to the composite packing [VR/(wA + wR)] is Vg’ = TVAVg’’ + WBVfB .. .. . . .. . . ( 2 ) K R = $ A K g A + $BKgB - ‘ . . . . .. . , (3) where W7 is a mass fraction. It is a simple matter to convert (2) to where K , is the experimental liquid - gas partition coefficient for A + B, Kg is the corres- ponding value for pure liquid substrate (A or B) and 4 represents a volume fraction.Equiva- lent equations to the foregoing can be written for gas - solid chromatographic or gas - solid - liquid chromatographic systems, of course. They can also be written in terms of other quantities than Vg or KR, for example, the capacity factor, K’, or retention ratio, a.The crucial quantity determining the extent of separation of a pair of components, 1 and 2, in chromatography is the retention ratio, a , defined as either Vf2/V:l or K,e/KR,. As equations (2) and (3) define straight lines, they allow calculation of a for a solute pair at any value of W , or $A if values of VJ’, and V:B or KgA and K& are known.Such data exist in the literature but can, in any case, readily be determined. From such data we can calculate a for every pair of components in the mixture at discrete values of or WA over the range 0-1. For convenience we keep a greater than 1, as we are uninterested in the order of elution. Plotting all values of a against W , or $A then yields a “window” diagram ; Fig.1 illustrates a computer-drawn diagram for a 29-component mixture, the solvents being squalane and dinonyl phthalate. The windows, which form approximate triangles, represent areas within which separations can be realised in practice ; areas above the envelope define unattainable situations. The volume of calculation needed can beApvil, 1979 WINDOWS ON CHROMATOGRAPHY 137 1 1 O r 107 106- 0 0 1 2 3 4 5 6 7 8 9 1 Volume fraction of DNP x 10 Fig.1. Window diagram for 29 component mixture. Sol- vents, squalane and dinonylphthalate. Column temperature, 100 "C ; carrier gas, nitrogen. Optimum composition indicated is r$squa~ane = 0.84, with corresponding cc f 1.05. Indicated column length E 45 ft. Mixture comprises alkenes, alkynes, napthenes and aromatics in the boiling range 30-210 "C.I greatly reduced by ignoring all pairs of lines that are well separated; thus, for example, any pair for which a is greater than 1.3 over the range can be ignored because at this a value separation is easy. The optimum, in terms of a, is defined by the peak of the highest window, which corresponds to the highest value of the minimum a among all values for component pairs as a function of +A or W,.This value, in fact, relates to two pairs of sample components of about equal difficulty of separation (see equation 4) as the window peak is made by the intersection of two lines. The theoretical plate requirement for base-line separation of any pair of Gaussian peaks of given a value is defined by the equation5 9 2 l+k' .. .. (4) where k' is the capacity factor for the second eluted of the pair to be separated. Because of the involvement of k' we normally use the earliest eluted of the two pairs at the window peak for further calculation. If k' exceeds about 10, the second bracketed term can be neglected and N,,, immediately calculated from the optimum a, which has defined the opti- mum +A.As we know the attainable values of theoretical plate height H from the test experiments that provided values of V: or K;, we can immediately calculate the required column length and substrate composition for total separation of all components. Fig. 2 illustrates the first time chromatogram produced in this way from Fig. 1. In practice, matters may be slightly more complicated in that pairs of peaks eluted early, although having a large a value, may have a very small k' value and hence (eft, equation 4) present greater difficulty in separation than the pairs of minimum a at a higher value of k'.Thus, as a precaution, it is useful to place the window peak pair hypothetically at k' = 10, evaluate the corresponding k' for all earlier pairs via relative retentions, and evaluate all N,,, via equation (4).Should any earlier pair demand a higher Nreq than those a t the window peaks, the k' required to permit their separation at the column length calculated for the window peak pair is evaluated. If the corresponding solvent - support ratio is reason- able, e.g., less than 20y0 m/m, the problem is resolved and the solvent - support loading is defined. If not, a new column length providing the higher required Nreq a t an acceptable solvent load is calculated.The foregoing calculation is very simply computerised6g7 and so presents no difficulty. It is sometimes found that several nearly equivalent (in terms of a ) window peaks exist. We can now exercise the secondary option of choosing the optimum +A (or bVA), being that138 WINDOWS ON CHROMATOGRAPHY Proc.Analyt. DiV. Chem. SOC. giving the fastest over-all analysis, i e . , the window in which the longest retained component comes out fastest. I , - - I - I \- ' .. - - i i 5 - Time/h I Fig. 2. First time chromatogram of 29 component mixture a t optimum ~ $ ~ ~ , ~ ~ l ~ ~ ~ indicated in Fig. 1. Experimental conditions as defined there except that column length was 37.5 f t (3 standard laboratory lengths in series).Hence the incomplete resolution of the two pairs a t optimum $. Front- ing of late peaks and lengthy analysis time is a consequence of the low analysis temperature required for the separation of low-boiling components. Perhaps the most appealing aspect of this procedure is that it can be applied in total ignor- ance of the nature and identity of the sample to be analysed.8~9 In this situation we need only run chromatograms with six columns of substrate composition ranging more or less uniformly from $A = 0 to +A = 1 and, from the results construct, for example, a KR/$A graph consisting of a set of unconnected points.Because all points for a given component must lie on a straight line, we can ascertain the maximum number of components that are likely to be present by drawing all possible straight lines.A window diagram can then be constructed through the points, bearing in mind that each line must have as many points as columns were used, and an optimum $*, and the required column length determined. If the sample is now analysed with this column all components present must be resolved.Thus, by inspecting the actual chromatogram, the exact number can be ascertained and redundant lines on the KR/$A diagram removed. The correct window diagram can then be constructed, optimum conditions ascertained, and the complete analysis achieved in total ignorance of the identity of the sample components. Several examples of this procedure, involving complex mixtures that had previously defied separation, have been handled by us in this way.*v9 As a purely practical point, K , or V: values for the unknowns are easily obtained by running with the test columns of pure A and B a standard solute of known characteristics and then converting the relative data.The foregoing procedures are neither limited to two-component substrates nor to gas - liquid chromatography.We have shown examples of the use of as many as five solvent components7 and of combinations of gas - liquid, gas - solid and gas - solid - liquid packings.1° The method thus has total generality and clearly can be applied to high-performance liquid chromatography (HPLC). What is more, it is not even limited to substrate composition optimisation.Thus, for example, it can be used to determine optimum analysis temperature and most other variables that are relevant to all forms of chromatography,ll including, as we have pointed out, optimisation of carrier The method is, in principle, very simple and, in practice, straightforward.Afi~il, 1979 EQUIPMENT NEWS 139 gas or the liquid composition or pH of the eluting agent in HPLC.Indeed, Deming and Turoff12 have already demonstrated an excellent example of pH optimisation by use of this window technique, while Pretoriusl3 has very recently shown an example of carrier-gas optimisation. Our current studies include further development of the foregoing, including examples of optimisation of gradients in gas chromatography and HPLC also.Of most importance, we believe, is our attempt at a general approach to the development of a com- puter program within which all dependent variables can be simultaneously optimised to give an optimum of optima for chromatographic separations. Finally, it is worthwhile to point out that the technique is not limited to chromatography. We have applied it very successfully already to lanthanide shift nuclear magnetic resonance interpretation and optimisationl4 and are currently participating in its application to examples in polargraphy and other electrochemical techniques, and to flow-injection analysis.There appear to be many areas of applicability and the method we have presented has, in conse- quence, elements of a general optimisation strategy for analysis.It will be interesting to see how far this proposition is realised in the years to come. References 1. 3. 4. 5. (5. 8. 9. 10. 1 1 . 12. 13. 14. 3 I . m Puniell, J . H., and Vargas dc Andrade, J . M., J . Am. Chenz. SOC., 1975, 97, 3586 and 3590. Laub, R. J., and Purnell J. H., J . Am. Ckenz. Soc., 1975, 98, 30 and 35. Laub, R. J., and Purnell, J. H., J . Chromat., 1975, 112, 71. Laub, R. J., and Purnell, J. H., AnaZyt. Chew., 1976, 48, 799. Purnell, J . H., J . Chem. Soc., 1960, 1268. Laub, R. J., Yurnell, J . H., and m’illiams, P. S., J . Chromat., 1977, 134, 249. Laub, R. J . , Purnell, J . H., and U’illiams, P. S., ,4naZytica. Chiin. Acta, 1977, 95, 135. Laub, R. J., and Purnell, J , H., Anal>$. Chem., 1976, 48, 1720. Laub, R. J., and Purnell, J. H., J . Chvomat., 1978, 161, 69. Al-Thamir, W. K., Laub, R. J., and Purnell, J. H., J . CIzvounat., 1977, 142, 3. h u b , R. J., and Purnell J. H., J . Chvomat., 1978, 161, 49. Dcming, S. N., and Turoff, M. L. H., A ~ a l y t . Chenz., in the press. Pretorius, V., J . High Hesolutzovz Clzvowzat., 1978, 1, 199. Laub, R. J., Pelter, A,, and Purnell, J . I I . , Analyt. Chenz., in the press.

ISSN:0306-1396    

DOI:10.1039/AD9791600136

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

EQUIPMENT NEWS 139 Equipment News Counter Pre-amplifer The A- 101 hybrid charge-sensitive preamplifier - discriminator and pulse shaper (PAL)) has been developed for instrumentation using high-gain photomultipliers, channel electron multipliers and other charge-counting detectors used in the pulse-counting mode. The TO-9 package housing the 14-101 is 0.6 in in diameter, which enables it to be mounted close to the multiplier collector.The power requirement is typically 15 mW. The input charge sensitivity is 0.16 pC, which corresponds to an electron gain of 1 x 106. A positive-going, 5-V pulse output will interface directly with CMOS or low-power TTL, or an open-collector output will drive up to 10 TTL inputs and can be wired with other units. Both outputs have a rise time of 6 11s and a fall time of 20 ns; the pulse width is nominally 220 ns, but can be adjusted with a trimming capacitor to a maximum of 3 p s .A typical count rate is 4 x lo6 counts s-l. Teknis Electronics Ltd., Teknis House, Meadrow, Godalming, Surrey, GU7 3QH. Refractometer Three modes of measurement are provided by a new Abbi: Brix Refractometer, namely Brix, uncompensated Brix and refractive index.In the Brix mode, analysis of hot or cold samples is possible ; temperature compensation is auto- matic and the measurement is presented a t the touch of a button. In measuring refractive indices, water circu- lation enables measurements to be made on aqueous and non-aqueous materials. Tem- perature measurement is carried out at the prism - sample interface and displayed digitally to 0.1 "C.The instrument incorporates its own adjustable light source. Reichert- Jung UK, The Scientific Division of British American Optical Co. Ltd., 820 Yeovil Road, Slough, Berkshire, SL1 4 JB.140 EQUIPMENT NEWS Proc. Analyt. DiV. Chenz. SOC. Isotope Mass Spectrometer : Pneumatic Valve Cylinders CompAir Maxam clamping cylinders are used to operate the all-metal ConipAir valves for both the gas inlet and manifold sections of the MM602D isotope mass spectrometer, a precision double-collector mass spectrometer for the exact measurement of isotope enrichment or depletion relative to a standard gas sample.Maxam intensifier cylinders, which provide clamping forces up to 24000 N, are fully bakeable to 160 "C. The introduction and ejection of the gas sample and reference, the Delta and 2u10 calculations, and printout of results are completely automated.The Maxam clamping cylinders respond to a signal, from a push-button control panel during manual operation or from the integral computer, to force a plunger into the front section of the valve, which is filled with oil. The difference in diameter between the pneumatic piston and oil plunger means that the oil acting on the clamp piston is under a pressure four times that of the air pressure.When the clamp piston is fully extended it provides the necessary clamp force to ensure a leak-tight seal of the valves. CompAir Maxam Ltd., Camborne, Cornwall. Cryostat Microtome A new cryostat microtome operates down to -40 "C with an open top.A heated cover rim and top window demist systems and an automatic dual defrosting programme are provided. The temperature is measured at knife-edge level, adjustable from + l o to -40 O C , and remains constant in both knife and sample during cutting. In its basic form, the Spencer 840 microtome is incorporated. Alternatively, the Jung Rotocut or Jung 1130 microtome can be fitted.Three auxiliary quick freezing devices are available, either carbon dioxide, heat abstrac- tion block or thermo-electric, the latter giving exceptionally quick freeze-down time (down to -40 "C in seconds). Reichert- Jung UK, The Scientific Division of British Amercian Optical Co. Ltd., 820 Yeovil Road, Slough, Berkshire, SLl 4JB. Kinetic Analysis Systems Rate Rack Systems, based on the SP8 Series scanning ultraviolet - visible spectrophoto- meters, permits the rapid automatic analysis of batches of 10 samples with printout in rate units.The systems, which are niulti-purpose, offer automatic addition of initiating reagent, low reagent consumption and can accomodate any wavelength or temperature. When used for non-rate assays they can be switched to measure the absorbance or concentration of each cell, or with appropriate accessories carry out a scan or wavelength selection pro- gram me. Accessories can also be fitted for densito- metry, fluorescence, turbidimetry and liquid column monitoring.Pye Unicam Ltd., York Street, Cambridge. Ultraviolet - Visible Spectroradiometer The Model 741 portable spectroradiometer is designed for measuring ultraviolet spectral irradiance of sunlight, solar simulators and other ultraviolet sources.The design and the selection of components are optimised for accurate spectral measurements over the 250- 400 nm wavelength region. The Model 741-V covers the extended wavelength range of 260-800 nm. Use of the Model 755 Automatic Data Reduction System enables the printout of spectral irradiance values of each wavelength or sorting of the collected data on magnetic tapes for future analysis.Glen Creston Instruments Ltd., 16 Carlisle Road, London, NW9 OHL. Ultraviolet - Visible Spectrophotometer The Model 552 is combined with a micro- computer to give fast and simple operation. The automatic base line compensation mode gives base line flatness of f 0.000 1 nm.Four fixed band passes can be selected by the slit control which is positioned on the front control panel. Automatic zero absorbance or 100% transmittance can be set by pushing a button and during each chopper cycle zero trans- mittance is monitored. The scan is stopped automatically a t 315 nm if the deuterium lamp is not switched on and source changeover is also automatic when scanning from the visible to the ultraviolet regions (900-1 90 nm) .Thermoelectric temperature control, X-Y recorder, specular reflectance, repetitive scan and first and second derivatives are available as accessories. Perkin-Elmer Limited, Post Office Lane, Beaconsfield, Buckinghamshire, HP9 1QA. Scan Superimpose Ultraviolet Spectro- meter The SPB-100 ultraviolet spectrophotometerApril, 1979 EQUIPMENT NEWS 141 can now- be extended with a new spectra superimpose accessory to provide automatic superimposition of spectra on systems incor- porating a wavelength programmer and pro- gramme controller.If-hen using the accessory, the scanning range is set on the wavelength programmer, with single or repeat modes selected on the programme controller.The interval between the start of scans can be set from 0 to 99 min by fitting the optional cycle timer. Pye IJnicam Ltd., York Street, Cambridge. High Pressure Valves A new series of compact shut-off valves for high pressure services up to 6 000 lb in-2 is available. The new design features relatively oversized end connections, allowing use in applications which otherwise would require larger and heavier valves. The valves are suitable for applications such as control systems, gauge isolation and instrument air.The one-piece barstock units are available with various combinations of and 4 in female and male National Pipe Thread end connections. Orifice sizes are and 4 in, allowing flow coefficients of C, = 0.21 and 0.73, respectively, with a maximum temperature rating of 450 OF.Construction is in 316 stainless steel, with PTFE packing and type 17-4PH stainless steel handle set screw. blanchester Valve & Fitting Co. Ltd., 12 Rufford Court, Hardwick Grange, Warring- ton, Cheshire, WA1 41iF. Pipette Fillers A plastic laboratory pipette filler, which can be operated with one hand, has been developed to fit all British and International standard sizes of pipettes.The bulb is made of PVC and is therefore resistant to most corrosive and noxious chemicals. Saffron, 5 Rowlands Road, Worthing, West Sussex, BNll 3JJ- Adjustable Sampler An adjustable sampler to dispense with high accuracy amounts from 2 to 1000 p1 is announced. The Boehringer Corporation (London) Ltd., Bell Lane, Lewes, East Sussex, BN7 1LG.Dispensers The Oxford range of adjustable dispensers has been extended to cover the range from 0.2 to 10 ml in three stages. The Boehringer Corporation (London) Ltd., Bell Lane, Lewes, East Sussex, BN7 1LG. Oscilloscope The 1000 series of line oscilloscopes give a choice of 10 or 16 MHz band width, a sensitivity of 5 mV a t full band width and 1 mV a t 4 MHz with choice of algebraic add, true X-Y and x 5 gain switch modes of operation.Telequipment U.K. Ltd., P.O. Box 69, Coldharbour Lane, Harpenden, Hertfordshire. Oscilloscope The OS1100 dual-trace oscilloscope features 30 MHz band width with 1 mV cm-I sensitivity. A single-sweep facility and variable trigger delay are included, and signal delay in the Y channel gives at least a 1 cm visible delay on the time base speed, which ranges from 2 s cm-I to 20 ns cm-1.Gould Instruments Division, Roebuck Road, Hainault, Essex, IG6 3UE. Recorder The 100 MSR is a recorder featuring options of plug-in range selector modules, roll or fan- fold chart cassettes, event pen single or multi- channel, ink or dry writing, with several chart speeds, all in readily changeable modular form. The Record Electrical Co.Ltd., P.O. Box 19, Altrincham, Cheshire, WA14 5DB. Recorder A small size d.c. recorder has been developed specifically for OEM use in portable medical and industrial equipment. With a 40 mm wide thermal chart and a chart speed of 25 mm s-l, the R1-4DCM miniature recorder operates from a 12 V d.c. supply and is thus particularly suitable for battery operated portable defi- brillators.Other recorders available on OEM modules offer 1-8 channels with chart widths of 20, 40, 50, 80 or 100 mm and multiple chart speeds. Laser Lines Ltd., 19 West Bar, Banbury, Oxfordshire, OX16 9SA. Germanium Lenses A selection of high precision germanium lenses, with laser power limits of 1 kW cm-2 con- stant and 400 MW cm-2 pulsed, is announced. The lenses have been optimised for 10.6pm, and are spherical within h/40.Because the refractive index of germanium varies only slightly between 2 and 13 pm, they can be used a t any wavelength in this spectral range.142 EQUIPMENT NEWS Proc. Analyt. Div. Chem. SOC. In order to achieve maximum transmission through the lenses, each lens has been coated with a high efficiency, broad band, anti- reflection coating, which substantially meets all requirements of MIL 13508 B and MIL C 675 A. Rlelles Griot B.V., Xieuwe Kade 10, Arnheni, The Netherlands.Flow Meter A portable flow meter carries out the accurate measurement of waste water flow-rates auto- matically, even in the presence of surface foam, scum or floating objccts. The PW 9816 meter uses a dipping probe attached to a weighted flexible cable mounted on a rotating drum, which is raised and lowered a t regular intervals to sense the level of water in a measuring channel of known cross section, thus giving a direct correlation with the rate of flow.This direct-reading instrument eliminates tlie problems that can be caused by the presence of foam, floating or suspended matter, corrosive substances, etc., when using rotating, floating or orfice-plate types of sensor.This output can also be linked to the PW 9815 portable sampler, which provides a means of collecting a sample whenever a given volume of waste has passed. Pye Unicam Ltd., York Strcet, Cambridge. Diaphragm Pump A new diaphragm-type aspirator pump that relies on a new concept has been developed. In this design the diaphragm is actuated by hydraulic fluid pressure so that the displacing thrust is equally distributed over the diaphragm area.The working fluid is caused to oscillate by a solenoid-driven piston. The frequency of the pumping strokes is controlled by simple, reliable, solid-state electronic circuitry operating on a variable frequency pulse system. The flow-rate can be varied by means of a poten- tiometer, or by digital or analogue signals.The pump can handle flow-rates of up to 750 ml min-l and as the material to be pumped is completely isolated from the pumping section, it is possible to handle a wide variety of materials. Robertshaw Ski1 Ltd., Greenhey Place, East Gillibrands, Skelmersdale, WN8 9SB. Electrophoresis System The flat bed appa.ratus FBE 3000 is designed for all types of electrophoresis and electro- focusing; a self-levelling base unit supports a 21 5 nim square PTFE-coated aluminium cooling plate, which can limit temperature rises to 15 "C with 70-W power loadings.This can be used in conjunction with either the isoelectric focusing (IEF) kit for analytical electro-focusing, the preparative IEF kit using thick layers of Sephadex or the electrophoresis kit for all flat bed and immunoelectrophoretic techniques.The power supply for electro- focusing applications is provided by the ECPS 2000/30 and for immuno- or gel electro- phoresis by the EDS 500/400. Agarose and Sephadex IEF, a selected grade of Sephadex G-75, are designed for use in isoelectric focusing and the Pharmalyte range of carrier ampholytes gives even, linear pH gradients, An illustrated brochure is available.Pliarmacia (Great Britain) Ltd., Prince Regcmt Road, Hounslow, Middlesex, TW3 1 YE. Immunoelectrophoresis System Recently introduced immunoelectrophoresis equipment includes the Model 600 electro- phoresis chamber, a modified version of the Kohn design. Manufactured in high impact plastic, tlie chamber will take one 200 x 80 nini plate or two 100 x 80 mni plates; other support bars enable other plate sizes to be accomnio- dated for imniunoelectrophoresis. A new safety interlock system gives protection from potentially lethal voltages.A system for cutting gel patterns has been developed, based on gel punches and templates. Two templates are available, which allow accurate cutting of patterns for imniuno- electrophoresis according to Grabar and \.'illiams, Laurel1 rocket immunoelectro- plioresis, counter-current immunoelectro- yhoresis and immuno diffusion techniques.Ancillary products for use with the system include a cooling platen which will cool the whole area o f gel on the platcs, Canibrelle wicks, staining accessorics and a levelling table manufactured in smoked plate glass and fitted with three adjustable feet and a circular spirit level.Shandon Southern Products Ltd., 93-96 Chatlwick Road, Astnioor Industrial Estate, Runcorn, Cheshire. Pumps The Kerren Kunststofftechnik of West Germany range of contemporary, rotary vane, self- priming, corrosion resistant, precision pumps are now marketed in the UK. Currently, the range includes high performance models with delivery rates from 20 to 800 1 h-l, coupledApril, 1979 NEW BRITISH STANDARDS 143 with a maximum pressure of 20 bar (280 lb in-2), with the ability to run “dry” for relatively long periods.Appliance Components Ltd., Cordwallis Street, Maidenhead, Berkshire, SL6 7BQ. New Materials Lipid Panel Assays X comprehensive range of assays in the field of lipid chemistry, namely Quantazyme choles- terol, Quantazyme triglycerides and the Bio- Gram A lipoprotein electrophoresis test system, is announced, together with the HDL choles- terol system. This last consists of a one-vial, pre-dispensed, lyophilised separation system that elimates refrigeration steps. The choles- terol and tryglycerides assay systems are also single-vial, fully enzymatic, easily auto- mated end-point assays. Bio-Rad Laboratories Ltd., Caxton Way, Holywell Industrial Estate, Watford, Hertford- shire, WDl 8RP. Folate Standards Six folate standards, covering the range 0-20 ng ml-1 PGA (nominally zero, 1.0, 2.5, 5.0, 10.0 and 20.0 ng ml-l) are now available. The lyophilised standards are in a protein base, contain preservative and are stable for 1 month when reconstituted with distilled water . Bio-Rad Laboratories Ltd., Caxton Way, Holywell Industrial Estate, Watford, Hert- fordshire, WD 1 8RP.

ISSN:0306-1396    

DOI:10.1039/AD9791600139

出版商:RSC    

年代:1979

数据来源: RSC

摘要:

April, 1979 NEW BRITISH STANDARDS 143 New British Standards BS 4289: iVetlzods for the Analysis of Oilseeds. Part 1. Reduction of Contract Samples to Analjlsis Sanzples. Part 3. Determination of iWoistuve and Volatile Matter Content. BSI has published the above two parts. Part I is concerned with the division of a sample into parts of suitable mass for undergoing the various analytical procedures following the removal of impurities of large size.Several items of dividing apparatus are listed and a table indicates the mass of each of a number of species of seed that is required as an analytical sample. Part 3 describes a loss on drying procedure for the determination of the moisture and volatile matter content of the seeds. The price of each of these two parts of BS 4289 is i1.60.BS 5666: Methods of Analysis of Wood Pre- sevuatives and Treated Timber. Pavt 1. General Considerations and Sainpling and Preparation of iWatevials for Analysis. The first part of the new standard deals with the general background and the sampling procedures. Later parts of the standard will deal with the identification of preservatives in treated timber and the analysis of preservatives, both as supplied and in samples of timber.While the sampling and testing of pre- servatives is comparatively simple, treated timber presents a much more complex problem. It is often not practicable, by the analysis of samples of treated timber, to verify whether a specified treatment has been carried out, so this is normally done by supervising the treatment and checking plant records.However, analysis of treated timber is an important tool for the development and control of processing. Advice is given on the sampling of both solid and liquid preservatives. In the guidance on sampling treated timber i t is recognised that considerable professional skill is necessary in deciding how to sample in order t o obtain the desired information.Practical advice is given on the cutting of timber sections and the preparation of sawdust samples. The stan- dard places considerable emphasis on the need for precautions to minimise hazards to health and safety. A method for the determination of the moisture content of treated timber is also described. The price of BS 5666 Part 1 is k2.20. BS 5657 : Petroleum Products-Gasoline-De- termination of Lead Content-Iodine Mono- chloride Method.This standard method is required in connection with the revision of BS 4040: Petrol (Gasoline) for Motor Vehicles, and reproduces the text of IS0 3830. However, as an alternative to the dimethyl yellow indicator specified in the inter- national standard, provision has been made to use bromothymol blue indicator.This is because dimethyl yellow has recently been listed by the Occupational Safety and Health Administration of the USA as a potential carcinogen. Laboratory tests in the UK have identified bromothymol blue as the most convenient alternative, and confirmed that the change does not significantly affect the results144 PUBLICATIONS RECEIVED Proc. Analyt. Div. Chcm. SOC. obtained.The matter has been brought to the attention of the international committee responsible for IS0 3830 in the expectation that this standard will be amended. The method in IS0 3830 has also been called up in the EEC directive for the control of the lead content of petrol, agreed in 1978. The price of BS 5657 is L2.20. BS 2690: Methods of Testing Water Used in Industvy. Part 100.Foveword, Scope and General Requirements. Part 102. Hydrazine. The British Standards Institution has published two parts of a revision of BS 2690. These and later parts in the revision will be published in loose-leaf form, with a completely new num- ber sequence, and it will be essential to read the general requirements laid down in Part 100 when using any subsequent part as they specify the quality of reagents and water necessary for the methods of test.US 2690 describes methods for testing and analysing water for constituents and parameters of importance in various industrial processes. The types of water may range in quality from raw waters, such as river water, to those of extremely high purity used in steam generation. Part 102 deals with a spectrophotometric method for the determination of hydrazine which is technically equivalent to the hydrazine method in Part 2 of the previous edition of BS 2690.The price of Part 100 is ,&2.20 and of Part 102 is i1.60. BS 5659 : Metlzods of Test for Acid-grade Fluor- spar. Part 1. Determination of Flotation Agents. Part 2. Determination of Loss in Mass at 105°C. Part 3. Determination of sulphide content.The test methods in these three parts are the first of a series and are identical with IS0 3703, 4282 and 4284, respectively. Other international standards for the material are to be published in due course and it is expected to issue them as further parts. Parts 1 and 2 are Ll.60 each and Part 3 is L2.20. BS 5697: Methods of Test for Stavch, and its Derivations and By-products.Part 1. Deter- mination of Nitrogen Content by the Kjeldahl Method (Titrimetvic Method). Pavt 2. Detev- mination of Nitrogen Content by the Kjeldahl Method (Spectrophotometric Method). The British Standards Institution has published two parts of BS 5697. Part 1 describes a method for the determination of the nitrogen content of starch that is suitable for nitrogen contents greater than O.Olyo m/m.It is identical with IS0 3188. Part 2 describes a method suitable for nitrogen contents of less than 0.025% m/m and is identical with IS0 5378. Both parts are provided with national forewords which cross-reference relevant Inter- national and British Standards, and give further requirements for certain reagents and apparatus listed. The price of each part is k2.20. All British Standards can be obtained from BSI Sales Department, 101 Pentonville Road, London, N1 9ND. Water Research Centre Technical Report The following recently published report is available from the Water Research Centre, Medmenliani Laboratory (P.O. Box 16, Marlow, Buckinghamshire, SL7 2HD) or Stevenage Laboratory (Elder Way, Stevenage, Hertford- shire, SG1 1TH): TR89 Analysis of Relatively Non-polar Organic Compounds in Sewage Efflu- ent Using Amberlite XAD-2.

ISSN:0306-1396    

DOI:10.1039/AD9791600143

出版商:RSC    

年代:1979

数据来源: RSC