ISSN:0144-557X    

DOI:10.1039/AP98926FX045

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

ANPRDI 26( 12) 41 7-444 (1 989) Analytical Proceedings Proceedings of the Analytical Division of The Royal Society of Chemistry 'An Intelligent Sample Changer' by C. Angelikaki and M. Usher 'Contaminants, Taints and Off-Flavours in Beer' by N. A. Silk 'Detection of Migration From Packaging Materials' by P. A. Tice 'Microbial Contamination of Food: Control Measures' by Gerald I. Forbes CONTENTS 41 7 SAC 89-Cambridge. A Personal Recollection 41 8 New Members of Council 422 Analytical Chemistry Trust Fund (Rules) 422 The Analytical Chemistry Trust (Accounts and VSO) 424 Analytical Viewpoint 424 428 SUMMARIES OF PAPERS 428 Determination of Trace Contaminants in Food and Drink 428 429 43 1 43 1 'Determination of Ethyl Carbamate in Alcoholic Beverages' by R.I. Aylott and D. A. WaI ker 434 Equipment News 438 Gordon F. Kirkbright Bursary Fund 439 Award t o Member of Analyst Editorial Advisory Board 441 Conferences and Meetings 443 Courses 444 Analytical Division Diary Typeset and printed by Black Bear Press Limited, Cambridge, England December 1989 ANALYTICAL PROCEEDINGS, DECEMBER 1989. VOL 26 STUDENT BURSARIES FOR EUROANALYSIS VII The Analytical Chemistry Trust Fund is offering a limited number of student bursaries o f f 120 each for student members of the Society to attend Euroanalysis VII. This conference, which covers all aspects of analytical chemistry, is to be held in Vienna, Austria, from August 26th-31st, 1990. Applications should be made in writing to the Secretary of the Analytical Division, The Royal Society of Chemistry, Burlington House, Piccadilly, London WIV OBN, before May 31st, 1990.Each application should be supported by the student’s supervisor. The bursaries will be paid on proof of registration. TOPICS EUROANALYSIS VII Vienna, Austria August 26-31,1990 A. Applications of Analytical Chemistry v €3 3) €3 4) Separation Techniques Electrochemical Methods Sensors Radiochemical and Nuclear Techniques Thermal Analysis Local and Surface Analysis Photometry, Kinetic Analysis, Process Analysis, C. Special Sessions andworkshops C 1) Sampling and Sample Preparation C 2) COBAC V (Computer Based Analytical Cherni stry ) C 3) Quality Assurancein Analytical Chemistry C 4) New Trends in Teaching Analytical Chemistry Flow Injection Analysis A 1) EnvironmentalSystemsandFood B 5 ) A 2) PharmaceuticalandBiomedical Science A 3) Biotechnology A 4) MaterialsScience A 5 ) ArtsandArchzology B. Methods of Analytical Chemistry B 1) Atomic Spectroscopy B 2) Molecular Spectroscopy PREREGISTRATION AND INFORMATION: EUROANALYSIS VII Prof Dr M Grasserbauer, c/o Interconvention Austria Center Vienna, A-1450 Vienna, Austria Phone: +43-222-2369-2647. Telex: 11 18 03. Telefax: +43-222-2369-648 B 6) B 8) B 9) €3 7) Structure Analysis of Solids B 10) Immuno as say B 11) Other Methods, such as . . . 111

ISSN:0144-557X    

DOI:10.1039/AP98926BX047

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 417 SAC 89-Cambridge. A Personal Recollection Cambridge, along with the rest of the United Kingdom, was enjoying an unusu- ally warm “English Summer” as delegates to SAC 89 assembled in the last days of July. The willows, dangling their finery of leaves in the cool flowing waters of the Cam, mocked the perspiring analytical chemists arriving in Cambridge with their burdens of luggage. A range of diverse topics, a characteris- tic of this and previous SAC meetings, had brought the conferees together from around the world. During the meeting, at least after the Plenary Lectures, they were scattered to the different lecture theatres housing the four parallel sessions. Spec- ialist talked and listened to specialist. matography. Whether the techniques be “twins or siblings” is not proven; however, they were shown to be partners in the analyst’s armoury.The following day the Plenary Session was provided by Professor Pirkle, who elegantly described the molecular details underlying the sepa- ration of chiral molecules using specially designed chromatographic phases. Professor Kateman, in the third Ple- nary Lecture on Thursday, presented a view of chemometrics, arguing the case that “chemometrics optimises analytical information and its production.” In the last Plenary Session Professor Townshend described recent developments in the application of chemiluminescence and Prior to the Conference Banquet: (L-R) Professor J . M . Ward (President of the RSC), Professor D. Thorburn Burns (President of the Analytical Division) and Mr.M. W. McCrum (Vice-Chancellor of Cambridge University) enzymes in analytical chemistry. Plenary lectures presented in this way by carefully chosen speakers provide a valuable focus for a large meeting and they set the standard and tone of the whole proceed- ings. In Cambridge this year this philo- sophy was successful. After the Plenary Sessions a selection had to be made to decide which presenta- tions were to be attended. At such meet- ings as SAC 89 it is essential to plan the presentations to be attended by making a detailed preview of the submitted abstracts. Even having done this it is possible to miss a topic of interest. With Flow Analysis alongside Electroanalytical Chemistry, and Atomic Spectroscopy overlapping with Chemometrics, the deci- sions for some conferees can be difficult.The development of flow injection techniques to include automated proce- dures of sample preparation is a rapidly growing topic. An excellent example of this was presented by the group from the Queen’s University of Belfast, in which an extraction procedure was included in a flow injection technique used for the determination of cobalt. Polymers and surface analysis are being examined by a number of spectroscopic techniques and interesting developments relating to depth profiling of sampling using FTIR - photoacoustic spectroscopy were discussed by C. Yang of Marshall University, WV, USA. Recent developments in the application of Raman Spectroscopy were discussed in two especially interesting lectures.Firstly, the problems of fluorescence and photodegradation, which have not helped the application of the technique to organic molecules, have been overcome to some Those with more general interests and responsibilities were to be seen hurrying from place to place between lectures and occasionally trying to enter a darkened lecture theatre in ghostly silence when timing and enthusiasm for one lecture had overcome interest for the next. However, all delegates were in many respects together and the dust of one discipline brushed off on to those from another. Chromatographers met atomic spectro- scopists and those with an interest in food analysis met those to whom food was an interest. The Plenary Lectures, each on a topic of current interest, were for all.These are subjects that all analytical chemists should be aware of, to apply as required or to store in the memory until the need arises. Professor RfiiiCka described aspects of flow analysis and compared some of the technique’s capabilities to those of chro- At the reception before the Conference Banquet: (L-R) Mr. G. M . Telling (SAC 89 Scientific Programme Co-ordinator), Mrs. A . Evenson and Dr. A. Evenson418 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 extent by the use of FT methods and the use of infrared excitation. Such instrumental developments permit col- oured samples to be examined more easily than hitherto. Further application to organic molecules also appears attractive by using surface enhanced Raman scatter- ing techniques. Supercritical fluid chromatography is becoming accepted as a technique com- plementary to the existing chromato- graphies and developments are demon- strating its potential as more applications are being reported. Use of SFC as a separation stage in hyphenated tech- niques was well exemplified by presenta- tion of SFC - MS methodology and its application to organic additive analysis in fibres using SFC - FTIR.Any reduction of sample preparation techniques is a desir- able goal and for many atomic spectro- scopic applications the introduction of solid samples for analysis would be a significant advantage. The relative merits of various sample introduction protocols were discussed including slurry nebulisa- tion, laser ablation and electrothermal vaporisation. Perhaps one of the most exciting de- velopments discussed at SAC 89 was the coupling of gas chromatography to micro- wave induced plasma emission spec- trometry.With commercial equipment now being available the future applica- tions of the technique may increase signif- icantly as new possibilities are explored. Scientifically, SAC 89 was as varied as its predecessors, abstracts were included in the June edition of Analytical Proceed- ings and many of the papers presented will be published in a future issue of The Analyst. No conference is complete without its social events, for it is here that the previously unasked questions may be posed and the liaisons for the future be made. At Cambridge there was ample opportunity for both scientific delegates and accompanying persons to enjoy some of the events and trips.It is impossible to describe here, in such a personal recollec- tion of the meeting, all but a few of the social events, for to do otherwise would mean that no scientific topics could be included. A guided walking tour of Cam- bridge on the Monday evening gave parti- cipants a glimpse of the city, the Univer- sity Colleges and the underlying tradi- tions. On Tuesday evening, as the sun sank into the west, a visit to Chilford Manor vineyard was organised. A tutored wine-tasting followed a tour of the wine making facilities and a surprisingly long but enjoyable stroll to view the grapes. The splendour of King’s College lent an unforgettable atmosphere to the Confer- ence Banquet on Thursday evening. After the final scientific sessions and the closing ceremony an organ recital by Anne Page made a fitting end to the formal meeting with music spanning four centuries and, to match the international character of the meeting, originating from six nations.Surprisingly, few delegates appeared to feel the need to be “updated.” Despite the small numbers, which in some instances makes it easier for the organ- isers, those who did take the opportunity of joining a course found the experience rewarding. With five update courses to choose from selection was the most diffi- cult task. Information Technologies for Analytical Chemists attracted a slightly larger following than the others, probably because of the wider applicability of the topic. The objectives of the course, to increase awareness of the possibilities that IT has to offer the analytical chemist, were very adequately met.Some partici- pants even went away with particular information relating to their own interests as a result of raising queries for demon- stration of on-line searching routines. The other update courses attracted smaller, but enthusiastic groups. This part of the SAC conference should, I believe, be nurtured and developed for the future. An active discussion of the role of analytical chemistry and the analytical chemist was promoted by Mr. D. C. M. Squirrell’s presentation of the findings of the Working Party on the Future of Analytical Chemistry. Practitioners of the discipline of analytical chemistry need to establish an identity and a comprehen- sible role in the light of rapid develop- ments towards increased instrumentation and automation. The conferees should have left Cam- bridge with new ideas, with increased awareness and with new professional friendships. By providing such opportuni- ties as these, the conference may be regarded as a success. As the memories of Cambridge mellow the anticipation of SAC 92 in Reading will grow and flourish. J . D. GREEN

ISSN:0144-557X    

DOI:10.1039/AP9892600417

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

418 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 New Members of Council A biography of Professor Stuart Bark was published in the July, 1980, issue of Analytical Proceedings. Since that time he has served his term as the President of the Division and Immediate Past President and also a term as a National Member of the RSC Council (1987-89). He has rep- resented the AD as an observer on the International Committee since 1981 and has been the Assessor for the Certificate in Applied Chemistry for the RSC since 1982. Outside of the RSC, he remained as Professor of Analytical Chemistry and Dean of the Faculty of Science of Salford University until 1984, when he was appointed Research Professor in Analyt- ical Chemistry. He has also undertaken a number of foreign visits as a Consultant.In 1984 he visited Albania on behalf of UNESCO, while in 1984, '86 and '87 he visited the Universities of Sokoto and Kano in Nigeria in connection with academic links with Salford. He has also visited the University of Malawi (1987) in order to establish a link with the Univer- sity of Salford. His research interests include rapid methods of assay of some industrial materials by use of thermal methods and the chromatography of Ian- thanide complexes. A biography of Dr. Denys Coomber appeared in the March, 1980, issue of Analytical Proceedings. He retired as the Honorary Assistant Secretary (Pro- grammes) of the Analytical Division in 1988 (after 20 years in post) and became Secretary of the Analytical Methods Trust in 1983. He served as a Vice-president of the Division in 1982-83.Faced with the prospect of writing a new biography or updating the last, Stan Greenfield (who admits to being as vain as the next man!) chose the latter course, since he did not write the last biography (published in July, 1982) and could not, in all modesty, emulate its flattering tone! After establishing the Plasma Spec- trometry Unit at Loughborough Univer- sity, Stan was appointed IndustrialANALYTICAL PROCEEDINGS. DECEMBER 1989, VOL 26 Professor at the same university, a post which he held from 1983 to 1986. He was then made Visiting Professor, a position he still holds. Tempting providence, he has just signed on for another three years! He describes himself as semi-retired, which means that his scientific work is undiminished but his income from such work is greatly so: he fulfils the RSC definition of retired. Stan sees this con- tinued interest in scientific work more as a conditioned reflex than a dedication! A late convert to atomic fluorescence spectrometry, which he believes to be a superior technique to emission, especially when inductively coupled plasmas are used as sources and as atomisers, Stan Greenfield has built, with his colleagues and postgraduate students, a unique instrument to which he has given the acronym ASIA (Atomiser, Source, Inductively Coupled Plasmas in Atomic Fluorescence Spectrometry).Despite having produced some eight or more papers detailing the progress which has been achieved with ASIA he feels exactly the same as he felt in the 1960s, when he was preaching to unbelieving colleagues the virtues of plasma in emission! Stan is in residence at the university about one week in five, commuting from Cornwall where he now lives. Having been persuaded by his family to sell his motorcycle, he has replaced it with an MGB roadster and a boat.After some quite hairy trips from Holland across France and around Spain with his son, last year he took the MG (and h i s wife!) on a 6000 mile tour of the entire coastline of Italy. Boating he regards as more dan- gerous than motorcycling, especially around Cornwall’s coasts. Stan still retains his love of wine, food and cooking and enjoys travelling as much as ever. Having bought a property in Tuscany he looks forward to spending more and more time there, interspersed with trips to more distant places, and is reconciled to the fact that he will have to pay for more and more of these out of his own pocket! A biography of Dr.M. A. Leonard appeared in the,August, 1983, issue (p. 396). David Littlejohn was born in Glasgow on May lst, 1953. He lived for 14 years in the Govan district of the city, close to the yards of “Upper Clyde Shipbuilders” (Jimmy Reid and all!). Having fallen into the Elderpark boating pond on at least three occasions he considers himself to be a true Govanite, which explains, in part, his tendency to frequent Ibrox Park in his youth! Although his family moved to East Kilbride, David continued to make daily trips to the city to attend the University of Strathclyde, where he obtained a First Class Honours degree in Chemistry in 1975 and a PhD in 1978. His research was conducted under the supervision of John Ottaway, who became a firm friend and mentor until his untimely death in 1986.David’s first job (and he claims his only real job!) after leaving Strathclyde was in the Research and Technology Depart- ment of ICT Petrochemicals Division at Wilton, near Middlesbrough. In 1981, he was enticed by John Ottaway to return to the University of Strathclyde to take up the Pye Foundation Lectureship in Analy- tical Chemistry. He was appointed a senior lecturer in early 1988 and, follow- ing John Ottaway’s death, became the first incumbent of the Philips Chair of Analytical Chemistry at the University of Strathclyde in August, 1988. Professor Littlejohn was awarded the fifteenth SAC silver medal in 1987 and currently serves on the Scottish Region Committee and the Programmes Com- mittee.He was appointed the Analytical Division Schools’ Lecturer for 1989/90 and will be the Scientific Programme Chairman of Euroanalysis VIII, to be held in Edinburgh in 1993. Professor Littlejohn is heavily involved 419 in the teaching of analytical chemistry at both undergraduate and postgraduate level at the University of Strathclyde and he has research interests in a wide variety of fields including atomic spectrometry, HPLC, ion chromatography, X-ray flu- orescence and radioanalytical techniques. He has published over seventy papers and has supervised more than thirty MSc and PhD students. He is married and his wife Lesley is also an analytical chemist with interests in chromatography.His busy professional life does not allow much in the way of spare time for hobbies, but if pressed, he will admit to having walked around the odd golf course (playing an odd style of golf!). Colin Peacock is Chairman of the North West Region of the Analytical Division of the RSC and lecturer in chemistry at the University of Lancaster. Coming origi- nally from Balham, in South West Lon- don, his first conscious career decision was to get out so, after finishing “A”- levels at Battersea Grammar School, he went to Bristol to study chemistry and stayed there to obtain a PhD, firstly with Dr. F. H. (Fred) Pollard and then, after Pollard’s untimely death, with Dr. Gra- ham Nickless. At that time his interests were in inorganic chemistry: his PhD topic was on the amido- and thiophosphates, but vibra- tional spectroscopy looked fascinating so he undertook postdoctoral research in Goettingen, FRG, with Dr.A. Mueller on vibrational analysis and model force fields. Marriage, and an innate patriotism, brought him back to England for postdoc- toral research on the Raman spectroscopy of polymers with Dr. Pat Hendra at Southampton. When Lancaster advertised, in 1969, for lecturers in inor- ganic chemistry, spectroscopy or polymer chemistry, he felt that must be the place to go. Over the years he has tried to keep fresh by changing his role inside the University: firstly spectroscopy and poly- mers; then moving towards analytical420 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 chemistry, spurred, no doubt, by an emotional attachment to his PollardlNick- less days.He also got elected to Lancaster City Council and found himself to be an expert on local government finance, eco- nomic development and town planning. He used these local connections when, for four years, he was part-time Industrial Liaison Officer for the University. More recently he has extended his interests in the analyst-as-problem-solver to develop the chemistry department’s analytical consultancy. The next chal- lenge is as an “enterprise tutor” to intro- duce the TA initiative “Enterprise in Higher Education” to the chemistry students. Outside chemistry he spends what time his three teenage daughters leave him by: tending his one acre garden; cooking and fermenting the produce therefrom; run- ning slowly; as Secretary of the local area association of Parish Councils; and as a sidesman in his village church.A biography of Dr. Diana Simpson appeared in May, 1984. Since then she has served as an Elected Member of Council until 1986 and from 1987 to the present, as an Elected Member of the Professional Affairs Board, 1986 to 1989 and 1989 to present, and a Member of the Working Party on Women Chemists from 1987 to the present. She currently represents the Analytical Division on the United King- dom Council for Food Science and Tech- nology, the Health and Safety Executive Committee on Analytical Requirements and the steering committee of Workplace Analysis Scheme for Proficiency (“WASP”), on whose behalf she is the Editor of “WASP News”. Dr. Simpson is a life member of the Institute of Directors and was the first woman to be elected Chairman of an IoD centre; she is still a United Kingdom delegate to International Standards on plastics (IS0 TC/61) and now also soil quality (IS0 TC/190), CEN committees, etc.She is a Fellow of the Royal Microscop- ical Society and a member of the Forensic Science Society. Her family-run consult- ing practice is a member of the Associa- tion of Consulting Scientists and the Union Internationale des Laboratoires Independants. Since last serving on the Council of the AD she has become a Fellow of the Institute of Food Science and Technology (FIFST) and a Chartered Engineer (CEng). The RSC recently published a book that she wrote with her husband entitled: “An Introduction to Applica- tions of Light Microscopy in Analysis.” Away from work Dr.Simpson is a member of the Royal Over-Seas League. Her hobbies still include reading, compil- ing and solving crosswords, trying to make herself proficient in computer pro- gramming and fending off the gentle attentions of her affectionate Great Dane (not the same one as in the last mention but another, more rumbustious, with the full name “Edstaston Blest Samantha”, which is frequently shortened to “dog!” or similar). She still enjoys watching cricket, sup- porting Essex and Lancashire, and says she was totally underwhelmed by the recent “ashes” series. Janet Warren was born in Lancashire but moved to Scotland at the early age of 5 weeks when her father, a chemist by training, was appointed Print Works Manager of the United Turkey Red Com- pany in the Vale of Leven, near to Loch Lomond. After attending the local school she studied Chemistry at Glasgow Uni- versity, where she gained a BSc degree.After graduation she took up employ- ment as a Research Assistant on an MRC funded project to investigate the Uptake of Fallout Strontium-90 in Children. This study was directed jointly by Professor John Lenihan, Professor of Clinical Physics, and successive Professors of Child Health at Glasgow University. Dur- ing this time Janet worked towards an MSc(1965) in Chemistry, and later a PhD which was awarded by the Medical Fac- ulty of Glasgow University in 1974. Her thesis was entitled “Studies in Strontium Metabolism.” In 1968 she was awarded an Exchange Fellowship to work in the Metabolic Unit of Dr.Herta Spencer at Hines V.A. Hospital near Chicago, and to gain further experience in the field of mineral metabolism. She spent three very rewarding years in Illinois before return- ing to continue her work in Glasgow. In 1972 Janet took up an appointment as Senior Biochemist in the Royal Hospi- tal for Sick Children in Glasgow, but in 1980 her interest in trace elements re- sulted in her returning to work in the Environmental Health Laboratory within Professor Lenihan’s Department of Clin- ical Physics and Bioengineering, Greater Glasgow Health Board. In 1984, with the retirement of J. M. A. Lenihan, this laboratory was amalgamated with the Trace Element Unit at Glasgow’s Royal Infirmary, where Janet is now employed as a Principal Biochemist with particular interest in occupational exposure to toxic trace elements.Janet first became involved in the Analytical Division’s Scottish Region Committee in 1980, and after two years as a Committee member she served as Assis- tant Secretary and then Secretary, before becoming Regional Treasurer in 1988. She enjoyed the fellowship of the SAC 83 Conference Organising Committee and is now hoping to put that experience to use in the planning of Euroanalysis VIII, which is to be in Edinburgh in 1993. Janet has also been an active member of the Scottish Region of the Association of Clinical Biochemists, and is currently serving on the Organising Committee for their annual National Meeting, to be held in Glasgow in 1991. Until recently Janet was very active in Girl Guiding, and was most recently a District Commissioner in the Vale of Leven, which is in the Guide County of Dunbarton.She is a committee member of the Glasgow Association of University Women and a representative on the Com- mittee of International Relations of the British Federation of University Women; she finds travel to the International meet- ings of IFUW particularly interesting. Other leisure interests include gardening and music. Phil Weston was born in Dartford, Kent, in 1943, but the family wisely moved back to its roots in Lancashire in 1948. After his initial education at Lancaster Royal Grammar School he obtained an Honours degree in Chemistry at Manchester Uni- versity in 1964. He then moved to the City University in London to do a Postgradu- ate (now MSc) course in the new area of Information Science; this was only the second year of running the first such course, with just six students, in a subject that is now available at several universi- ties.ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 421 In 1965 he travelled north again to join ICI Heavy Organic Chemicals Division at Billingham, Teesside, where he became a Senior Information Chemist in the Intel- ligence(!) Section.Here he developed and produced a number of internal in- formation and news bulletins and acquired his liking for the editorial and journalistic world. Deciding to move more directly into this field, in 1968 he joined the Society of Chemical Industry in London, where he was eventually promoted to Deputy Edi- tor of the Journal of Applied Chemistry, the British Polymer Journal and the Brit- ish Corrosion Journal and also assisted with the Journal of the Science of Food and Agriculture.However, in 1971 the Society decided to hive off most of its journals to a commercial publisher, retaining only the administrative function in-house. Avoiding being thrown on to the streets, Phil moved a couple of miles from Belgrave Square to Savile Row to join the SAC and Jimmy Attrill as his No. 2 on The Analyst and the then Proceed- ings of the Society for Analytical Che- mistry. With the reorganisation on amalgama- tion with the Chemical Society, Jimmy Attrill moved to the Books Department and Phil Weston took over as Editor of The Analyst and Analytical Proceedings. The journals flourished in the new envir- onment and a fairly static situation with The Analyst was turned into a steady expansion.The annual submissions of papers eventually increased over three- fold, and in 1988 it had the largest intake of any of the RSC’s journals except Chemical Communications. In the last few years the layout of the journals was substantially overhauled, the printing methods were changed and the covers modernised. The Journals Department of the (now) Royal Society of Chemistry underwent a complete reorganisation and expansion in recent years, and in 1981 Phil was pro- moted to Assistant Manager of Journals, responsible for the administration and other aspects of the Department. However, he retained his position as Editor of The Analyst and Analytical Proceedings, and assisted with the launch of the Journal of Analytical Atomic Spec- trometry (JAAS) in 1986.During his time with the RSC, he served as Secretary of the RSC Manage- ment Advisory Group and of the Journals Management Committee and was a mem- ber of the Analytical Editorial Board. He is currently a member of AD Programmes Committee. He is a Fellow of the RSC and a Member of the Institute of Informa- tion Scientists. In 1988 the RSC, in its wisdom, moved the bulk of its operations, including publi- cations, to a new building, Thomas Gra- ham House, in the Science Park to the north of Cambridge. After some heart searching, Phil and his family decided that the delights of the Siberian flat-lands were not for them and, as the Society made it far more attractive for long-serving senior staff to leave than to stay, he reluctantly resigned from the Society at the end of September, 1988.Since then he has been building up a long-standing freelance editorial opera- tion and now has his own business. He works for a number of commercial and society publishers in the UK, The Nether- lands and Germany in a varied range of scientific subjects, and reckons he has never worked so hard in his life! Phil is married with a 16-year-old daughter. His wife Janine teaches French at King’s School, Rochester, and in April 1989 they moved from south-east London to the Medway area where they are battling to excavate the flint from what the builder jokingly called a garden! With a love of walking and climbing, their main holiday is usually spent trying not to fall off the French Alps, and visiting Janine’s French family and friends.It also brings Phil closer to one of his sources of pleasure, good wine and food! Paul Worsfold is currently a New Blood Lecturer in Analytical Chemistry at the University of Hull. He was born in Christchurch, Dorset, in 1954 and was educated at the local grammar school and Brockenhurst College before studying at Loughborough University of Technology, where he obtained a BSc in 1976. In 1974/5 he gained industrial experience with Akzo in The Netherlands and AEG- Telefunken in the FRG. He then went to the University of Toronto in Canada and was awarded a PhD in 1980 for work in the field of biosensors. A Royal Society postdoctoral fellowship then took him to the Technical University of Denmark in Copenhagen, where he was initiated into the world of flow-injection analysis (FIA). This was followed by a lecturing appointment at Sheffield City Polytechnic in 1981 and the move to his present position in 1984. His current research interests include FIA, analytical applications of chemi- luminescence, environmental analysis (particularly water quality monitoring) and instrumentation for process analysis. He has over 50 research publications and was recently awarded the SAC Silver Medal. He is currently Chairman of the North East Region and Treasurer of the Molecular Spectroscopy Group. Dr. Worsfold lives in Cottingham with his Canadian wife Linda and their one year old daughter Alison. He has an all embracing interest in sport and his blood is still new enough to represent the University at squash, cricket and indoor cricket, but has thickened sufficiently to make him hang up his football boots this season.

ISSN:0144-557X    

DOI:10.1039/AP9892600418

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

422 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 The Analytical Chemistry Trust An article describing the creation of the Trust and the ways in which the interest accruing from the invested capital of the Trust Fund is used to further the objects of the Trust was published in the July, 1988 issue of Analytical Proceedings. The statement of account for the year ending December 31st, 1988, is presented below. The RSC Analytical Chemistry Trust Fund Income and Expenditure Account for the Year Ended December 31st, 1988 INCOME Income from Investments . . . . . . . . . . . . . . . . . . . . . . . . Interest on Deposit Accounts (Note 1) . . . . . . . . . . . . . . . . . . Less: EXPENDITURE Contribution to Expenses of RSC Analytical Division . . . . . . . . . . . . . . Studentships, Grants and Prizes .. . . . . . . . . . . . . . . . . . . . . Student Bursaries . . . . . . . . . . . . . . . . . . . . . . . . . . Gold and Silver Medals . . . . . . . . . . . . . . . . . . . . . . . . Audit Fees . . . . . . . . . . . . . . . . . . . . . . . . . . . . Legal and Professional Fees . . . . . . . . . . . . . . . . . . . . . . Donations to New Groups . . . . . . . . . . . . . . . . . . . . . . . . Production of Video . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous Expenses . . . . . . . . . . . . . . . . . . . . . . . . EXCESS OF INCOME OVER EXPENDITURE CARRIED TO BALANCE SHEET . . . . . . . . . . E 164 866 52 067 2 216 933 29 850 34 644 500 2 798 1150 18 526 23 480 - 110 948 2105 985 NOTES- investments is accounted for on a receipts basis.1. Interest on Deposit Accounts includes accrued interest, but income on fixed interestANALYTICAL PROCEEDINGS. DECEMBER 1989, VOL 26 Balance Sheet INVESTMENTS AT COST Quoted Investments (Market Value f 3 532 752) Balance as at January lst, 1988 . . . . . . Add: Investments Purchased During the Year Less: Cost of Investments Disposed of CURRENT ASSETS National Savings Investment Account National Savings Deposit Bonds National Savings Income Bonds . . Deposit Account with Bank . . Investment Deposit Account . . Income Tax Recoverable . . . . Cash at Bank . . . . . . . . Sundry Debtors . . . . . . . . RSC Loan. . . . . . . . . . Less : Sundry Creditors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . f 2 731 508 1523 013 423 6: 4 254 521 1 141 934 3 112 587 118 379 118 812 50 000 310 000 121 283 42 524 25 419 29 843 19 495 . . . . . . . . . . . . 835 755 105 858 729 897 &3 842 484 ADVANCED BY TRUST CAPITAL ACCOUNT Balance as at January lst, 1988 . . . . . . . . . . . . . . . . . . . . . . 2 462 603 Add: Profit on Sale of Investments 312 792 . . . . . . . . . . . . . . . . . . . . 2 775 395 INCOME AND EXPENDITURE ACCOUNT Balance as at January lst, 1988 .. . . . . . . . . . . . . . . . . . . . . 961 104 Add: Excess of Income over Expenditure for the Year 105 985 . . . . . . . . . . . . 1 067 089 &3 842 484 Voluntary Service Overseas The Trustees of the Analytical Chemistry now announced that Mr. Gregory benefit from this support. Mr Archer will Trust recently approved expenditure on Archer, who holds the BSc degree in work at Bikita, Zimbabwe, and will (it is supporting a volunteer within the Volun- Environmental Sciences from the Univer- hoped) report on his work in these col- tary Service Overseas programme. It is sity of East Anglia, is the person who will umns. LIGHT MICROSCOPY WORKSHOP ON THE IDENTIFICATION OF FOOD HYDROCOLLOIDS Wednesday June 6th, and Thursday June 7th, 1990 This meeting will be organised by the Department of Food Science, University of Leeds, together with the Laboratory of the Government C h em i st. For details write t o Dr. Olga Flint, Department of Food Science, University of Leeds, Leeds LS2 9JT.

ISSN:0144-557X    

DOI:10.1039/AP989260422b

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

424 Analytical Viewpoint The following is a member of a continuing series of articles providing either a personal view of part of one discipline in analytical chemistry (its present state, where it may be leading, etc.), or a philosophical look at a topic of relevance to chemists in general or analytical chemists in particular. These contributions need not have been the subject of papers a t Analytical Division Meetings. Persons wishing to provide an article for publication in this series are invited to contact the editor of Analytical Proceedings, who will be pleased to receive manuscripts or to discuss outline ideas with prospective authors. An Intelligent Sample Changer C. Angelikaki and M. Usher DeDartment of Cvbernetics, The Universitv of Reading, 3 Earley Gate, Whiteknights, Reading, Berkshire RG6 2A L There is an urgent need to automate laboratory analysis in the radiochemical industry.The most important reasons are: improvements in sample throughput; improvement in sample analysis reproducibility; release of qualified staff; flexibility in changing procedures; and removal of staff from hazardous chemicals and environments.’ Although several specially designed sample changers are available, none of them uses any form of “intelligence” in the manipulation of the samples. This paper describes the development of an intelligent sample changer. The sample changer used was provided by AERE Hanvell. It is a cylindrical geometry manipulator, supplied with a variety of end-effectors, such as grippers and sensors, suitable for different tasks.The materials used during a particular test are supplied to the manipulator in trays or sample holders in accurately specified positions within the robot’s working area. No proximity or visual sensors are used to guide the robot, which is driven by stepper motors and has a positional accuracy of about 1 mm.2 ANALYTICAL PROCEEDINGS. DECEMBER 1989. VOL 26 The intention of this project was to provide the Hanvell manipulator with a real-time low cost vision system, which in a second stage would be used to optimise the search and thus the performance of the sample changer. The vision system registers and reads labels containing strings of alphanumeric characters. In order to be suitable for real-time operation fast techniques for digitisation, image processing and classification were required.The Optical Sensor and the Digitiser Two types of optical sensor were tried. The first was the Microneye camera, whose sensing device consists of the IS32 optic RAM chip, composed of 64 k light-sensitive elements (Micron Technology3). It was found that the camera has two severe disadvantages for this application, both concerning the topology of the chip. Firstly, the separations of the cells are not equal, resulting in the elongation of images, and secondly there is a “dead” horizontal line in the middle of the image resulting I d K L ’-10 Fig. 1. The character setANALYTICAL PROCEEDINGS. DECEMBER 1989, VOL 26 425 in loss of information. The second camera, and the one used in the project, was the Hitachi KP-220 solid-state, black and white ultra-compact camera.It consists of an array of MOS-type imaging devices with a resolution of 320 by 244 elements. Fig. 2. A typical label A low-cost scanning binary digitiser was needed to transfer the data directly to the screen memory of the BBC computer. The digitiser was designed so that during each video frame, an 8-bit, 244 lines long column, is digitised. This was achieved by making eight comparisons in sequence and transferring the data to a serial-to-parallel shift register. The byte of informa- tion was created in such a way that it was in the format required for the BBC screen and the 320 by 244 binary image was produced in less than 2 s, which is adequate for this application. The Character Set and the Labels Each sample presented to the sample changer normally has a bar-code label attached to it containing important information about the sample.Characters contain much more information in a given space than bar codes and a stylised human-readable character set was designed to replace them. The characters consist of straight lines and are designed to fit a rectangular grid. The character set is shown in Fig. 1. Ten characters are placed in two rows and are enclosed by a rectangle of 14.5 by 10 mm. The rectangle is used to register the label and calculate its orientation. The bottom left character is a triangular symbol consisting of the left hand vertical line of the grid, the bottom horizontal line and the diagonal which connects the two loose ends of these lines. As the distance between the characters is always the same, once the triangle is found and accurately located the coordinates of the grid, where the rest of the characters lie, can be calculated.Another rectangular “blob” symbol is placed just above the triangle in between the two rows of characters. This ensures that the label is in the upright position and gives a first estimation of the triangle’s location. A typical label is shown in Fig. 2. Registration of the Label The first problem encountered was that of detecting the presence of the label in the image area of the camera. The background of the image was expected to be blank, and two light bulbs installed on either side of the camera were used to ensure that no shadows were thrown on the image. The detection of the label is performed in two steps.First the image is segmented, so that areas where a large population of black pixels exist are located. Then, a localised search is performed to find the exact position of the label (rectangle) on the screen. This is carried out by scanning the image (vertically and horizontally) at specified heights and widths. The first and last occurrence of black bars indicates the location of the rectangle. Visual feedback is applied to the robot until all the label is in view. Screen Rotation Once the label is registered, a further check is performed to find its orientation on the screen. The angle of rotation is measured with reference to the horizontal axis of the screen. As will be described below, the character recognition is Fig. 3. Results of screen rotation426 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 performed by pattern matching, so the rotation problem can be solved either by rotation of the pattern or rotation of the screen.We opted for the latter solution because pattern rotation is computationally expensive and we were able to rotate the screen very quickly and efficiently as described below. Instead of rotating the screen point by point, a character by character (8 bit x 8 bit) rotation can be achieved at the expense of some distortion. A clockwise rotation is achieved as follows. First, the original image is stored in a block of memory. Then, working with each 8 bit column, each character is placed under the previous one but shifted rn pixels to the left. For the following column, and each column until the whole image is processed, the top character of the column is placed rn pixels down and the characters below it are placed as before.By varying the number of pixels to be shifted and the frequency of the column shifting, different degrees of rotation can be achieved. A look-up table is incorporated into the algorithm to enable a correct rotation to be obtained. The gaps that result from the rotation are removed by a fast noise-removal algorithm. The results are shown in Fig. 3. Fig. 4. Character skeletons Solving the Character Recognition Problem Thinning A first stage in most character recognition tasks is to thin the characters and then analyse their skeletons.4 Thinning is a very computationally expensive task, but as the label on the screen has a fixed size, the exact location of the character is known, which simplifies the problem.In order to find the skeleton of a character the grid on which the character is based is placed over it. An “and” logical function of the pixels of the grid with the pixels of the screen under it reveals the skeletal shape, which is one pixel wide. The individual lines from which it is formed are used as the “features” of the character, as described below. A typical label showing the characters and their skeletons is shown in Fig. 4. Pattern Matching The 20 lines that comprise the character grid can each be described by the equation of a line Y = rn * X + b. In order to check the existence of a certain feature on the screen, the coordinates of each point of the feature are calculated and the pixels on the screen that correspond to these coordinates are checked.The feature exists if the number of points found on its line exceeds a certain threshold. The thresholds for each feature are measured empirically and depend on the size of the character and the positional relation of the feature with respect to the other features of the character. A table of acceptable feature combinations ensures that there are very few inconsis- tencies. The Binary Tree Classifier The most usual approach in classifying the characters statistic- ally is to design a one-stage classifier that calculates the probabilities for every class of the problem. The pattern space is divided into the number of classes which describe the classification problem (36 in our case) and the classifier assigns the unknown input to the class with the smallest distance from it.5 This approach is time consuming because the same amount of calculation is needed for each input irrespective of its structural characteristics.In this work a binary tree classifier was designed instead. The way that each feature contributes to the values of the other features for each character was first analysed and recorded on a coincidence plot. From this analysis the characteristics and the particular difficulties in measuring the features were deduced. Then the binary tree classifier was designed, which accepts the unknown input at the root and carries it to a leaf (a class) according to its structural characteristics. The tree is shown in Fig. 5.Fig. 5. Binary tree classifier A tree classifier has a number of advantages.6 It has high classification accuracy as only features which are pertinent at a given stage are used. In addition, there is a reduction in computational cost and a natural division into classes. Results and Conclusions The system was tested on thirty labels, placing six labels at a time in their nominal positions on the sample tray. The results were very satisfactory, and the confidence matrix of Fig. 6 wasANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 427 ..... A... II ... C... I) ... A ... 64.. 0 .... 0. ... 0 .... I1 .... C .... U .... li ... [-‘----(i .... I I - - - I . . . . J - - - - K . . . I . - - - h l . . N - - - O _... l’----Q .... H - - - S .... ’ l - - - U .... V - - - W .. . X - - - Y .... Z - - - 1 _.... 2 - - - - 3 ...._ 4 - - - - 5 ._,. 6 ...._ 7 _.._.. 8 ,.,_ y _,__ 0 0 ..... 0 ..... 0 ..... 0 ..... 0----0 ..... 0 - - - - 0 ..... 0----0 .... o----0 ..... 0--0 ..... 0----0 ..... 0----0 ..... 0---so ..... 0----0 ...., 0 - - - - 0 .... 0 - - - - 0 _.... 0----0 ..__. 0 - - - - 0 ...,_ 0 ,,,., 0 ,,_.,, 0 ,,,_ 0 _,,. 0 M... 0 ...._ 0 ___. 0 ..... 0 - - - - 0 ...., 0----0 ... . 0 - - - - 0 ..... 0 - - - - 0 . .. 0 - - - - 0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 ..... 0--0 ..... 0----0 ..... 0----0.. .. 0----0 _.._. 0 - - - - 0 ,..._ 0 ..._ 0 .,,,,. 0 ,,__ () _,,, 0 . 0 - - - - 0 ..... 0 - - - - 0 .... 0 - - - - 0 ..... 0----0.. .. 0--0 ..... 0 - - - - 0 . .. 0----0 ...__ 0 - - - - 0 .._. 0 - - - - 0 ._.. 0 .,__. 0 (__,_, 0 _,,_ 0 ,.,, 0 0 .....0 .....a,.. 0 ..... 0----0 -... 0 - - - - 0 ..... 0 - - - - 0 . . . 0----o .... 0 - - - - 0 ..... 0 - - - - 0 .... 0 - - - - 0 .... 0----0 ..... 0----0 ..... 0----0 .... 0----0 _,... 0 - - - - 0 ._.. O - - - - 0 __.._ 0 __._, 0 .,,,,, 0 _,., 0 ..., 0 li ... 0 ..... 1 ,.... 0 ..... 0 .... 63 ... 0 - - - - 0 .... 0----0 .... 0----0 ._.. 0 - - - - 0 .. 0----0 _.... 0 - - - - 0 ... 0 - - - - 0 ._... 0----0 _.... 0----0 .,,._ 0 - - - - 0 ._._. o----o _.,, o----o ..,,. 0 - - - - 0 ..,,( 0 . , ( , 0 ,,,_,, 0 ,_,, 0 ,,,, 0 I‘ ... O..... 0.....0..... O..... O..... 62 -- O..... 0-1--0 ..... 0----2 .... 0 - - - - 0 .... 0--7-0 _... 0----0 ..., 0----0 ..... (i ... 0 ..... 0 ..... 0 ..... 0 ..... 0 ..... 0 - - - - 64.. 0 - - - - 0 . .. 0 - - - - 0 ....0 ---0 .... 0----0.’ _... 0----0 ..... 0----0 ..... 0----0 . _ _ _ . 0--0 .,... 0 - - - - 0 .,... 0 - - - - 0 . _ _ . _ o----o , , _ , 0----0 ,.,,_ 0 , _ _ , 0 ,-,_,, 0 .__, 0 ,,,, 0 H... 0 ..... 0 ..... 0 ..... 0 ..... 0 .... 0----0 ..... 64 - 0 .... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 ..... 0----0 0----0 ..... 0----0 ..... 0--0 ..... 0 - - - - 0 ..... 0 - - - - 0 .. . 0 - - - - 0 . _ . _ . 0 - - - - 0 _..._ 0. .._ 0 ..(... 0 .,.. 0 ,_,. 0 I .... 0 ..... 0 ..... 0 ..... i) ..... 0 ..... 0----0 .... 0-7- a... 0----0 ..., 0 - - - - 0 ..... 0--0 ..... 0----0 .__. 0----0 ...._ 0----0 ..... 0--0 _._._ 0----0 ...._ 0 - - - - 0 . _ _ o----o .,,_, o----o ._,_, () ,,.. 0 _., , 0 _(,, 0 (,(. 0 J . . . . O..... O..... O..... O..... O..... O - - - - O ..... O - - - - O.....64 - - 0 .... O - - - - O .... 0----0 ..... 0----0 ..... O - - - - O ..... O----O ..... 0----0 .... 0-- - - O..... 0---- O..... 0---- O..... 0----O.... 0 _... 0 .__.. 0 __.. 0 .,.. 0 K... O..... O.....O..... O..... O..... O----O ..... 0----0 .... O----&.. 0 - - - - 0 . ... 0 - - - - 0 ..... O - - - - O ..... O - - - - O ..... O----O ..... 0----0 ..... O - - - - O .... 0---- O..... 0---- 0 .... 0. ... O... ._ 0 _... 0 .... O I .... 0 ..... 0 ...__ 0 ..... 0 ..... 0 ..... 0----0 ..... 0 - - - - 0 .... 0----0 ...61 - - 0 .... 0 - - - - 0 ..... 0----0 ..... 0--0 ..... 0----0 ..... 0--0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0---,0 ..... 0 ..... 0 ,..... 0 .._. 0 .._. 0 M..o.....o.....o..... o..... o.....o----o..... 3-0 .... o----0 .....o----sH . 3 - - 0 ..... o--0 ..... o--0 ..... O----0 ..... o----0 ..... o----0 ..... o----0 ..... o----0 .... o- - - - o..... o .... o...... o.... n.... o N... 0 ..... 0 _.... 0 ..... 0 ..... 0 ..... o--.-o ..... o----o ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 64 --0 ..... 0----0 ..... 0----0 ..... 0----0 ..... 0--0 ..... 0--0 ..... 0----0 ..... 0----0 _.... 0----0 ..... 0 ...., 0 ...... 0 .... 0 .... 0 o... 0 .,... 0 ...., 0 ..... 0 .... 0 ..... 0----0 ..... 0--0 ..... 0 - - - - 0 ... . 0 - - - - 0 ..... 0---- a,.. 0----0 ..... 0----0 ..... 0----0 _._._ 0--0 (.._. 0----0 .,... 0 - - - - 0 .,_,, o----o _ , _ . o----o _,., 0 (,,,, 0 ,,_,., 0 ,_, 0 _ _ _ , 0 P...O.....O.....O..... o..... o.....o----o..... 0 - - - - 0 ..... 0----0 .... 0 - - - - 0 ..... 0----0 .....a -- o.....o----o.....0----0 ..... 0----0 ..... 0 - - - - 0 . . 0- - - - o..... 0 - - - - 0 .... 0 - - - - 0 .... O.....O...... o.... o.... 0 0 ..... 64... 0 ..... 0 _.... 0 - - - - 0 ..... 0----0 .... 0--0 . .. 0----0 O - - - - O ,,,, o,,.,, 0 ,,,,. 0 _, , 0 ,,,, 0 Q... O..... 0. ... O..... O..... O..... O----O ..... O----O ..... O - - - - O ..... O----O ..... 0----2 ..... 0----62 ... 0----0 ..... 0----0 ..... 0----0 ..... 0- --- O..... 0----0 .... 0.- - - O..... 0 ._._ 0 ...,. 0 .__. 0 _ _ _ . 0 H... O..... O..... O..... O..... O..... O----O ..... O - - - - O ..... O----0 ..... 0 - - - - 0 . ... 0----0 ..... 3----0 ..... 61 -- O..... 0----0 ..... 0----0 ..... 0 - - - - 0 ..... 0---- 0 ..., 0 - - - - 0 ..... 0----0 ..... O.... O...... 0 ._.. 0 . _ _ _ 0 s ...0 ..... 0 ..... 0 ..... 0 ..... 0 ..... 0----0 ..... 0--0 ..... 0 - - - - 0 .... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 .... 0----64... 0----0 ..... 0--0 ..... 0 - - - - 0 ..... 0 - - - - 0 .... 0 - - - - 0 ..... 0 - - - - 0 ..... 0 ..... 0 ..... 0 ..,. 0 .... 0 T... O..... O..... O..... O..... O..... O----O ..... O----O ..... 0----0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 ..... O - - - - O ..... 64 -- O..... 0----0 ..... O---- O . . . . . 0---- 0 _... 0 - - - - 0 ..... 0 - - - - 0 .... 0 .... O...... 0 .... 0 .... 0 u... 0 ._... 0 .._.. 0 ..... 0 ..... 0 ..... 0----0 ..... 0----0 ...._ 0----0 ...._ 0----0 .,... 0--0 ._... 0----0 ..._. 0----0 _.... 0---- 64.. 0----0 ..._. 0--0 .... 0 - - - - 0 .... 0----0. ... 0 - - - - 0 ..... 0 ..... 0 ......0 .... 0 .... 0 v... 0 ..... 0 _.... 0 ..... 0 ..... 0 ..._. 0--0 ...._ 0----0 ..... 0 - - - - 0 .... 0 - - - - 0 .._.. 0----0 .,_._ 0----0 ._._. 0 - - - - 0 _.... 0----0 ..... 59 - 0 ..... 0 - - - - 0 ..... 0 - - - - 0 ._... 0 - - - - 0 ..... 0 - - - - 0 .... 0 .... 0 ...... 0 .... 0 .... 0 x... 0 ..... 0 ..... 0 ..... 0 ._... 0 _.... 0--0 ..... 0----0 ..._. 0----0 .._.. 0 - - - - 0 ..__. 0--0 .._.. 0----0 ..., 0 - - - - 0 ..... 0--0 ..... 0--0 ..._. 64 - - 0 . _ . 0----0 _ _ . 0----0 ..... 0 - - - - 0 ..... 0. ... 0 ...... 0 .... 0 .... 0 Y... o..... o..... o..... o..... o.....o----o..... o----0 ..... o----0 ..... o----0 ..... o----0 ..... o----0 ..... o----0 ..... o----0 ..... 0-0 ..... o - - - - a ... 0-0 ..... o----0 ..... o----0 ..... o..... o ..... o ....o .... o W..O..... O.....O..... O..... 3----0 .... 0----0 .... 0 - - - - 0 ..... 0----0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 ..... 0----61 ... 0 - - - - 0 .... 0 - - - - 0 ... . O - - - - 0 .... 0 - - - - 0 .... 0 . ..O ..... 0 .... 0 .... 0 Z... O..... O..... O..... O..... O..... 0 - --- O..... 0----0 ..... 0----0. .., 0 - - - - 0 ..... 0----0 ..... 0 - - - - 0 ..... 0.- -- O..... 0----0 ..... 0---- O..... 0----0. _.. 61 -- O . . . . . 0---- 3..... O----0 ..... O..... 0 ..... O .... O .... O 1 ... O..... O..... O..... O..... O..... 0----5 ..... 0 - - - - 0 ..... 0 - - - - 0 ... . 0----0 ..... 0----0 .,.. 0----0 ..... 0----0 ..... 0----0 __._ 0----0 ..... 0----59 ... 0----0 ..... 0 - - - - 0 ..... O..... O...... 0 .... 0 .... 0 2 ... 0 ..... 0 _....0 ..... 0 ..... 0 _.... 0----0 _.... 0--0 _..._ 0--0 .__.. 0----0 . . _ _ . 0----0 .._.. 0--0 ..__ 0--0 ..... 0----0 ..... 0--0 __.. 0--0 ._... 0----0 ..... 64 - - 0 _.,._ 0 - - - - 0 ..... 0 ..... 0 ...... 0 .... 0 .... 0 3 ... 0 ..... 0 ..... 0 ..... 0 ..... 0 ..... 0----0 ..... 0--0 ..... 0--0 .... 0--0 ..... 0----0 ..._. 0----0 __... 0----0 ..._. 0--0 ..... 0--0 ..... 0----0 ..... 0----0 ..... O - - - - a , . . 0 - - - - 0 .... 0 ..... 0 ...... 0 .... 0 .... 0 4 ... 0 ..... 0 ..... 0 ..... 0 ..... 0 ..... 0----0 .._.. 0--0 _.._. 0----0. .._ 0----0 ..._. 0--0 ..... 0 - - - - 0 ._... 0 - - - - 0 ..._. 0--0 ._.__ 0----0 __.. 0----0 ._.. 0----0 .... 0--0 ..._. 63 - - 0 .... 0 .... 0 ...... 0 .... 0 .... 0 5 ... 0 ..... 0 _.... 0 _.... 0 ..... 0 _.... 0----0 _.... 0----0 .....0----0 ._... 0 - - - - 0 ..._. 0----0 ___._ 0----0 ...._ 0----0 ..._ 0--0 _.._. 0--0 ..... 0 - - - - 0 ..... 0 - - - - 0 ..... 0----0 .... o - - - - a ... 0 ..... 0 ..... 0 .... 0 .... 0 6... 0. .... O..... O..... O..... O..... 0----O..... 0----0. ... 0- -- O..... 0-- -- O..... 0----0 ..... 0----O..,.. 0---- O..... 0----0 .. . 0----0 ..... O----0 ..... 64... O...... O .... O .... O 7 ... 0 ..... 0 ..... 0 ..... 0 ..... 0 ..... 0----0 ..... 0----0 ..... 0--0 ...., 0----0 _.... 0----0 _.... 0----0 __... 0--0 ..... 0----0 ...._ 0----0 _.._. 0----0 ..... 0----0 ..... 0 - - - - 0 ..... 0--0 ..... 0 ..... 64 .... 0 .... 0 .... 0 8 ... 0 .,... 0 ..... 0 ..... 0 ...._ 0 ..... 0----0 ..... 0--0 ..... 0--0 ..... 0----0 ..... 0----0 ..... 0----0 ___._ 0--0 ...._ 0----0 .....0----0 .,... 0----0 ..... 0----0 ..... 0----0 ..... 0----0 ..... 0 .... 0 ...... 64 .. 0 ._.. 0 9 ... 0 _.... 0 ..... 0 ..... 0 ..... 0 ..... 0----0 ..... 0----0 ..... 0--0 ..... 0--0 ._... 0----0 ..... 0----0 ...._ 0----0 ..... 0----0 .._.. 0----0 ._... 0--0 ..... 0--0 ..... 0--0 ..... 0----0 ..... 0 ..... 0 ...... 0 .... 64 .. 0 0 ... 0 ..... 0 ..... 0 ..... 0 ..._. 0 ..... 0--0 ..... 0----0 ..... 0--0 ..... 0----0 ._... 0--0 ..... 0----0 _._._ 0--0 _.... 0--0 ..... 0--0 ..... 0----0 ..... 0----0 ..... 0--0 ..... 0----0 ..... 0 ..... 0 ...... 0 .... 0 .... 59 Fig. 6. The confidence matrix constructed. Unstable characters were found to be those which consist of a large number of lines, such as M and W, or very similar characters such as I and 1.The error rates are very dependent on illumination conditions and it is not easy to improve the recognition rates for these characters. If the complete character set is not needed for some application such characters could be omitted, but otherwise very tight control of environmental conditions would be required.’ The aim of this research was to add a low-cost character recognition system to the Harwell sample changer, with a view to the development of an intelligent self-optimising sample changer. This would read all the labels on the samples presented to it, and decide on the best programme of analysis for the complete set. Although limitations in computer memory imposed various restrictions, it has been shown that by devising fast techniques for digitisation, image processing and classification, a reliable low-cost real-time vision system can be produced using a small computer. The authors wish to express their thanks to AERE Harwell for their loan of equipment and for their help and encouragement in the project. References 1. Huddleston, J., Anal. Proc.. 1988, 25, 178. 2. Huddleston, J., “A Stepper Motor Controller Utilising MOUSE Module Hardware,” AERE Harwell Report R9766, 1980. 3. Micron Technology Inc. “IS32 Optic Ram.” 4. Ballard, D. H., and Brown. C. M., “Computer Vision.” Prentice Hall, Englewood Cliffs, NJ, 1982. 5 . Fukunaga, K., and Hammels, D. M., “Bayes Error Estimation Using Parzen and k-NN Procedures,” IEEE Trans. PAMI, 1987, 9, 634. Swain, P. H., and Hauska, H., “The Decision Tree Classifier; Design and Potential,” IEEE Trans. Geoscience Electr., 1977, 15, 142. Angelikaki, C., “An Intelligent Sample Changer,” PhD Thesis. Department of Cybernetics, University of Reading. 1988. 6. 7. MICRO 90 Hammersmith, July 2nd-6th, 1990 As a result of discussion between the Micro & Chemical Methods Group of the Analytical Division and the Royal Microscopical Society, it has been agreed that members of the Analytical Division may register for MICRO 90 at the same reduced rate as members of the RMS. Further details, and a copy of the “Call for Papers” can be obtained from the Group Secretary, Mr. P. R. W. Baker, 55 Braemar Gardens, West Wickham, Kent BR4 OJN (Tel. 01-777-1225).

ISSN:0144-557X    

DOI:10.1039/AP9892600424

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS. DECEMBER 1989, VOL 26 428 Determination of Trace Contaminants in Food and Drink The following are summaries of four of the papers presented at the Joint Meeting of the Scottish Region and the Chromatography and Electrophoresis Group held on March 14-1 5th, 1989, in Heriot-Watt University, Edinburgh. Contaminants, Taints and Off-Flavours in Beer N. A. Silk Scottish & Newcastle Beer Production Ltd., 760 Canongate, Edinburgh Raw Materials The potential for contamination in beer occurs at all stages of the brewing process and can be of both biological and non-biological origin. Taking as the starting point the arrival of malt in the brewery, the malt itself must be of the correct quality and the barley used must have been properly malted. Sources of contamination of the malt include micro-organisms, both from the original barley and due to incorrect storage of the malt, and pesticide residues.It is possible that these contaminants of the barley and malt can be found in the final beer. An example of this which was recently described was the presence of 1-napthol in beer, this compound being a hydroly- sis product of the pesticide carbaryl . I Mycotoxins from fungal growths have only been shown to be carried through into beer under artificial conditions. and then at very low levels,’ but what has been well documented is the phenomenon of gushing in beer induced by fungal polypeptides.3 The addition of water to the ground malt, leading to solubilisation and hydrolysis of protein and starch, and giving a fermentable wort, provides another possible source of contam- ination.With the use of mains water, the acceptability of the water is essentially taken for granted. However, as far as the brewer is concerned, the presence of certain ions is desirable, and it is common to add Ca’+ and SO4’- ions. The addition of hops to sweet wort and the subsequent boiling of the wort for approximately 1 h provides another potential source of pesticide contamination. Hops are also known to be able to transfer not inconsiderable amounts of nitrate to the boiling w0rt.j Fermentation and Microbiological Contamination After boiling, the wort is cooled and yeast is added. This should be done as quickly as possible, and the yeast culture should not be contaminated. In our breweries the yeast is acid-washed prior to pitching in order to destroy any acid-sensitive micro-organisms, although this is by no means a universal practice.During fermentation yeast produces, as well as ethanol, a wide range of higher alcohols, carboxylic acids, esters and various other organic compounds. In a good beer, the compounds enhance one another and produce a well-balanced flavour. When the fermentation “goes wrong,” some of these flavours get out of hand. For instance, there is the buttery taste and smell of diacetyl (butane-2,3-dione) associated both with deficient worts and contaminating bacteria. Contaminating baceteria can produce a variety of off-flavours, including acetic acid, lactic acid and sulphur containing compounds, while yeast contaminants can give estery and phenolic off-flavours. The course of the fermentation can be regularly monitored, both for carbohydrate uptake and ethanol production, while one of the common methods of analysis of flavour/aroma compounds is headspace analysis; samples are placed in enclosed vessels and, after equilibrium has been attained, the headspace is analysed by gas chromatography.Microbiological contamination can often b e seen in results from the above methods, and isolation of contaminating organisms, both during and after fermentation, is practised by propagation on selected media. The medium can be both deficient in certain compounds ( e . g . , contain lysine as the only nitrogen source, for the isolation of wild yeasts) or can contain additional compounds ( e . g . , copper sulphate, again for the isolation of wild yeasts, or cycloheximide, which inhibits yeasts and moulds at a high enough concentration).More specialised tests, to identify individual strains, such as immunofluor- escence, polyacrylamide gel electrophoresis. etc., can be carried out but are not routinely used. After beer has been packed and pasteurised, further microbiological tests are performed to check for the presence of any micro-organisms. Samples are plated on a non-selective medium, since the presence of any organisms is undesirable. A recent and more rapid method involves the determination of ATP, which is present in all living organisms. The test, based on the luciferin - luciferase system, seems to be gaining acceptance in the brewing industry. Packaged Beer At all stages of the brewing process contamination from OH Iso-&-acids [R = CH(CH3)2 CHz-CH(CH3)z I CH3 or CH -CH,-CH3] *Y -co/ I SH 3-Methyl but-2-ene-1 -thiol Fig.I . Decomposition products of iso-&-acidsANALYTICAL PROCEEDINGS. DECEMBER 1989. VOL 26 429 vessels, pipes, etc., can occur, and similarly contamination from the final packaging material is not unknown. Further- more, the type of packaging material can be important for one of the recognised flavour defects in beer, that is, when beer is packaged in clear bottles. Exposure to strong light leads to the formation of so-called “sunstruck” flavour in beer, due to the formation of 3-methylbut-2-ene-I-thiol. This is derived from the bitter iso-a-acids in beer. At wavelengths below approxi- mately 300 nm the iso-a-acids are degraded to a complex mixture of products,5 while at wavelengths above 300 nm the side chain at the C-4 position is cleaved, giving one of the two radicals shown in Fig.1. Reaction of the 3-methylbut-2-ene radical with a thiol produces 3-methylbut-2-ene-1-thiol. The main interest on sunstruck flavour at Scottish and Newcastle is concentrated on Newcastle Brown Ale, which is sold in clear glass bottles. To determine 3-methyl-2-ene- I-thiol, nitrogen is bubbled through the beer and the volatiles trapped on a synthetic adsorbent. These are desorbed by rapid heating and analysed by gas chromatography with flame photometric detection. In forcing tests, we can detect 3-methylbut-2-ene-l-thiol, but because market pressures prevent us replacing the clear bottles, prevention in the form of proper storage has to be the only counter measure.It is known, though, that reduced iso-a-acids (that is, where the carbonyl group on the C-4 side chain is reduced to an alcoholic group) are not susceptible to sunstruck flavour,h and indeed at least one American brewer uses these. As regards contamination from the packaging, we were recently involved in evaluating kegs coated with a new lacquer. It was noticed that keg rinsings had an “organic” smell, and subsequent analysis showed the presence of isophorone (3,3,S-trimethylcyclohex-2-en- 1-one), the solvent for applying the lacquer. Obviously, the new kegs were not used. Conclusion This paper can only give a brief overview of some o f the causes of contamination and off-flavours in beer.There is very much more that could be included; t h e influence of malts on the final flavour has not been covered at all, while the various flavours produced by brewing yeast, let alone contaminants, has only been briefly mentioned. However, all sources of contamina- tion and off-flavours are controllable, and the vast majority of beer produced in this country is of a consistent quality. Whether you like it is, of course, another matter. I would like to thank the many members of the Research and Central Laboratories with whom I have had much helpful discussion and also the Directors of Scottish and Newcastle for permission to publish this work. References 1. 2. Jones. R. D., Kavanagh. T. E.. and Clarke. 6. J., Am. Soc. Brew. Chem.J . . 1988. 46. 43. Gjerston. P.. Myken. F.. Krogh. P.. and Hald. 6.. “European Brewery Convention. Proceedings of the 14th Congress. Salzburg.” 1973. 373. Amaha. M.. Kitabatake, K.. Nakagawa. A., Yoshida. J . , and Harada. T., “European Brewing Convention. Proceedings of the 14th Congress, Salzburg.“ 1973, 381. Pfenninger. H.. Schur. F.. and Anderegg. P., in Pollock. J. R. A., Editor, “Brewing Science.” Volume 1. Academic Press. London, 1979. p. 451. 5. Blandeel, G . M. A.. DeKeukeleine, D.. and Verzele. M.. J. Clrem. SOC. Perkin Trans. I , 1087. 27 IS. 6. Clarke, B. J.. J. Inst. Brew.. 1986. 92, 123. 3 . 4. Detection of Migration From Packaging Materials P. A. Tice Pira, Randalls Road, Leatherhead, Surrey KT22 7RU With any material or article which comes into contact with foods there is a possibility that components of the material or article will transfer, or migrate, into the food.If transfer or migration does occur, it will be of particular concern if the food is rendered unfit to eat either for toxicological reasons or because of tainting. Even if the migrating substances are neither toxicologically harmful nor likely to cause tainting, any excessive adulteration of the food is still unacceptable. It is therefore necessary, with any packaging that is intended for foods, to establish the nature and quantity of substances which are likely to migrate from the packaging into the foods. Regulations and Codes of Practice The awareness over recent years that food could become contaminated with harmful substances from packaging has, in most countries, resulted in either comprehensive regulations or codes of practice; the American FDA regulations’ and the West German BGA code of practice’ being the most well known.These regulations and codes of practice contain few migration limits, but impose restrictions on those substances which are considered to have some undesirable properties by limiting the level allowed to be present in the packaging material-compositional limits. These compositional limits are usually arrived at after assessing data on the extent of migration of the substance in question, either into foodstuffs or food simulants. Although ideally the measurements should be made in foodstuffs, the analytical difficulties of measuring what are often trace amounts of the substance in foodstuffs can prevent reliable results being obtained.Consequently, food simulants are also used to obtain migration data. Food simulants are usually “simple” liquids or solutions. The difficulties with migration detection and measurement in foods and food simulants has been a principal reason for not including migration limits in present regulations and codes of practice for “food contact materials and articles.” I t has recently been realised, however, that for certain chemicals which have known toxic properties and which are technically necessary for the manufacture of plastics for food packaging, that there is a need to place restrictions by regulation on the levels present in foods. The first chemical to receive this attention by the EEC,3 and subsequently the UK,J is the monomer vinyl chloride (VCM), used in the manufacture of PVC plastics.The EEC regulation states that vinyl chloride monomer should not be detectable in foods when tested by the official analytical method of analysis. This official method of analysis has a detection limit of 10 p.p.b. (0.01 mg kg-1) and uses the well established headspace gas chromatography method of analysis.5 PIas t ics As the substances of concern which can migrate from plastic packaging into the food are often at the p.p.m. levels or below, gas chromatography is an appropriate analytical technique for a wide range of these substances from the very volatile monomer residues, such as vinyl chloride, mentioned above, to residual solvents from printing. In many cases the ubiquitous430 ANALYTICAL PROCEEDINGS.DECEMBER 1Y8Y. VOL 26 flame ionisation detector (FID) can be used, but in order to achieve the detection requirements for some substances specific detectors are required, such as a nitrogen detector for detecting the monomer acrylonitrile and an electron capture detector for the monomer vinylidene chloride. When using gas chromatography to measure migration into foods, in contrast to food simulants, it is often necessary to use mass spectrometry as the detection technique in order to ensure that the chromatogram peak of the substance in question can be positively identified. A preliminary clean-up is usually also required by, for example, a size exclusion column, and an internal standard incorporated to correct for losses during the clean-up and handling stages.An analytical procedure such as this has been used in a number of migration studies by the MAFF Norwich Food Science Laboratory. An example is the work carried out in the migration of plasticisers from PVC [poly(vinyl chloride)] plastics used for food wrap- ping. The internal standards used were deuterated derivatives of the plasticisers.6 For the detection of the migration of “non-volatile” sub- stances from plastics into food simulants, high-performance liquid chromatography (HPLC) methods are well established for additives such as antioxidants, slip agents and stabilisers. Many of these substances are ultraviolet absorbers and the standard ultraviolet detector can consequently be used. The procedures for the aqueous based food simulants, water, aqueous ethanol and aqueous acetic acid, are usually relatively straightforward, but with the “fatty food” simulants, such as olive oil and sunflower oil, there are often difficulties with isolation from the food simulant and interferences. The widely used plastics antioxidant lrganox 1010 { tetrakis-[methylene- (3,S-di-tert-butyl-4-hydroxyhydrocinnamate)~-methane} can, however, be determined in the fatty food simulants by direct injection on to the HPLC column without prior separation.The HPLC technique is also used for the determination of terephthalic acid in food simulants. Terephthalic acid is a principal monomer of PET (polyethylene terephthalate) plas- tics and is expected to have a migration limit of 8 mg kg-1 in the future EEC legislation o n “Food Contact Plastics,” which is due to be passed by the EC Council this year.Migration tests carried out on a range of PET plastics have given migration values well below this limit.’ The other principal PET monomer is ethylene glycol, which can be determined in food simulants by gas chromatography. This monomer is also expected to have a migration limit of 30 mg kg-1. Reported results have been well below this limit.8 Over-all Migration Tests for Plastics In order to measure the total amounts of substances which can migrate from plastic packaging into foods, over-all migration tests are carried out. In these tests no attempt is made to identify the substances which migrate, and consequently no toxicological significance can be placed on the results.The principal purpose of these tests is to determine the level of adulteration of the food by the packaging. The future EEC legislation, mentioned above, is expected to include a limit o n over-all migration .‘) The over-all migration tests cannot practic- ally be carried out with foods and usually food simulants are used. An EEC Directive has defined the food simulants to be used for future regulation migration testing, and these are: water, 3% acetic acid solution, 15% ethanol and olive oil -sunflower oil -synthetic triglyceride HB307.1() When test- ing with water and the two other aqueous based food simulants a relatively simple gravimetric procedure is used. With the olive oil and other oil simulants, the over-all migration is determined as a mass loss on the test specimen by a lengthy and involved procedure.Paper and Board The migration studies and measurements that have, in the past, been carried out on paper and board food packaging have concentrated mainly o n substance which can cause odour and taint, such as aldehydes from the pulp and residual solvents from printing. The recent attention directed to the presence of the very toxic dioxins in products made from pulp which has been chlorine bleached, has prompted work to establish the extent of migration of these dioxins into food products. As the levels of dioxins detected in the paper and board are in the region of 10 parts per trillion (p.p.t. E 101’ g-I), the amounts that have been detected in foods due to migration are extremely low.ll To produce reliable results at these very low levels, gas chromatography with high resolution mass spectrometry is used, with preliminary clean up procedures and internal standards.Toxic Heavy MetaldElements The presence in foods of the toxic heavy metals/elements, such as lead, cadmium, mercury and arsenic, have been of concern for many years and consequently there is a need to measure any migration of these metals/elements from packaging into foods. Atomic absorption spectrometry is the standard analytical technique for these measurements, but as the acceptable limits are reduced the basic technique is nearing the limit for reliable results. For colorants used in plastics intended for food packaging, it is expected that future EEC regulations will specify a purity requirement for the toxic heavy metals/elements, as already detailed in various Codes of Practice.1’ In addition, it is expected that the finished packaging made from plastics will also have to meet migration limits for the toxic heavy metals/elements, but the limits will most probably be low, and for lead and cadmium possibly below those which have recently been ware 1.2. 3. 4. 5. 6. 7. 6. 9. 10. 11. 12. 13. introduced under EEC legislation for ceramic cook- 13 References “US Code of Federal Regulations,” Title 21, Food and Drugs, National Archives Records Administration, Washington. DC. USA. ”Kunstoffe Im Lebensmittelverkehr,” Carl Heymanns Verlag. Koln. FRG. EC Council Directive 78/142/EEC. Off. J . Eur. Comnz., L44, 15.2.1978. “Materials and Articles in Contact with Food Regulations,” (SI 1987 No.1532). HM Stationery Office, London, 1987. EC Council Directive 81/432/EEC, Off. J . Eur. Comm., L16, 24.6.1981. Startin, J. R.. Parker, I., Sharman, M., and Gilbert, J., J. Chromatogr., 1987, 387, 509. Tice, P. A., Food Addit. Contant., 1988, 5, 373. Ashby, R., Food Addir. Cotiram., 1988. 5 , 485. Commission of the European Communities. Draft on “Com- mission Directive-n the approximation of the laws of the Member States relating to plastic materials and articles intended to come into contact with foodstuffs,’’ III/3473/88-EN (Rev. 1). EC Council Directive 82/71 l/EEC, Of& J . Eur. Comrn., L297, 23.10.82. Ryan, Panopio and Lewis. “Dioxin 88.” UMEA, Sweden. BPF/BIBRA “Plastics for Food Contact Applications.” British Plastics Federation, London, 1986.EC Council Directive 84/500/EEC, Off. J. Eur. Comm., L277, 20.10.1984.ANALYTICAL PROCEEDINGS. DECEMBER 1989. VOL 26 10 000 5000 2500 43 1 - Scotland - Microbial Contamination of Food: Control Measures Gerald 1. Forbes Scottish Home and Health Department, St. Andrew’s House, Edinburgh EH7 3DE Scotland has the unenviable reputation of having the worst food poisoning record in Europe. Statistically this would appear to be the case but everything is not as it seems and an explanation of this position is given. For control measures to be successful a start must be made with a comprehensive surveillance programme which encom- passes: (a). notification of disease condition by the clinician and laboratory to a central body such as the Communicable Diseases (Scotland) Unit; ( b ) , the detailed investigation of the incident by well trained officers such as Community Medicine Specialists and Environmental Health Officers; ( c ) , the accu- rate recording of incidents and the detailed documentation of outbreaks of unusual interest in professional journals; ( d ) , the dissemination of collated information back to investigation officers, and to national and international organisations; and ( P ) , the use of legislative procedures where administrative measures are not adequate.In 1979 the World Health Organisation convened a meeting of European countries requesting them to participate in a foodborne disease control system which would have two elements: an “early warning system” where participating countries would inform each other of incidents of a severe nature, incidents of an unusual type, incidents associated with internationally distributed foods or international carriers (air, land or sea) and a “routine reporting system’’ where household or general outbreaks of foodborne disease would be reported as and when they occurred, with annual summaries to the co-ordinating centre in West Berlin. The protocol for this programme was prepared in Scotland and implemented, as far as the “early warning system” was concerned, by June 1979, and January 1980 for the “routine reporting system.” After the initial launching of the scheme in Scotland a further 23 countries had joined by the end of 1988 but none other than Scotland had met the full requirements of the programme which is now known as the World Health Organisation Programme for the Surveillance of Foodborne Infections and Intoxications.During the 9 years the WHO programme has been in operation the following contributions to it have been made by Scottish workers. 1. A WHO definition for foodborne disease. 2. A WHO protocol for investigation of foodborne disease. 3. WHO guidelines for the control of foodborne infections. 3. WHO guidelines for the control of salmonellosis. 5. Introduction of compulsory pasteurisation of milk and 6. Costing studies for milkborne and poultryborne salmonel- 7. Cost benefit analysis for irradiation of poultry. 8. An international study of milkborne disease. 9. Detailed studies of foodborne disease in: (a), hospitals; cream. losis. ( h ) , other institutions; and ( c ) , offshore installations.10. Introduction of a national surveillance programme for reportable infect ions including I isteriosis, cryp tosporidio- sis. campylobacteriosis and E. coli 0.157 infections. Returning to the point of Scotland’s reputation for having thc worst food poisoning statistics, it would appear that we are suffering from our own success in ensuring that all food poisoning incidents are notified, recorded and assessed and that as tight a surveillance programme as possible is continually undertaken. This is in comparison with most European countries, where few foodborne diseases are notifiable and fewcr, if any, are investigated or recorded. 1981 1988 Fig. 1. Salmonclla isolations, EnglandWales and Scotland. 198 1-88 Finally, an example is given (in Fig.1) of how statistics can be misleading. In 1981 loo00 notifications of salmonella were recorded in England and Wales (20/100000 population) and 2500 in Scotland (50/1OO 000 populations), a ratio of 4 : 1, while in 1988 25000 notifications of salmonella were made in England and Wales (50/1OOOOO) with the number in Scotland remaining at 2500 (50/100 OOO), now a ratio of 10 : 1. England and Wales should have had 25000 notifications in 1981, but because of inadequate surveillance 60% of their cases which should have been recorded were not, and it is only now that a reasonably accurate picture is emerging in England and Wales and the “epidemic” of salmonellosis, which has been reported, has not occurred: the United Kingdom has been in an epidemic situation for years. Determination of Ethyl Carbamate in Alcoholic Beverages R.I. Aylott and D. A. Walker United Distillers, Group Central Laboratory, Menstrie, Clackmannanshire FK 7 7 7ES Ethyl carbamate (EC). otherwise known as urethane, is a naturally occurring compound present in most fermented foods and beverages. However, it has been shown to be a carcinogen to laboratory animals and this has led to concern in recent years432 ANALYTICAL PROCEEDINGS. DECEMBER 1989. VOL 26 about its trace presence in alcoholic beverages. Background to Current Interest in Ethyl Carbamate The carcinogenic properties of ethyl carbamate were first reported by Nettleship et af. in 1943.1 Subsequently, important reviews were published by Mirvish in 1968' and the Interna- tional Agency for Research on Cancer in 1974.' In 1971, the antimicrobial agent diethyldicarbonate (DEDC), was implicated in EC formation.4 However, sub- sequent work by Fischers and Ough6.7 showed that ethyl carbamate was, in fact, a naturally occurring compound rather than a contaminant and that DEDC was not a significant EC precursor under normal conditions of use.Ethyl carbamate has been detected at low p.p.b. concentra- tions in bread and beer.6 Wines, distilled spirits and liqueurs contain higher concentrations. The results of a recent survey by the United States Bureau of Alcohol, Tobacco and Firearms (BATF) indicated EC concentrations up to 151 p.p.b. in wines, up to 166 p.p.b. in sake and rice wines, up to 740 p.p.b. in bourbon whiskey and up to 4146 p.p.b.in fruit brandies.8 Regulatory Limits During 1985, the Liquor Control Board of Ontario found abnormally high ethyl carbamate concentrations in some home produced sherries and liqueurs. In December of that year Health and Welfare, Canada, set maximum allowable concen- trations in table wines (30 p.p.b.), fortified wines (100 p.p.b.), distilled spirits (150 p.p.b.) and fruit spirits, liqueurs and grape brandies (400 p.p.b.). Subsequently, a 200 p.p.b. limit was established for sake. These limits were based upon a tolerable daily intake of 0.3 pg of ethyl carbamate per kg of bodyweight and the estimated mean daily intake by that portion of the population which consumes alcoholic beverages.9 In December, 1987, the United States Food and Drugs Administration agreed with the Distilled Spirits Council of the United States a target level of 125 p.p.b.of ethyl carbamate for all new whiskey production as of January lst, 1989.10 The United States wine industry also agreed voluntary EC limits of 15 p.p.b. for table wines and 60 p.p.b. for desert wines. The only other country to have a regulatory limit is Germany, where 400 p.p.b. was set for all alcoholic beverages. Analytical Procedures Ethyl carbamate is very soluble in water and alcohol. It is relatively involatile, with a boiling-point of 182-184°C. It is stable in alcoholic solutions and has had medical uses as a hypnotic, an anti-neoplastic drug and as an anaesthetic for laboratory animals. Ethyl carbamate is determined at the parts per billion (ng ml-1) level by capillary column gas chromatography with either nitrogen specific or mass selective detection in the presence of an appropriate internal standard such as n-propyl carbamate.11.12 Other internal standards reported include methyl and butyl carbamates. The 13C15N- and ethyl-deuter- ated stable isotopes incorporated into EC have also been used with mass spectrometric detection. Sample preparation can be divided into three distinct sample matrix types depending upon alcoholic strength and amount of dissolved solids. These preparations involve either simple addition of internal standard, solvent extraction or solid-phase extraction, as summarised in Table 1. Our solvent extraction procedure, developed for Scotch whisky, involves buffering the sample to pH 9, pre-extracting with pentane, followed by extraction into dichloromethane in the presence of sodium chloride.12 Solid-phase extraction is particularly useful for extracting EC from beers, wines and liqueurs, which may contain sugars, flavourings, emulsifiers and other additives. It has also proved useful in the analysis of process samples, such as fermented wash, spent wash and distillery by-products. A sample, with added internal standard, is diluted with water down to a maximum of 4% V/V ethanol. Twenty millilitres of this solution are then introduced on to an Extrelut column and lypophilic species including EC are eluted with 40 ml of dichloromethane. Eluent (25 ml) is then collected and concen- trated down to approximately 1 ml under a gentle stream of nitrogen prior to analysis by mass detection.Table 1. Summary of sample preparations used prior to analysis for ethyl carbamate Sample preparation Sample strength, YO VIV Matrix type Analytical method >5s Low residue Direct injection >ss High residue Dilution and solvent <ss Low residue Solvent extraction <S5 High residue Solvent or solid phase < 10 Various Solid phase extraction The chromatographic separation for EC is best performed on chemically bonded polyethylene glycol capillary columns with vapourising splitless injection. We prefer vapourising splitless injection rather than cold on-column injection because this was found to maintain the integrity of the column for a longer period of time with high throughput analysis. Wide range temperature programmes, often multi-ramping, are desirable, particularly when extra separation is required prior to nitrogen selective detection.Ethyl carbamate normally elutes from the column between 120 and 135 "C. extraction extraction 200 180 160 140 Average EC concentration, 43 p.p.b. v) 933 Samples, March '89 ; 120 .c 100 80 Z 60 40 20 0 a 5 0 20 40 60 80 100 120 140 160 180 200 Concentration of ethyl carbamate, p.p.b. Fig. 1. Histogram showing the range of ethyl carbamate concentra- tions in 933 samples of blended Scotch whisky Three main types of analytical detectors have been used for EC analysis. Some workers have generated results using the non-selective flame ionisation detector (FID). However, bearing in mind the large number of congeners present in Scotch whisky,13.14 we find that determining EC at the low p.p.b.level in this product requires either nitrogen or mass-selective detection. Nitrogen selective detectors reported in the literature for EC analysis include the alkali flame ionisation detector, the thermionic specific detector, the Coulson detector, the Hall detector and the thermal energy analyser in the nitrogen mode. However, the mass selective detector is being increasingly used in EC analysis due to its good selectivity and sensitivity. Both ethyl and n-propyl carbamate exhibit similar mass spectra with reasonably abun- dant fragments at mlz = 44, 62 and 74.11.12 We prefer to monitor m/z = 62 rather than 74 because of its greater relative abundance and selectivity. Mass 44 could be monitored, but it is in a region of the mass spectrum which can result in potential interferences from co-eluting species.ANALYTICAL PROCEEDINGS.DECEMBER 1989. VOL 26 433 Various combinations of detectors for EC have been compared by a number of workers, including Dennis et al. at the Ministry of Agriculture, Fisheries and Food in Norwich.ls Connacher et al. at Health and Welfare, Canada,l6 Cairns et al. at Los Angeles District Laboratory,17 and Pierce et al. at the University of Louisville. ‘ 8 The detection systems compared included the FID, the Hall detector, the thermal energy analyser and the mass spectrometer. Our own work comparing the thermionic specific detector with mass detection indicated generally good correlation between the methods but with preference for mass detection owing to its greater selectivity. 12 Recent Analytical Results Analysis of 933 samples of blended Scotch whisky in our laboratory between January, 1986, and March, 1989, have indicated EC concentrations ranging between 15 and 115 p.p.b.with an average at 43 p.p.b. (Fig. 1). Concentrations are quoted to the nearest 5 p.p.b. and are normalised to a 43% V/V alcoholic strength, this being a typical export strength. The bulk of this data represents 6 major brands, the EC concentra- tions of which ranged from 25 to 75 p.p.b. (Table 2 ) . These results were generated using a combination of direct injection and solvent extraction sample preparation techniques, offering a limit of detection of 5 p.p.b. Table 2. Ethyl carbamate concentrations. expressed as p.p.b. (ng ml-I) at 43% V/V alcoholic strength. in individual brands of blended Scotch whisky sampled between January.1986. and March. 1989 Number of Range. Average. samples p.p.b. p.p.b. Buchanan’s Black and White 49 25-6s 42 Buchanan’s Deluxe 24 30-75 50 Dewar’s White Label 54 25-60 43 Johnnie Walker Black Label 130 25-75 51 Johnnie Walker Red Label 316 2545 41 White Horse 56 25-55 41 EC was not detected in four alcohol-free lagers (limit of detection <1 p.p.b.), 7 beers and stouts contained up to 6 p.p.b., and 8 wines and liqueurs contained up to 45 p.p.b., all of which were prepared for analysis using solid-phase extrac- tion. Samples of fermented wash, the beer in whisky produc- tion prior to distillation, contained up to 6 p.p.b. at different stages of the process.Research into Formation Mechanisms In 1976 Ough postulated EC biosynthesis from ethanol and yeast carbamyl phosphate .6 However, there are many synthetic routes to EC. For example, the Merck Index entry for urethane suggests its synthesis from urea and ethanol.19 It was, therefore, not surprising that the high EC level observed in certain Canadian sherries was associated with the use of urea as a nutrient during fermentation. Recent work published by Ough has shown that a range of N-carbamyl compounds, including allantoin, arginine, citrul- line and ornithine, can react with ethanol to form ethyl carbamate. These pathways are obviously important in alco- holic beverages such as beer and wine, where the final product is still associated with the solution from which it was fermented.It may also represent a mechanism for EC formation in any food matrix in which ethanol is or has been present .?“.?I Workers investigating EC formation in stone fruit brandies and other distillates have also implicated hydrocyanic acid and cyanate, together with vicinal dicarbonyl compounds such as diacetyl, pentane-2,3-dione and methyl glyoxal. Some EC formation reactions have been shown to take place in the distillate and show light dependence.22.23 Finally, recently published work on EC formation in pot-still whisky has implicated reactions involving copper and de- scribed the relative involatility of EC in pot-still distilla- tions.24.25 It is therefore quite reasonable to expect volatile precursors to be involved in EC formation in distillates.Conclusions In conclusion, the last 3 years have seen considerable effort by the alcoholic beverage industries in many countries in the development of appropriate analytical techniques for ethyl carbamate and into the understanding and control of its formation in their products. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. References Nettleship, A.. Henshaw, P. S.. and Meyer. H. L.. J. Nut. Curicer Inst., 1943. 4. 309. Mirvish. S. S.. Adv. Cancer Res.. 1968. 11. 1 . “IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man.” Volume 7, IARC. Lyon. 1974. p. 11 1. Lofroth. G.. and Gejvall. T.. Science, 1971. 174. 1248. Fische r . E . . Z . Lebensm . - Un te rs. - Forsclr . 1 97 1-2, 147-148. 221. Ough, C. S.. J. Agric. Food Chem.. 1976. 24. 323. Ough. C. S.. J. Agric. Food Chem.. 1976. 24. 328. Food Cliem. News. March 13. 1989. 23. Conacher. H. B. S.. and Page. D. 9.. Proc. Euro Food Tox 11, Zurich, 1986. 237. Food Cliem. News. January 4. 1988. 33. Walker, D. A,. Aylott. R. I., and McNeish, A. S., “Proceed- ings of the Second Aviemore Conference on Malting, Brewing and Distilling,” Institute of Brewing, London, 1986, p. 425. Aylott, R. I.. McNeish. A. S., and Walker. D. A., J. Inst. Brew.. 1987.93, 382. Swan. J . S.. Howie. D., Burtles. S. M., Williams, A. A.. and Lewis, M. J., in Charalambous. G.. and Inglett. G. E.. Editors. “The Quality of Foods and Beverages.” Academic Press. New York, 1981. p. 201. Nykanen. L.. and Suomalainen. H.. “Aroma of Beer, Wine and Distilled Alcoholic Beverages.” D. Reidel Publishing Company. Dordrecht, The Netherlands, 1983. Dennis, M. J.. Howarth. N., Massey. R. C., Parker. I.. Scotter. M.. and Martin, J.. J. Chromatogr.. 1987. Conacher. H. B. S.. Page. D. B.. Law. B. P.-Y., Lawrence, J . F.. Bailer, R.. Calway. P.. Hanchay, J.-P., and Mori, B.. J. Assoc. Off. Anal. Chem.. 1987, 70, 749. Cairns. T., Siegmund, E. G.. Luke. M. A.. and Doose. G. M.. Anal. Chem., 1987. 59.2055. Pierce, W. M.. Clark, A. 0.. and Hurst. H. E., J . Assoc. Ofj. Anal. Chem.. 1988. 71.781. The Merck Index. Ninth Edition. Merck and Co. Inc.. Rahway. NJ. USA, 1976, 1267. Ough. C. S., Cromwell. E. A., and Gutlove. B. R.. Am. J. Enol. Vitic.. 1988. 39. 239. Ough. C. S., Cromwell. E. A.. and Mooney, L. A.. Am. J. Enol. Vitic.. 1988, 39. 243. Baumann, U.. and Zimmerli. B.. Mitt. Gebeite Lebensm. Hyg.. 1987.78, 317. Baumann. U.. and Zimmerli. B.. Mitt. Gebeire Lebensm. Hyg.. 1988. 79. 175. Riffkin, H. L.. Wilson, R.. Howie. D.. and Muller, S. B., J. Inst. Brew., 1989. 95, 1 15. Riffkin, H. L.. Wilson. R.. and Bringhurst. T. A., J. Inst. Brew.. 1989. 95, 121.

ISSN:0144-557X    

DOI:10.1039/AP9892600428

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

434 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 Equipment News Sampling Attachments for Infrared Analysis Two EDAPT fibre optic sampling attach- ments for the makers’ InfraAlyzer 500 are externally mounted and easily retrofitt- able. The EDAPT 1 is a hand- or robot- held probe which contains a gold coated integrating sphere; it allows accurate analysis of large areas or bulky objects. The EDAPT 2 spectrometer extension provides precise, dual-beam chopped transmission measurements at wave- lengths from 600 to 2500 nm. A wide range of commercially available cells can be used in its sample compartment to provide a high level of flexibility. Bran and Luebbe (GB) Ltd., Beech- wood, Chineham Business Park, Basing- stoke, Hampshire RG24 OWA. FT - IR Spectrometers The Model 205 incorporates a sealed, desiccated optical bench, a high perfor- mance computer with fast, high-resolu- tion graphics, a touch-sensitive, push-but- ton control panel and a flexible sample compartment, featuring a sample mount- ing system that permits the use of plug-in, pre-aligned sampling accessories.An entire suite of spectroscopic functions is available at the push of a button. The including FT - Raman, SFC - FTIR, GC - FTIR and microspectroscopy. Nicolet Instruments Ltd., Budbrooke Road, Warwick CV34 5XH. Diode Detector Software High speed software for the Shimadzu SPD-M6A photodiode array ultraviolet - visible detector enhances its perfor- mance. The SPD-M6A delivers a resolu- tion of 1 nm and an accuracy of f l nm across its 195-4570 nm wavelength range.A free software update will be offered to all existing customers. Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le Spring, Tyne and Wear DH5 ORH. Mass Spectrometers for HPLC The AX500 series instruments feature the FRITEAB interface, which is particu- larly suited to non-volatile and, espe- cially, thermolabile compounds, such as drug metabolites. Other AX500 LC - MS series interfaces include E l , CI and ther- mospray. The spectrometer also accom- modates standard GC - MS measure- ments using SIM and high-speed scan techniques, including EI, CI, ACE, FD, DCI, FBA and positive - negative switch- ing. The El - CI ion source can be Nicolet Model 205 FT - IR spectrometer System 800 is a benchtop, high-perfor- mance research instrument. It features a dynamic alignment system, on-screen optical bench status and monitoring, wide spectral coverage from 30000 to 10 cm-l, totally expandable optical path, support for multiple detectors and highly efficient purge characteristics.It accommodates a wide range of applications accessories upgraded to a FAB - EI - CI - DCI com- bination, permitting push-button selec- tion of the ionisation mode without changing the ion source block. The AX500 provides resolutions of at least 25000 and a mass range of 2300 at full accelerating voltage. Parent ion, daughter ion and constant neutral loss scans can be performed using the linked scan feature of the AX500. Park, Colindale, London NW9 OJN. Jeol (UK) Ltd., Jeol House, Grove Capillary Detector The capillary detector 433 offers high sensitivity for microbore liquid chromato- graphy, capillary zone electrophoresis and supercritical fluid chromatography.In CZE detection is boosted by a factor of 100-500 compared with conventional on- column detection. The capillary detector 433 features a wavelength range of 198- 800 nm, dual wavelength recording and collection of spectra through the makers’ data system 450MT2. Kontron Instruments Ltd., Blackmoor Lane, Croxley Centre, Watford, Hert- fordshire WD1 SXQ, Gas Chromatograph Mass Spectrometer System and Sample Concentrator The Shimadzu GCMS-QP2000 system has been designed for flexibility, bringing GC - MS within the range of inexperien- ced users. The CDS 300 sample concen- trator has been developed to meet the needs of the environmental scientists for a low cost purge and trap system.Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH. Capillary Columns Stabilwax from Restek is an alternative to Carbowax 20-M. It incorporates free rad- ical scavengers to protect the polymer from oxidative degradation while still retaining the upper thermal stability of 280°C and true Carbowax polarity. Thames Chromatography, 16 Raymead Court, Maidenhead, Berkshire SL6 STN. Liquid Chromatography System The BAS 200A gradient LC system pro- vides rigorous deoxygenation, ensuring minimal base-line drift for critical low wavelength ultraviolet gradient separa- tions and reductive mode electrochemical detection. High sensitivity (0.0005 AUF) variable wavelength ultraviolet - visible and multi-electrode electrochemical detection are among the multiple detec- tion configurations available, with data reduction capabilities for up to four exter- nal detectors.The ternary gradient sol- vent delivery system does not require pulse damping. Pump heads are easily removed. A refrigerated autosampler is available as an option. Biotech Instruments Ltd., 183 Camford Way, Luton, Bedfordshire LU3 3AN.ANALYTICAL PROCEEDINGS. DECEMBER 1989. VOL 26 435 Sequential ICP Spectrometer The new Spectroflame ICP accomplishes wavelength selection with an accuracy of 0.0008 nm. Selection is typically achieved in less than 1 s for any wavelength, analyte signal or background. Because peak search routines are not required, the imprecision inherent in computing peak maxima and the ambiguity of searching for peaks at or near the detection limit are graphy ofjacidic and neutral sample com- ponents is unchanged.) Resolution, peak shape and detection are significantly better than with conventionally deacti- vated or non-deactivated columns.Supelchem UK Ltd., Shire Hill, Saf- fron Walden, Essex CBll 3AZ. Guard Column Kits Progel-TSK guard column kits provide Spectroflame sequential ICP spectrometer avoided. Moreover, the analytical throughput, expressed in elemental deter- minations min-’, is three to five times faster than with peak search ICPs. The instrument offers the option of adding simultaneous ICP operation, up to 64 channels, in the field at a later date. Further information is given in the May, 1989, issue of Spectro Live.Spectro Analytical Instruments, Bosch- strasse 10, D-4190 Kleve, FRG. Capillary Column A pre-tested environmental capillary col- umn, the PTE-5, has been designed for EPA methods 625, 1625 and 8270 for the analysis of semi-volatile pollutants. It is equivalent in polarity to generic bonded SE-54 columns with special modifications to improve inertness and bleed perfor- mance. Supelchem UK Ltd., Shire Hill, Saf- fron Walden. Essex CBll 3AZ. HPLC Column The Suplex pKb-100 column operates on a principle that virtually eliminates inter- actions between basic sample components and residual silanol groups on the packing surface. Even very basic compounds can be analysed under mobile phase condi- tions of neutral pH and low ionic strength, without amine modifiers.(Chromato- convenient protection for Progel-TSK columns and can help to prolong column life. Bulk quantities of resin are available to refill the guard columns or voids that may develop in the packing bed. Supelchem UK Ltd., Shire Hill, Saf- fron Walden, Essex C B l l 3AZ. HPLC-Grade Water System The Milli-Q Plus system, with the Organex-Q cartridge, gives an organics- free conductivity of 18 MB cm-1. Also available is a booklet entitled “Ultrapure Ion-Free/Organic-Free Water for Trace Analysis.” Millipore (UK) Ltd., The Boulevard, Blackmoor Lane, Watford, Hertfordshire WD18YW. Disposable Filter for HPLC Pharmaceutical preparations containing carboxy methyl cellulose can be routinely analysed by HPLC, without having repeatedly to re-pack the column if an ANOTOP 25 Plus disposable syringe filter is used as part of the sample clean-up procedure.Anotec Separations Ltd. , Wildmere Road, Banbury, Oxfordshire OX16 7JU. Auto-Injector for HPLC The Shimadzu SIL-9A stand-alone auto- injector, now down in price, features a sample rack that accepts six types of sample vials and a sampling needle that moves in X , Y and 2 directions, permit- ting random access to different vials. Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH. Control Software for HPLC New control software is announced for the makers’ System 400 series of HPLC instrumentation. The latest 457 controller software will run on any IBM-PC, XT, AT, PS-2 or compatible computer, offer- ing simultaneous control of up to two system components via an RS-232C inter- face.Alternatively, up to 12 system modules can be interfaced when using the maker’s multiport interface controller. This allows for control of peripheral equipment via contact closure, and also of column or solvent switching valves. Beck- man/Altex and Waters pump modules can also be controlled. Kontron Instruments Ltd., Blackmoor Lane, Croxley Centre, Watford, Hert- fordshire WD1 SXQ. Chromatography Data System The data system 450/MT2 offers com- pletely independent control and monitor- ing of two chromatography systems plus data acquisition and integration from six additional detector signals. It also offers real-time multi-tasking for complete system control, data acquisition and inte- gration as background tasks, whilst rein- tegration of stored chromatograms or DOS applications can be conducted as simultaneous foreground tasks.Kontron Instruments Ltd., Blackmoor Lane, Croxley Centre, Watford, Hert- fordshire WD1 SXQ. HPLC System The Turnkey HPLC system is a complete package enabling users to begin applica- tions immediately. It consists of a 351 pulseless pump, 750/12 variable wavelength ultraviolet detector, 7125 Rheodyne injection valve, Techsphere 5 ODS column, injection syringe and all required connecting tubing and fittings. It comes with a 3-year warranty, total system installation, commission and pro- duct training by experienced staff and free delivery and membership of the ACS/ HPLC Technology Executive Club (including a complimentary place at a HPLC beginners training course).Applied Chromatography Systems Ltd., The Arsenal, Heapy Street, Macclesfield. Cheshire SK11 7JB. HPLC Column Following the UK launch of the high- performance reversed-phase polymeric column, Asahipak ODP-50, the GS and ES series columns for gel permeation and ion exchange chromatography are an- nounced. Also announced is a preparative version of the ODP-50, the ODP-90,436 ANALYTICAL PROCEEDINGS, DECEMBER 1989. VOL 26 designed for the preparative separation of proteins, peptides and amino acids. May and Baker Laboratory Products, Liverpool Road, Eccles, Manchester M30 7RT. Detector The AD-200 absorbance detector for capillary electrophoresis and HPLC offers interchangable flow cells for both HPLC and HPCE applications; they can be installed in minutes.The AD-200 also offers high sensitivity, a wide wavelength range (190-700 nm), auto zero, auto ranging, remote auto zero, event mark inputs and an optional RS232. SpectroVision, Scientia Park, 25 Indus- trial Avenue, Chelmsford, MA 01824, USA. Chromatography Data System The Apex chromatography data system is a PC-compatible based integration system for gas and liquid chromatography. It is truly multi-tasking and allows the user to utilise his PC for other tasks, such as word processing and spreadsheet analysis, whilst collecting chromatographic data. It is available as a single-, four- or fifteen- channel system, all channels being able to accept up to four detector inputs. Severn Analytical Ltd., Unit 2B, St. Francis Way, Shefford Industrial Park, Shefford, Bedfordshire SG17 5DZ.Amino Acid Analyser The System 6300 is a dedicated liquid column chromatograph which performs automated ion-exchange chromatography with ninhydrin detection for high resolu- tion of hydrolysate and physiological sam- ples. A touch of the keys on the panel allows selection of a pre-programmed method or entry of new method paramet- ers. Up to four methods can be stored and extra methods can be retained on the makers’ Memory-Pak cassettes. A real- time visual display shows flow sequence, operating temperatures and pressures. Panel key pressure directs the system to measure flow-rate and provide readings in ml h-1. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Bucking- hamshire. Component Package for Capillary Electrophoresis The CE component package includes the choice of either the AD-200 variable wavelength absorbance detector or the FD-100 filter fluorescence detector, the DA-30 high voltage power supply, a safety-interlocked instrument housing and a CE starter kit.The package can also be purchased with the FD-200 variable wavelength and/or the FD-300 dual monochromator fluorescence detector. SpectroVision, Scientia Park, 25 Indus- trial Avenue, Chelmsford, MA 01824, USA. Fluorescence Detectors for Capillary Electrophoresis A full range of FD series fluorescence detectors for capillary electrophoresis applications is announced. A capillary electrophoresis flow cell can be easily installed into existing FD series detectors, allowing the capability to do either HPLC or HPCE. SpectroVision, Scientia Park, 25 Indus- trial Avenue, Chelmsford, MA 01824, USA.Gel Analyser The software for the Gemini gel analyser has been enhanced. The system, which has the ability to acquire and process 1- and 2-dimensional electrophoresis gels, now offers “task listing,” which allows the operator to train Gemini to capture, pre-process and extract up to 1000 spots per gel. This is done in a few minutes and the tasks can be replayed on as many gels as necessary. ASCII data files can be produced for processing by the makers’ RESULTS package or by proprietary data bases. The new software allows the user to acquire scans on the Gemini system, process the data and provide a full range of analytical interpretations, including relative molecular mass calibration and multiple track comparisons.The operator can also look qualitatively at gels by programming pseudocolour tables which can transform the gel image at video rate, and Gemini now has the wire frame 3-D reconstruction facility with hidden line removal which graphically shows surface and spot variations. Joyce - Loebl Ltd., Dukesway, Team Valley, Gateshead. Data Analysis Package for Electrophoresis Scanner The new software for the makers’ Chro- moscan scanner features the ability to calibrate measurements to relative mole- cular mass standards, provide multiple track comparisons, quantify the differ- ences between gel tracks and output data files in data base, spreadsheet and ASCII formats. It maintains its ability to perform automatic background correction, auto- matic peak location, peak naming, label- ling and numbering, as well as manual correction and editing.It offers the ability to convert scanned data acquired in a 2-dimensional raster scan into an image format which can be read on the mini and research grade Magiscan image analysers, as well as the Gemini electrophoresis gel analyser . Joyce - Loebl Ltd., Dukesway, Team Valley, Gateshead. Oxygen Analyser The Model 316R trace oxygen analyser monitors oxygen contamination in nitro- gen, argon, helium and other pure gases and gas mixtures from p.p.m. to p.p.b. levels. It features four full-scale, switch- selectable ranges: 0-10, 0-100, 0-1000 and 0-10000 p.p.m. of oxygen. Also available are optional ranges as low as 0-1 p.p.m.Teledyne Analytical Instruments, The Harlequin Centre, Southall Lane, South- all, Middlesex UB2 SNH. Nitrogen - Protein Analyser The Macro N is a fully automated ana- lyser providing fast and accurate determi- nations of the nitrogen and protein con- centrations in organic solids and liquids. It has been developed for handling large samples without the time consuming procedures associated with wet chemical digestion methods. It can continuously analyse up to 90 samples, each with a maximum volume of 5 mi or weighing up to 2 g; each result is produced in less than 10 min. Heraeus Equipment Ltd., 9 Wates Way, Brentwood, Essex CM15 9TB. Combustion Analysis An optical system for high temperature, chemical analysis is announced. It employs coherent anti-Stokes Raman scattering (CARS) in a laser-based non- destructive method, which can simul- taneously measure temperature and the presence and concentration of molecular species in transparent media.In particular it can be used to measure properties of the molecular species found in flames, plasma, aerodynamic jets and, generally speaking, in any medium where tempera- tures are high and where fast chemical kinetics necessitate rapid data acquisi- tion. Spectrolab Ltd., P.O. Box 25, New- bury, Berkshire RG16 8BQ. Moisture Analyser The Promet process moisture analyser is a precision hygrometry system which offers analysis in the humidity range fromANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 437 - 100 "C dewpoint to saturation. The hygrometer uses a programmable micro- processor to effect all electronic measure- ment, conversion, display and analogue output functions, and offers display of results in user-specified units.The instru- ment makes provision for applications in which compensation is required for pres- sure changes occurring at the sample source. Michell Instruments Ltd., Unit 9, Nuf- field Close, Nuffield Road, Cambridge CB4 1SS. Portable pH, Conductivity and Resistivity Analyser A compact version of the 7082 series analysers is announced. The 7082 instru- ments are designed for high-purity water measurements in the power, micro-elec- tronics, chemical, pulp and paper and pharmaceutical industries. They elimi- nate grab sample contamination by car- bon dioxide or questionable handling and they precisely match the temperature properties of all common applications automatically.Features include accurate temperature compensation algorithms for specific applications. Leeds and Northrup L,td., Wharfdale Road, Tyseley, Birmingham B11 2DJ. Measuring Electrodes The Dulcotest technology developed for chlorine probes has now bcen extended to cover the continuous measurement of chlorine dioxide and ozone in water for process control of water and waste water quality. The makers' range of electrodes has also been extended to include pH and ORP (Redox) probes. ProMinent Fluid Controls (UK) Ltd., Queens Drive, Newall, Burton upon Trent, Staffordshire DEll OEG. Combination Electrode The Star Series combination electrode is the newest in the Futura Plus range. The Star, rugged bulb and flat bulb electrodes feature the pHresh Performance Pac, which protects the pH sensing bulb from contamination with dried salts.Offered in glass and epoxy body styles, the Star electrodes respond rapidly to tempera- ture changes and permit accurate measurement in situations where move- ment from one temperature to another is frequently required. Beckman, Progress Road, Sands In- dustrial Estate, High Wycombe, Buckinghamshire. Combined pH Glass Electrode The new combined pH electrode is offered in compact double junction con- struction, is 123 mm in length and is equipped with a plug-in head. For pH measurement or titration of samples incompatible with K+, C1-, Ag+ or aqueous solutions the answer to the prob- lem is a bridge electrolyte (double junc- tion) compatible with both the internal filling solution and the sample.In the new electrode the contact between the analysis solution and the reference electrolyte is established through a glass sleeve dia- phragm, which can be cleaned if neces- sary; the external electrolyte can be easily changed. The electrode comes from Metrohm Ltd. in Switzerland. V. A. Howe Ltd. Titration Program TITRAFILE is a laboratory computer pro- gram which can archive fresh titration information when simultaneously work- ing with previously stored data. The latest accessory for the Titralab automated ti- tration laboratory, the TITRAFILE P c pro- gram, archives data from the makers' VIT90 video titrator, automatically tag- ging the data file with the method used, date and other identification. It facilitates display andor printout of reports and examination and review of titration curves, enables construction of user- designed reports and it will produce sum- mary plots and statistical reports, com- piling data from various files.Radiometer Ltd., The Manor, Manor Royal, Crawley, West Sussex RHlO 2PY. Carrier Ampholytes Two additions to the Resolyte range of carrier ampholytes for isoelectric focus- ing, 3-6.5 and 6-9.5, complement the makers' existing 3.5-10 and 4-8 ranges. They maintain excellent resolution and gradient stability and are available as 40% mlV filter-sterile solutions in 5-, 25- and 100-ml packs. BDH Ltd., Broom Road, Poole, Dorset BH12 4". Sample Concentrator The CDS 300 sample concentrator has been designed to meet the needs of the environmental scientist for a low-cost purge and trap instrument.Microproces- sor controlled, it meets or exceeds all EPA requirements. Up to 9 EPA methods can be stored and the Model 300 can be optionally configured to perform thermal desorption of air sampling cart- ridges or soil samples. It can accept a host of options including an intelligent auto- sampler for unattended operation. Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH. Digestion Software A software package for the automatic Microdigest A300 speeds the digestion process of sample preparation for AAS or ICP. The number of power and time settings has been doubled to four for each digestion step and includes a waiting period to allow the breakdown of the molecules.The software allows the auto- matic addition of reagents in up to 16 flasks. The latest generation of Micro- digest has a new hydrofluoric acid pump and the maximum acidoxidant volume added has been increased from 10 to 50 ml, whilst reagent pumps now have nine speeds as opposed to four. May and Baker Laboratory Products, Liverpool Road, Eccles, Manchester M30 7RT. Weighing Accessory A triangular stainless steel holder can be positioned in various ways to hold a wide variety of samples, such as round-bot- tomed flasks, syringes or pipettes. Being of stainless steel construction, it elimi- nates the problem of errors due to mois- ture uptake associated with plastic or cork holders. Mettler Instrumente AG, CH-8606 Griefensee, Switzerland. Insertion Mass Flow Monitors Designed for industrial applications, Sier- ra's all-316 SS Steel-Trak single point probes and Sting multi-point probe arrays monitor the mass flow-rate of air and process gases.The Sting multi-point arrays insert into pipes or ducts and accurately average the outputs of up to 10 probes each with up to 5 individual velocity points. Acal Auriema Ltd., 442 Bath Road, Slough SL1 6BB. Moisture Analyser The Aqua Measure Instrument Com- pany's Model MC-64 is a computer-based instrument which quickly determines the moisture content of foods, chemicals, aggregates, etc. , by simultaneous measurement of the radiofrequency dielectric constant and sample mass. When not being used to determine pro- duct moisture or specific gravity it can function as an electronic weighing scale or computer.Acal Auriema Ltd., 442 Bath Road, Slough SL16BB. Peristaltic Pump Tubing Norton-Performance Plastics have intro- duced PharMed tubing, an autoclavable, biocompatible tubing for applications demanding extraordinary flex-life. Made from a specially processed thermoplastic elastomer formulation, PharMed tubing lasts up to 30 times longer than silicone rubber in peristaltic pump tests. It is non-cytotoxic, non-haemolytic and passes USP Class VI criteria for direct contact with food. It meets NSF criteria for food handling equipment . Universal Biologicals Ltd., 12-14 St Ann's Crescent, London SW18 2LS. Fume Cupboards Airone workstations have been designed to protect laboratory operators from toxic vapours, gases, fumes and particulate contaminants in line with COSHH Regu- lations and internationally recognised438 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 safety standards.Airone fume cupboards can be installed as non-ducted filtration fume cupboards, as ducted fume cup- boards or as combined ducted - filtration fume cupboards for work with radioiso- topes or as specified by the International Cancer Research Institute for handling carcinogens. Safelab Systems Ltd., 62 Prince Street, Bristol BS14QD. New Laboratory Equipment Several new instruments are announced: a high performance capillary electro- phoresis system, a series of liquid scintilla- tion counters, a DNA synthesiser, an ultracentrifuge range and a side-loading instrument for the Biomek automated laboratory workstation.Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Bucking- hamshire. Literature A brochure entitled “Design Features of a Flame Atomisation System” reveals details of the PU92OOX and PU94OOX atomic absorption spectrometers. It points out that optimum results cannot be achieved by the use of computerised techniques alone but that the design of the instrument, particularly the spray cham- ber, is crucial. Also announced are two books: “Atomic Absorption with Elec- trothermal Atomisation” and “Atomic Absorption Data Book.” Philips Scientific, Analytical Division, York Street, Cambridge CB1 2PX. A catalogue describes a vast range of spares for HPLC pumps and covers virtu- ally every HPLC pump now manufac- tured. HPLC Technology Ltd., Wellington House, Waterloo Street West, Maccles- field.Cheshire SKll 6PJ. A brochure describes the Model 3550 microplate reader, which offers fast reli- able readings, flexibility for diverse analy- sis and is capable of kinetic ELISA. Plates can be custom formatted, and the 80 x 16 character LCD allows on-screen examina- tion of complete formats, protocols and reports. Bio-Rad Laboratories Inc., Brussels, Belgium. A series of 25 Elemental Analysis news- letters describe applications of the Model 2410 nitrogen analyser and the Model 2400 CHN analyser to a wide range of samples. Perkin-Elmer Ltd., Maxwell Road, Beaconsfield, Buckinghamshire HP9 1QA. A brochure describes silver metal mem- branes fabricated as a crystalline metallic lattice of pure silver in a homogeneous structure. The membranes are extremely thin (50 pm) for high flow-rates with particle retention ratings from 0.2-5 .O pm. They withstand temperatures up to 550 “C and they can be autoclaved, steam or hot-air sterilised a number of times. They can withstand pressures of 103350 kPa and they perform well in viscous fluid applications. Osmonics Cnc., 5951 Clearwater Drive, Minnetonka, Minnesota 55343, USA. A brochure describes Variomag electro- magnetic stirrers. A range of eight stan- dard models for general laboratory use can be used in incubators up to 50°C. The brochure also gives details of remote operation models, a micro test plate stirrer, stirring block thermostats, bio- systems and large capacity stirrers. Camlab Ltd., Nuffield Road, Cam- bridge CB4 ITH. A catalogue gives details of the full range of over 450 Nalgene labware products including filterware, Cryoware and Unwire test-tube racks. New products include PTFE PFA bottles, square media bottles, affinity chromatography pro- ducts, low-profile bottles, full-size poly- propylene Unwire test-tube racks, 30 mm Unwire half-racks, a 5-ml Cryovial, a polycarbonate Cryobox to hold 5-mf Cryovials and Cryobox racks. Nalge Co., 75 Panorama Creek Drive, Box 20365, Rochester, New York 14602- 0365, USA.

ISSN:0144-557X    

DOI:10.1039/AP9892600434

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

438 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 Gordon F. Kirkbright Bursary Fund The fund was established in 1985 as a memorial to Gordon Kirkbright and his contributions to analytical spectroscopy and analytical science in general. The fund is now administered by the Commit- tee of the Association of British Spectro- scopists and the ABS Trust; it aims to enable promising young scientists of any nation (e.g., postgraduate students or those in their first postdoctoral position) to visit a recognised scientific meeting or place of learning. In 1989, two bursaries were awarded, to Simon Branch and to Susan Darke. Simon Branch, a postgraduate student in Profes- sor Ebdon’s research group at Polytechnic South West (formerly Plymouth Poly- technic), attended the XXVI CSI in Sofia and presented a poster. Susan Darke, a postgraduate student at Loughborough University, will be attending the Winter Conference on Plasma Spectrochemistry at St. Petersburg, Florida, in January 1990, and presenting a paper there. Applications for the award of Gordon F. Kirkbright bursaries in 1990 are now invited. Full details and application forms can be obtained from Professor M. S. Cresser, Department of Plant and Soil Science, Aberdeen University, Aberdcen AB9 2UE. Completed application forms must be received not later than February 28th, 1990.

ISSN:0144-557X    

DOI:10.1039/AP9892600438

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

439 ANALYTICAL PROCEEDINGS, DECEMBER 1989, VOL 26 Award to Member of Analyst Editorial Advisory Board Professor Alan Bond, a member of the Editorial Advisory Board of The Analyst, was awarded the 1989 Medal of the Analytical Chemistry Division of The Royal Australian Chemical Institute at a Ceremony held during Chemistry Inter- national, held at the Sheraton Brisbane Hotel on Wednesday, August 30th, 1989. The Award marks the greatest contribu- tion to Analytical Chemistry in Australia over the last 15 years. Professor Bond is Foundation Profes- sor of Chemistry at Deakin University, Geelong, Victoria, and is a graduate of Melbourne University (1966), being awarded his PhD in 1971 and DSc in 1977. He is the author of “Modern Polaro- graphic Methods in Analytical Chem- istry,” published by Dekker in 1980, and is the recipient of various awards, includ- ing a Fulbright Scholarship (1972), the Rennie Medal (1975) and the David Syme Prize (1977).During 1988-89 he was a Visiting Fellow in the Inorganic Chem- istry Laboratory at the University of Oxford. Professor Bond’s Award address was enti (led “Analytical Chemistry in the 1990s: Teaching, Instrumentation and a Biased View of the Role of Electroana- lytical Chemistry.” Professor A. M . Bond (L) receiving his medal during the meeting “Chemistry International” 100 MODERN REAGENTS Consultin Editor: Dr. N.S. Simpkins, The challen e of carrying out highly selective chemical transformations on ever more complex molecules, has reagents which have found significant application in organic synthesis. Ziversity of Nottingham resulted in t a e development of a vast armoury of organic reagents.This book brings together a selection of 100 100 Modern Reagents features less familiar reagents which have been identified in ’Methods in Organic S nthesis’ those which a1 low important transformations or show interesting and varied reactivity. during the last five years. The selection reflects reagents which have found widespread use, with emp 1: asis on The book provides current, up-to-date information and includes the following data on each reagent listed: name *t. structure *& molecular formula molecular weight *:* physical properties preparation and modifications 4 price range safety precautions needed The reagents are arran ed in alphabetical order and cover two pages each, with the second page providing three reaction schemes high P ighting the use of the reagent.ISBN 0 85186 893 2 October 1989 A5 Flexicover 203 page Price f 19.95 ($39.00) ROYAL SOCIETY OF CHEMISTRY lnformat ion Services For further information, please write to: Royal Society of Chemistry, Sales and Promotion Department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK.ROYAL SOCIETY OF CHE MlSTRY _____ lnformat on Services SAFE PRACTICES IN CHEMICAL LABORATORIES This booklet is the successor to the Society’s ‘Guide to Safe Practices in Chemical Laboratories’. Like its predecessor the new booklet points out relevant statutory requirements and provides general guidance on which specific in-house procedures can be based.The new booklet contains a Foreword by HM Chief Inspector of Factories. ‘Safe Practices in Chemical Laboratories’ takes account of recent technical and legislative developments affecting health and safety in chemical laboratories. In particular the Control of Substances Hazardous to Health Regulations 1988 (COSHH) will have profound implications for many laboratories and users are strongly recommended to read the new booklet in conjunction with the Society’s publication ‘COSHH in Laboratories’. ISBN 0 85186 309 4 Softcover, 50 pages June 1989 Price f 10.00 ($21 .OO) For further information, please write to: Royal Society of Chemistry, Sales and Promotion department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K. To Order, please write to: Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1HN.U.K. or telephone (0462) 672555 quoting your credit card details. We can now accept AccessIVisal MasterCard/Eurocard. RSC Members should order from: The Membership Manager, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K.ANALYTICAL PROCEEDINGS. DECEMBER 1989, VOL 26 44 1 NUTRIENT A VAILA BILITY: CHEMICAL AND BIOLOGICAL ASPECTS Edited by D.A.T. Southgate, I.T. Johnson and G.R. Fenwick, Institute of food Research, Norwich SPECIAL PUBLICATION No. 72 This new book covers an increasin ly important aspect of human nutrition and i s unique in approaching the subject from both a 5 tological and a chemical viewpoint. Nutrient much interest in the field i s the bioavailability of the major eoretical aspects of the subject, workshop summaries, nutrition. ISBN 0 85186 856 8 August 1989 Hardcover, 424 Pages Price f45.00 ($92.00) For further information, please write to: Royal Society of Chemistry, Sales & Promotion Department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK. Herts SG6 1 HN, UK. or telephone (0462) 672555 quoting your credit card details. We can now accept Access/Visa/MasterCard/Eurocard. ROYAL SOCIEpr'OF CHEMISTRY To order, please write to: Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, RSC Members should order from: The Membership Mana er, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Carn%ridge CB4 4WF, UK. Information Services

ISSN:0144-557X    

DOI:10.1039/AP9892600439

出版商:RSC    

年代:1989

数据来源: RSC