摘要:

Proceedings of the Society for Analytical Chemistry Analytical Division Chemical Society CONTENTS Editorial . . . . . . . 25 Proc. SOC. Analyt. Chem. Vol. 10 No. 2 Pages 25-48 Council Meetings . . . . 26 Reports of Meetings . . . . 26 Debate . . . . . . 27 in Animal Foodstuffs" . . 28 Microchemicai Methods Group "Non-prescription Antibiotics "Multi-residue Detection Systems" . . . . .. 31 "industry and Forensic Science" 38 "Analytical Applications of Mol- ecular Complexes . . . . 39 "Examination of Plastics for Pharmaceutical Use' ' . . 41 Correspondence on Amalgama- tion . . . . . . . . 43 Short Courses . . . . . 44 Chemical Society Annual Con- gress . . . . . . . . 45 Notices .. .. .. .. 46 Papers Accepted for The Analyst 47 Publications Received . . . . 48 Forthcoming Meetings Back Cover February 1973 Vol.10 No.2 PROCEED1 N G S February I973 OF THE SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Officers of The Society f o r Analytical Chemistry and the Analytical Division of The Chemical Society President C. Whalley Hon. Secretary W. H. C. Shaw Hon. Treasurer Hon. Assistant Secretaries G. W. C. Milner D. I. Coomber O.B.E.; D. W. Wilson Secretary Miss P. E. Hutchinson 9/10 SAVILE ROW LONDON W I X I A F Telephone 01-734 9864 Editor J . 6. Attrill Assistant Editor P. C. Weston Proceedings i s published by The Society f o r Analytical Chemistry. Members’ subscriptions must be sent to The Chemical Society. Non-members can be supplied w i t h Proceedings only as part of a combined subscription w i t h The Analyst and Analytical Abstracts.Single copies can be obtained direct from The Chemical Society Publications Sales Office Blackhorse Road Letchworth Herts. SG6 IHN (NOT through Trade Agents) price 3Op post free. Remittances MUST accompany orders. 0 The Scciety for Analytical Chemistry Joint Meeting of Chromatography and Electrophoresis Group and Scottish Region on Aspects of Chromatography at The University of Dundee will be held on Thursday afternoon April 12th and Friday morning April 13th 1973 Papers w i l l be presented on Characterisation of long-chain fatty acids GLC of waxes Determining free fatty acids O i l pollution indentification Determin- ation of structural isomers Affinity chromatography High-speed liquid chromatography Determination of isotopically labelled lipids and TLC and TLE of cephalexin. For further information write t o Dr. I. E. Whitley Honorary Secretary Scottish Region Scottish Universities Research and Reactor Centre East Kilbride Glasgow G75 OQU.

ISSN:0037-9697    

DOI:10.1039/SA97310FX005

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

SOCIETY FOR AKALYTICAL CHEMISTRY AK‘ALYIICAL DIVISION CHEhTICAL SOCIETY Forthcoming Mectings+onti.nued fronz back c o u w March-coiztinued \Vcclnesday 7th MANCHESTER KORTH WEST REGIOK jointly with the Manchester and District Section of the CS. “Liquid Chromatography,” b3. Mr. Simpson. John Dalton Faculty in Technology ’The Polytechnic llancliestcr; 6 p.m. PARTICLE SIZE AKAI-YSIS GROUP on “On-line hlcthorls of Particle Size .Inal\.sis.” \Vecliiesday 7th Tliurscla)- 8th BIOLOGICAL PIETIIO~S GROUP. I,OKGHBOROUGH University of Technology Loughborough ; 2.30 p.m. [,ONDON “The Rationale o f Control of Sterile Areas,” by I . Martin. Pharmaceutical Society of Great Britain 17 Bloomsbury Square Ixmdon n’.C.l; 2.30 p.m. Friday 9th SVESTERP; KEGIOI~ CHLPSTOIY Discussion on “Instruments-Breakdo~~n and Running Repairs.” Gcorge Hotel Chepstow; 6.30 p.m.(N.B. Change of date.) l’uc.stlay. 13th SPECIAL TECHK1QUL.S GROW and Easr ASGLIA REGION on “Chcniilumi- “Candoluminescence-.A Stir Technique of 1-lame Spcctroscopic A4i1alysis,” “The r s e of Cheriiiluminescent Reactions in Gas Xnalysis,” 11y C,. Narairi. Lecture ’Theatre Ipswich Civic College Rope \Talk Jpsivich ; 2.30 p.m. (N.B. Change of venue.) NORTH EAST REGIOK joi??tl>’ uith the RIodern llethotls of -1nalysis Group of the SheMeld Metallurgical and Engineering Association on “ Iiecent Trcnds in I I’S\YICH nescence . I ’ by A. Townshend. \\-i.tlnt.sdav 14th F’ritlay 23rd EKISTOL Alonday Nth to I.‘riday 30th SIT AXSEA Thimday. 29th LIVLKPOOL “Kon-flame Methods of Atomisation in Xtoniic-~ihsorption Spectroscopy xvith “Determination of Metal Traces by Catalytic Analysis Hxetl on Lancliilt “Thermometric and Enthalpinietric Xethod i n Analytical Clieniistrs,” b!.“Sacred Coa or \'\'bite Elephant ? ” by l< -4. Chalmers. B.I.S.R..A. Corporate I,aboratorizs Hoyle Strwt ShefYieltl; 2 p.m. SXC hnnual General Neeting ; 2 p.m. Xnalytical Division CS Annual Gcneral Meeting ; 2.20 p.m. lietiring President’s Address ; 2.45 p.m. “’I‘lie Analytical C‘lieniist His Pro- Scientific Societies Lecture Theatre 23 Savile I<oxv London W. 1 . Biennial Formal Dinner Clothworkcrs’ Hall. l h n s t c r Court hiinciiig I/ane ~IIDLAIWS REGION. “Enzyn7;itic Methods of Analysis,” by A. Townshend The Boots C,o. Ltd. Pennyfoot Street Sottinghani; 6.30 p.m. \\:ESTERK REGIOX and ATOMIC SPECTROSCOPY GROYP j o i n l ~ ~ ~ it’fiij thc l3ristol Chemistry Department The T.-niversity Rristol ; 12.15 p.m.CS Annual Chemical Congress. Second Theophilus liedwood Lecture by Professor C,. T. J . .illmnade Two Sjmposia organiscd by the SrlCIXnalytical Division on “Scn.er Methods for Environmental Pollution Analysis” and “Physical llethods for A4nal!,sis in the 70s,” to be held on \\‘ednestiay and ’Thurstlay lI;ircli 28th and 29th University College Swansea. (See also p. 45.) NORTH \\-EST REGIOX’ j o i ~ i t f j ~ wilh the Liverpool and District Sectinn of the CS. “The Chemist a t Sea,” by Professor J . P. Iiilev. The Polytechnic Livupool; 7 p.m. Particular Reference t o the Analysis of Alloys,” by J . B. Hcadritlge. Reactions,” by G. Svehla. L. S. [<ark. fession and His Socicty,” by C~. LVhalley. London E.C.3; 7 p.m.for 7.30 p.m. Section of the CS on “Separation and Concentration Tcchniqries.” SOCIETY FOR ASALYTICAL CHEMISTRY ANALYTICAL DIYISIOX CHEMICAL SOCIETY February Tuesday 20th LOSDON Tuesday 20th COVENTRY Wednesday 21st NEWCASTLE Thursday 22nd CHESTER FridaJ- 23rd RIANNINGTREE Wednesday 28th LOKDOK Wednesday 28th LOUGH- BOROUGH March Tuesday 6th LONDON Tuesday 6th BIRM INGHAhI Forthcoming Meetings SAX/A4D organised by the SPECIAL TECHNIQUES GROL~P on “Modern Develop- “-Analytical Microwave Spectroscopy,” by Professor J . Sheridan. “The Xicrowave Plasma Detector for Gas Chromatography,” by \Y. K. RIcLean. “Hadamard-transform Spectrometry,” by J . A. Decker. Scientific Societies Lecture Theatre 23 Sayile Ron. Idondon I V . 1 ; 2.30 p.m. MIDLANDS REGIOK. “Yon-selective Reagents,” by 31.J. Toogood and C. \\‘atson Lanchcster Polytechnic Coventry; 6.30 p.m. KORTH EAST REGION and XLTTONATIC METHODS GROUP on “Future Trends in “Latest Techniques and Future Aspects of Xuto.lnalysers,” by R. J . King. “LYhither Discrete Automatic Chemical hnalysers ? ” by 1C. J . LIills. “Automated Techniques for the Analytical Chemist,” by Professor C. T. “Trends in -Automatic X-ray Analysis,” by P. Hurley. ‘‘Automatic Analysis with a Computerised Quontovac Emission Spectrometer,” “A Selective Detector for Gas Chromatography,” by A. Dawson. Chcniistry Department The University Sewcastle; 2 p.m. KORTH \VEST REGION. “Control of Pharmaceutical Products,” by -4. G. Fishburn. Chester; 7.30 p.m. EAST ANGLIA REGION on “Plastics.” “Some Methods Used in the Analysis of Plastics Formulations,” by Diana Simpson.“The Application of Gel Permeation and .\finity Liquid Chromatography to the -4nalysis of Polybutadienes,” by E. J . Gallacher and R. J . J . Simkins. “Fluorescence and Phosphorescence Characteristics of Some Antioxidant and Ultraviolet Absorber Compounds Used as .Additives to Polynicrs,” by G. F Kirkbright Bakelite Xylonite Ltd. Research and Development Laivford Place &fanning- tree Essex; 2.30 p.m. ~KICROCHEMICAL METHODS GROUP London Discussion Neeting. Discussion on “n’on-aqueous Titrations,” introduced by D. C. M. Squirrel1 Imperial College London S.IV. 7 ; 6.30 pm. ELECTROARALYTICAL GROUP on “Electrochemical Techniques for Oxygen “Electrochemical Membrane Sensors for Oxygen,” by I. Bergman. “Applications of Fuel Cell Electrodes for Oxygen and Related Analysis,” by “Electrodes for Ion-level Oxygen Measurement,” by M Riley. “Oxygen Measurement Respirative Physiology,” by D. Parker. Chemistry Department CTniversity of Technology Loughborough ; 2.30 p.m. ments in Spectroscopy.” hutomated Analysis.” Rhodes and R. E. Hone. by K. Liddle. Determination.” B. Fleet. ShCjL4D Special Meeting. “New Volumetric Reagents and Reactions in Complesometry,” by R. Piibil. Laboratory of the Government Chemist Annexe 4th Floor Room A408 Cornwall House Stamford Street London S.E.l; 3.30 p.m. (See also p. 46.) MIDLANDS REGION. “The Future of the Analytical Chemist,” by =1. G. Jones. Lecture Theatre 203 Haworth Building The University Edgbaston Birmingham 13 ; 6.30 p.m. [continwed inside back muev Printed by W Heffer L Sons Ltd Cambridge England

ISSN:0037-9697    

DOI:10.1039/SA97310BX007

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

February 1973 Vol. 10 No. 2 PROCEEDINGS OF THE SOCIETY FOR ANALYTICAL CHEMISTRY ANALYTICAL DIVISION CHEMICAL SOCIETY Editorial New SACjCS Analytical Division Monograph Series THE primary objects of the Society for Analytical Chemistr\:'ClieInical SocietS- Analytical DilTision are to encourage assist and extend the knowledge and stud!. of analytical chemistry. To this end the publication of journals reports and books has been recognised since its inception as an essential function of the SIC. Today- more than ever before there exists a need for publications through which analytical chemists can readily keep abreast of develop- ments in their own and other specialist techniques and fields of endea\:our. Measured in terms of the man-years taken to produce it the chemical literature is the most cxpcnsi\.e tool available to the practising chemist.A4bmt four million papers reports patents etc. have been published and this number doubles approximately every 10 years. The author of a recent volume1 calculates that if plausible estimates are made for the number of man-hours each item in the chemical literature represents to producr and store and if this is costed at current levels the literature probably represents LIO1" to _110l1 worth of chemical research already completed. IT'e are thus surrounded by an ever-expanding ocean of literature ivlrich we cannot afford to waste or misuse; although some may question the value of secondary or tertiary publications critical and selective guidance over these waters hh- expert authors frequently offers the only hope for many workers of retaining close contact with a number of fields of research or application.The SAC has for many years sponsored this type of service via the publication of review articles in The Amlyst and has more recentl). initiated several projects the aim of which is to extend this approach. The sales of the two new series publica- tions Selected Ann.ual Reviews o j tizc A nnlyticnl Scicizccs and .4 niiual Rcpovts o n Analytical -4toiizic Spectvoscopy already confirm that members feel a need for this type of volume. In addition to these publications the SAC has commissioned a series of llonograplis whicli icill be devoted to comprehensive and critical appraisal of selected specialised topics. Some of these volumes will provide basic information on the scope and applications of irarious tecli- niques of analysis and others will review analytical procedure for specific types of product or material.The first volume of this new series which is to be published this month is devoted to High-precision Titrimetry and has been prepared by C. Woodward and H. K. Kedman of Imperial Chemical Industries Limited Agricultural Division Teesside. Other Monographs in preparation are concerned with Pyrolysis Gas Chromatography Water Analysis Catalytic Methods of Analysis and Applications of Computers in Analytical Chemistry. It is intended that these short Monographs will each present a critical and timely review of the subject concerned and that they will attract a substantial readership. Further information can be obtained from and orders placed with the Book Department Society for Analytical Chemistry 9/10 Savile Row London \\'lX lAW. REFERESCE 1. Bottle R. T. "The Use of The Chemicai Literaturc," Second Edition Buttcnvorths London 1969.

ISSN:0037-9697    

DOI:10.1039/SA9731000025

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

Reports of Meetings XORTH \YEST REGIOS A JOIST Meeting of the Region with the Sort11 Lancasliire Section of the Chemical Society \fa\ held a t 7.30 p.m. on II’ednesday January loth 1973 at the Harrii College Preston. The Chair was taken by the Chairman of the Sort11 Lanca.;Iw-e Section of t h e Cheiiiical Society RZr. ,A. C. Bushnell. 4 lecture on “Thermometric Analysis” was given by L S. Bark. February 19731 MICROCHEMICAL METHODS GROUP DEBATE 27 SCOTTISH REGIOK A JOIKT Meeting of the Region with tlie Glasgow and \Vest of Scotland Section of the Chemical Society was held at 5 p.m. on Tuesday January 23rd 19i3 in the Library Sational Museum of Antiquities of Scotland Queen Street Edinburgh. The Chair was taken by the Chairman of the Scottish Region Mr. 11:. Dunnet. The following paper was presented and discussed “.lnalysis and Arcliaeology,” by H.1IcKerrell. lIICROC,HEi\lICAL METHODS GROUP THE eighty-fourth London Discussion Meeting of the Group was held at 6.30 p.m. on il’ednes- day January 2ith 1973 in the Senior Common Room Imperial College London S.iV.7. The Chair was taken by the Chairman of the Grocp Dr. D. A. Pantony. -\ discussion on “Standard Substances and Reagents for Organic Analysis” was intro- duced by E. Bishop. BIOLOGICAL METHODS GROVP THE twenty-eighth Annual General Meeting of the Group was held at 6.30 p.ni. on Thursday December i t h 1972 at “The Phoenix,” 14 Palace Street London S.\V.l The Chair was taken by the Chairman of the Group hlr. J. \I Lightboun. The following office bearers were elected for the forthcoming year Clzaz‘rrmziz-Dr.L. Singleton. Vice-Clzazrmm- Miss A. Jones. Honornv! Secretary--JIr. V. J. Birkinshaw The Boots Co. Ltd. Pharma- utical Research Perm>-foot Street Kottingliam SG2 3XA. H o n o r q Treasztrer-hlr. \IT. IYebb. ;Ileitabers of Committee- Nr. D. hl. The Annual General Meeting was followed by a Discussion Meeting at which the Chair A discussion on “Biological Standards” Honorary 24ssistuizt Secretar>f-Miss F. K. 1Iulholland. Slr. D. h;. Hossack Nr. J . \V. Lightbomn Dr. ill. M’. Parkes and Mr. K. Sinar. I*.reeland and Dr. J. H. Hamence were re-appointed as Honorary Auditors. was taken by the new Chairman Dr. I*. Singleton. \vas introduced by D. R . Rangham. This was followed by a Cheese and \I:ine Party. ATOMIC SPECTROSCOPY GROUP THE eighth =\nnual General Meeting of the Group was held at 2 p.m.on l;rida>r December lst 1972 at the Cafi. Royal Regent Street London IY.1. The Chair \vas taken by the Chairman of the Group Alr. \Y. R. Sall. The following oflice bearers were elected for tlie fortlicoming year Chuirnzan-Dr. G. 1;. Kirkbright. ~~’l’cc-(‘hniviizui2-Dr. R. Smith. HOJZOYLW~ Secretary nizd Treasurer-hIr. C. P. Cole Rank Precision Industries Ltd. ’Analytical I)ivision \Vestwood Industrial Estate Ranisgate Road Jlargate Kent. H o i i o r a v ~ Assistaizt .Sccrchm>~-JIr. \V J. Price. Mcmbers of Cowimittrt,-Dr. I;. Alder Nr R. 0. Coclirane Ur. G . R. lIarshall SIr. J. Jlendhani Yr D. 11. Peake and Nr. 1’. Salt. 11r. 11. Noore and Jlr. R. A. IYIiite were appointed as Honorary Auditors. The Annual General Meeting was followed by an Ordinary Meeting at Tvliich tlle Chair u ~ i s taken by tlie new Chairman of the Group Dr. G . 1;. Kirkln-ight. The subject “The Past Trn Years” was reviewed by the four past Chairmen of the Group I$’. T. Elwell J. €3. Dawson \V. .J. Price and LV. R. Nall. This was followed by a Dinner to mark the tenth anniversary of tire Group.

ISSN:0037-9697    

DOI:10.1039/SA973100026b

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

February 19731 MICROCHEMICAL METHODS GROUP DEBATE 27 Has the Microchemical Methods Group Outlived its Usefulness? A Debate 0s December 13th 1978 tlie Microchemical 3Iethods Group held a lighthearted Christmas Debate wit11 the President Mr. C,. Whalley in the Chair on the motion “Tliat this House considers that the Microchemical Methods Group has outlived its usefulness.” The motion was proposed by Professor R . Belcher wlio began bv outlining some of tlie Iristory of the Group and the part he had played in founding i t . He went on to say that 100 years ago there was only “macro” analysis until Emicli and Pregl introduced “micro” analysis. Further division into “semimicro,” “submicro,” etc. followed and at the present time there was no longer At that time there appeared to be two distinct scales of working.28 ANTIBIOTICS I?I ANIMAL FOODSTUFFS P l O C . SOC. Analyt. Chem. “macro” and “micro,” but a continuum from very small to large samples. Consequently as the Group could no longer concentrate on this one small section of the whole spectrum it had outlived its usefulness. He recommended howei~er that the Group should not disband but should change its name to something more appropriate and expand its activities. The motion was opposed by Professor T. S. \Yest who posed a number of questions Is the Group senile? Has the membership declined? Are the programmes interesting? Does the Group fulfil a useful function? etc. He maintained that the answers to all these questions were favourable to the Group. The Group had broadened its horizons beyond organic microanalysis in recent years and was particularly active in promoting meetings on interdisciplinary techniques-an essential area not really catered for by any other Group.It had originated Discussions and Debates with a success that had been recognised by S.4C members. The Group had certainly not outlived its usefulness but he agreed that it might change its name possibly to include trace analysis. The motion was seconded by Dr. D. .I. Pantony the present Chairman of the Group who admitted that the past of the Group liad been full of glory but that we were now concerned with the present day. He said that lie was seconding tlie motion for three reasons (1) the poor attendance a t meetings (he noted that only 35 out of a nominal membership of 1200 had come this evening) ; ( 2 ) the term “micro” is no longer distinctive-users of particular instru- ments would be better served by a “user group” ; and (3) Committee members are hard to find.He agreed that the Group had played a rBie in arranging joint meetings and said that it represented the analyst’s attitude towards the sample and the meaning of an answer but suggested that these were not its jobs; these were the jobs of the SAC. He said that neither the Chairman nor the Committee nor the members of the Group had outlived their usefulness. He agreed that the Group had expanded its sphere of activity but said that a Group could not be too rigid. Many subjects at present studied by SAC subject groups were more physical than chemical- did vie want the SAC to become a branch of tlie Institute of Physics? I t was he concluded impossible to pull the Group to pieces to dissect it and to expect it to live.Many of the members present spoke for and against the motion from the floor of the House until the Chairman before closing the debate invited tlie two opening speakers to say a final word for their respective sides. Before putting the motion to the vote the Chairman who had earlier expressed his intention of remaining neutral summed up in a brilliantly impartial manner. He urged that all feelings of sentiment s h d d be put aside; we were concerned with tlie facts. However he suggested that it was up to tlie proposers of the motion to prove their case. If any doubt existed then the benefit of this should be given to the Group. The motion was finally put to the vote and on a sliow of hands was decisively defeated by a majority of approximately five to one. Mr. D. \V. IVilson seconded the opposition.

ISSN:0037-9697    

DOI:10.1039/SA9731000027

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

28 ANTIBIOTICS I?I ANIhIAL FOODSTUFFS P l O C . SOC. Analyt. Chem. Non-prescription Antibiotics in Animal Foodstuffs - Their Nature and Analysis The following are summaries of three of the papers presented at a meeting of the Bio- logical Nethods Group held on October ISth 1972 and reported in the November 1972 issue of Proceediizgs (p. 232). Determination of Flavomycin in Feeds BY G. NESE~IANX (Farbwwke Hoechst A.G. Fvaizkfuvt (.Uuiiz) Geiwiany) FLAVO~T~-CIN is an antibiotic developed by Farbwerke Hoeclist A.G. and is intended solely for application in animal nutrition. I t is produced by common fermentation procedures and its elemental analysis shows C H 0 1\ and 1.8 per cent. of P. The free acid and the alkali metal and alkaline-earth metal salts are readily soluble in water and methanol.The compound lowers the surface tension of water. A reversible association is observed in salt solutions a t neutral pH which can be disintegrated by the addition of water-miscible solvents. February 19731 ANTIBIOTICS I N ANIMAL POODSTCFFS 29 The structure of Flavomycin is very complicated. It consists of phosphorus a hydro- phobic part represented by the lipid alcohol moenocinol and a liydrophilic part consisting of several sugars a uronic acid and an ultraviolet chromophor. Flavoniycin is effective mainly against gram-positive bacteria. The most suitable method of determining Flavomycin in the concentrate is by means of a turbidimetric test. For determining Flavomycin in feeds samples have to be ground to a fine powder then extracted with 50 per cent. methanol boiling under reflux for 15 minutes.The extract is assayed by an agar diffusion method in which agar-well plates are used. The test organism is Bacillus cereus. Comparisons are being made between the standard and the unknown the readings being made from the standard graph. Experts in the E.C.C. prefer a (4 + 4) x 4 factorial block test to allow a statistical decision. A large plate method is used with B. stemothernzop/zilz.ls as the test organism. In this test the relative activity can be determined in a purely mathematical manner. X specific qualitative identification is possible only by paper chromatograph>- and evaluation of the bioautogram. Four solvent systems have been found to be suitable for the circular paper chromatographic evaluation. X problem that sometimes occurs in connection with the high dilution ratio of Flavo- mycin in the feeds is the non-specific inhibition due to other substances in the feed ingre- dients.I t is therefore advisable to purify the extract and in some instances it is recommended that Flavomycin be separated from the extract. The purification can be carried out by treating the extract with a cation exchanger (Dowex 50 LLr-X8). For the micro-scale separ- ation of Flavomycin it is adsorbed on an anion exchanger (Dowex l-X2) and the column is washed and then eluted with 0-7 per cent. of potassium chloride in 80 per cent. methanol. The eluate is tested as described earlier. Virginiamycin-Composition and Analysis BY B. BOON (Rechrvche et Indztstvie Thdyapeutiques B-1320 Genvai BeZgzur,z) THE antibiotic virginiamycin* is a mixture o€ two biologically active compounds the 11 and S factors.These two compounds show a definite in vitro and in Z I ~ ~ D ' O synergistic a ~ t i o n . l - ~ The structure and nomenclature of virginiamycin have recently been reviewed.4 The h1 factor is assayed by a colorimetric procedure after reaction with the Ehrlich reagent.j The fluorescent S factor is spectrofluorimetrically assayed a t 444 mi (excitation band a t 315 nm). The chromatographic analysis of virginiamycin is performed on paper or a thin layer of silica gel6; the S component is detected under ultraviolet light and the 11 component by spraying the Ehrlicli reagent. The biological activity results from the marked synergistic effect between both factors ; it depends on the relative contents of the M and S factors in the antibiotic.Each sensitive micro-organism shows a specific synergistic curve slightly or sometimes completely different from the others2 The virginiamycin potency measured by its activity against StaphyLococc,us aztvezis 6938 P is defined by comparison with a batch arbitrarily taken as a reference. Consequently the test organism used in a microbiological assay for virginiamycin must sliow the same synergy as the reference organism. The very sensitive Coryuebacteviwiz xerosis KCTC 9755 satisfies this requirement and is used for the assays at low levels. .ill extraction procedures must take into account the low solubility of virginiamycin in water. \Yhen the antibiotic is incorporated in feed in its granulated form,t a mixture of equal proportions of acetone and 0.1 x aqueous citric acid solution will permit quantitative recovery; the presence of water is necessary so as to release the virginiamycin from the granules.l'irginiamycin is assayed in concentrated feed or in pre-mixes by the classical agar diffusion method in cups or cylinders. The use of paper discs loaded with small amounts of the feed extract is proposed for the assay in finished feed. A sodium hypochlorite inactivation procedure was developed in order to prepare the reference solutions in bIank feed extracts. Lower alcohols acetone or halogenated solvents are suitable. * Formerly known under its trade-name Staphylomycin. Marketed under the trade-name Stafac 500. 30 ANTIBIOTICS IN ANIMAL FOODSTUFFS :PYOC. SOC. Analyt. Chem. The identification of virginiamycin in feed is performed by a chromatographic procedure Complete descriptions of the assay and identification methods followed by bioautography.are in preparation. REFERENCES 1. 2 . 3. 4. 5. 6. de Somer P. and van Dijck P. Antibiotics Chemothev. 1955 5 632. van Dijck P. Vanderhacghc H. and dc Somcr P. Ibid. 1957 7 625. van Dijck P. Chewzotherapy 1969 14 322. Crooy P. and de Neys K. J . Antihiot. 1972 25 371. VaIiderhaeghe H. van Dijck P. Parmentier G. and de Somer P. Antibiotics Chenzothev. 1957 Gosselinckx F. arid Parmentier G.. J . Pharm. Belg. 1963 181 7 606. The Assay and Identification of Zinc Bacitracin in Feeds and Feed Suplements BY B. GRYNNE ( A 1.5 A pothekevnes Laboratoriuin for Specialpvaeparater. Oslo-2 Sovway) THE paper discussed the physical and chemical properties of zinc bacitracin the assays of supplements interference in the assay and identification.Bacitracin complexes with several metal ions such as copper nickel cobalt magnesium zinc arid manganese ions some being more stablc than the uncomplexed bacitracin. I t is important that sufficient zinc is present for the optimum activity against bacteria. Zinc bacitracin in feed supplements containing at least 40 g per kilogram is extracted with a phosphoric acid solution and diluted in phosphate buffer 1 per cent. m/V pH 6.5 before assay on '$1. jlar1.s plates as described ear1ier.l The methanol extraction technique1 is suitable for concentrates and feedstuffs containing down to 4 p.p.ni. of zinc bacitracin. I t has been found that if the methanol concentration is below 60 per cent. VlV when phosphate buffer is added low results are obtained.Inter- ference from components in the feedstuffs can be overcome by (1) diluting to volume (2) applying tlie incremental method and (3) adding an extract of the unfortified feed to the standard. The only substance found to interfere in the assay and which cannot be eliminated by using representative blanks is copper. Jntcrferences of antibiotics are shown in Table I. TABLE I INTERFEREKCE I N THE ASSAY OF FEEDS WITH 10 p.p.m. OF ZIKC BACITRACIK Ahtibiotic Chlortctracycline . . .. . . Erythromycin . . . . .. . . Oxytctracyclinc . . . . . . Virginiamycin . . . . . . . . Amprolium . . .. .. . . Copden 26 . . .. . . . . Flavomycin . . .. . . . . Xeomycin sulphate . . . . . . Penicillin . . .. . . . . Furazolitlone . . .. . . . . Sitrovin . . . . .. . . Lcvcl p.p.rn . .. . 0.4 * . . . 20 .. . . 1.0 . . . . 0 . 6 .. . . 7.5 . . 125 126 . . . . 20 . . . . 20 . . . . 50 .. . . 10 .. .. Of the non-prescription feedstuff antibiotics onIy virginianiycin will interfere when Copper when present at a copper to zinc ratio greater than I t has been found that the modified extraction method is not suitable for concentrate9 In this event tlie concentrate is diluted at present at the permitted level. 4 1 is inactivated by thc addition of 3 to 4 mol of ammonium sulphatc per mole of in which the copper to zinc ratio exceeds 4 1 . least ten-fold with soya bean meal before applying the modified technique. February 1973; MULTI-RESIDUE DETECTIOT SYSTEMS 31 For the identification of bacitracin in the presence of other antibiotics a modification of the electrophoresis techniques of Lightbown and de Rossi3 and Thomas and Broadbridgel is used.j Increased sensitivity is obtained by using thin layers of lightly inoculated medium to compare migration rates of the test antibiotics.Results are given in Table 11. TABLE I1 AIIGRATION RrlTES OF TWELVE AKTIBIOTICS Migration tou ards .htibiotic anode/mm Test organism Xeomycin . . . . . . . . 22 S . epadernzidas Penicillin . . . . .. . . 11 S. lactt~a Flavomycin . . . . . . . . 8 B stearolhemophilus Dihydrogtreptompcin . . . . .. 1 B subtalis Chlortetracy-cline Oxytetracycline Zinc bacitracin Spiramycin . . Erythromycin . . Oleandomyin . . Lincomycin . . Tylosin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nigration towards cathode/mm 19 20 43 69 6 3 66 6 3 74 B . cepeus B. ceveus S . lutea S . Izctea S. lictea S . Zzttea S . lutea S . Iutea d turbidimetric method with Staphylococcus aimiis for the assay of bacitracin is being investigated but has been found to be more prone to interference than the -If. j a w s plate ahsay. REFEREKES 1. 2. 3. Grynne B. A77alyst 1971 96 338. Grynne B. Hoff E. Silsand T. and T'aaje I<, Ibid. submitted for publication Liehtbown. T . TT'. and de Rossi P. Ibid. 1965 90 89. 4. 5. Thomas A H . and Broadbridge R . A. Ibid. 19i0 95 459. Grynne B. Ibid. submitted for publication.

ISSN:0037-9697    

DOI:10.1039/SA9731000028

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

February 1973; MULTI-RESIDUE DETECTIOT SYSTEMS 31 Multi-residue Detection Systems The following are summaries of four of the papers presented a t a Joint Meeting of the SXC!Analvtical Division and the Pesticides Group of the Society of Chemical Industry held on Sovember Ist 1952 and reported in the Xovember 1972 issue of Proceedings (p. 231). Mercury and Organochlorine Residue Determination in Fish and Aquatic Mammals BY A. V. HOLDEN (Freshwater Fisheries Laboratory Pitlochvy Pevthshire PH 16 5LB Scotland) AQL-ATIC animals are continually exposed to contamination by many substances of industrial or agricultural origin and mercury and organochlorine compounds are accumulated to give high concentrations in tissues relative to those in water. Mercury is of interest in respect of its presence as a contaminant in human food but organochlorine compounds such as tlie pesticides DDT and dieldrin and the industrial polychlorinated biphenyls (PCBs) may also have a significant ecological influence.The paper described the methods in use a t the Pitlochry laboratory. Nercury is determined both as methylmercury the form in which most mercury in fish is usually found to occur and as total mercury. Methylmercury is determined by electron-capture gas chromatography on Carbowax 2051 following its extraction from acidified biological samples with benzene clean-up of the benzene extract by transfer to a cysteine acetate solution and re-extraction into benzene. An inter-laboratory check-sample 32 MC‘LTI-RESIDUE DETECTION SYSTEMS I P m . SOC. Aizalyt. Clzeiiz. programme showed a coefficient of variation of k20 per cent.between laboratories for this form of analysis the mean recovery of methylmercury added to fish tissue being 103 per cent. of the true value. Total mercury is now most commonly determined by flameless atomic-absorption spectrophotometry following digestion of the tissue samples with acid and reduction of a diluted aliquot of the digest in an aspiration vessel from which the mercury vapour is passed into a silica cell fitted to the spectrophotometer in place of the normal burner. In the method described a nitric acid - sulphuric acid digestion is carried out at 180 “C in flasks fitted with air condensers. After complete digestion further nitric acid is added and an aliquot of the solution is reduced with tin(I1) chloride solution. The apparatus used gives a rapid and sharp response and mercury concentrations in tissues can be determined down to 0.005 mg kg-1.The procedure described for the determination of organochlorine residues involves extraction of lipids and residues in Soxhlet extractors and removal of lipids on columns of dry alumina with n-hexane as eluting agent. The n-hexane solution is further fractionated on columns of partially deactivated silica separating the PCBs $$’-DDE and hesachloro- benzene (with a few minor compounds) from the BHC isomers p#’-DDT @j‘-TDE dieldrin and some less common residues. Of these compounds the PCBs the DDT group and dieldrin are the most common especially in marine fish. Electron-capture gas chromatography with the use of two types of column that give different separation characteristics enables all the major residues to be identified and deter- mined the relative retention values (R,) being calculated for confirmation of identity.Full details of the types of column Rx values and the separation of residues on the silica columns will be given in the published paper. PCB concentrations are determined only on chromato- grams that show at least eight peaks corresponding to known PCB peaks four peaks being used for calculation by coinparison with a commercial PCB mixture selected as a standard. Collaborative studies of organochlorine residue determinations among a number of analysts have shown that the coefficients of variation for several insecticides arid PCB residues were similar in the range =10 to 518 per cent. In the determination of organochlorine residues care must be taken to avoid contamina- tion from a Yariety of potential sources in the laboratory including both impure chemicals and materials such as plastics paints and human skin.The precautions taken a t the Pitlochry laboratory were described. Compounds other than Organochlorine pesticides and PCBs may occur in fish and some can be detected by the routine analytical procedure but most can be distinguished by their different retention \,slues. These compounds include phthalate plasticisers chlorinated naphthalenes chlorinated terphenyls and aliphatic chlorinated compounds. The terphenyls would require a higher gas - liquid chromatographic operating temperature for determination while the aliphatic compounds can be detected only at a much lower temperature. Other stationary phases and detectors are available for gas - liquid chromatographic analysis in special instances as well as chemical reactions for certain confirmatory procedures but these are not used routinely.One operator can analyse 20 to 30 samples daily. Organophosphorus and Carbamate Detection Systems BY J. H. A . RGZICKA (Defiavtmeizt of Trade and Industry Labovatovy of the Goceivzme+tt Chewcist Corizwnll Hozise Stamford Street Loladoit SE1 9SQ) ORGANOPHOSPHORCS pesticides are used principally as insecticides whereas carbamates with a broad spectrum of biological activity have a wide range of pesticidal uses. They may be used as fungicides insecticides nematocides miticides or molluscicides. Earlier methods of residue analysis involving colorimetry and paper chromatography have now been generally superseded by gas and thin-layer chromatography.Thin-layer methods have been improved with the introduction of polyamide and cellulose layers and more sophisticated detection methods. Organophosphorus and certain carbamate pesticides have the ability to inhibit enzymes such as carboxylesterase and in particular cliolinesterase. As a result several w~rkersl-~ have used combined thin-layer chromatographic - enzyme February 19731 MULTI-RESIDUE DETECTION SYSTEMS 33 inhibition procedures with indoxyl acetate as the fluorigenic agent. Studies have been conducted to find the most sensitive esterases and it has been shown that pig-livcr esterase is preferable for carbamatcs and beef-liver esterase for organophosphorus compounds. Typical detection limits are carbaryl 0.05 carbofuran 5 aprocarb 10 parathion 0-1 and malathion 25 ng.Another detection system for thin-layer chromatograms is the formation of fluorescent derivatives such as dansyl chloride; with optimum conditions 1 rig per spot can be a n a l y ~ c d . ~ Gas - liquid chromatography is invalua.ble for tlie detection and determination of carba- mate and organophosphorus pesticides. Flame-ionisation detection is perhaps the most widely used detection method in general use today but i t lacks specificity. The ICarmen- Giuffrida detector (thermionic detector) is basically an alkali salt ring placed on the tip of a flame-ionisation detector but having more enhanced sensitivity and selectivity to phos- phorus- and nitrogen-containing compounds. By using this detector the clean-up step can often be dispensed with although a charcoal column clean-up is frequently used prior to injection so as to prevent column contamination.A therrnionic detector with a rubidium sulphate tip operating under optimum conditions has been reported to have a sensitivity of 1 pg for a number of organophosphorus pesticides6 Patented as early as 1962 the flame-photometric detector has come to the fore only in the last 2 or 3 years. When organopl-iosphorus compounds burn various emissions are produced which are monitored with filters and photomultiplier tubes. There arc two wave- lengths of prime importance 526 nm due to the HPO species and 394 nm due to the S-S species when sulphur is present. The response in the phosphorus niode is essentially linear and 1 ng is readily observed. The disadvantage with the sulphur niode is that the response lacks linearity being approximately proportional to the square root of concentration and consequently a calibration graph is essential.Also sulphur compounds can simulate smaller amounts of phosphorus although this problem can be resolved if botli modes in tlie dual photomultiplier arrangement are used simultaneously. The gas - liquid chromatography- of certain carbamates is difficult because of thermal breakdown but derivatives with good heat stability suitable for gas chromatography can he prepared. Derivatives prepared and successfully detected with an electron-capture detector include the trimethylsilyl,7 2,4-dinitroplienyl derivatives of the amines or phenol9 moieties the trichloroacetates10 and N-perfluoroacyl compounds.ll The response of the electron- capture detector to the trifluoroacetyl derivatives of carbaryl was approximately one-fifth that of lindane and linear over the 0.5 to 10 ng range.The current trend is direct gas chro- matography of carbamates after extraction and clean-up by using highly silanised columns which reduce the tendency for thermal decomposition to occur. Thermionic detectors are commonly used for carbamate analysis because of their selectivity to nitrogen compounds and simplicity of construction. Other nitrogen-selective detectors used for the analysis of carbamate residues are the microcoulometric detector which gives an absolute and stoicheio- metric measure of nitrogen at the nanograni level but is easily poisoned and the electrolytic conductivity detector which has the advantage of simplicity as no amplification of signal is necessary.The electrolytic conductivity detector has a sensitivity approximately twice that of the rubidium chloride thermionic detector for nitrogen-contairiirig compounds without phosphorus but the latter detector is one hundred times more scnsitive to phosphorus compounds that contain nitrogcn than the conductivity detect0r.l' A highly selective detcctor reported as early as 1965 but yet to come to tlie fore is the microwave-excited plasma-emission detector. Relatively few papers have been published involving its use and commercial instruments are only just coming on to the market but this may be the detector of the future. It is based on the emission that results from the atoms of a specific element in a helium or argon stream eluting from a gas chromatograph when passed into a microwave-sustained plasma discharge at either atmospheric or reduced pressure.Reduced pressure permits the use of helium as the carrier gas with the advantages of less background radiation and higher excitation energy than argon plasmas. All elements of organic compounds can be detected so i t is possible to examine for phosphorus and nitrogen simultaneously. For most elements including phosphorus the detectable limits are of the order 0.1 to 1.0 ng s-l and for oxygen and nitrogen about 3 ng s-l. A useful qualitative technique is the coupling of gas - liquid chromatography with mass spectrometry. For simultaneous quantitative analysis a flow splitter is uscd which passes 3 4 MULTI-RESIDUE DETECTION SYSTEMS IPYOC. SOC.dnalyt. Chem. part of the effluent to a conventional detector. With suitable enrichment 0.1 pg is adequate to provide a good spectrum for most compounds but nanogram and picogram amounts can bc detected if the mass spectrometer is focused on a single mass number. A technique that appears promising especially for those carbamates which are thermally unstable is high-pressure liquid chromatography. Helium is used to force a solvent usually organic through an analytical column to the dctector. The column can be packed with a variety of materials but it has been found that surface-coated beads with chemically bonded stationary phases give the most efficient separations. The detection systems used are Aamc ionisation (after removal of the solvent) refractometry polarography or ultraviolet with How-through cells.Polarography13 and cyclic voltamrnetry14 have been used for the analysis of organoplios- phorus and~carbamate pesticides but generally are more suitable as confirmatory techniques The present trend in the use of sophisticated instrumentation has resulted in an interest in automated procedures. An automated cliolinesterase inhibition niethodlj gave satisfactory results for formulations of organophosphorus and carbamate insecticides. About twenty samples per hour were determined with a detcction limit of 0.1 Ing kg -l dependent on the compound inhibition mode used. With this sensitivity residue lcvel analyses may be possible. 1. 2. 3. 4. 5 . 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. REFERENCES Mencloza C. E. Wales P. J. McLeod H. h. and McKinley. 11'. P. .Ana/j,st 1968 93 34 Geike F.J . Chromat. 1970 53 269. Gardner A. M. J . Ass. Off. Analyt. Chew.. 1971 54 517. Mendoza C. E. and Shields J. B. Ibid. 1971. 54 507. Frci. R. W.. and Lawrence J. F. J . Chronzat.. 1972 67 87. De Loach H. I<. and Hemphill U. U. J . A s s . Off. Axalyl. Chenz. 1969 52 533. Fishbein T,. and Zielinski W. L. J . Chronzat. 1965 20 9. Cohen I. C. and Wheals B. B. Zbid.. 1969 43 233. Cohen I. C. Norcup J.. Kuzicka J. H. A, and Wheals R. R. I b i d . 1970 49 215. Fishbein L. and Zielinski W. L. Ibid. 1966 23 298. Seiber J. N. J . Agric. F d Chew. 1972 20 443. Greenhalgh R. and Cochrsne 1%'. P. J . Chronzat. 1972 70 37. Gajan R. J. J . Ass. Off. Analyt. Chenz. 1969 52 811. Booth M. D. and Fleet. B. Talanta 1970. 17 491. Voss G. J . Ass. Off. AnalyL. Chern. 1969. 52 1027.An Approach to the Detection of Pesticide Poisoning in Wildlife BY P. J. BUNYAN (itfinislry of Agvicullure Fisheries a$zd Food Pest Infestation Control Lnborutovy Tohorth Survey KT6 7NF) THE problems involved in demonstrating the exposure of wildlife to organophosphorus or carbamate pesticides are not easily overcome even with modern sensitive analytical tech- niques as these compounds are usually readily absorbed or metabolised by animals and leave little or no extractable residue in tissues. In addition where rcsiducs remain tlie chemical identification is difficult and time consuming owing to the wide variety of these types of chemicals in use and if successfully accomplished does not answer the question of whether exposure was lethal to the animal. For these reasons the Pest Infestation Control Laboratory has utilised the well establishcd propensity of these pesticides to inhibit esternses in order to produce a method for the diagnosis of poisoning.The knowledge that esterases are relatively stable in post-mortem tissue was an essential prerequisite to the approach. The background information necessary for satisfactory diagnosis was obtained from a study of cholinesterase triacetin esterase cr-naphtliyl acetate esterase and phenyl benzoate esterase levels in extracts of liver kidney and brain from pigeons pheasants and Japanese quail following acute sub-acute and chronic dosing of a variety of organophosphorus and carbamate pesticides. Details of the chemicals thc methods and tlie results of much of the work have already been p ~ b l i s l i e d . ~ - ~ Although carly experimental work on inhibition had been performed mainly on blood this tissue was not examined in our programme as February 19731 MULTI-RESIDUE DETECTIOS SYSTEhlS 35 it is rarely obtainable from wildlife pesticide casualties.Investigations were carried out on both fresh and old tissue so as to simulate the condition of animals found dead in the wild. The activities of the esterases were determined in the whole extract and related to the protein content. The activities were also determined by the densitometric scanning of isoesterase patterns after electrophoresis of the same extracts in starch gel with subsequent histochemical staining for esterase activity under carefully controlled conditions. The latter part of the investigation was undertaken in order to test the theory that the different molecular forms of the esterases might have various affinities for each pesticide leading to unique changes in the isoesterase pattern and a positive identification of the pesticide.Measurements on control groups of birds reveal that esterase levels particularly in extracts of brain tissue and to a lesser extent in extracts of liver are grouped within acceptable limits around the mean and are reproducible for each species. Significant deviations (greater than two standard deviations from the control mean values) as a result of exposure to inhibitors are identifiable in both fresh and old tissue. Isoesterase patterns are also highly reproducible in all tissues and are species- and organ-specific. Measurements on dosed birds reveal that lethal organophosphorus poisoning is generally accompanied by greater than 90 per cent.inhibition of brain cholinesterase levels and also by the complete inhibition of the fastest running “true” cholinesterase band of brain electro- phoregrams stained for cholinesterase activity. In addition there is often considerable perturbation of brain liver and kidney electrophoregrams stained for x-naphthyl acetate esterase activity. The latter observations allow the classification of pesticides according to their effect but do not allow a unique identification. Few pesticide-inhibited esterases show signs of spontaneous reactivation when examined by these methods. Sub-acute and chronic intoxication is usually accompanied by significant alterations of less severity than those outlined above. Similar work on carbamate poisoning is a t an earlier stage but first results show similarities to organophosphorus poisoning with little signs of spontaneous reactivation as might have been expected.However unlike organophosphates lethal poisoning is accompanied by large but not necessarily greater than 90 per cent. inhibition of brain cholinesterase and the “true” cholinesterase band in brain electrophoregrams is not always completely absent. A particular diagnostic feature of this type of poisoning seems to be an apparent increase in liver a-naphthyl acetate esterase levels when measured on electrophoregrams particularly in comparison with those measured by the conventional “test-tube” technique and even in comparison with con- trol values. This may reflect a combined effect of the elevation of hepatic microsomal enzyme levels including esterases by carbarnate9 followed by reactivation of the increased but inhibited esterases during the passage through starch gel.With suitable control esterase values and isoesterase patterns the approach outlined above allows a rapid and positive diagnosis of lethal or sub-lethal exposure of wildlife to organophosphorus or carbamate pesticides. Furthermore these measurements can indicate which pesticides might have been responsible. Control figures particularly for isoesterase patterns can often be adequately determined from as few as two control animals although more are desirable. If the diagnosis is positive use is now made of recent more sensitive and specific analytical techniques to examine ether extracts of the gizzard wall and contents.In many instances the identity of the pesticides responsible can now be determined by a suitable combination of gas - liquid chromatography7 with a therniionic detector thin-layer chroniatography with esterase inhibition detection* and gas - liquid chromatography combined with mass spectro- metry following a suitable column clean-up (e.g. Holden and Marsdens). Although residues can often be identified in gizzard contents by these methods they are seldon found in tissue. An example of how this combined approach is used in practice has been published.1° The incident involved the deaths of Greylag geese in Scotland as a result of carbophenothion poisoning. CONCLUSIONS -4 combination of biological and analytical chemical methods for the diagnosis of pesticide poisoning in wildlife yields a more powerful diagnosis than either alone.The use of esterase measurements allows a positive diagnosis of lethal exposure even if no residues are present. 36 MULTI-RESIDUE DETECTION SYSTEhlS :P?’OC. SOC. Aplalyt. Chem. REFERENCES 1. 2. 3. 4 5 6. 7. 8. 9. 10. Bunyan P. J . and Taylor A, J . Agrzc. Fd Chem. 1966 14 132. Bunyan P. J. Jennings D. M. and Taylor .I. Ibid. 1968 16 326. -,-,- Ibid. 1968 16 332. -__-_ Ibid. 1969 17 1027. Bunyan P. J . Jennings D. >I. and Jones F. J . S. Pestic. S c i . 1971 2 148. Puyear R. L. and Paulson G. D. Toxic. .appl. Phavnzac. 1972 22 621. Watts R. R. and Storrherr R. IV, J . Ass. Off. Analyt. Chem. 1969 52 513. Mendoza C. E. \Vales P. J . McLeod H. A and hIcIiinley W. P. Analjjst 1968 93 34. Holden A. \-. and Marsden I<.J . Chromat. 1969 44 481. Bailey S. Bunyan P. J. Hamilton G. :I. Jennings D. M. and Stanley P. I. I17iZd,fowl 1972 23. 88. A Problem Family-the PCBs BY R. EDWARDS ( H . J . Heinz Co. L t d . Hayes Park Hayes .Widdlesew) THE polychlorobiphenyls (PCBs) are now well known contributors to the environmental pollution picture. While levels in human food are generally low and the compounds are only moderately toxic nevertheless they have been the cause of two major incidents in the past few years. In Japan a number of people have died because of contamination of rice oil thousands have been poisoned and teratogenic effects observed; and in the United States thousands of poultry had to be destroyed because of contamination of feed. Both of these incidents were caused by the leakage of PCBs from heat exchangers..A number of the analytical and toxicological problems stem from the fact that the commercial products are complex mixtures of compounds. While a general picture of the toxicology of these compounds is not yet available it is clear that their toxicity varies and bears some relation- ship to the degree of chlorination. The toxicology is however complicated by the fact that some commercial products may contain as trace contaminants highly toxic chlorinated dibenzofurans. The primary difficulty in the analytical field is that the PCBs have very similar properties to those of organochlorine pesticides and there are difficulties in separation. Here again the picture is at least theoretically complicated by the fact that other families of chlorinated hydrocarbons also have similar properties.This applies to the chlorinated naphthalenes and indeed the chlorinated terphenyls that are used in mixtures with the PCBs. Many analytical materials are contaminated by PCBs and there are further problems in the quantitation of these compounds. PCB residues in living organisms are more usually of the higher chlorinated compounds and in gas chromatography they have retention times that overlap with those of the DDT group. One approach to the non-separation in analysis has been to alter the pesticides chemically radically altering gas chromatographic retention times leaving the PCBs intact and enabling pesticides to be determined by difference. To facilitate the quantitation of PCBs the compounds can be hydrogenated or perchlorinated to produce a single gas- chromatographic peak.\Vhatever secondary treatment may be used it is more satisfactory to be able to separate the PCBs from pesticide residues. This separation is difficult but can be effected with a reasonable degree of success by using either thin-layer or column chromato- graphy. A partial separation was obtained by Reynolds1 by using Florisil column chromato- graphy. Heptachlor and aldrin were not separated from the higher chlorinated PCBs but there was little mutual interference during gas chromatography. However DDE where there is a gas-chromatographic overlap was also not separated from the PCBs which has proved a much more difficult problem to solve. Armour and Burke2 showed that separation of DDE from the higher chlorinated PCBs could be obtained with silicic acid but later work showed that the separation from lower chlorinated members could not be carried out under the conditions described.Work in this laboratory with Florisil and silicic acid has been directed towards the effect of various adsorbent activation conditions on the key pesticide - PCB separations and clarification of what in fact are the problems when gas and column chromatography are used in combination. With Florisil materials of high and relatively low activity were February 19731 MULTI-RESIDVE DETECTION SYSTEhlS 37 compared in terms of the effect on retention volumes of pesticides and PCRs. Material was re-activated for 23 hours a t 600 "C or overnight at 115 "C. With light petroleum as eluting agent most organochlorine pesticides (including aldrin) had almost identical retention volumes on both materials but some (DDE dieldrin and methoxychlor) gave markedly different values.IVhile the lower activity adsorbent gave higher DDE retention volumes relative to aldrin this was still insufficient to obtain an adequate separation of this pesticide from PCBs. Because of the extreme sensitivity of high-activity Florisil to atmospheric deactivation a by-product of this work was the use of a technique to avoid this risk. Pre- heated columns were charged with hot activated adsorbent cooled under vacuum and solvent was admitted directly into the evacuated apparatus. Silicic acid as used by Armour and Burke2 was activated for a minimum of 7 hours at 130°C and then deactivated with 3 per cent. of water. Repetition of their work with a test mixture of aldrin heptachlor and DDE eluted with light petroleum indicated that from the retention volumes useful separation of PCB from DDE would not be obtained.Omission of the admixed Celite and of the deactivation stage together with the use of the handling technique described above did give an effective separation of DDE from a 54 per cent. chlorinated PCB mixture. Silicic acid - silica gel can be usefully activated a t tempera- tures up to 200 "C and so the effect of different activation conditions on retention volumes relative to aldrin were explored. Initial work at 130 150 and 170 "C indicated that as with Florisil optimum activation times existed a t each temperature and if this time was exceeded deactivation began in terms of decreasing retention volumes both absolute and relative. This effect was examined more closely a t 170 "C and accurate retention volumes for the three pesticides were determined with various activation times.The relative retention volume for DDE was 4.92 a t an optimum of 9 hours compared with 3.72 a t 1 hour and 4.11 at 18 hours. The Armour and Burke procedure gave a relative retention volume of 1.62 and in fact a t this lower temperature about 50 hours of activation would be needed to secure optimum activity. As with water controlled deactivation with diethyl ether gave poorer separations without any improvement in resolution. Retention volumes for the range of PCBs found in 42 and 54 per cent. chlorinated mixtures were determined and it was confirmed that in general terms lower chlorinated members were eluted later. As this order is the reverse of that in partition gas chromato- graphy the separation problem revolves round those few PCB compounds and pesticides which have very similar properties in both chromatographic techniques.With the non- polar gas-chromatographic column used (OV-1) two PCB peaks interfere with $p'-DDE but by using fully activated silicic acid these peaks can be almost completely separated from that of the pesticide. Thus even with a mixture of lower chlorinated PCBs the bulk of the PCB can be separated from DDE and those lower chlorinated members which are not separated will of course give no interference with the pesticide as they have low gas- chromatographic retention times. To obtain this separation fully activated adsorbent clean samples and pure solvents must be used and the column should not be overloaded. The use of deliberately deactivated material is precluded. REFERENCES 1. 2 Reynolds L. M. B d l . Ei7uir. Conianz. Toxicol. 1969 4 128. Xrmour J. A and Burke J . A . J . A s s . Off. -3naIyt. Chew. 19i0 53 761.

ISSN:0037-9697    

DOI:10.1039/SA9731000031

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

38 INDUSTRY AND FOREKSIC SCIENCE Industry and Forensic Science [Proc. Soc. Analyt. Ckem. The following is a summary of the paper presented at a Meeting following the Annual General Meeting of the Scottish Region held on November 3rd 1972 and reported in the January issue of Proceedings (p. 2). Industry and Forensic Science BY JAXES K. JICLELLAN (Chief Consiable Lanavkshii e Comtabtilary Harnalloia ML3 OB U Scotland) FORENSIC scientists are supported in their work by the assistance rendered by the technical and scientific staff attached to trade industry and the professions. In almost all instances information is willingly provided on methods of analysis features by which commodities can be distinguished from apparently similar products of other manu- facturers and dating features which give a limit to the time the commodity could have been in existence.Forensic scientists are frequently beset by having to work to a very tight schedule and while they should be able to find methods of analysis suitable for all occasions this is needless work when the information can be so easily obtained. Furthermore they would be unlikely to discover with any certainty distinguishing features that would separate one manufacturer’s commodity from another and dating features almost invariably can be known only to the manufacturers. This is particularly true of paper and ink which are very frequently studied in forensic laboratories for a variety of reasons. It could be that a substitution has taken place of part or all of a document or the text of part of a document has been altered for a fraudulent purpose.Other reasons might be the tracing of anonymous theatening or ransom letters and the dating of documents is often required for criminal and civil cases. Here everything including the postage stamp the envelope the paper and the ink or the typewriting is scrutinised to see if dating features can be discovered. Most of the forensic scientist’s work falls into three categories-the comparison of substances to establish a connection between them the examination of a substance to find out what it is or what it contains and the examination of a situation to see how it occurred. Paint is widely used for decorative and protective purposes and the examination of large or small particles of paint can be required when hit-and-run road accidents have occurred or there has been forced entry to premises where violence has damaged a painted surface.On occasion paint itself is the subject of theft and the use of paint occurs very frequently in instances of vandalism. Dyestuff manufacturers are often consulted when articles bearing or containing dyes are involved particularly when the amount of material to be examined is small or the minimum amount of damage has to be made to the production. Examples are the examination of counterfeit notes textiles and other articles which are dyed such as human and animal hair. The latter occurs when animals are stolen which have markings put on with dyestuffs and on one occasion the examination was made of the hair from a greyhound that had been substituted in a race. A number of years ago the use of explosives for criminal purposes was confined almost entirely to attacks on safes and the occasional poaching of salmon in some rivers.The situation has unfortunately changed and explosives are being increasingly used as part of a plan for civil disorder. I t is extremely useful to be able to identify explosives before or after combustion and particularly to identify the brand and in any way whatsoever trace the source. While murder by poisoning is not common in this country nevertheless it occurs on occasions and furthermore there are numerous cases involving the misuse of pharmaceuticals where samples taken from the body have to be examined for the substance taken or its breakdown products. The chemists attached to pharmaceutical companies and hospitals have been of in- valuable assistance on numerous occasions in suggesting methods whereby these complicated problems might be solved.On one occasion the analysis of a sample of urine was carried out February 19731 ASALYTICAL APPLICATIONS O F MOLECULAR COMPLEXES 39 in order to determine the concentration of alcohol. Very shortly after that analysis was required on the same sample of urine for a completely different purpose and here invaluable assistance was obtained from a hospital biochemist. A criminal rarely waits at the scene of a crime to give himself up to the police and one of the most useful ways of establishing his presence is by means of a comparison of his fingerprints with fingerprints found a t the locus. The methods of rendering fingerprints visible in order that they may be photographed generally involve dusting with coloured powders but certain surfaces are very difficult in this connection and particularly with paper it is rarely possible to make the latent print visible by this means.A research worker in the field of amino-acids noted that on a large number of occasions his fingerprints were becoming visible on the paper he was using in connection with his experiments and this has led to a new practice in the development of fingerprints that is particularly useful in connection with frauds with cheques and other documents. Murder is often committed by shooting and when this occurs the forensic scientist has the problem of establishing the weapon which fired the shot and the person who held the weapon when it was so used. This may involve the determination of the time that has elapsed since a weapon was fired and the presence of particles of the propellant on the hand of the person who fired the weapon. Neutron-activation analysis has been applied with some success in this connection. When a forensic scientist sets out to examine a substance often for the first tinie in his career he is painfully aware that in the world outside there will be many scientists who have spent a large part of their working lives examining such substances. I t is only natural that they should be very much more acquainted with the problem than the forensic scientist and he is extremely grateful for the ready assistance which he receives from them.

ISSN:0037-9697    

DOI:10.1039/SA9731000038

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

February 19731 ASALYTICAL APPLICATIONS O F MOLECULAR COMPLEXES 39 Analytical Applications of Molecular Complexes The following is a summary of the paper presented at a meeting of the SAC/Analytical Division held on December Gth 1972 and reported in the December 1952 issue of Proceedbigs Analytical Applications of Molecular Complexes BY A. TOWNSHEKD (p. 259). (Chemistvy Department Bivmingham University P.O. Box 363 Biriiziughanz Bl5 2 T Z ) MOLECULAR complexes1*2 are complexes formed between uncharged molecules. They range from the strongly bound complexes of iodine with trimethylamine to the very weakly bound self-complexes of nitroaniline. The nature of the bonding in the complexes is not clearly understood but bond formation involves partial donation of electrons from a donor component to the acceptor component.Typical donors are amines and aromatic hydrocarbons whereas widely used acceptors are 2,4,7-trinitrofluorenone chloranil pyromellitic dianhydride and tetracyanoethylene. As with the extensively studied complexes of metal ions molecular complexes have physical and chemical properties that can be exploited for analytical purposes. The com- plexes have a definite ratio and orientation of the components. They have a measurable although often low stability. They are usually formed very rapidly and have typical spectral characteristics. Absorption of ultraviolet or visible radiation results in an excitation process in which the electron is transferred from an orbital mainly on the donor component to an orbital mainly on the other component. This is an example of charge-transfer excitation which gives rise to high molar absorptivities.APPLICATION TO SEPARATION PROCESSES- Complexation between an acceptor in the stationary phase slows the movement of a donor in the moving phase with respect to more weakly or uncomplexing species. In gas chromatography 2,4,7-trinitrofluorenone is sufficiently stable to be used as a stationary phase and has been used to separate nitrotoluenes and napl~thalene,~ benzene andits alkyl derivatives4 and aminese5 The formation of molecular complexes is useful in chromatography. 40 AXALYTICAL APPLICATIOKS OF MOLECC'LAR COMPLEXES [ P V O C . SOC. Analyt. ChWZ. Brown6 proposed an ingenious system for identifying compounds based on their gas-chromato- graphic RF values by using threedifferent stationary phases an acceptor ( I ,3,5-trinitrobenzene) a donor (a polyester) and inert material (*\piezon).Molecular complexing agents also find use as stationary phases for thin-layer and column chromatography. Polycyclic hydrocarbons for instance can be separated by using pyromel- litic anhydride as the electron acceptor,5 and amines and olefins (including carotenes and vitamin A) by using nitro-aromatic acceptors.s Many of these complexes are coloured so that spraying is not required for the detection of spots. I t is also possible however to utilise molecular complexing agents as reagents for this purpose. Iodine usually gives brown colours with organic compounds on thin-layer chromatographic plates although a few com- plexes such as that with narceiiie (R. Belcher and A. Townshend unpublished work) are blue.Antimony trichloride forms coloured molecular Complexes with polycyclic hydr~carbons.~ Synergic effects in solvent extraction often arise from the formation of molecular com- plexes. For example the extraction of the uncharged chelate of scandium with thenoyltri- fluoroacetone (TTFA) is greatly enhancedlO>ll by tributyl phosphate (TBP) owing to the forma- tion of the complex Sc(TTFA),(TBP),. XPP1,ICATION TO DETECTION AXD DETERMIXATIOX- The formation of molecular complexes finds some use in qualitative organic analysis. Saphthalene can be detected as its brick-red complex with chloranillZ; amines can also be detected with chloranil,13 and nitro-compounds with tetrabase or di~heny1amine.l~ The Karl Fischer titration reagent contains molecular complexes of iodine with sulphur dioxide and pyridine.The spectral properties of molecular complexes have hardly been exploited analytically. Iodine forms complexes with benzene and its derivatives. The complex with benzene has a molar absorptivity* of 16 400 a t 292 nm but that with triethylamine has a molar absorptivity of 26 000 at 278 nm. -1 brief investigation of the use of toluene as an extractant for iodine has been made with subsequent spectrophotometric measurement.14 Some molecular complexes display fluorescence including those of polycyclic aromatics with 2,4,7-trinitrofl~orenone~~ and of antimony trichloride with ~hrysene.~ These effects have merely been used for the location of spots on chromatograms. A more recent investigation of the fluorescence of the 2,4,7-trinitrofluorenone complexes (F.Al-Sulimany and A. Townshend unpublished work) has shown that fluorescence can be stimulated only in the solid complexes so that quantitative applications cannot readily be developed. Excimer formation is also thought to arise by molecular complexation. Recently in this Department spectrophotometric methods for determining several substances have been developed based on the formation of molecular complexes. Sulphur dioxide16 (0.7 to 84 p.p.m.) can be determined by extraction from acidified EDTA-stabilised suIphite solutions into o-xplene as a molecular complex (Amax. = 296 nm) with that solvent. Nitrite ions are the only interferent and are destroyed by treatment with sulphamic acid. Sitrate ions (1 to 18 p.p.m.) can be determined by rapid nitration of toluene in 56 per cent. sulphuric acid a t 70 "C and extraction of the nitrotoluene into toluene as a molecular complex with the solvent.The few interferents (SO,- I- Br- SCK- SO,'- and Hg2+) are easily eliminated. Kitrite ions can also be determined after oxidation to nitrate ions with bromine water and a method for the determination of nitrite and nitrate ions has been devised. Dimethylaniline is found to gitre the most intense colour and has been used to determine 5 to 100 per cent. of oxygen in gaseous mixtures.19 The colour is developed by bubbling the gas through the purified amine. If the latter is stabilised with EDTA colour development is completely reversible and is rapidly discharged by passing nitrogen or carbon dioxide through the solution. Amino-acids form coloured (Amax. = 360 nm) molecular complexes with chloranil in aqueous solution a t pH 9.All other amino-acids have molar absorptivities in the range 6000 (glycine) to 28 000 (lysine).20 Al- though some complex formation occurs instantaneously colour development is not complete unless the reaction mixture is heated e.g. at 65 "C for 10 to 50 minutes depending on the amino-acid. Heating the more rapidly reacting species for 50 minutes usually had no detri- mental effect. Few applications to quantitative analysis have been reported. Oxygen forms yellow molecular complexes with aromatic amines.l* Only 3,4-dihydroxyphenylalanine does not react. February 19731 EXAMINATION OF PLASTICS FOR PHARMACEUTICAL USE 41 vitamin A gives a transient blue complex with iodine in chloroform which rapidly changes to a yellow colour.Appreciably less than 1 p.p.m. of the vitamin can be determined by monitoring the yellow colour (F. Al-Sulimany and A. Townshend unpublished work) but 13-carotene gives a similar response. I t is possible partially to stabilise the blue colour by using l,%dichloroethane cooled with liquid air. Measurement of the blue colour gives a less sensitive measure of vitamin A but p-carotene does not interfere. They give reasonable sensitivity and with one exception are extremely rapid. The interferences are often few and those that exist can usually be eliminated without difficulty. The author thanks Dr. hI. Bhatty and hlr. F. Al-Sulimany for their invaluable contribu- tions to the work described above and Professor R. Belcher for his continued encouragement and support. All of the spectrophotometric methods described above are inherently simple.1. 2. 3. 4. 5 . 6. i. 8. 9. 10. 11. 12. 13. 14. 15 16. 17. 18. 19. 30. Foster R . “Organic Charge-Transfer Complexes,” Academic Press London 1969. Rose J “hIolecular Complexcs,” Pergamon Press Oxford 1967. Xorman K. 0. C. Pvoc. Chew. Sac. 1958 151. Fabrizio F. A King K. TI‘. Cerato C. C. and Loveland J . IV. Analyf. Chem. 1959 31 2060. Cooper A. R. Crowne C. 1%;. P. and Farrell P. G. Z’va77s. Favaday Sac. 1966. 62 2725. Brown I. S n t u v e L a n d . 1960 188 1021. Short G. D. and Young K. Analyst 1969 94 259. Dwivedy -4 K. Parchar D. B. Sharma S. P. and Yerma I<. K. J . C h i v i m t . 1967 29 120. Thielemann H. 3likrochinz. A d a 1971 838. .Aliniarin I. P. Zh. L4rza/it. Kikim. 1968 23 1321. Butts TV C. and Ranks C. V. Annlyt. Chem. 1970 42 133. Yeigl F. d ~ z k ~ ~ o c h i n z . A d a 1957 350. - “Spot Tests in Organic Analysis,” Seventh Edition Elsevier -Amsterdam 1966. Overston T. C . J . and Rees W. T. Analytica Chzm. Ada 1951 5 123. Gordon H. T . and Huraux B. J. Analyt. Chem. 1959 31 302. Bhatty XI. K . and Townshend A . Analytica Chiin. Acta 1971 5 5 401. __ ~ Ibid. 19i1 56 5 5 . Evans I). F. J . Chew. Sac. 1961 1987. Bhatty 11 K. and Townshend A Analyt. Lett. 1971 4 357. Al-Suliinany F. and Townshend A, Amdytica Chim. Acta 1973 in the press.

ISSN:0037-9697    

DOI:10.1039/SA9731000039

出版商:RSC    

年代:1973

数据来源: RSC

摘要:

February 19731 EXAMINATION OF PLASTICS FOR PHARMACEUTICAL USE 41 Examination of Plastics for Pharmaceutical Use The following is a summary of one of the papers presented a t a Meeting of the Biological Pllethods Group held on May 25th 1972 and reported in the June 1972 issue of Proceediizgs Practical Problems in the Examination and Control of Plastics for Pharmaceutical Use By J. E. PESTELOW THE problems concerning plastics for pharmaceutical use are best considered from two aspects tlie examination of new plastic formulations and the routine control of such formula- tions. THE EXA.RIIKATION OF NEW PLASTIC FORMULATIOXS- solutions the main properties that will affect the choice of plastic will be- (p. 124). (Quality Coittrol The Boots Company Ltd. .“\Tolfinghawz S G 2 34.4) Desirable properties of plastics-Considering the use of plastics for containers for injection (a) The ability to be sterilised and remain sterile.The seal must be such that it is proof against the ingress of bacteria and moulds but it must also be such that an administ- ration set for blood or sterile fluids will make a leak-proof connection. ( b ) The toxicity 2‘.e. leachable ingredients must be minimal. (c) The transparency. ( d ) The permeability to moisture and gases. (e) The adsorption of constituents of the drug formulation by tlie plastic. (f) The desirable impact resistance and mass of the final container. 42 EXAMINATIOS OF PLASTICS FOR PHARMACEUTICAL USE [PYOC. S O C . Aiialyt. Chent. Xajor plastics used-The main plastics likely to be encountered are the polyethylenes of various densities polypropylene poly(viny1 chloride) polystyrene and to a lesser extent nylon and polycarbonate.Poly(viny1 chloride) is unstable during fabrication unless a stabiliser is present. On breakdown of the polymer hydrochloric acid is given off and it is necessary to use a hydro- chloric acid absorber. Heavy metal salts such as lead cadmium and barium stearates and organotin salts are commonly used as stabiliscrs. For pharmaceutical use it is necessary to use calcium or calcium plus zinc salts. Furthermore polyjvinyl chloride) is rigid and in order to make it flexible about 20 to 30 per cent. of a plasticiser must be incorporated. Di-2-ethylhexyl phthalates are commonly used but other plasticisers are available such as poly(propy1ene adipate) and poly(propy1ene sebacate). Polystyrene may contain an impact modifier in order to improve resistance to breakage.High-density polythene and polypropylene require about 0.05 per cent. of an antioxidant in order to ensure stability during processing. Medium-density and low-density polythene do not require any additives. Sylon and polycarbonate would be expected to contain only small amounts of additives. Tests j o y plastics-Provided that sufficient interest is shown in a plastic it is normally possible for a pharmaceutical manufacturer to obtain confidential information concerning its composition. Such information often cannot easily be obtained when making preliminary surveys of possible plastics. It is therefore useful to screen plastics and to eliminate as many as possible by using simple chemical tests. TheGerman Authori- ties have never issued a German standard based on this Draft because of the problems that it raised.However it is a formidable document of twenty-five pages and it is hardly surprising that parts of it should be controversial. Such reservations in no way detract from the useful- ness of the document for the purpose of screening plastics. The tests in the DIN 58368 include aqueous autoclaving of the plastic and examination of the autoclavate for the following chloride sulphate ammonium ions heavy metals reducing substances change of pH residue on evaporation colour turbidity and surface- active agents. Also a sulphated ashing of the plastic and determination of its metal content are carried out. In addition to these tests an ultraviolet scan of the autoclavate and extrac- tion of the antioxidant have proved useful.If any additives are detected then it is necessary to discuss the toxicological significance of the extracted material with a toxicologist. Tests carried out with this system are the basis of a paper by Braun and KummelL2 If the plastic gives satisfactory results in the above tests then biological tests can be used. The main tests available are pyrogen acute toxicity isolated frog heart haemolytic intra- cutaneous reactivity and cat.3 The United States Pharmacopoeiad and the National Formulary5 contain tests similar to those of the DIN 58368 1965. One should use only one authority and standardise on its tests in order to accumulate strictly comparable data. After this preliminary work it is always necessary to store the individual solutions to be administered in the final container over an extended period of time at a range of temperatures examining samples at intervals.At this stage the biological tests are invaluable for many of the chemical tests become meaningless e g . mass on evaporation. I t is only with such long- term keeping tests that the extraction of known additives can be measured e.g. antioxidants in high-density polythene. Furthermore any absorption by the plastic of the components of the drug formulation can be checked. Useful tests on such an occasion are set out in the British Pharmacopoeia Commission Committee report on plastic containers3 The report gives details of tests for lead tin cadmium and barium in the plastic these being the most likely undesirable metals to be encountered. I t gives an ether-soluble extract of the injection solution .to exclude certain plasticisers and exclude poor fabrication of the poly(viny1 chloride)].It also gives two biological tests an acute toxicity test and a cat test in which an electrocardiographic tracing blood pressure determination and rate and depth of respiration are used as parameters for measurement. A 2 per cent. level of stabiliser is adequate. Such tests can be found in the German Draft DIE 58368 1965.l -4uthorities may supply analysts with filled sterile containers and ask for reports. February 19731 CORRESPOKDEKCE ON AMALGAMATIOS THE ROUTIKE COKTROL OF PLASTIC FORMULATIOKS- 43 \Then a plastic has been chosen the quality of that plastic must be maintained in routine production. Polymers can have various chain-lengths and the difference in chain-length is one of several variables that lead to a multiplicity of grades of the primary polymer.No change in the grade of polymer or the final plastic formulation can be tolerated for in such a sensitive field the addition of a small amount of perhaps mould lubricant could well be enough to cause difficulty for the pharmaceutical manufacturer. I t is essential to test the final container as contamination or admixture can occur a t any stage. A system that has been used is that of first isolating an amount of plastic granules from continuous production and giving it a batch number. Each bag of granules is numbered sequentially as filled. Sample containers are then made from bags of granules selected from the number sequence on the bags so as to obtain a reasonable sampling spread.These containers are submitted to chemical tests based on the DIN 58368 together with melt-flow index and density measurements to confirm the identity of the plastic. -4 pyrogen acute toxicity and intracutaneous reactivity test are also carried out on extracts from pieces of cut-up containers. When the first production is available from the batch further samples are submitted to a full chemical analysis. I t would be wrong t o leave the impression that the testing as described above is all that is necessary. A very close relationship must be built up between fabricator and pharma- ceutical manufacturer so as to ensure that the fabricator realises the seriousness of contamina- tion. The tests are not complete assurances of non-toxicity and must be backed up by good housekeeping.THE GROWTH OF OFFICIAL TESTISG FOR PLASTICS- The DIS 58368 was published in 1965 and the National Formulary has had chemical and biological tests since 1963. The United States Pharmacopoeia XVII (1965) had biological tests and the United States Pharmacopoeia XVIII (1970) biological and chemical tests. The first serious interest in analysing extractives from plastics took place in about 1960 and the tests selected were straightforward. Tests grow as a result of experience but so far the original tests have been found to be adequate in most instances. A weakness in the tests selected may be discovered a t some time. \Ye do not know when but I trust that further discussion may reveal a particular weakness that can be strengthened. It is interesting to note the age of many of the tests now used. REFEREXES 1. 2. 3. Phavm. J. 1971 374. 4. 5. “Plastic Containers for the Preservation and Transfusion of Whole Blood and Blood Components Tests of Equipment and Containers,” D I S 58368 1965 Deutsche Sormen (Draft Standard). Braun B. and Kummell H. J. Dt. ApothZtg 1963 103 46i. “The United States Pharmacopoeia,” Eighteenth Revision Mack Company Easton Pa. 1970 National Formulary S I I I Mack Company Easton Pa. 1970 pp. 840 to 847. pp. 926 t o 930.

ISSN:0037-9697    

DOI:10.1039/SA9731000041

出版商:RSC    

年代:1973

数据来源: RSC