ISSN:0144-557X    

DOI:10.1039/AP99128FX029

出版商:RSC    

年代:1991

数据来源: RSC

ISSN:0144-557X    

DOI:10.1039/AP99128BX031

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 24 1 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 at 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. Strategies in the Design of an Effective Fibre Optic Sensor for the Detection of Paralytic Shellfish Poisons R.Guevremont," M. N. Quigleyt and M. SchweitzerS National Research Council Canada, institute for Marine Biosciences, 14 I I Oxford St., Halifax, Nova Scotia B3H 321, Canada The occurrence of 'red tides' around many coastlines of the world can lead to the infestation of shellfish with various toxic dinoflagellates. Dinoflagellates are tiny unicellular organisms, which, together with the diatoms and other phytoplankton, occupy the bottom of the food chain. As such, they are of major ecological importance. Species of dinoflagellate such as Gonyaulax tamarensis (found along the East coast of the northern USA and Canada in addition to the North Sea coasts and England), G. catenella (West coast USA and Canada) and Gymodinium breve (coasts of Florida and southern Gulf of Mexico states) are capable of producing extremely toxic compounds, which have been given the generic name 'gonyau- toxins'.1.2 Amongst the most poisonous of the many types of toxin are saxitoxin (CA Reg. No. [35523-89-81) and neosaxitoxin (CA Reg. No. [64296-20-4]), see Table 1. Saxitoxin for instance has a lethal dose (median) [intraperitoneal (i.p.) mouse] of 8-10 pg kg-1, with an estimated fatal human dose of 0.2-1 mg. This makes it more toxic than notorious poisons such as sodium cyanide, strychnine or curare. The purpose of the gonyautoxins in the dinoflagellate has long been questioned, as they do not seem to affect those shellfish they come into contact with. Recent evidence suggests that the dinoflagellates themselves might be the 'victims' of bacterial producers of gonyautox- ins.4.5 Whatever the route to the production of the gonyautox- ins is, concentration of the toxic dinoflagellate by filter-feeding shellfish is a great threat to human health and can, as a result, pose major coastal and national economic problems.No effective way of predicting the occurrences of the red tides has been found, although there are certain high-risk periods when the harvesting of suspected shellfish is forbidden-usually by government directive. Unfortunately, infestation of shellfish with toxic dinoflagellate cannot always be linked to the occurrence of a red tide, so year-round monitoring pro- grammes have become common practice amongst affected countries. * Present address: National Research Council Canada, Institute for Environmental Chemistry, Ottawa, Ontario K1A OR6, Canada.t To whom correspondence should be addressed. Present address: Department of Chemistry, Chevron Science Center, University of Pittsburgh. Pittsburgh, PA 15260, USA. f Present address: Department of Chemistry, McGill University, Otto Mass Building, 801 Sherbrooke St. W., Montreal, Quebec H3A 2K6, Canada. Table 1 Molecular structures of paralytic shellfish poisons. STX = saxitoxin, NEO = neosaxitoxin, and GTX = gonyautoxin (data from reference 3) Substituted group Abbreviation used R' R2 R3 H H H OH H H OH H OS03- H H OSO3- H OSO3- H OH OS03- H Carbamate toxins STX NEO GTX I GTX I1 GTXIII GTX IV N-Sulpho- carbamo y 1 toxins B1 B2 c 3 c 1 c 2 c 4 Decarbamoyl toxins dc-STX dc-NEO dc-GTX I dc-GTXII dc-GTX I11 dc-GTX IV R4\ 42 Two methods for the detection and determination of paralytic shellfish poisons (PSPs) in dinoflagellate and shellfish are in common use around the world today; the classic method is the mouse bioassay, which measures total toxicity regardless of the individual toxins present.68 The major instrumental method for PSP analysis is based on the separation of individual toxins by reversed-phase high-performance liquid chromatography (HPLC) followed by post-column oxidation242 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 to fluorescent derivatives.9-13 Both the bioassay and HPLC methods have advantages and disadvantages.Separation of individual PSPs, together with high precision and sensitivity, makes the HPLC method more attractive than the mouse bioassay for the routine screening of shellfish extracts.14.15 Unfortunately, the HPLC method is tedious and the system has been found by many workers to be difficult to set up.Although some alternatives to the mouse bioassay and HPLC methods for PSP determination have been proposed, e.g. , those based on an enzyme-linked immunosorbent assay,16 electrophoresis,17 autoanalysers,*8.19 and gas chromato- graphy,20 they have either proved unpopular or suffer from low sensitivity. In addition, the methods are relatively time and labour intensive as much preparation is required prior to analysis. As a result, a convenient and rapid method for the accurate detection and determination of PSPs is at present unavailable. It is believed that the many advantages afforded by fibre optic chemical sensing might prove suitable in the design of a fibre optic PSP sensor. Obviation of an extraction step would complement the advantages usually associated with fibre optic chemical sensors including ease of miniaturization (with concomitant low expense) , fast response time and freedom from electrical interference.Fibre Optic Chemical Sensing A large amount of literature has accumulated since the inception of the technique in the 1980~~ and the theory and practice of sensing chemical species by light interaction using a fibre optic cable to transmit light to the test environment are well established.21-25 A number of components are essential to any experimental test apparatus: (i) a light source, e.g. , tungsten filament lamp, laser or light emitting diode; (ii) a mechanical or electronic chopper to modulate the light source; (iii) a fibre optic cable of composition appropriate to the type of radiation being used; (iv) a chemical sensor; (v) a monochromator; (vi) a photomul- tiplier tube or other suitable detector; and (vii) a lock-in amplifier, responding only to radiation of the frequency generated by the chopper.With such instrumentation, the light can be directed along a cable terminated by the chemical sensor. In the presence of analyte, the sensor should respond by changing the character- istics of the incident radiation and this ‘altered’ radiation will be reflected in all directions. Detection can be accomplished either at the proximal end of the same fibre (with the aid of a beam splitter), or at the end of another fibre adjacent to the one carrying the incident radiation.In practice, the latter technique requires the use of a cable containing at least two fibre cores, but multicore cables are preferred. The changes in characteristics of the incident radiation can be observed either as fluorescence or a change in absorption. Such apparatus allows for great freedom in the choice of wavelength, fre- quency rate and ultimately in the detection capability. The technology does exist, however, for miniaturization in order to create a dedicated instrument the size of a portable pH meter. Sensor Fabrication The reagent can be either contained as a solution in a membrane-sealed reservoir at the tip of the probe, or immobilized on a powdered inert support.The reagent can best be immobilized by mixing it as a solution with the support material. Powdered ion-exchange resins of the Amberlite XAD type have proved successful in other applications.26 Thus immobilized, a small amount of the reagent saturated support can be applied to the tip of a fibre optic cable. The tip can then be covered with a piece of membrane [e.g., poly- (tetrafluoroethylene)] and secured by a small piece of ‘heat- shrink’ tubing. Although a reversible reaction is preferred, sensors based on non-reversible reactions are cost effective, even though they are less convenient. Connectors would allow non-reversible sensor tips to be discarded and replaced. Discussion Although colorimetric methods for PSP determination have been reported, they are not well suited to fibre optic chemical sensing applications.27.28 Derivatization of PSPs to fluorescent derivatives is preferred, although periodate oxidation29.30 is believed not to be the only method available.26 The structure of the saxitoxin molecule provides a number of clues to the potential reactivity with certain reagents [see Fig.l(a)]. In particular, the presence of two amino groups indicates a degree 0 H ( b) Fig. 1 Molecular similarity between (a) saxitoxin and (b) guanine (a) OPA (d) NBD-F Ci ( b ) FMOC-CI (c) NBD-CI S02CI (e) DANS-CI ( f ) Fluorescamine ?CH3 \ \ \ S03Na rn (9) DAS-Na (h) DABS-CI Fig. 2 Molecular structures of reagents considered suitable for the fluorimetric detection of paralytic shellfish poisons (for definitions of reagents see Table 2)ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 243 Table 2 Potentially useful reagents for the fibre optic chemical sensing of paralytic shellfish poisons Chemical name Abbreviation CA Registry No.o-Phthalaldehyde in presence of 9-Fluorenylmethy lchloroformate FMOC-CI [28920-43-61 mercaptoethanol OPA [ 643-7943] 4-Chloro-7-nitrobenz-2,1,3-oxadiazole NBD-Cl [ 10199-89-01 4-F1uoro-7-nitrobenz-2,1,3-oxadiazole NBD-F [29270-56-21 chloride DANS-CI [605-65-21 5-Dimethylamino-l-naphthalenesulphonyl 4-Phenylspiro[furan-2(3) ,1 ‘-phthalanl- 9.10-Dimethoxyanthracene-2-sulphonic 4-N. N-Dimethylaminoazobenzene- 3,3’-dione Fluorescamine [38183-12-91 acid, sodium salt DAS-Na [ 67850-39-61 4-’sulphonyl chloride D ABS-Cl [56512-49-31 Phen y lgl yoxal [ 1074-12-01 References 32-46 47-49 50-53 54-57 58-64 65-69 70,71 72,73 31,74 of similarity between saxitoxin and other amine containing molecules. For example, the guanine molecule [shown in Fig.l(b)] resembles saxitoxin in the location of the one amino and two imino groups. Guanine has been determined by reaction with phenylglyoxal as fluorimetric reagent31 but reaction of the reagent with saxitoxin proved inconclusive.26 However, as there are a large number of other fluorimetric reagents available for the detection and determination of primary and secondary amines, it is believed that at least one might also prove useful for PSP detection. Table 2 lists a number of fluorimetric reagents that have been used for amine analyses and their molecular structures are shown in Fig.2. Initial trial batch mixing of PSP containing solutions with some of the reagents listed in Table 1 has provided evidence to suggest that suitable reactions do indeed exist for the detection of PSPs.26 This should also be of interest to chromatographers searching for new HPLC methods. One major problem relates to the interference effects of other amine containing compounds. Amines with a relative molecular mass (M,) of greater than that of saxitoxin ( i . e . , M, >300) can be prevented from entering the probe interior by using an ultra-filtration type membrane with a low M, cut-off ( e . g . , M , cut-off = 500). At present, it is not so easy to see how low M, amine containing compounds can be prevented from interfering with PSP detection.Possibly, fast ultrafiltration of the test solution through a membrane with an M, cut-off below that of saxitoxin, prior to probe analysis, might be the answer. Conclusion A convenient and accurate method of determining PSPs is believed possible in the construction of a dedicated fibre optic PSP sensor. It is believed that reagents able to react with amine containing compounds to form fluorescent derivatives might react similarly with saxitoxin and other PSPs. Although fast, accurate and portable, any such probe system would be unable to respond to the presence of individual toxins. Because of this, the fibre optic PSP sensor should be viewed primarily as a field test aid, complementing and not replacing present or future HPLC methods. Thanks are due to I,.Alzo for preparation of the figures. References Kodama, M., and Ogata, T., Mar. Pollut. Bull., 1988,19, 559. Cembella, A. D.. Sullivan, J . J . , Boyer, G. L., Taylor, F. J . R., and Andersen, R. J . , Biochem. Syst. Ecol., 1987, 15, 171. Sullivan, J. J., Wekell, M. M., and Kentala, L. L., J. Food Sci., 1985, 50, 26. Kodama, M., Ogata. T., Shigeru, S., and Sakamoto, S., Mar. Ecol. Prog. Ser., 1990, 61, 203. Kodama, M., Bioact. Mol.. 1989, 10, 391. Nagashima, Y., Noguchi, T., Kawabata, T., and Hashimoto, K., Nippon Suisan Gakkaishi. 1990, 56,765. Adams, W. N., and Furfari, S. A., J. Assoc. Off. Anal. Chem., 1984. 67, 1147. 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 Schmidt, R. J., and Loeblich, A. R., 111, J. Mar.Biol. Assoc. U K , 1979, 59,479. Sullivan, J . J . , ACS Symp. Ser., 1990, 418,66. Sullivan, J. J . , and Wekell, M. M., in Seafood Quality Determination, Proc. Int. Symp. Univ. Alaska, eds. Kramer, D. E., and Liston, J., 1986, pp. 357-371. Boyer, G. L., Sullivan, J. J . , Andersen, R. J . , Taylor, F. J. R., Harrison, P. J., and Cembella, A. D., Mar. Biol. (Berlin), 1986, 93, 361. Sullivan, J . J . , in Mycotoxins and Phycotoxins, 6th International IUPAC Symposium on Mycotoxins and Phycotoxins, Pretoria, eds. Steyn, P. S., and Vleggar, R., 1985, pp. 317-327. Sullivan, J. J . , and Iwaoka, W. T.. J. Assoc. Off. Anal. Chem., 1983, 66, 297. Salter, J. A., Timperi, R. J . , Hennigan, L. J., Sefton, L., and Reece, H., J. Assoc. Off. Anal. Chem., 1989, 72, 670. Sullivan, J .J . , Simon, M. G., and Iwaoka, W. T., J. Food Sci., 1983,48, 1312. Chu, F. S., andFan, T. S. L., J. Assoc. 08. Anal. Chem., 1985, 68, 13. Fallon, W. E., and Shimizu, Y., J. Environ. Sci. Health, 1977, A12,455. Jonas-Davies, J . , Sullivan, J . J . , Kentala, L. L., Liston, J., Iwaoka, W. T., and Wu, L., J. Food Sci., 1984,49, 1506. Buckley, L. J . , Oshima, Y., and Shimizu, Y., Anal. Biochem., 1978,85, 157. Hove, H. T., Grahl-Nielson, O., and Rogstad, A., Anal. Chim. Acta, 1989, 222, 35. Wolfbeis, 0. S., Anal. Proc., 1987, 24, 14. Narayanaswamy, R., Anal. Proc., 1985, 22, 204. Kirkbright, G. F., Narayanaswamy, R., and Welti, N. A., Analyst, 1984, 109, 15. Kirkbright, G. F., Narayanaswamy, R., and Welti, N. A., Analyst, 1984, 109, 1025. Seitz, W. R., Anal.Chem., 1984, 56, 16A. Authors’ unpublished results. Gershey, R. M., NevC, R. A., Musgrave, D. L., and Reichardt, P. B., J. Fish. Res. Board Can., 1977,34, 559. McFarren. E. F., Schantz, E. J., Campbell, J. E., and Lewis, K. H., J . Assoc. Off. Anal. Chem., 1958, 41, 168. Bates, H. A., and Rapaport, H., J. Agric. Food Chem., 1975, 23,237. Stoptaugh, N. H., Carter, P. W., Foxall, T. L., Sasner, J . J., Jr., and Iwawa, M., J. Agric. Food Chem., 1981, 27, 198. Kai, M., Ohkura, Y., Yonekura, S., and Iwasaki, M., Anal. Chim. Acta, 1988, 207, 243. Whiteside, I. R. C., Worsfold, P. J., and McKerrell, E. H., Anal. Chim. Acta, 1988,212, 155. Whiteside, I. R. C., Worsfold, P. J . , Lynes, A., and McKerrell, E. H., Anal. Proc., 1988,25,60. Memon, M. H., and Worsfold, P.J.,Anal. Proc., 1986,23,418. Memon, M. H., and Worsfold, P. J . , Anal. Chim. Acta, 1986, 183, 179. Sternson, L. A., Stobaugh, J. F., and Repta, A. J., Anal. Biochem.. 1985,144, 233. Stobaugh, J . F., Repta, A. J . , Sternson, L. A.. and Garren, K. W., Anal. Biochem., 1983. 135, 495. Onoue, Y., Noguchi. T., Nagashima, Y., Hashimoto, K., Kanoh, S., Ito, M., and Tsukada, K., J. Chromatogr., 1983, 257. 373.244 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 Petty, R. L., Michel, W. C., Snow, J. P., and Johnson, K. S., Anal. Chim. Acta, 1982, 142, 299. Braithwaite, J. I . , and Miller, J. N., Anal. Chim. Acta, 1979, 106,395. Lindroth, P., and Mopper, K., Anal. Chem., 1979,51, 1667. Hill, D. W., Walters, F. H., Wilson, T.D., and Stuart, J. D., Anal. Chem., 1979, 51, 1338. Roman, R. J., Bonventre, J. V., and Lechene, C. P., Anal. Biochem., 1979,98, 136. Carroll, S. F., and Nelson, D. R., Anal. Biochem., 1979, 98, 190. Roth, M., Anal. Chem., 1971,43,880. Zlatkis, A., and Zak, B., Anal. Biochem., 1969, 29, 143. Einarsson, S . , Folestad, S., Josefsson, B., and Lagerkvist, S., Anal. Chem., 1986, 58, 1638. Einarsson. S., J. Chromatogr., 1985, 348, 213. Einarsson, S., Josefsson, B., and Lagerkvist, S., J. Chromat- ogr., 1983,282,609. Whiteside, I . R. C., Worsfold, P. J., and McKerrell, E. H., Anal. Chim. Acta, 1988, 204, 343. Johnson, L., Lagerkvist, S., Lindroth, P., Ahnoff, M., and Martinsson, K., Anal. Chem., 1982, 54, 939. Fager, R. S . , Kutina, C. B., and Abrahamson, E.W., Anal. Biochem., 1973, 53, 290. Ghosh, P. B., and Whitehouse, M. W., Biochem. J., 1968,108, 155. Watanabe, Y., and Imai, K., Anal. Chem., 1983,55, 1786. Watanabe, Y., and Imai, K., J. Chromatogr., 1982,239,723. Watanabe, Y., and Imai, K., Anal. Biochem., 1981, 116,471. Imai, K., and Watanabe, Y., Anal. Chim. Acta, 1981,130,377, 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 Tapuhi, Y., Schmidt, D. E., Lindner, W., and Karger, B. L., Anal. Biochem., 1981, 115, 123. Lawrence, J. F., J. Chromatogr. Sci., 1979, 17, 147. Ahiya, S . , J. Chromatogr. Sci., 1979, 17, 168. Frei, R. W., Santi, W., and Thomas, M., J. Chromatogr., 1976, 116, 365. Bayer, E., Grom, E., Kaltenegger, B., and Uhmann, R., Anal. Chem., 1976,48, 1106. Engelhardt, H., Asshauer, J., Neue, U., and Weigand, N., Anal.Chem., 1974, 46, 336. Seiler, N., J. Chromatogr., 1971, 63, 97. Stocks, S. J., Jones, A. J. M., Ramley, C. W., and Brooks, D. E., Anal. Biochem., 1986, 154, 232. Evans, C. H . , and Ridella, J. D., Anal. Biochem., 1984, 142, 411. Felix, A. M., and Jimenez. M. H., J. Chromatogr., 1974, 89. 361. Udenfriend, S . , Stein, S., Bohlen, P., and Dairman, W., Science, 1972, 178,24. Weigele, M., DeBernardo, S. L., Tengi, J. P., and Leimgruber, W. L., J. Am. Chem. Soc., 1972,94,5927. Gfeller, J. C., Frey, G., Huen, J. M., and Thevenin, J. P., J. Chromatogr., 1979, 172, 141. Westerlund, D., and Borg, K. O., Anal. Chim. Acta, 1973,67, 89. Lin, J.-K., and Lai, C.-C., Anal. Chem., 1980, 52, 630. Lin, J.-K., and Chang, J.-Y., Anal. Chem., 1975, 47, 1634. Alcaide, B., Escobar, G., Perez-Ossorio, R., Plumet, J., and Sanz, D., J.Chem. Res. (S), 1984, 144. Supervision of Technical Staff: An Introduction for Line Supervisors by R. Weston, Leicester Polytechnic D.C. Norton, Ex-Chief Technician, Brornley College of Technology M. Grimshaw, North East Surrey College of Technology This unique book forms an introduction to supervisory skills for line supervisors employed in scientific, educational, medical and industrial laboratories. Unlike other publications on supervision it is written specifically for supervisors working in laboratories and concentrates on the specific skills associated with the control of staff in scientific laboratories. The authors have considerable experience as laboratory supervisors and in teaching technical staff, and have included practical examples from their own and their colleagues’ experience, so that readers can gain from the problems faced by others. Highly recommended Softcover x + 242 pages ISBN: 0 85186 423 6 (1989) Price: f15.95 Customers wishing to obtain an inspection copy of this title should contact the Sales Promotion Manager at our Cambridge address.ROYAL SOCIETY OF CHEMISTRY To Order, Please write to the: Royal Society of Chemistry, Turpin Transactions Ltd, Blackhorse Road, Letchworth, Herts SG6 1 HN, UK. or telephone (0462) 672555 quoting your credit card details. We can now accept AccessNisalMasterCardd/Eurocard. Turpin Transactions Ltd, distributors, is wholly owned by the Royal Society of Chemistry. For lnfonnation on other books and~outnals, please write to the: Royal Society of Chemistry, Sales and Promotion Department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF.UK. RSC Abtnbem should obtain members prices and order from : The Membership Affairs Department at the Cambridge address above. Information Services Guidance on Laboratory Fume Cupboards The need for authoritative yet practical guidance for users of laboratory fume cupboards has become urgent since the Control of Substances Hazardous to Health (COSHH) Regulations came into force. This booklet provides such guidance. It will also be of interest to those who design, manufacture or install fume cupboards. Topics covered include: 0 an introduction to the subject 0 factors affecting the performance of fume cupboard systems (the working chamber, the extract system, the laboratory, the air supply, the system of work) 0 filtered extract fume cupboards 0 materials of construction 0 performance testing (including user tests) 0 the legal position in the United Kingdom 0 a review of the literature on factors affecting the efficiency of fume cupboard systems 0 references and suggestions for further reading. This publication complements the Society’s other guidance booklets “COSHH in Laboratories” and “Safe Practices in Chemical Laboratories”. It was prepared by an Expert Working Party of the Society’s Health, Safety and Environment Committee which was also responsible for the companion booklets. Softcover Approx 35 pages ISBN: 0 85186 329 9 Price €10.00 September 1990 ROYAL SOCIETY OF CHEMISTRY To order, Please write to the: Royal Society of Chemistry, Turpin Transactions Ltd, Blackhorse Road, Letchworth, Herts SG6 1 HN, UK, or telephone (0462) 672555 quoting your credit card details. We can now accept AccessNisalMasterCardlEurocard. Turpin Transactions Ltd, distributors, is wholly owned by the Royal Society of Chemistry. For fuurfher infomatlon, please write to the: Royal Society of Chemistry, Sales and Promotion Department,Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. UK. RSC Members should order from: The Membership Affairs Department at the Cambridge address above. Information Services

ISSN:0144-557X    

DOI:10.1039/AP9912800241

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS. AUGUST 1991, VOL 28 245 Chemometrics Papers The following are two papers originally written for the newsletter of the United Kingdom Chemometrics Discussion Group. Two Applications of Principal Components Analysis of an Industrial Process and Quantitative Analysis of Water in a Substrate C. J. P. Scott Glaxo Operations UK Ltd., Barnard Castle, Co. Durham DL 12 8DT Two applications of principal components analysis will be discussed, first qualitative investigations of a batch manufac- turing process for purification. Subsequently, a simple quanti- tative method for water in a substrate is investigated which also yields some qualitative information. A common thread is drawn to highlight the problems of the source of standards and their preparation. Qualitative Principal Components Analysis The batch manufacturing process is summarized in Fig.1. The impure product and eluent are loaded on to a column, and an operator directs the column eluate to one of three collecting tanks. The operator monitors the colour of the column eluate in order to determine the switching times. Principal components analysis was employed to study the interaction between the operator switching time and the purity and amount of product collected in one of the tanks. Initially all of the solution is directed to tank 1, but at the appropriate colour change the operator directs the solution to tank 2. This tank contains the main fraction for the subsequent crystallization stage. Then, after a set volume has passed, the remaining eluate is transferred to tank 3.Column Monitor point t Collecting tanks Fig. 1 Diagram of purification process The first switching time, determined by the colour change, is critical as it coincides with the elution front of the product. The second switching time, a constant volume after the first, occurs during a gradual reduction in the concentration and purity of the product. Should the first switching time be early or late a smaller amount and lower concentration (fixed volume) of product is collected in tank 2. Furthermore, the cost of crystallization is spread over a smaller yield of product. A colour measurement system was set up in order to monitor the actual colour of the eluate at the initial switching time determined by the operator. Simultaneously, a product and impurity profile was created for the process by measuring samples of the eluate at set times by high-performance liquid chromatography, including the switching time. A sharp change in one of the colour parameters coincided with elution of the main product.By setting a limit on this value the eluate could be directed almost at the ideal time with almost no loss of product. Analysis of the colour at the first switching time indicated a wide variation both within and between operators. Unfortu- nately, the human eye detects a very gradual colour change and this compounds the natural variation in sensitivity between operators. A total of 52 batches were analysed for yield, purity and impurities. Various colour parameters also were recorded at the switching time; in total, nine variables were measured.The large number of batches were needed to ensure a proper representation of raw material feedstock which came from a variable natural process. Principal components analysis was used to look for patterns between batches and correlations between the measured variables. Fig. 2 displays the contribution of the original nine variables to the most significant factors (axes) in the resulting model. This factor explained 73% of the variation in the original data. Most variables do not feature (are zero), but three do--one colour, the yield and the operator. The main contributions are from the first two and suggest a negative correlation between the variables of yield and colour. It is 1 .o Yield A Purity Colour Operator --0.5 Fig.2 Factor 1 loadings246 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 important to note that it does not prove any connection between the two. This particular colour variable represents the parameter which demonstrated a sharp colour change on elution of the main product-the change in value is positive. The negative correlation may be rationalized thus: when the operator manually switched to main product too late the value of the colour parameter was large and positive. In this instance, as explained earlier, the yield is reduced, hence there is a negative correlation. As the switching time is brought forward the measured colour parameter reduces and the yield increases. However, this analysis misses an important point. Should the switching time occur too early, at a small value for the colour parameter, the yield would also decrease-a positive correlation.This suggests a conflict. However, inspec- tion of the original data revealed that all operators switched too late as determined by the colour measurement of column eluate at the switching time. None of the factors showed any correlation between purity and the switching time. Although more impurity is passed through to the main product when a sub-optimum switching time is selected, no effect on final product purity was indicated. This suggests that the crystallization stage following eluate collection completely determines the final purity and, in itself, does not dramatically affect the over-all yield of product. The qualitative analysis suggested both expected and unex- pected connections, but also demonstrated the dependence of results on the input data, i.e., the fact that all operators switched too late and none switched early.Quantitative Principal Components Analysis The quantification of water in a substrate was achieved by combining principal components analysis with linear regres- sion. Normally the result is determined by Karl Fischer titration, but analysis by near-infrared (NIR) spectroscopy would give quicker results as well as being considerably simpler. As no theory links the NIR spectrum to water content a set of standards was produced, the NIR spectrum measured and the water content determined by Karl Fischer titration. Following principal components analysis of the spectra, a regression model was developed to relate water content with the scores (of significant factors) of each sample in the standard set.The model created is calibrated with Karl Fischer data and is therefore strongly dependent on the quality of these results. If the primary method (Karl Fischer titration in this instance) is found to be inaccurate the resulting method will be equally or more inaccurate. Imprecision in the primary method can be partially overcome in the resulting model. The loadings for the first two factors of the model are shown in Fig. 3 (water absorbs at 1940 nm). The first factor contains high loadings at the centre of this peak. The second factor shows contributions on the side regions of this peak, but not in the centre. Principal components analysis models linear variations in the data but non-linear variations are approximated by incorporat- 0.40 1 0.20 0 -0.20 1700 1780 1860 1940 2220 Wavelengthtnm Factor loadings: 1, first; and 2, second Fig.3 I 0.040 t 5 t 0.020 m 3 4 1 614 -1.20 -0.90 -0.60 -0.30 0 0.30 0.60 Factor 1 Fig. 4 Discrimination of sample type Table 1 Quantification results for water in substrate (% m/m) Content measured by Karl Fischer titration 0.2 4.8 5 .O 5.1 5.1 5.2 5.3 Content predicted by principal components regression 0.1 4.7 4.9 5.1 5.1 5.3 5.2 ing extra factors. Pre-treatment of the spectra removes any background due to variation in the substrate; thus, only one factor would be expected for modelling the water content in this narrow region. As two factors are necessary it is suggested that the second factor is modelling non-linearity on the sides of the water peak.The standards used in the preparation of the model were of two types: those where water was added to an anhydrous substrate and those prepared by partially heat-drying a hydrated substrate. An additional requirement was the dis- crimination between the two sources of material. The third factor in the model enabled this, Fig. 4. The scores for factor three show a dividing line between the two types of sample which in some way must relate to the different bonding mechanisms for water in them. Analysis of the loading for factor three tends to support this. The initial model was calibrated in the range 0.1-7% m/m of water in the substrate. The results in Table 1 show predictions of the first set of unknown sample spectra presented to the model.In fact this material came from a production process and in addition contained an NIR transparent component not present in the initial standards. Conclusion The source of materials used in these two analyses described represents a general dichotomy. On the one hand, for the first example the incoming material was of biological origin and showed a wide variation. No attempt could be made to alter this material or select a representative set for model building- a common situation with industrial processes simply for economic reasons. Thus, a large number of batches of material were included in the model in order to ensure a general representation. On the positive side the material is genuine and not manufactured in the laboratory.On the other hand, in the second example calibration samples were prepared in the laboratory while the test material came from the manufacturing process which also included an additional transparent component. This example was a suc- cess, but it is often impossible to match laboratory samples to production materials. This may be due to a reduction in batch size affecting the work-up of a complex solid matrix, and chemical factors such as the alkalinity of glass or its adsorptivity may also affect the preparation of mixtures.ANALYTICAL PROCEEDINGS. AUGUST 1991, VOL 28 247 Often synthetic standards are the only option that will give a sufficiently wide range of properties in a realistic time scale. In most industries the variability of output from production processes is small compared with the expected range required of the analytical technique and the product specification.Some processes are run so infrequently that sufficient samples are not available. The main advantage of synthetic samples is that the content is accurately known because gravimetric preparation methods may be used. Process samples require an independent reference method of analysis to generate the analyte calibra- tion values. Principal components analysis is primarily a qualitative method which can show patterns within samples and correla- tions between measured variables in data much more complex than those described above. The method can be extended also to give quantitative results and this can be enhanced by an adaptation known as partial least-squares regression (a com- plementary technique).The two examples also demonstrated in different ways the importance of the input data to the results obtained. In the first example a negative correlation was seen only because the collected data all fell into one of two possible representations (late switching time, none early). The second example pro- voked discussion of the difficulty of creating synthetic stan- dards that match the real process. Applications of Cluster Analysis in Molecular Modelling and Drug Design David J. Livingstone SmithKline Beecham Research, The Frythe, Welwyn, Hertfordshire AL6 9AR Some of the earliest applications of cluster analysis to drug discovery concerned the selection of compounds for synthesis, testing or analysis; in other words experimental design.For example, in 1973 Hansch et al. 1 carried out a cluster analysis of 90 substituents characterized by seven physico-chemical des- criptors. The resulting dendrogram was partitioned into sets of five, ten, twenty and sixty clusters so that experimental sets could be constructed containing these numbers of compounds. The selection of a substituent from each cluster ensured that the chosen set spanned a wide range of physico-chemical property space. A later report considered the relationship between 166 substituents.2 Cluster analysis has also been used to examine the relationships between physico-chemical parameters, i.e., an investigation of the columns of a data matrix as opposed to the rows. Takagi et aZ.3 identified four clusters in a set of 18 descriptors.These were characterized as: the steric effect, the inductive electronic effect (through space), the resonance electronic effect (through bonds) and a cluster of 'others'. A later study by van de Waterbeemd et aZ.4 examined a much larger data set of 74 parameters but they concluded that cluster analysis was not an entirely satisfactory method for the description of the relationships between the 59 substituents in their data set. A feature of cluster analysis is its ability to display the relationships between objects or variables in a multivariate data set. There is an increasing use of the techniques of computational chemistry in order to generate physico-chemical properties for use in the establishment of quantitative relation- ships between chemical structure and biological activity.5-h This leads to large data sets which contain considerable redundancy, and cluster analysis has proved a useful tool to display the correlation structure of such data.Fig. 1 shows the associations between a set of 70 molecular descriptors which were used to characterize a set of pyrethroid analogues.7 The solid lines indicate the parameters which were retained after a correlation reduction procedure8 and the broken lines indicate the correlation structure of the complete set. Computational chemistry methods are now used routinely to produce models of molecules. However, a common problem encountered in this modelling process is the determination of a 'reasonable' conformation for flexible molecules.One approach to the determination of conformation is molecular dynamics,9 which is an extension of molecular mechanics, by the inclusion of the dimension of time. The use of molecular dynamics in order to search conformational space often results in the generation of a large amount of information; a 200 ps simulation, for example, may yield 1000 accessible conforma- tions. A recent report'" describes how cluster analysis was used to analyse the results of such a simulation. The conformations were described by using the values of the torsion angles of four rotatable bonds; the resulting dendrogram is shown in Fig. 2. Although other methods were examined, it was found that a suitable technique for extracting representative conformations 0.2 O I 1 0.8 1 .o Descriptor Fig.1 Parameter associations Fig. 2 Similarity based on torsion angles248 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 from this simulation was to choose them at equally spread intervals across the dendrogram. There have been few reports of the use of cluster analysis as an aid to the prediction of biological activity or in the establishment of quantitative structure-activity relationships. A recent study,” however, has shown that cluster analysis has been useful in an examination of the toxicological interactions of a variety of compounds with carbon tetrachloride. The final application which will be mentioned here is cluster significance analysis (CSA) which is not the use of cluster analysis in the commonly accepted way but an attempt to evaluate the ‘significance’ of groupings observed using un- supervised methods of pattern recognition.”,*3 This method involves the calculation of the tightness of a cluster of compounds revealed by some display method such as a bivariate plot.The measure of tightness used is the mean squared distance (MSD) between all pairs of compounds in the cluster. Values of MSD are calculated for all other possible clusters of the same number of compounds in the data set and a value A is designated as the number of clusters with an MSD less than or equal to the MSD value of the cluster of interest (usually active compounds). The A value includes the active cluster and a probability may be calculated by dividing the A value by the number of possible clusters containing that number of compounds.It was proposed that this procedure gives the probability that such a cluster could have occurred by chance. A comparison of this method with linear discriminant analysis, SIMCA (soft independent modelling of class analogy) and ‘relative odds’ appears to support the contention that this technique is complementary to other analytical tools used in the analysis of quantitative structure-activity relationships. l4 In conclusion, cluster analysis has been used successfully in a number of areas of molecular modelling and drug design. Although it has not often been used directly in the analysis of biological data it has proved a powerful technique in certain situations. This is a common feature of many multivariate methods and it is perhaps worth pointing out that it is often difficult to say, apriori, that a particular technique will work or should even be applied in any particular situation.1 2 3 4 5 6 7 8 9 10 11 12 13 14 References Hansch, C . , Unger, S. H., and Forsythe. A . B.. J . Med. Chem.. 1973, 16, 1217. Hansch, C., and Leo, A . , in Substituent Constants for Correla- tion Analysis in Chemistry and Biology, Wiley. New York, 1979, pp. 48-63. Takagi, T . , Iwata. A . , Sasaki, Y., and Kawaki. H . , Chem. Phurm. Bull., 1982,30, 1091. Van de Waterbeemd, H., El Tayar, N . , Carrupt, P. A . , and Testa, B . , J. Comput. Aided. Mol. Des., 1989, 3, 111. Hyde, R. M., and Livingstone, D. J . , J . Comput. Aided Mol. Des., 1988, 2 , 145. Kikuchi, 0.. Quant. Struct. Act. Relat., 1987, 6, 179. Ford, M. G . , and Livingstone, D.J . , Quant. Struct. Act. Relat.. 1990, 9, 107. Livingstone, D. J . , and Rahr. E., Quant. Struct. Act. Relat., 1989, 8, 103. Karplus, M., Brunger, A . T., Elber, R . , and Kuriyan, J . , in ‘Molecular Dynamics: Applications to Proteins’, Cold Spring Harbor Symp. Quant. Biol. 1987, 52, 381. Hudson, B . D . , George, A., Livingstone, D . J., and Ford, M. G . , Pestic. Sci., 1991, 31, 99. Trieff, N. M., Weller, S. C., Sadagopa Ramanujam, V. M., and Legator, M. S., Teratog. Carcinog. Mutagen., 1990, 10, 165. McFarland, J . W.. and Gans, D . J . , J . Med. Chem., 1986, 29, 505. McFarland, J . W., and Gans, D. J . , Drug Inf. J . , 1990.24705. McFarland, J . W., and Gans, D. J . , J . Med. Chem., 1987, 30, 46. Nuclear Magnetic Resonance Vol20 Senior Reporter: G.A. Webb, University of Surrey Series: Specialist Periodical Reports Nuclear Magnetic Resonance Vol. 20 reviews the literature published between June 1989 and May 1990. Contents: N.M.R. Books and Reviews, Theoretical and Physical Aspects of Nuclear Shielding, Applications of Nuclear Shielding, Theoretical Aspects of Spin-Spin Couplings, Applications of Spin-Spin Couplings, Nuclear Spin Relaxation in Liquids and Gases, Solid State N.M.R., Multiple Pulse N.M.R., Natural Macromolecules, Synthetic Macromolecules, Conformational Analysis, Nuclear Magnetic Resonance of Living Systems, Nuclear Magnetic Resonance Imaging of Living Systems, N.M.R. of Paramagnetic Species, N.M.R. of Liquid Crystals and Micellar Solutions, Author Index. Hardcover xxii + 602 pages 216 x 138 mm Price f 140.00 ISBN 0 85186 432 5 April 1991 Electron Spin Resonance Vol 128 Senior Reporter: M.C.R. Symons, University of Leicester Series: Specialist Periodical Reports This latest volume contains critical reviews of developments during mid 1989 - mid 1990 in the field of inorganic and bio-inorganic aspects of electron spin resonance. Brief contents: Transition Metal Ions, Laser Magnetic Resonance Spectroscopy, ESR of Transition Metal Ions in Zeolites, Metalloproteins, EPR Imaging, Inorganic and Organometallic Radicals, Author Index. Hardcover xiv + 258 pages 216 x 138 mm Price f 105.00 ISBN 0 85186 891 6 April 1991 ROYAL SOCIETY OF CHEMISTRY 6 Fi;ya;cd;f:’y?$, Sales and Promotion Department, Thomas Graham House, Science Park, Milton Road, Information Services To Order, Please write fo the: Royal Society of Chemistry, Turpin Transactions Ltd, Blackhorse Road, Letchworth, Herts SG6 lHN, UK. or telephone (0462) 672555 quoting your credit card details. We can now accept AccessNisa/MasterCard/Eurocard. Turpin Transactions Ltd, distributors, is wholly owned by the Royal Society of Chemistry. For information on other books and journals, please write to: RSC Members should obtain members prices and order from : The Membership Affairs Department at the Cambridge address above.

ISSN:0144-557X    

DOI:10.1039/AP9912800245

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 249 Protecting the North Sea: The Analytical Challenge The following are summaries of nine of the papers presented at a Joint Meeting of the Analytical Division and the North East Region held on February 20th-21st, 1991, in the Grange Park Hotel, Willerby, Humberside. Analytical Difficulties in the Full Characterization of Industrial Effluents Paul A. Johnston and Ruth L. Stringer Greenpeace QM W, School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E l 4NS Currently, industrial effluents are increasingly regulated in terms of levels of relatively few components using lists such as the UK ‘Red List’ and the list contained in the 1990 North Sea Ministerial Declaration. For complex effluents, regulation has traditionally been based on group parameters such as bio- chemical oxygen demand or chemical oxygen demand.Recently, in the pulp and paper industry, restricting discharges of organically bound chlorine (AOX, EOX and POX) has been practised. The use of total organic carbon (TOC) measure- ments is being widely explored as a regulatory instrument. Neither listing procedures nor group parameters can fully account for the complexity of effluents. Even with additional toxicity testing procedures, there are problems with the extrapolation of results in order to predict the effects in the wider environment. Lists contain chemicals already identified as causing problems in the environment. The prospective effort, directed towards identification of new sources of environmental chemical risk, has been unable to prevent serious problems.Even the recent identification of tributyltin compounds as priority action chemicals was retrospective to their widespread use. An increased understanding of the nature of contaminants being discharged to the North Sea is necessary, therefore, to its future protection. Experimental Extraction and Cleanup Modern gas chromatography-mass spectrometry (GC-MS) methods theoretically allow characterization of many, though not all, unknown elements of effluent samples. The first stage in the analysis of an environmental sample is the extraction of the analyte. The recovery of a given analyte and any modification will depend upon its properties and the extractive conditions. At this stage, GC-MS screening of the ‘raw extract’ may result in the isolation of over 150 peaks.Refinement of the chromatographic conditions sometimes allows further separ- ation but it is frequently impossible to resolve samples fully. This is particularly the case if common pollutants such as oil are present in sufficient quantity to obscure minor components. Sequential cleanups may be applied to remove many interferences; solid phase extraction is a method of preference owing to its simplicity, flexibility and low cost. High perform- ance liquid chromatography (HPLC) is also gaining promi- nence as a preparative separation stage ( e . g . , for the poly- nuclear aromatic hydrocarbons). The choice of clean-up method is generally somewhat subjective. Analytical methods 7.0 ; Q) 6.0 5.0 d 4.0 5 3.0 1 .o 2 2.0 0 10 20 30 40 Ti me/m i n 8.0 /- 7 3.0 0 10 20 30 40 Time/mi n 10.0 t 1 ‘f 9.0 t I I $ 8.0 7.0 Q) 6.0 2 5.0 d 4.0 5 3.0 1 .o 2 2.0 0 10 20 30 40 Ti me/m i n Fig.1 Analytical traces obtained from a hexane extract of a discharge of the River Tees. These samples, taken on three separate occasions, clearly show the variability of the effluent are naturally tailored to the removal of all but the specific target compounds. Painstaking work is required to assure accurate isolation and precise determination of a target analyte whose properties are poorly known. With this in mind, the dischargers themselves have a great contribution to make in that they will be aware of the materials in use at the time of sampling. Hence, publication of a toxic use audit, as is becoming standard in the USA, is helpful in regulation and250 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 Table 1 Peaks resolved under identical conditions from hexane extracts of effluent samples discharged into the Tees estuary.Peaks matched against the National Institute of Standards and Technology spectral library at the 90% and 50% level are recorded with the percentage remaining unmatched at each probability in parentheses Peaks Sample Industrial sector resolved A Steel 9 B Mixed sewage/industrial 22 C Chemical/agrochemical 10s D Combined chemical 30 E Combined chemical 131 F Combined chemical 158 Matched > 90% Matched > 50% (% unmatched) (% unmatched) 4 (55.6) 4(11.2) 3 (86.4) 13 (27.8) 8 (92.6) 46 (50.0) 6 (80.0) 16 (26.6) 20 (84.7) 46 (49.7) 36 (77.3) 79 (13.5) enforcement activities.Even so, interactions of effluent components in mixed effluent systems producing new chemi- cals are not unknown. Results Identification Once the required separation has been achieved chromato- graphically, the problem of identification remains. This is generally done by computer probability based matching of analytical mass spectra against library spectra. Effectively, one imperfect set of data is compared with another using an imperfect algorithm. There is a high potential for false positive and negative identifications. Where a compound is not present in the library, spectra must be evaluated by a specialist. Differing spectra, moreover, might be obtained from different types of mass spectrometers.Most of the spectra in commercial libraries were originally recorded on various instruments of the magnetic sector type and some manufacturers of other types of machines modify the spectra to compensate for this. In addition, original data are already known to be partly corrupted by artefacts and impurities in reference compounds, causing further identification problems. Automated analyses are therefore best considered as an interpretative aid rather than a process leading to absolute identification. Currently, the analyst must rely on judgment when examining library search results in order that obvious false positive results are not reported. It is unlikely that this subjective element will be able to be completely removed from this type of work despite efforts made to do so.It is unlikely, in addition, that the library compilers can ever hope to catch up with the five million or so known organic structures, far less deal with the quantity of new chemicals produced per year, with their associated contaminants and by-products. Retention indices may be of use in backing up the spectral matching but a suitable database has first to be established by the laboratory. It would, however, be limited to those compounds that have already been the subject of research and for which standards exist. Retention indices, furthermore, are dependent on the stationary phase used in the chromato- graphic column and would need to be recalculated if this were to change. Quantification Full quantification is naturally impossible when dealing with analytes for which no standard is available and for which relative detector response is unknown.Semi-quantitative results may be obtained from comparison with internal standards or as a proportion of a TOC reading, if available. In either case, however, it is difficult to correct accurately for recovery and this must be accounted for when assigning uncertainty factors to results generated in this way. Inter- laboratory comparisons of analyses have shown that extensive problems exist with quantification. All in all, this adds up to the characterization of effluents being a somewhat inexact science , but one whose importance is being increasingly recognized. Con c 1 us i o n The work undertaken in this laboratory has largely been restricted to industrial effluent but similar problems clearly attach to other environmental media; air and sediments also present extreme analytical difficulties. Given this, the current moves by various international bodies towards a more precau- tionary approach to contamination of the North Sea environ- ment, underpinned by clean production methods to reduce waste generation, must begin to look increasingly attractive to analysts and regulators alike.Environmental Monitoring and Analysis in the North Sea Under the North Sea Task Force Robin J. Law and John E. Thain Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Burnham on Crouch, Essex CMO 8HA The North Sea Task Force (NSTF) has established a harmon- ized international scientific programme, coordinated within their Monitoring Master Plan (MMP).The objective of this plan is to develop an adequate coverage of good quality data to allow assessment of the condition of the North Sea, and of time trends of physical, chemical and biological parameters. In the short term, the monitoring data will be incorporated into an updated Quality Status Report to be completed by 1993. Although the NSTF plan covers only the North Sea and English Channel, the UK National Monitoring Programme will extend the coverage to include the Irish Sea, Cardigan Bay and the Bristol Channel. The MMP incorporates a range of determinands, some of which are mandatory at all NSTF stations while others are optional. In addition the matrices to be analysed are defined for the purposes of assessing possible hazards to human health, the existing level of marine pollution, and the effectiveness of measures taken to reduce marine pollution.The main gap inANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 251 the monitoring data is considered to be the spatial distribution of concentrations of contaminants in sediments. One of the aims of the MMP is to coordinate both biological and chemical monitoring over the whole North Sea area, and a number of techniques for monitoring biological effects have been recom- mended for use in addition to chemical measurements. These are the study of benthic macrofauna, the use of the oyster embryo bioassay to assess water quality, and both the incidence of disease and the induction of mixed function oxidase [ethoxyresorufin-0-de-ethylase (EROD)] in dab (Limanda limanda) .Fig. 1 shows the track of a research cruise conducted in June 1990, one of three undertaken last year for NSTF purposes. Sampling was carried out directly from the research vessel at coastal and offshore locations, including NSTF monitoring stations. Further sampling was carried out in the estuaries of the Rivers Tweed, Tyne, Tees, Humber and Mersey, and in Morecambe Bay, from an inflatable boat deployed from the research vessel. Bioassays and the simpler of the chemical analyses were performed at sea, but the majority of the samples collected were returned to the laboratory for final analysis. Chemical Analysis Metals in Sediments In response to the requirements of both the NSTF and the Joint Monitoring Group of the Oslo and Paris Commissions a sediment baseline investigation is being undertaken in the waters around England and Wales, involving the analysis of up to 1000 sediment samples. In order that sediment normaliza- tion techniques1 can be applied to distinguish between natural and anthropogenic sources of metals, unsieved samples will be dissolved in hydrofluoric acid with microwave heating.Ana- lysis of the resulting digests will be made using flame or electrothermal atomic absorption spectrometry (AAS) depending on the concentrations of each metal present. 56 54 aY -0 3 t d 4- .- 52 50 -8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00 48 1 -8 -6 -4 -2 0 2 4 Longitude Track of RV Cirolana. cruise 6, 5-20th June 1990. Fig. 1 56 54 52 50 48 Metals in Sea-water In order to prevent contamination of sea-water samples, manipulations are carried out in a ‘containerized’ clean laboratory mounted on the deck of the research vessel.Sub-surface samples are collected by using an air operated polytetrafluoroethylene (PTFE) bellows pump to draw water, via perfluoroalkoxy (PFA) tubing, from a buoy positioned away from the sampling vessel.2 The water is pumped directly into the clean laboratory, where filtering and pre-treatment of samples are carried out in laminar-flow hoods. Deep-water samples (>5 m below the surface) are taken using modified ‘Go-Flo’ bottles deployed on a Kevlar hydrowire, and trig- gered using PTFE coated messengers. These methods have been in use since 1985, particularly in the context of the 1985-7 Baseline Survey coordinated by the International Council for the Exploration of the Sea (ICES),3 and have a proven record of producing good quality data.Comprehensive data have been produced for cadmium, mercury and lead in the waters around England and Wales, and some investigations were made for copper and zinc. Analyses were carried out at sea, with cadmium and lead analysed using differential pulse anodic stripping voltammetry (DPASV), and mercury by cold-vapour AAS or atomic fluorescence following preconcentration on gold.4 Concentrations of these metals in sea-water are low, in the ng I-’ range (Table 1). Further work on trace metals in sea-water to be undertaken from 1991 onwards will utilize a chelation/solvent extraction technique rather than DPASV, so as to allow the determination of a larger suite of metals.5 Organics in Sea-water Only for the more soluble organochlorine compounds such as lindane (y-HCH) is sea-water recommended as a monitoring matrix, and they can be determined at the ng 1-1 level by gas chromatography with electron capture detection. Allchin6 has reported concentrations of y-HCH in coastal waters of England and Wales in the range <O.1-1.3 ng 1-1. For other compounds the use of gas chromatography with mass spectrometry (GC-MS) can yield specific detection in the ng 1-1 range, and surveys carried out in 1988-9 combined dichloromethane extraction of sea-water with GC-MS, operated in both multiple ion detection and scanning modes, in order both to determine concentrations of a range of target compounds and to screen samples with the aim of identifying compounds present in estuarine water.Samples for trace organic analysis are collected by means of glass Winchester bottles held in a weighted stainless-steel frame and sealed with PTFE stoppers. The bottles are lowered to the sampling depth either by means of hand-held ropes (1-10 m) or attached to a Kevlar hydrowire (10-50 m), and are only opened at the sampling depth so as to avoid contamination from the surface film.’ The water samples are extracted immediately, and the extracts stored in crimp-top glass vials with PTFE lid liners at -20 “C. Fig. 2 shows representative mass chromatograms obtained from the mul- tiple-ion detection analysis, and Table 2 the range of concen- trations found for a number of industrial organic chemicals in coastal/estuarine waters of England and Wales.Results for individual samples from the Tees, Tyne, Humber, Mersey and other locations have been published elsewhere.8 As part of the analytical support being provided to the biological effects Table 1 Ranges of concentration and limits of detection for cadmium, mercury and lead in sea-water Concentration Limit of range/ng I - I detectiodng 1-1 Cadmium 8 to 500 2 Mercury 0.5 to > 200” 0.1 0.5 to lot 0.1 Lead 11 to loo00 4 * Total mercury, unfiltered. t Total mercury, dissolved.ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 252 100 50 > m o + .- M, = 11 6.035 f 0.500 n 300 350 400 450 500 Scan 1 I I I I 4.01 4.42 5.22 6.02 6.42 Time/m i n Fig. 2 Mass chromatogram of (a) alkylbenzenes of M, = 106 (xylenes and ethylbenzene) and (b) the relevant internal standard of M, = 116 (o-xylene-dlo) Table 2 Concentration ranges of eight industrial chemicals in coastal and estuarine waters Concentration Compound rangehg 1- 1 Xylene <1 to 29 000 Styrene <1 to 1700 Chlorobenzene <1 to 500 Diethyl phthalate <1 to 430 Di-n-butyl phthalate <50 to 9600 Di-(2-ethylhexyl) phthalate 4 0 to 2200 Dimethyl phthalate <1 to 11 Diisobutyl phthalate <10 to 1100 component of the MMP, a range of polycyclic aromatic hydrocarbons will be determined in estuarine water.Samples collected for this purpose in 1990 will be analysed shortly using similar methods. Organics in Sediments Hexachlorobenzene and chlorobiphenyls (PCB’s analysed on a congener basis) are the only mandatory determinands under the MMP, and methodology for these compounds is well established.Optional determinands include tributyltin, chlor- danes, dioxins, PAH and toxaphene. Biological Effects Methods Two techniques are simple to use at sea, and yield results quickly. Oyster Embryo Bioassay This bioassay was developed to assess biological water quality, and has been in use since 1976. The bioassay determines the ability of oyster embryos to develop normally and reach the D- shaped larval stage within 24 h.9 This ability is reduced when water quality is poor. Algal Growth Bioassay This bioassay will respond to nutrient stimulation as well as the detrimental effects of contamination, and it has been deployed in the last year in estuarine and coastal waters to assess the biological importance of nutrient enhancement.Algae from active cultures (those in an exponential growth phase) are grown in sampled water for 120 h under controlled light conditions, and their growth is assessed by counting the algal cells. More than one algal species is normally used; commonly these include Skeletonema costatum, a diatom requiring silicate for growth, and Isochrysis galbana and Tetraselmis suecica , both flag ell at es . Further Requirements There will always be a requirement for extending the range of determinands studied, both in the inorganic/organometallic and organic categories. Amongst the organics, trace-level determinations have concentrated on compounds of low polarity as these are easier to extract and concentrate from samples than are more polar compounds, and better tech- niques need to be developed for such compounds.The assessments that can be made by NSTF will, however, be limited by the quantity of data available. Ideally, measure- ments should be repeated under varying conditions of weather, tide, river flow, etc., in order that the influence of such variables on concentration is understood. Because the need for on board sampling and analysis will restrict opportunities to a small number of discrete observations for each determinand, this ideal is unlikely to be realized. Improved analytical methods, capable of independent deployment and continuous measurement, are required before this can be met. Compound specific sensors may provide such data in the future, but not in the short term. References Report of the ICES Advisory Committee on Marine Pollution, ICES Cooperative Research Report No.167, 1989. Harper, D. J . , Mar. Chem., 1987,21, 183. Monitoring and Surveillance of Non-radioactive Contaminants in the Aquatic Environment 1984-1987, Ministry of Agriculture Fisheries and Food Directorate Fisheries Research, Lowestoft, 1990, pp. 140. Harper, D. J., Fileman, C. F., May, P. V., and Portmann, J. E., Methods of Analysis for Trace Metals in Marine and Other Samples, Aquatic Environmental Protection: Analytical Method, Ministry of Agriculture Fisheries and Food Directorate of Fisheries Research, Lowestoft, 1989. Fileman, C. F., Althaus, M., Law, R. J., and Haslam, I., Mar. Pollut. Bull., in the press. Allchin, C. R., Concentrations of alpha- and gamma-hlexa- chlorocyclohexane (Lindane) in the Coastal Waters of England and Wales, Proceedings of the International Conference on North Sea Pollution: Technical Strategies for Improvement, Amster- dam, 1990, IAWPRCJEWPCAJNVA, 1990, pp. 279-286.Law, R. J.. Fileman, T. W., and Portmann, J. E., Methods of Analysis of Hydrocarbons in Marine and Other Samples, Aquatic Environmental Protection: Analytical Method, Ministry of Agriculture Fisheries and Food Directorate of Fisheries Research, Lowestoft, 1988. Law, R. J., Fileman, T. W., and Matthiessen. P., Phthalate Esters and Other Industrial Organic Chemicals in the North and Irish Seas, Proceedings of the international Conference on North Sea Pollution: Technical Strategies for Improvement, Amster- dam, 1990, IAWPRC/EWPCA/NVA, 1990, pp.251-264. Thain, J. E., The Oyster (Crassostrea gigas) Embryo Bioassay, ICES Techniques in Marine Environmental Sciences, 1991.ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 253 Determination and Speciation of Heavy Metals in Sea-water: An Overview of Methods Available and Results Achievable Pierre del Castilho Institute for Soil Fertility Research, P.O. Box 30003, 9750 RA Haren, The Netherlands Metal speciation measurements are currently performed on a wide scale. Nowadays much attention is paid to soils and sludges by, for instance, European Community working parties (Community Bureau of Reference, Brussels). Discrimi- nation between different metal species is important in order to estimate the environmental impact of metals in soils, surface waters and the sea.The definition for metal speciation ‘distribution of metals over distinct molecular binding forms’ is not easily applicable in the natural sciences. Many natural molecules are too complex to be exactly defined. Therefore an additional definition ‘operationally defined classification of heavy metals according to a certain behaviour or characteristic’, is preferred. An example of the latter definition is the distinction between dissolved and particulate bound metal in water. By convention, in water, a distinction is made between the two forms by deposition on or passage through a 0.45 pm pore size filter. Although it is not to be expected that a 0.40 and 0.50 pm particle from a natural sample will differ much in properties, for instance in bioavailability of metals, it is clear that size fractionation can be useful.A small molecular size might lead to an easier passage of an organism through biological membranes. As biological membranes themselves are often covered with a layer of mucous material, dissolved metal species must pass through by the process of diffusion and often the metal has to dissociate from its binding sites before it becomes available. Diffusion velocity depends largely on the molecular size, shape and electrical charge of a molecule. The dissociation rate depends on the type of the metal binding. Thermodynamics can only predict final situations, not necessarily the present situation. In order to know more about availability kinetics of metals, dissociation/association and diffusion will have to be measured. Available methods for size fractionation of labile and non-labile bound metals are membrane (ultra-)filtration, gel filtration and high performance size exclusion chromato- graphy, specific mass by centrifugation, and Elm separation by electrophoresis.Table 1 Methods for the determination of labile fractionation Fraction of metal Free Equilibrium dialysis Method of measurement Ultrafiltration Ion-selective electrode Complex formation and cathodic- stripping voltammetry (CSV) Complex formation ion-exchange chromatography Labile Anodic-stripping voltammetry (ASV) Cation-exchange Non-labile csv Gel-permeation chromatography Sorption on CI8 resin Mineralization, complexation and CSV Complexationhiquid extraction and AAS Complexationkoprecipitation and AAS Total Mineralization and ASV During the separation process, the equilibrium may shift and adsorptive losses may occur.It has not always been realized that the best use of these techniques is for the purpose they were designed for, i.e.? size separation. Simultaneous lability fractionation and the study of equilibria should not be attempted. Once a class of molecular/colloidal size is separated and possibly purified (e.g., dialysis against pure solution) it can be further studied. Available methods for lability fractionation are summarized in Table 1. In general, the methods have their own specific traps and errors. These are difficult to detect if working on a routine basis. Therefore it is recommended that two or more independent (fractionation) techniques should be used in parallel. For speciation, both anodic-stripping voltammetry (ASV) (at low pH, e .g . , acetate buffer added) to measure free plus labile metal and ammonium-Chelex column exchange followed by atomic absorption spectrometric metasurement of the total dissolved and the non-labile metal (the difference between these two is the free plus labile metal) might be applied. This is illustrated by the results (Del Castilho et al., 1991, yet to be published) for copper in filtered (0.45 pm pore size) soil 0 0 I I I I I I I I I I 1 1 10 Log (IC~exchangeab~eV~~g I-’) Fig. 1 Log-log relationship between labile copper (pH = 4.5; 10-fold diluted sample) and ion-exchangeable copper from an NH4-Chelex column (pore volume, 1.5 ml; elution rate, 3.0 ml min-1; pH = 7-8) in nine membrane-filtered soil solutions 15 m I -u 0 10 E - .5 - 01 c m 2 5 0 3 0 5 10 15 [Cu,,,~,,l/pmol d w 3 Fig. 2 Correlation between the concentration of copper retained on Sep-Pak CI8 and ASV-inactive copper in fractions of membrane- filtered North Sea water (0-60 km from the coast)254 ANALYTICAL PROCEEDINGS. AUGUST 1991, VOL 28 0 ./. /. r = 0.78 Fig. 3 Computer simulation of the measurement by two independent laboratories (or methods) of the same parameter in 50 samples with a relative standard deviation of 10%. ( a ) The best and ( b ) the worst correlation from 10 computer runs is shown solutions (Fig. 1). A fair correlation between the methods for measurement of free and ionic copper is obtained. The complement of the labile fraction is called the non-labile fraction and this is believed to consist of chelates and macro-molecular (organic) metal species. Most of the latter probably have an apolar nature and because of this can be sorbed on to an organic column material (e.g., Sep-Pak CI8 column material).Non-labile copper, measured by ASV, and copper sorbed on Sep-Pak CI8 from North Sea water1 (0.2 ym filter) appear to yield reasonably comparable concentrations (Fig. 2). The correlation found may be compared with the results of a computer simulated inter-comparison where a measurement relative standard deviation of 10% and a bias of 0 is assumed. In Fig. 3(a) and ( b ) , the extremes from ten computer runs are shown.2 The conclusion seems appropriate that the measure- ment precision which is in the order of 10-15% can explain the variation, while the systematic difference of about 25% can be a real one or merely a methodological bias.In cases of extreme deviation of the observation pairs, further investigation to establish the reason for this may be attempted, although rejection of outlying values might be just as practical. Measurement of the speciation of heavy metals in gel permeation chromatography (GPC) size fractions may have several advantages; the samples are better defined and the very active surface components, which may interfere with the measuring techniques, are often removed by the gel material. References 1 Rijkswaterstaat, DGW, Report T17, Biologische beschikbaar- heid van contaminanten in het Nederlandse kustwater, Water- loopkundig Laboratorium, 1989.2 del Castilho, P., Salle, H. J. A.. and Zielhuis. R. L., T. SOC. Geneesk., 1979, 57, 376. Interpretation of Inorganic Nutrient Distributions in the North Sea David Hydes Institute of Oceanographic Sciences, Wormle y, Godalming, Surrey GU8 5UB Helen Edmunds School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ Intensification of agricultural production, improvements in sewage disposal and detergent formulations have greatly increased the input of nutrients to the North Sea during this century.' These excess nutrients have been blamed for many of the ills of the North Sea, such as the occurrence of nuisance blooms and anoxic events, although due to the complexity of the eco-system, no direct evidence exists to connect excess nutrients with these phenomena.A network of interactions needs to be understood before predictive mathematical models can be developed for use in the management of the North Sea. In 1987, the UK Natural Environment Research Council (NERC) initiated a five-year programme of research into the North Sea, the NERC North Sea Community Programme (NSCP). The NSCP consists of a number of multi-disciplinary studies directed towards the formulation of a 3D hydrodynamic model to improve our understanding of chemical, biological and sediment processes in the North Sea. The nutrient work reported here was part of that programme. The work was concentrated on the southern North Sea, south of 56"N. This is the area where man's activities have had most impact.Gerlachl suggested that for the area south of 56"N the contribution to the over-all concentrations of nitrogen and phosphorus in the sea from rivers and dumping had increased from natural levels of 14 and 7% to levels of 34 and 36%, respectively, in 1980. This paper discusses some points of the qualitative assess- ment of the NSCP nutrient data carried out prior to developing a quantitative description. Experimental The data presented here were collected between August, 1988, and October, 1989. Each month, a twelve day long survey was conducted along a track similar to that shown in Fig. 1. Nutrient samples were taken using Niskin bottles attached to a conductivity, temperature and depth (CTD)-rosette. Up to 122 stations were occupied on each survey depending on the weather.Colorimetric determinations of ammonia, nitrate, nitrite, phosphate and silicate were carried out on board ship using a continuous flow analyser.2 Results and Discussion Nutrients entering the North Sea from rivers do not enter a simple well mixed system. The day to day current patterns can vary widely, although long term averages have been charac-ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 255 55 54 53 52 a, -0 2 51 .- + J 55 54 53 52 51 -2 0 2 4 6 8 Longitude Fig. 1 Distribution of ( a ) dissolved nitrate and ( b ) nitrate corrected for the weighting of salinity (pmol dm-3) in surface waters. The positions of the samples are shown by the dots terized for some time.3 The nutrient distribution patterns, drawn by Johnston,4 reflect the influence of the average flow pattern.The most significant feature of Johnston’s diagrams is the way that the anti-clockwise circulation concentrates the inputs from the major river systems in the German Bight and along the Danish coast within the Jutland Current. Firstly, we will consider what our new data tells us about how nutrients are transported into the German Bight. Composite diagrams such as Johnston’s show a continuous flow of nutrients from the Rhine-Scheldt into the German Bight. Such simple flow patterns are not seen in satellite images and this is reflected in the more approximately synoptic NSCP data. In January, 1989 [Fig. l(a)], a flow of nutrients from the Rhine-Scheldt to the south-west was observed. This is in agreement with predictions of a climatically driven circulation model for the North Sea.5 Other signs of discontinuity in the flow are discernible. North of the Rhine and round into the German Bight, a wave like structure is present in the contours (in October, November, January, February, March and April).h A corresponding structure is present in the salinity distributions.‘Correcting’ Maps for the Fresh Water Content The features in Fig. l ( a ) are biased by the freshness of the waters being mapped. Maps for the winter months of nitrate and silicate (for which the primary source in the southern North Sea is river inputs) are similar to maps of salinity. Numerical analysis of the full data sets from between Decem- ber and March shows that linear correlations (close to 0.9) exist between nitrate concentrations and the salinity of the water. This suggested to us that it might be possible to re-map the nitrate data ‘corrected’ for the salinity of the water.This has been done in Fig. l(h) for January, 1989. The corrected nitrate values were arrived at by using the equation from a least squares fit applied to the nitrate-salinity data for January to 55 54 a, U c CI .- 4 53 52 51 -2 0 2 4 6 8 Longitude Distribution of dissolved silicate ‘corrected’ in the same way as Fig. 2 the data in Fig. 2 for the salinity of the water. Units are p ~ - 1 predict a nitrate concentration. This value is the amount of nitrate in the sample which can be considered to be due to the mixing of average river in-flow and average nutrient depleted sea-water. It was subtracted from the observed concentration to give a residual value which is plotted in Fig.l(b). Identification of Differing Sources The map [Fig. l(b)] reveals areas which have received higher or lower than average inputs of nitrate in terms of the concentration in the fresh water. This is a characteristic signal of a particular river at a particular time. It may also reveal areas of input from sediments or of removal by growing plankton. Comparing Fig. l(a) with l ( b ) , the high nitrate concentra- tion area to the north of the Wadden Sea now appears to be discontinuous from the Elbe river inflow. This suggests that it has its source in the Rhine, which is consistent with accepted ideas about the circulation. The silicate distribution map for January, 1989, looks very similar to that for nitrate with two patches of high silicate concentration along the coast of Holland, north of the Rhine.However, when the linear regression residuals are mapped (Fig. 2) both of these patches are seen as lows. This suggests that when the data for concentrations of nutrients in the Rhine become available, there is potential for an interpretation that connects the nitrate to silicate ratios in these patches to their origin in the Rhine outflow to give an estimate of advection rate round the Dutch coast. There is little data available on actual rates of advection to ‘ground truth’, that derived from meteorologically-driven models. Hence, any method providing this ‘ground truth’, such as the one suggested above using the nitrate-silicate ratios, is potentially important.References 1 Gerlach, S. A.. in Environmental Protection of the North Sea, eds. Newman, P. J . , and Agg. A. R., Heineman, Oxford, 1988, Hydes, D. J., A Manual of Methods f o r the Continuous Flow Determination of Ammonia, Nitrate-Nitrite, Phosphate and Silicate in Sea-water, Institute of Oceanographic Sciences, Report No. 177, 1984, p. 37. Carruthers, J. N., The Water Movements in the Southern North Sea. Part I-The Surface Currents, MAFF Fisheries Investiga- tions Series 11, 1925. 8, 1-114. 4 Johnston, R . , in North Sea Science, ed. Goldberg, E. D., MIT-Press. Cambridge, 1973, pp. 293-307. 5 Proctor, R . , personal communication. 6 Hydes, D. J., and Edmunds, H., NERC North Sea Community Research Programme: Qualitative Assessment of Nutrient Measurements, September 1988 to August 1989, Institute of Oceanographic Sciences Deacon Laboratory, Report 269, 1989, pp.147-175. 2 3 pp. 1-33.256 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 Purge and Trap of Volatile Organics in the Marine Environment Using Gas Chromatography-Mass Spectrometry Mark Varney and Alex Bianchi Department of Oceanography, Southampton University, High field, Southampton SO9 5NH Sea-water is a complex environment. The changes in concen- tration of chemical species are so fast that there is insufficient manpower, ships and time to gather a clear, global view of all the possible interactions at any one instant. There is, therefore, a distinct challenge for the marine scientist to collect sufficient and meaningful data and interpret them in a sensible and rational manner.Certain pollution ‘events’ can easily be identified by remote sensing. High definition, specific wavelength Landsat satellite images, which show the presence of oil slicks, convergence zones of river systems, contamination of discharges from land sites, zones of high biological productivity, aerial vapour trails from chimney stacks, ships wakes and so on, can now be obtained easily, and manipulated on personal computers. The images obviously need to be validated with ‘ground truth’ data 100 50 0 collected manually, but they provide valuable evidence and physical information on the mixing processes involved when two water streams meet or diverge, the mechanics of sediment transport, tidal volume and flow data and much more. A useful feature is that ‘fugitive discharges’ can be observed using remote sensing. Much of the volatile organic carbon (VOC) that is found in the estuary and its sediments comes from single but significant events.These can range from accidental spillages from tankers, to a home car mechanic pouring his used sump oil into the storm water drainage system, rain overfilling retaining tanks for the collection of waste products, and purely accidental releases of material into the water. Such discharges may only represent small amounts when considered in relation to the total quantity of water in the marine system, but when taken in isolation these discharges, at 1 1 I I I I 100 50 0 I 1 1000 2000 3000 Scanlnm 4000 5000 8:20 16:40 25 : 00 33 : 20 41 :40 Ti me/m i n Fig.1 Reconstructed ion chromatograms of purged sea-water taken from ( u ) the head (Redbridge), ( b ) the middle (Hythe) and (c) the mouth (Calshot) of Southampton Water taken on the same day under identical conditions, showing distinct changes in the ranges and concentrations of volatile compounds below a boiling-point of 100 “CANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 257 100 600 1200 1800 2400 3000 3600 Scan/nm 5:OO 1O:OO 15:OO 2O:OO 25:OO 30:OO Fig. 2 Reconstructed ion chromatogram of simulated bloom condi- tions when a vast range of compounds is released into an F40 culture medium by the phytoplankton, Phaeocysris duernii. Many individual compounds are present at concentrations 0.014.1 ppm Timehin 400 600 800 1000 1200 Scan/nm Ti me/m i n L I I I I 1 I 6:41 1O:Ol 13:21 16:41 20:Ol Fig.3 Reconstructed ion chromatogram of a water sample taken during a June red tide in Southampton Water. A vast range of volatile compounds is released into the water column by the phytoplankton Mesodinium rubrum, many being present at concentration 0.014.1 ppm. Peak 400, 2,3-dimethylpentane; peak 400, methylcyclopentane; peak 510, cyclohexane; peak 622, 2,4-dimethylhexane; and peak 716, dimethyl disulphide. Except for the last, none of these compounds was previously thought to be generated in siru at these concentrations the point of discharge, can represent a major threat to the stability of various ecosystems and can create major damage. The tide and the weather are the two most significant elements that affect VOC distribution.The concentrations are often highly erratic and variable, and depend on a multitude of factors, especially if the VOC is directly discharged into the water. The effect of ‘pulses’ of high concentrations of material is a common feature and plagues the analytical monitoring of the aquatic environment. What is probably not well understood with respect to this sort of research is the relationship between land, sea and air. The environment is a highly interactive system; all of the components interact strongly with one another. Any com- pound is likely to be (dynamically) partitioned. There are physical, biological and chemical processes occurring which may result in an uneven spatial and temporal distribution of compounds. ‘Spot’ sampling is clearly inadequate for VOC analysis and most other organic analyses.The distribution of VOC can never be predicted to be simple. The environment is first and foremost a natural ecosystem. It is important to know a lot more about an ecosystem before we can say anything at all about the possible impacts of marine pollution upon it. Marine research continues to reveal the presence and proliferation of an ever widening array of low-level toxic organic compounds in the natural aquatic and terrestrial environments. Volatile organic compounds are found everywhere within the marine system, some are nat- urally occurring and some are man-made. Harmful compounds can be found in very high concentrations, but very little is known about their origins and pathways into the marine environment. Their detection and their effects have been largely overlooked in the past, owing to complexities in their determination. They now represent a growing threat to the environment.These compounds include: volatile alkanes and alkenes; branched and cyclics; aromatics; oxygenated species; and halogenated species. Many of these are potentially mutagenic and carcinogenic at low concentrations and are increasingly found in coastal sea-water, rivers and domestic drinking water supplies. Volatile organic carbon in coastal and estuarine sediments has received comparatively little attention in the past, compared with, for instance, petroleum or polynuclear aromatic hydrocarbons. There are a multitude of volatile organic compounds both natural and man-made and some are extremely hazardous, while some are completely inert. Volatile organic carbon constitutes a wide range of compounds, a large number of which are found in the marine environment, and many may be considered to be toxic and harmful.In an estuarine survey, the levels of VOC may constitute as much as 10% of the total dissolved organic material in the water, and up to 30% of the dissolved organic carbon levels in the sediments. As such, VOC will significantly affect estimates of carbon budgets within the marine environment, which, presumably up to the present, have been underestimates of the actual situations. Volatile organic carbon is an unseen and, up till now, an unmeasured quantity. It is an environmental hazard that may catch us unawares unless measures are taken to qualify and quantify the extent of the problem.Potentially, up to 600 distinct, identifiable compounds may be found in any one sample, and might consist of potentially lethal compounds such as benzene, toluene, xylene, etc. The classes and concentra- tions of VOC gives rise to concern over the ‘water quality’ of rivers, estuaries and enclosed bays where volatile organic compounds accumulate. Sub-lethal exposure to marine flora and fauna can give rise to possible narcotic effects, growth retardation and birth defects. However, it is important to recognize that certain compounds can be generated in situ by natural, biogenic processes. Synthetic cultures of Phaeocystis have revealed that a wide range and high concentration of compounds are generated and released by the organisms during their growth-plateau-decay cycle.A considerable amount of VOC is found during bloom events in estuarine and coastal regions (Figs. 1-3). Many regulatory authorities do not realize that these compounds are present, let alone appreciate that their concen- trations may be sub-lethal at the ppb level. The potential for damage to the environment by discharge of industrial and domestic effluents, and the distribution of VOC within the water column and the sediments, is poorly understood and even less documented. There is a distinct and essential need for both preliminary and fundamental research into the VOC levels in coastal and riverine environments in order to determine the extent of the problem and the deleterious biological effects that this might cause to local communities.The study of trace gases and trace volatile organic com- pounds can yield a wealth of fundamental information. Improvements in the massive gaps in our present knowledge of VOC will only come from collecting more measurements and performing more research which will enable substantial inroads to be made in understanding the fundamental chemical and biological processes that occur in nature. The objectives of VOC research, therefore, are to identify: (i) the ranges and concentrations of volatile organic micro-pollutants; (ii) their sources, distributive mechanisms and fates; (iii) the extent to which compounds are derived de nuvu by biological or biochemical means; and (iv) the extent of man’s involvement.258 ANALYTICAL PROCEEDINGS, AUGUST 199 1, VOL 28 Co-ordination of North Sea Research and the North Sea Database Philip C.Reid and Michael J. Roberts Department of the Environment, Room A233, Romney House, 43 Marsham Street, London SWlP 3PY The total effort by the UK on marine research is widely dispersed between a large number of organizations: Govern- ment Departments, the National Rivers Authority, River Purification Boards, Research Councils, Universities, Poly- technics, Agencies, Museums, Private Companies and Non- Governmental Organizations. Each agency has distinct objec- tives for its programmes and there are various arrangements for joint funding and co-ordination and discussion of overlap- ping interests. The Co-ordinating Committee on Marine Science and Technology (CCMST) has reviewed the area as a whole and advised on the case for a national plan in its report of March, 1990.l There is an increasing recognition of the importance of monitoring and the need to develop time-series and spatial information on marine environmental parameters.A recent development in this area is the development of an International Monitoring Master Plan for the North Sea and the formation of a National Monitoring Plan for UK estuaries and coastal waters. While responsibilities for research and monitoring between the different organizations listed above are well defined and seem to work reasonably well, there is a continuing need for improved co-ordination. This paper describes the scale of the national effort on marine research and monitoring, and ways in which collabor- ation is being improved between UK and international organizations studying the North Sea.A brief outline is given of the North Sea Research Database, an international research project information system developed by the Department of the Environment (DOE). A summary is also provided of the main headings of the DOE research programme on the North Sea. Marine Research and Monitoring in the UK The total funding for marine science and technology in the UK was estimated by CCMST’ at f400 million divided approxi- mately equally between marine technology (funded by oil and gas companies), marine technology (funded by other indus- tries), marine technology (funded by Government, including defence) and marine science (mostly funded by Government). In turn, marine science is divided between Government departments which have responsibility for policy related research, protecting the marine environment, fisheries and defence, and the research councils (Natural Environment Research Council, Science and Engineering Research Council), universities and polytechnics which have re- sponsibility for basic and strategic science with some element of technology. Protection, monitoring and prediction involve half the Government’s civil marine research and developments in this area are increasing, partly because of: (a) our participation in monitoring exercises such as the Monitoring Master Plan of the North Sea Task Force; and ( b ) the National Monitoring Plan which is being co-ordinated by the Marine Pollution Monitor- ing Management Group (MPMMG) and will build on the new plan for England and Wales that has been put forward by the National Rivers Authority (NRA).This plan will involve sampling in estuaries carried out primarily by the NRA (River Purification Boards in Scotland) at three different salinities with the aim of establishing the current extent of contamination and biological status. The programme will also provide a foundation for determining trends in these factors. A parallel programme will be initiated for up to 30 coastal sites carried out by the Ministry of Agriculture, Fisheries and Food (MAFF) and the Scottish Office Agriculture and Fisheries Department (SOAFD) to determine the trends in physical, biological and chemical parameters and evaluate natural variability of the marine environment. Sampling for these programmes to include a range of chemical determinands in different media, biological effects techniques and other associated measure- ments has already begun.Co-ordination of North Sea Research The DOE has responsibilities for the co-ordination of policy and research on the marine environment between Government departments. It supports this responsibility through the marine unit of Environmental Protection Central which has as part of its co-ordinating role a marine research programme, intended to conipiement and help co-ordinate the marine programmes of other departments and agencies. This work is directed particularly towards North Sea research to support the policy objectives agreed by Ministers at successive North Sea Conferences and has used as a focus the ‘gaps in knowledge’ identified by the NSTF (see below).In the UK a North Sea Scientific Co-ordinator based in the DOE provides a central focus for contacts between the very wide range of organizations that have an interest in the North Sea. An agreement to establish an Irish Sea Co-ordinator, funded jointly by the Republic of Ireland and the UK, was made at the Irish Sea Conference on the Isle of Man in October 1990. Improved co- ordination has been stimulated by the development of a North Sea Research Database, by active participation in meetings and committees on the North Sea and through the organization of a North Sea Task Force (NSTF) Liaison Group. The research programme, funded by the Department of the Environment, on the North Sea, specifically addresses the ‘Gaps in Knowledge’ identified by the NSTF.’ This programme is intended to develop interdisciplinary and collaborative research on the North Sea. The programme places priority on the following themes: nutrients/eutrophication, organic con- taminants, trace metal contaminants, wildlife and ecosystem effects, sediment contaminant interactions and the coastal margin.North Sea Task Force At the 2nd Ministerial Conference on the North Sea in London (1987), Ministers recognized that there was an urgent need to improve our knowledge of the state of health of the North Sea. To this end they recommended that a special ‘Task Force’ should be formed to develop co-ordination and harmonization of research, monitoring and modelling between the eight North Sea states around the North Sea.2 Membership of the NSTF includes, France, Belgium, Germany, The Netherlands, Den- mark, Sweden, Norway and the UK with the Commission of the European Community, the International Council for the Exploration of the Sea (ICES) and the Oslo and Paris Commissions (OSPARCOM).The Task Force has a primary remit to produce an assessment of the state of health of the North Sea (Quality Status Report) for 1993. In order to fulfil this task a five year plan of action and a Monitoring Master Plan have been prepared. For the Monitoring Master Plan, a range of mandatory and voluntary determinands are being measured in 1990/91, using standardized techniques, with a pattern of sampling stations which will give, for the first time, an accurate view of the geographical cover of contaminant concentrations across the whole of the North Sea.A number of parallel initiatives by the Oslo and Paris Commissions and the International Council for the Exploration of the Sea are also inANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 259 hand and will feed into the Quality Status Report (QSR) process. These include, for example, the PARCOM 1990 input survey and the ICES working group on marine mammals. Co-ordination of research has so far been limited to holding workshops to try to integrate sea-going research programmes between North Sea states and by the prodution of national directories of research projects. As a contribution to this work of the NSTF the UK has developed a database to bring together national inventories of ongoing research to allow a more useful and easier interrogation and use of this information. North Sea Research Database At an early stage in the work of the North Sea Scientific Co- ordinator, it was recognized that a system to provide readily accessible contact information to the wide diversity of indi- viduals and organizations involved in the North Sea was needed.At the same time up-to-date information on ongoing projects within the UK was required to help assess research priorities and provide information to the Government and the NSTF. A pilot research database was produced to assess the value of providing the above information in a computerized and readily accessible form. Following a successful trial the DOE agreed to support the development of an operational PC- based database for use by the NSTF.In order to ensure that the system met the requirements of the NSTF and would be available to operators at minimum cost, a compiled system using DBASE 111 PLUS and CLIPPER has been produced. Users therefore have no requirement to purchase either software or licences to run the system. Completion of a fully operational version of the database was achieved within 6 months of the planning stage and circulated to all North Sea states by the eleventh month. There were three stages in the development: (1) acquiring the data; (2) design and construction (database structure); and (3) the user interface. The first of these stages was sub-divided into targeting the sources of project information and the design and circulation of a questionnaire.In order to ensure ease of response and to obtain the maximum amount of information, a carefully designed questionnaire was produced which covers contact information and details of research projects. The core of the database is structured around projects which are linked in turn to project leaders, project institutes, geographical area in which the work is undertaken, reference to gaps in scientific knowledge identified by the Task Force, a definition of the type of research, products of the projects such as maps, text, databases, keywords and funding (which can be confidential). The user interface provides a hierarchy of simplified menus for the establishment and maintenance of the database, for interrogation (i.e., the identification of individual projects) and for import/export of information between the international database co-ordinator, national co-ordinators, institute co-ordinators and individuals. The following interrog- ation parameters are available: country, keywords, research type, geographical area, organization, institute, product, Task Force gap, project leader and associated programme. Project details can include a long and/or short summary with additional information on the above interrogation parameters. Help screens are available at each menu level. The database also has a facility for a private ‘scratch pad’ and address list. For the next two years, until the system is fully operational, the DOE will act as the International Co-ordinator of the database on behalf of the NSTF Secretariat.Circulation of the system takes the following route. Firstly, questionnaires are passed from the International Co-ordinator to National offices whence they are distributed widely to research institutes and scientists. When returned they are input into a ‘national’ database which is exported to the International Co-ordinator on disk or tape. All the national inventories are then compiled by the International Co-ordinator and passed back down the previous route as a completed version of the fully international database. It is planned that the system will be updated in this manner at intervals of approximately 6 months in the first few years of its use. The first demonstration version of the database has been circulated and includes approximately 370 projects with at least 12 projects from all North Sea states. An update will be produced for the next meeting of the NSTF in May, 1991. It is expected that between 2000 and 4000 projects (maximum) will be included in the database within the next 12 months when completed questionnaires are input from other North Sea states and the Commission of the European Community. Conclusions The DOE has played an important role, following the 2nd Ministerial Conference on the North Sea, in co-ordinating the marine monitoring and research effort of the UK. This co- ordinating role is supported by a sizable research programme, currently g1.5 million per annum, which specifically addresses the gaps in scientific knowledge identified by the NSTF and supplements the larger research programme of MAFF, SOAFD and the Natural Environment Research Council. The Task Force provides an international dimension to this co- ordination. The DOE, with other UK delegates on the Task Force from the NRA, MAFF and SOAFD, has taken a very active role in the development of the Task Force programme and plans. A major contribution to this work has been the development of a North Sea research database funded by the DOE. This database will be an essential tool in the production of the next Quality Status Report of the North Sea, will help to avoid duplication of research effort and identify ongoing research and gaps in knowledge. The system will also help to improve communication and co-ordination between inter- national programmes and provide ready access to information on research products. The database is freely available to scientists, administrators and all interested in the North Sea. Enquiries should be addressed to: Mr. Brian Entwistle, Department of the Environment, Room A231, Romney House, 43 Marsham Street, London SWlP 3PY. References 1 Report of the Co-ordinating Committee on Marine Science and Technology, Marine Science and Technology in the United Kingdom, HM Stationery Office, London, 1990. Reid, P. C., Int. J. Estuarine Coastal Law, 1990, 5 , 80. 2

ISSN:0144-557X    

DOI:10.1039/AP9912800249

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

260 ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 Analytical Requirements in View of North Sea Environmental Policy Wim P. Cofino" Ministry of Transport and Public Works, Public Works Department, Tidal Waters Division, P.O. Box 20907, 2500 EX The Hague, The Netherlands The condition of the North Sea ecosystem is a cause for concern, and has a high priority in international policy as shown by the series of North Sea Ministers Conferences and the establishment of the North Sea Task Force. For a proper formulation of policy and for the evaluation of the effectiveness thereof information is required about the contamination and about the pathways and mechanisms along which chemicals enter and disperse through the North Sea environment. A considerable analytical effort is required in this context.Monitoring programmes have to supply a major part of the information required. The needs of particular regional concern are often covered by national programmes or by specific actions (e.g., monitoring near oil platforms). Internationally co-ordinated programmes include the Joint Monitoring Pro- gramme conducted within the framework of the Conventions of Oslo and Paris,' and the North Sea Monitoring Master Plan supervised by the North Sea Task Force.2 The results of monitoring programmes and research projects will form the basis of the next Quality Status report on the North Sea, which is due to appear in 1993. Proper management of the North Sea requires appropriate and reliable information. Incorrect information might lead to inadequate or wrong measures being taken, and hence the risk of impairing the environment or wasting finances.Adequate information requires a proper (monitoring) strategy, in which the whole process of assessment of the information need, design of the sampling programme, the requirements for methodology, the field and laboratory work, the assessment of the data and the presentation of information is carefully scrutinized, planned, executed and e ~ a l u a t e d . ~ The analytical aspect is one, albeit important, part.4 In principle, specifications for the analytical methodology, which is considered to include sampling, ought to be derived by the process described above. The concentrations of the chemicals of interest, spatial and temporal variability, and specific statistical requirements should be considered in the context of the information need.Such a systematic approach is, however, not often followed in the international context. For the priority pollutants measured in the international monitor- ing programmes it is necessary that the actual concentrations can be measured, and that the group of laboratories involved provide data which are mutually consistent. These require- ments also follow directly from the definition of environmental monitoring provided by the United Nations Environment Programme (UNEP), which stresses the use of comparable method~logies.~ It implies that laboratories validate their methodology properly, assessing both statistical control6 and a c ~ u r a c y . ~ In addition, traceability to a common set of standards has to be ensured within this group, so that 'transfer of accuracy' is achieved.8 About 50 laboratories are involved in routine monitoring of the North Sea.Problems are encountered in several areas. A concise overview is given here on the comparability of analytical data, based on intercomparison exercises, nearly all of which have been organized within the framework of the International Council for Exploration of the Sea (ICES). The underlying analytical problems are beyond the scope of this paper and are not discussed; information can be found in the appropriate references. * Present address: Free University, Institute for Environmental Studies, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands. Trace Metals in Biota Results for intercomparisons on Cu, Hg, Pb and Cd are summarized in Fig.1 .9310,12 A profile with interlaboratory variability increasing as the concentration decreases is e ~ p e c t e d . ' ~ Copper clearly exhibits such a profile, in spite of the time span over which the exercises were performed. 50 40 30 20 10 0 '0 . I I I 10 20 30 40 40 30 - I . A 0.5 1.0 1.5 2.0 2.5 p 80 I I I 1 2 4 6 8 1 0 0 100 ( d ) 40 0 0 0.5 1.0 1.5 2.0 2.5 3.0 Consensus concentration/mg kg-1 (dry mass) Fig. 1 Plots of the relative standard deviation versus the consensus concentration. ( a ) Cu; (b) Hg; ( c ) Pb; and (d) Cd. 0 , Data from ICES intercomparison exercises organized before 198093'0; A, data from second IOC/UNEP intercomparision exercise on trace metals in biological tissue;11 and ., data from ICES 7/TM/BT parts 1 and 212ANALYTICAL PROCEEDINGS.AUGUST 1991, VOL 28 261 Table 1 Trace metals in sediments Sample A* Sample B* Mead Mead mg kg-' RSD mgkg-' RSD Element (dry mass) (%) (dry mass) (Yo) Cd 1 .s 31 2.0 29 c u 18 13 131 7 Zn 534 8 314 8 Hg Pb 318 10 217 11 - - - - * Samples A and B: ICES l/TM/MS." t Sample C: ICES/SCOR, 1984 (cited in reference 10). Sample C* Oyster grounds Mead mg kg-' RSD (dry mass) (%) 0.79 60 28 10 158 17 0.09 38 54 9 Unfrac- tionatedlmg kg-' (dry mass) 0.02 4.7 0.04 36 14 <63 pm/ (dry mass) 0.11 mg kg- 17.8 115 40 0.16 Relatively experienced laboratories took part in the first exercises organized in the early 1970s. Successively, more and less experienced laboratories participated. The net effect appears to be that, on average, the performance of the whole group of laboratories which participated in the exercises (which differed over the years) has not increased significantly over a period of 15 years.Copper has been monitored in fish liver and mussel tissue; an interlaboratory variability of 10% is a reasonable estimate for most of the concentrations encoun- tered. For Hg, an improvement in laboratory performance appears to be apparent. The most recent data exhibit no clear relationship between concentration and relative standard deviation; an interlaboratory variability of 20% can be anticipated. The data for Cd and Pb also suggest an improve- ment of laboratory performance. Here, interlaboratory varia- bility is estimated to be about 15 and 20%, respectively. The data appear reasonable, but the number of laboratories rejected in the statistical analysis is not insignificant.In addition, in the most recent exercise (1987), only four laboratories were able to determine Cu, Zn, Cd and Pb successfully in all five samples provided. l2 Trace Metals in Sediments Results of intercomparison exercises on trace metals in sediments are given in Table 1. Unfortunately, the concen- trations of the metals in the sediments studied are rather high. For instance, measurements of trace metal concentrations in unfractionated sediments of the oyster grounds give values of 0.2,4.7,36,0.04 and 14 mg kg-' (dry mass) for Cd, Cu, Zn, Hg and Pb, respectively.1s The concentrations are higher by a factor of 4 when the measurements are performed in the fraction <63 pm, obtained by sieving.It is clear that severe problems exist for the mandatory elements Cd and Hg. Trace Metals in Sea-Water Results of intercomparison exercises on trace metals in sea- water are given in Table 2. Mercury, Pb and Zn appear to present problems, whereas Cd and Cu appear to present fewer problems, although a fairly large amount of data were rejected. The National Research Council Canada organized, on behalf of ICES, the 1986 exercise specifically for Joint Monitoring Group of the Commissions of Oslo and Paris (JMG) labora- tories. Only two of these laboratories accurately determined all four mandatory metals, Hg, Cu, Cd and Zn, and only five accurately determined Cd, Zn and C U . ' ~ Nutrients in Sea-Water The results of a recent intercomparison exercise18 are given in Table 3.The results compare favourably with those obtained for trace metals and chlorobiphenyls. However, the analyses were performed in the laboratory, whereas measurements are often carried out on board ship, in which case the results appear to be significantly less comparable [nutrient data from the Baltic Sea Patchiness Experiment exhibit an over-all discrepancy of over and results from the Skagerrak Table 2 Trace metals in sea-water Number of Number Mead Element Year* laboratories of outliers pg I-' Hg 1986 Cd 1984 1986 1986 c u 1984 1986 1986 Pb 1984 1986 1986 Zn 1984 1986 1986 24 43 39 39 36 40 42 30 25 24 34 32 31 6 0.0068 14 0.020 5 0.108 11 0.050 13 0.12 12 4.15 13 1.31 10 0.050 6 0.190 7 0.050 7 10 11 0.39 13 1.36 * 1984: ICES 5/TM/SW.'6 1986: ICES 6/TM/SW.'7 Relative standard deviation 38 24 24 22 19 8 14 5s 23 41 38 14 19 (Yo 1 Table 3 Nutrients in sea-water.Data from reference 18. Parentheses indicate that the uncertainty is too large to establish acceptable consensus concentrations Number of Number of Mead Parameter laboratories outliers kmol I-' RSD (%) Nitrate + Nitrite 67 16 16.19 4.5 67 16 6.9 4.3 67 9 0.548 11.6 Phosphate 68 10 1.144 10 Silicate 40 - (0.60 k 2.76) - 12 - (0.18 f 0.12) - Nitrite Experiments (SKAGEX) show differences between vessels20]. In addition, the preservation of the samples can affect the results to a large extent. Chlorobiphenyls An ICES/IOC/OSPARCOM (IOC being the International Oceanographic Commission and OSPARCOM the Commis- sions of Oslo and Paris) improvement programme is currently being conducted for chlorobiphenyls.The programme consists of a series of exercises, in which the analysis of chlorobiphenyls is systematically carried out in a step by step fashion. Two steps have now been completed, both co-ordinated by the Nether- lands Institute for Fishery Investigations (RIVO). The first part, held in 1989, dealt with standard solutions. The standard deviation for the congeners studied was approximately 15% for a group of about 40 laboratories.21 In 1990, the second step was organized, with more than 80 participating laboratories. Standard solutions, a seal blubber extract and a sediment extract were distributed. The relative standard deviation varied from approximately 15% for the standard solution to more than 30% for the sediment extract.The results were not satisfactory. 22262 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 Discussion and Conclusions Extrapolations from intercomparison exercises provide an ‘optimistic’ impression, because well prepared, partially worked-up samples are provided. Sampling, the preservation of samples and part of the sample work-up are not assessed, but can have a substantial effect on the over-all variability. Measurements on trace metals and nutrients in sea-water provide clear examples. In addition, the results submitted might not be representative of the general performance of a laboratory .23 The results of the intercomparisons indicate that the determination of the mandatory metals in biological tissue currently presents the fewest problems.An interlaboratory relative standard deviation of approximately 20% is antici- pated, implying that for one sample the ratio of the highest to the lowest result is about 2.3 (95% of the accepted labora- tories, i.e., mean +2s, are included). There is scope for improvement, however, considering the number of outliers and the rather small number of laboratories that have determined all the mandatory metals successfully. The determination of trace metals in sea-water and sediment requires improvement. The results for nutrients are encourag- ing but could be (slightly) misleading, because the effects of sampling and sample preservation or measurement on board ship are not accounted for. The results for chlorobiphenyls are not satisfactory. The analysis of chlorobiphenyls is at present not sufficiently developed in North Sea countries to meet the information need of international North Sea policy, and requires improvement for all matrices.Problems can be foreseen with respect to the evaluation of results of the North Sea Master Plan-Monitoring Programme, for which trace metals and chlorobiphenyls in sediments are mandatory. The analytical problems are due to several factors: the application of inappropriate methodology, problems with calibration and contamination control, incomplete recovery of the analyte, etc. However, for all contaminants in all matrices appropriate and reliable methodology is available. The prob- lems can be attributed to a lack of quality assurance. The development and implementation of quality systems within laboratories is a necessary condition for impr~vement.~ The European standard EN 45001 or I S 0 guide 25 provides proper guidelines in this respect .24*25 The necessity of using (certified) reference materials has been emphasized adequately, and need not be commented on in more Finally, it should be noted that monitoring agencies have the primary responsibility to ensure that monitoring programmes render the information needed in an efficient manner.The quality of the whole process from analysis of the information need to the evaluation and presentation should be As part of such a quality system, clear requirements have to be stated which laboratories have to meet in order that their data are accepted, quality systems, traceability and quality control being the keywords. Procedures ought to be developed that allow verification of the data, e.g., the provision of laboratory reference materials, specific designs of sampling programmes, collective sampling stations and exchange of samples between laboratories.Fortunately, progress is being made in this direction (e.g., references 2 and 27), although much work remains to be carried out. References 1 Oslo and Paris Commissions, Principles and Methodology of the 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Joint Monitoring Programme (Monitoring Manual), London, 1990. The North Sea Task Force, North Sea Environmental Report No. 3 , North Sea Monitoring Master Plan, London, 1990. Cofino, W. P., Helgolander Meeresunters., 1989, 43, 295.Broderick, B. E., Cofino, W. P., Cornelis, R., Heydorn, K., Horwitz, W., Hunt, D. T., Hutton, R. C., Kingston, H. M., Muntau, H., Baudo, R., Rossi, D., van Raaphorst, J. G.. Lub, Tj. Th., Schramel, P., Smyth, F. T., Wells, D. E., and Kelly, A. G., Mikrochim. Acta, 1991, in the press. Meijers. E. M. J . , Environ. Monit. Assess., 1986, 7 . 157. Wernimont, G.. in Validation of the Measurement Process, ed. Devoe, J . R., ACS Symposium Series No. 63, American Chemical Society. Washington, DC, 1977, p. 1. Taylor, J. K . . Anal. Chem., 1983. 55, 600A. Uriano, G. A., and Cali, J. P.. in Validation of the Measurement Process, ed. Devoe, J . R., ACA Symposium Series No. 63, American Chemical Society, Washington, DC, 1977, pp. 14M61. Topping, G.. in Trace Metals in Sea Water, eds.Wang, C. S., Boyle, E., Bruland, K . W., Burton, J . D., and Goldberg, E.. Plenum Press, New York, 1983, pp. 155-173. Topping, G., Sci. Total Environ., 1986, 49, 9. Topping, G., personal communication. Berman, S. S . , and Boyko, V. J., ICES 7th Round Intercalib- ration for Trace Metals in Biological Tissue, Part I , ICES Cooperative Research Report No. 138, 1986; Part 11. ICES Marine Chemistry Working Group, Document 1987/7.1.1.1 A. Horwitz, W., Kamps, L. R., and Boyer, K. W., J . Assoc. Off. Anal. Chem., 1980, 63, 1344. Loring. D. H.. A Final Report on the ICES Intercalibration Exercise for Metals in Marine Sediments (IITMIMS), ICES Cooperative Research Report No. 136, 1985. Data from Dutch Contribution to Joint Monitoring Pro- gramme, Reported to the Joint Monitoring Group in National Comment of The Netherlands, Ministry of Transport and Public Works, Public Works Department, The Netherlands, 1986 and 1989.Berman, S. S . , Mykytiuk, A. P., Yeats, P. A., and Bewers, J . M., ICES 5th Round Intercalibration for Trace Metals in Sea Water, ICES Cooperative Research Report No. 136, 1985. Berman. S. S . , and Boyko. V. J . , ICES 6th Round Intercalib- ration for Trace Metals in Estuarine Waters (JMG 6ITMISW), ICES Cooperative Research Report No. 152, 1988. Kirkwood, D., Aminot, A,, and Perttila, M., ICES Fourth Intercomparison Exercise for Nutrients in Sea Water, ICES Cooperative Research Report No. 174, 1991. ICES Marine Chemistry Working Group Report, Document C.M. 1990/Poll:1, ICES, Copenhagen, Denmark.ICES Annual Report, ICES, Copenhagen, Denmark, 1991, p. 72. de Boer. J., Duinker, J . C., Calder, J . , and van der Meer, J., Report on the ICESIIOCIJMG Intercomparison Exercise on the Analysis of Chlorobiphenyl Congeners in Marine Media - First Step. ICES Statutory Meeting, Document E: 10, Copenhagen, Denmark, 1990. de Boer, J., Reutergbrdh, L., van der Meer, J., and Calder, J . A., On the ICESIIOCIOSPA RCOM Intercomparison Exer- cise on the Analysis of Chlorobiphenyl Congeners in Marine Media - Second Step, Draft Report, ICES, Copenhagen, Den- mark. 1991. Einerson, J. H., and Pei, P. C., Environ. Sci. Technol.. 1988, 22. 1121. CENICENELEC, European Standard EN 45001, General Criteria for the Operation of Testing Laboratories, Brussels, Belgium. 1989. International Organization for Standardization (ISO), Guide 25: General Requirements for the Competence of Calibration and Test ng Laboratories.ISO, Switzerland, 1990. Wells, D. E., Fresenius Z . Anal. Chem., 1988, 322, 583. The North Sea Task Force and the Joint Monitoring Group of the Oslo and Paris Commissions, Report of a Workshop on Monitoring Programmes in the North Sea and North East Atlantic Waters in 1990191, London, 1989.ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 263 Problems Associated With the Analysis of Hydrocarbons in Marine Sediments Robert Large M-Scan Limited, Silwood Park, Sunninghili, Ascot, Berkshire SL5 7PZ The qualitative and quantitative analysis of petroleum hydro- carbons in marine sediments is complicated by a wide range of factors, including: ( a ) the chemical complexity of crude oil and refined products (the analyte); ( 6 ) the variable nature of sediments (the matrix); ( c ) the difficulty in obtaining a truly representative sediment sample; (d) the variability of sediment extraction procedures; ( e ) the interference of co-extractants; cf) the complexity of work-up procedures; and (g) the variability and selectivity of analytical methods.The above factors often combine to produce unacceptably high variability in hydrocarbon data. Careful consideration needs to be given to each factor before high quality data are obtained. The Analyte Petroleum hydrocarbons in the marine environment can arise from the input of either crude oil or refined products, particularly kerosine, diesel, lubricating oil and heavy fuel oil.Each input consists of a complex array of aliphatic hydro- carbons (alkanes and naphthenes) , aromatic hydrocarbons and polar compounds. Moreover, the individual compounds can have widely differing boiling-points and susceptibility to biodegradation, photodegradation, evaporation and dissolu- tion in sea-water. ’These highly variable characteristics need to be considered carefully and appropriate analytical procedures selected. The Matrix Marine sediments are below water, often with an associated ‘floc layer’, and are inherently difficult to sample. The sediment is wet, presenting a problem in extracting hydrocarbons efficiently. The grain size varies, affecting hydrocarbon adsorp- tion and solvent desorption. Hydrocarbon contamination is often non-uniform (‘patchy’), making it difficult to obtain a representative sample. Environmental (sampling) variability can therefore be intrinsi- cally large (relative standard deviation as high as 95%), normally greater than analytical variability (precision; ideally better than 5%).Sampling Sea-bed sediment samples are normally collected using grabs or various coring devices, which permit random sampling, but which can disturb sediments. Divers have been used, but selective sampling can result. It is necessary to take sub-samples of sediment for analysis to a defined depth (normally the top 1-2 cm), to avoid hydro- carbon contamination (from oil and grease on the sampling vessel) and to stabilize the sample (normally by deep freezing) immediately after sampling to minimize hydrocarbon losses by biodegradation.The sample needs to be labelled clearly and permanently and to be transported carefully; it is unique. It is also necessary to relate analytical accuracy and precision to the objectives of the study in question and to anticipated environmental variability. With well validated analytical and sampling procedures and thorough quality control, single grab samples at each sampling point normally suffice in routine surveys. The resulting data are normally sufficient to establish concentration trends away from a point source of discharge and to detect significant changes from previous surveys in the same area or related surveys in different areas. Solvent Extraction It is important that the sediment should not be dried before extraction, as this will lead to loss of volatile hydrocarbons, particularly kerosinic drilling mud base oils.Moreover, the solvent system used should ‘wet’ the sediment sample to allow efficient extraction of hydrocarbons (for example, propan-2- ol-hexane or methanol followed by dichloromethane). It is also necessary to put energy into the system to allow efficient solvent extraction. Methods include ultrasonics, Soxhlet extraction and refluxing which can have similar efficiency. Ultrasonic extraction, however, has the advantage of being rapid and operating at room temperature, thereby minimizing any loss by evaporation, but requires relatively expensive equipment. It should be noted that heavy hydrocarbon residues, such as tars, are difficult to extract.Hydrocarbon contamination is therefore often underestimated; reported analytical results relate only to extractable material. Organic Extracts The analysis of petroleum hydrocarbons in marine sediments is complicated by the fact that the total organic extract of a sediment will consist of a complex mixture of: ( a ) petrogenic hydrocarbons and polar compounds from crude oil and/or refined products, including some asphaltenes and resins; (6) biogenic hydrocarbons, including heptadecane, pristane, polyenes and higher plant leaf waxes; and ( c ) other lipids, including esters, fatty acids and sterols. It is therefore normally necessary to purify the total organic extract and to isolate aliphatic and aromatic hydrocarbons for separate analysis. Purification of Solvent Extracts Low-boiling hydrocarbons (below decane or naphthalene) can be lost selectively during solvent removal by rotary evapor- ation.Therefore, light refined products (naphtha, gasoline) and condensates are difficult to estimate by standard solvent extraction procedures. In order to obtain definitive data on aliphatic and aromatic petroleum hydrocarbons it is necessary to purify the sediment extract using a detailed work-up procedure, incorporating particularly: (a) saponification of lipids and partition of resulting salts into water; (6) removal of elemental sulphur, which is co-extracted; and (c) preparation of discrete aliphatic and aromatic fractions, using techniques such as column chromatography, high-performance liquid chromatography and thin-layer chromatography.These fractionation procedures can produce equivalent separations, but all have some disadvantages. Clean separation of aliphatic and aromatic hydrocarbons by column chroma- tography is difficult to achieve. High-performance liquid chromatography is easy to automate, but might lead to cross- contamination. Thin-layer chromatography might result in selective loss of more volatile hydrocarbons. Asphaltenes, resins and heavy hydrocarbon residues are difficult to characterize and, if extracted, are normally lost during routine work-up. Total oil concentrations might there- fore be underestimates. This fact should always be borne in mind.264 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 Analysis A range of methods is in use for the qualitative and quantitative analysis of petroleum hydrocarbons extracted from marine sediments.These include: gravimetry; infrared absorption spectrophotometry; ultraviolet fluorescence; gas-liquid chro- matography (GLC); and GLC-mass spectrometry (GLC-MS). Gravimetry has the advantage of being an absolute method, but is non-specific. It also assumes 100% extraction efficiency. A major disadvantage is that the extract in question has to be dried before weighing, resulting in loss of volatile hydro- carbons and an underestimate of hydrocarbon concentration. Infrared absorption spectrophotometry monitors extracted aliphatic hydrocarbons, but suffers from major disadvantages. Firstly, co-extractants can interfere at the C-H stretch absorption frequency, resulting in overestimation of hydro- carbon contamination.Secondly, it is necessary either to dry the sediment before extraction with a solvent suitable for infrared analysis, such as Freon 112, or to dry the extract before dissolution in Freon 112. In both instances a loss of volatile hydrocarbons will occur, resulting in an underestimate of hydrocarbon contamination. The infrared method needs careful calibration with an appropriate oil, the choice of which is difficult, and assumes 100% extraction efficiency. Ultraviolet fluorescence monitors the aromatic, rather than the aliphatic, content of extracted hydrocarbons and is very sensitive. Again, 100% extraction efficiency is assumed. The method, however, needs very careful calibration and results are always expressed as equivalents of the calibrating oil.The adoption of ‘low toxicity’ drilling mud base oils has presented particular analytical problems. Such oils contain typically less than 2-3% of aromatic hydrocarbons, in distinct contrast to products such as diesel, which can contain 20-30% of aromatic hydrocarbons. A sediment contaminated with a low concen- tration of diesel can therefore appear to have a high concentration of a ‘low toxicity’ base oil. Specific information on the nature of the hydrocarbon input is required before ultraviolet fluorescence results can be interpreted with confi- dence; the ultraviolet fluorescence technique is therefore normally used in conjunction with GLC (see below). However, some qualitative information can be derived from the ultravio- let fluorescence technique, such as the proportion of bicyclic aromatic hydrocarbons. Synchronous scanning ultraviolet fluorescence has been proposed as a ‘fingerprinting’ method, but is inferior to the GLC-MS analysis of biomarkers (see below).Capillary column GLC with flame-ionization detection is the method of choice for sediment aliphatic hydrocarbon analysis. The method allows a detailed description of hydrocarbon input, an assessment of the extent of weathering and degrada- tion and a measurement of concentration. The use of internal standards allows for variable losses during extraction and improves precision in relation to techniques such as infrared and ultraviolet fluorescence. Attention needs to be paid to the GLC injection technique to maximize the recovery of higher- boiling hydrocarbons (up to (&).The GLC technique, however, is not suitable for heavy residues, which are not amenable to this method. Aromatic hydrocarbons are best analysed by capillary column GLC-MS, the results normally being expressed as the individual concentrations of 2-6 ring polycyclic (PAH) com- pounds. A range of internal standards of differing boiling-point is used to improve quantitative accuracy. In this respect it is important to include fragment ions, in addition to molecular ions, in PAH quantification procedures. The GLC-MS method is highly specific. The characteristic distributions of environmentally recalcitrant tetracyclic and pentacyclic naphthenes (steranes and triterpanes; biomarkers) are used to ‘fingerprint’ spilled oils and to relate an input to particular sources.The author thanks his associates and co-workers in this field over some 15 years, particularly Pete Tibbetts, Paul Brooks, Alan Aldridge, Steve Rowland, Geoffrey Eglinton, James Maxwell, Andy Revill, Steve Killops, Simon Hird, Karl Ropkins and David Norris. This paper is a distillation of their combined expertise. Sampling Considerations in the North Sea Anthony J. Bale Natural Environment Research Council, Plymouth Marine laboratory, Prospect Place, West Hoe, Plymouth PLI 3DH The philosophy underlying sampling theory is common to a wide range of data gathering exercises, from population censuses to quality control. Essentially, the requirements are to ensure that a sample is truly representative of a particular population or situation and to be able to assess the errors associated with a particular sample.In environmental studies, in addition to ensuring that the composition of an individual sample is ‘representative’, which is essentially a practical problem, the sampling scheme must consider the variability in time and space of natural systems (Table 1). This aspect is discussed by Morris4 in relation to estuarine studies, but the underlying concepts are equally relevant to shelf seas. The consensus of Morris4 and other workers is that the fundamental requirement is to obtain a sufficient number of.samples/readings in the appropriate time- space framework commensurate with economic considerations in order to be able to evaluate the variability and precision at each level of sampling.One method of optimizing field effort, which is assuming more prominence as modelling techniques develop, is to employ mathematical modelling of the system under examin- ation. By making use of the best available information, modelling can show where the information weaknesses are and hence focus attention on the essential aspects of a field exercise. Modelling can also help to define the precision required and hence the degree of effort and investment needed to acquire the sampleddata. Sampling in the North Sea Project The sampling scheme adopted for the NERC North Sea Project (NSP) involved 15 monthly surveys of the southern North Sea between August 1988 and October 1989. Each survey took 12 d and covered a track of 3000 km. During each survey, an average of 100 vertical profiles were undertaken where instruments were deployed and samples obtained through the water column.A total of 3000 vertical profiles were taken during the 15 month survey period. This resulted in over 7500 water samples (with up to 40 determinands on each sample). Many parameters, e . g . , salinity, chlorophyll fluorescence, dissolved oxygen, were measured underway at 30 s intervals (this alone generated 500000 data sets). In addition, over 700ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 265 Table 1 Time and space scales of various features and perturbations influencing marine environmental systems (adapted from reference 4) Temporal scales Time scale Feature <hours Turbulent eddying; incomplete mixing hours-da y s Tidal influences; (advection, sediment disturbances); diurnal cycles (irradiance, biological responses) residuals; weather systems days-mont hs months-years Seasonal cycles >years Climatic changes; geological processes Spring-neap cycles (lunar month); tidal Spatial features Spatial scale Processes and feature <m Turbulence; mixing; vertical structure (sediment) m-km Surface and interval waves; eddies; biological communities; sediment types; vertical structure (water column); sandbank circulation plumes systems aspects km-10 km 10 km-1000 km > 1000 km Coastal effects; tidal excursions; estuarine Monthly averaged circulation; weather Ocean circulation; weather patterns; global net hauls for plankton and 50 sediment cores were taken. One statistic which puts this effort into perspective is that more nutrient analyses were undertaken in the North Sea during this programme than during the previous 20 years.5 The average distance between vertical profiles measured during each survey was 18 km; hence the spatial resolution obtained with this sampling grid was of the order of 90 km and, consequently, resolved the major circulatory features and the seasonal influences on the structure of the main water masses.This survey frequency clearly resolved the seasonal cycle and, at this level, the 12 d period required to sample the area was effectively synoptic. In order to examine the higher frequency occurrences and smaller features within the North Sea, a series of 2 week ‘process’ studies covering a wide range of interests were alternated with the surveys.These studies looked at estuarine plumes, frontal systems between mainly stratified and well- mixed regimes, sedimentary features such as sand waves, sandbanks and the effects of sediment resuspension into the water column and phytoplankton blooms on water chemistry. Strategic Considerations Research vessels are the workhorses of marine science but are not the only method of obtaining data or collecting samples. Ships have the advantage of taking the laboratory to the site and of allowing the scientist to react to information gained by, for example, adjusting a sampling pattern to improve resolu- tion of a particular feature. They also carry a large equipment payload. However, a ship is expensive to run, slow, can only be in one place at one time and is generally ineffective during extreme weather. Certainly, the present day marine scientist must consider various approaches to sampling ranging from optical techniques using satellites6 and aircraft with the advantage of true synopticity , to remote, autonomous sensing and logging packages attached to moorings.Moored systems give very good temporal resolution; even in extreme weather. Continuous underway sampling and analyses with towed vehicles which are programmed to undulate through the upper 100 m of the water column provide a very informative surveying technique.’ Several of these alternative approaches were used for the sampling and data gathering phase of the NSP. Other options are helicopters for rapid, quasi-synoptic sampling surveys and ships of opportunity, e .g . , commercial vessels going about their normal business. The development of autonomous robotic vehicles has been proposed for oceano- graphic studies.8 Implications for Data Handling The inevitable outcome of intensive sampling and data gathering operations is the generation of large amounts of information. Within the NSP the collection of the samples and data was jointly undertaken by 14 research and academic establishments and a co-ordinated data handling and process- ing approach was therefore developed. The outcome was a centralized database managed by the British Oceanographic Data Centre at Bidston. This approach has revolutionized the standardization and quality assurance of data and the speed with which it can be accessed. For example, during the NSP surveys each survey cruise was able to set sail armed with the contoured data plots from the previous survey with which to compare measurements and determine priorities.At sea, this approach to data processing, made practical by modern computing power, is also practised at the level of individual surveys. Continuous underway logging of as many physical and chemical parameters as possible combined with on-board data processing allows the scientist to assess and update the strategy of a particular environmental study. Conclusion Environmental systems, exhibiting variability on a wide range of time and space scales, are particularly complicated to sample with confidence. In many instances the practical sampling problems are greatly outweighed by the statistical and strategic implications of matching the sampling frequency to the scales of variability at the level of the investigation. The essential requirements can be summarized as follows: (1) accurately define the study objectives and design the sampling scheme using statistically rigorous procedures; (2) commensurate with economic and logistical considerations, take sufficient samples to resolve the variability in time and space to the precision defined above; and (3) make full use of the wide range of sampling approaches made available by modern technology. References 1 Elliott, J . M., Some Methods for the Statistical Analysis of Samples of Benthic Invertebrates, Freshwater Biological Associa- tion, Ambleside, No. 25, 1971. 2 Cochran, W. G . , Sampling Techniques, Wiley, New York, 1977. 3 Green, R. H . , Sampling Design and Statistical Methods for Environmental Biologists, Wiley, New York, 1979. 4 Morris, A. W., in Practical Procedures for Estuarine Studies, ed. Morris, A. W., Natural Environment Research Council, Swin- don, 1983, pp. 1-19. North Sea Project Report, Gaining the Measure of the North Sea, Natural Environment Research Council, Proudman Oceano- graphic Laboratory, Birkenhead, 1990. 6 Holligan, P. M., Aarup, T., and Groom, S . B . , Continent. Shelf Rex, 1989, 9, 665. 7 Aiken, J . , in Mapping Strategies in Chemical Oceanography, ed. Zirino, A., American Chemical Society, Washington, DC, 1985. NERC Annual Report, UK Continental Shelf, Natural Environ- ment Research Council, Swindon, 1990, pp. 23-27. 5 pp. 315-332. 8

ISSN:0144-557X    

DOI:10.1039/AP9912800260

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

266 ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 Equipment News Mass Spectrometer The API I LC-MS, a single quadrupole mass spectrometer version of the API I11 LC-MS-MS system, is the newest member of the API (atmospheric pres- sure ionisation) LC-MS family of high performance mass analysers which can be coupled directly to any HPLC. It was developed in response to customer demand for an instrument simpler than the API I11 to serve as a workhorse in analytical service and quality control lab- oratories. It operates with the same Macintosh computer software as the API 111. SCIEX, Division of MDS Health Group Ltd., 55 Glen Cameron Road, Thornhill, Ontario, Canada L3T 1P2. Optical Emission Spectrometer The TJA 281 time resolved optical emis- sion spectrometer allows the user to integrate selectively at any portion of a spark signal in microsecond increments. It incorporates ThermoSPEC software, which gives users access to data via a simplified screen format with extensive ‘help’ messages during operation and set- up.The TJA 281 addresses the perfor- mance and price considerations of foundry laboratories. It determines up to 61 elements in less than 30 s, allowing the user to control a melt in real time. In the makers’ performance evaluation it was found to be equivalent to the precision and accuracy values for all the certified elements in the Low Alloy Steel (NIST) standard reference series SRM Thermo Jarrell Ash Corporation, 88 Forge Parkway, Franklin, MA 02038- 3148, USA. 1761-1767. Software for Optical Emission Spectrometers Designed for the makers’ 3460 metals analyser and 3560 OE spectrometer, the OE 386 software package is ideally suited for routine quality assurance in produc- tion control environments.Based on an IBM PS-2/55 hardware platform, it includes a full range of new capabilities in result presentation, storage and trans- mission. It is also available as an upgrade package capable of modernizing many of the previously installed ARL 3460 and 3560 OE instruments. Highlights include pull-down menus and windows, password protection and analytical tasks, which are the connections between the analytical program and the operating procedures that are best for the user’s laboratory. Several options are available. ARL Applied Research Laboratories SA, En Vallaire, 1024 Ecublens, Switzerland.ICP Spectrometer The new model D dual monochromator ICP system provides exceptional analyti- cal capabilities. Each optical system uses a fixed holographic grating, with four entrance slits, and a detector array with six exit slits and photomultiplier tubes. System wavelength coverage is 165-790 nm. All spectral lines are measured in the first order. Movement between lines is Spectro model D dual mono( minimized with very accurate wavelength positioning. Direct drive to the desired wavelength is accomplished without time- consuming peak searches and the asso- ciated positioning errors, particularly at analyte concentrations close to the detec- tion limit. The system is insensitive to temperature fluctuations. Spectro A. I., Boschstrasse 10, D-4190 Kleve , Germany.ICP Spectrometers The Maxim family of inductively coupled plasma-atomic emission (ICP-AE) spectrometers provides fast measure- ments of up to approximately 200 included emission lines. This capability is derived from the new echelle/prism double monochromator coupled by fibre optics to a novel line-multiplexing detec- tion system. With densities of more than 1OI6 electrons ~ m - ~ , the new axially- viewed plasma source shows surprising atomisation efficiency, eliminating several interferences encountered in diffi- cult sample matrices. The new plasma also provides impressive measurement precision. Three line sets containing from 72 to 200 analytical lines are available, covering requirements for fast, routine measurement of up to 70 elements com- monly determined by ICP-AE spec- trometry.All three Maxim instruments can be equipped with an autosampler to provide up to 3600 determinations h-’. ARL Applied Research Laboratories SA, En Vallaire, 1024 Ecublens, Switzerland. Scanning Software for Ultraviolet- Visible Spectrophotometers Capable of scanning between 195 and 1100 nm, a new software package to :hromator ICP spectrometer enhance the scanning and data handling capacity of the makers’ PUS625 and PUS620 series instruments is compatible with any IBM PC XT or AT computer. A comprehensive set of routines includes first and fourth order derivative, mode conversion to % Tor LogA, mathematical calculations with constants and other spectra and peak zoom options. Unicam, York Street, Cambridge CB12PX. Data Management Software Model U-2000 data management software is designed to interface the Model U-2000 ultraviolet-visible double beam scanning spectrophotometer with an AT compat- ible computer.All instrument parameters are selected by moving a cursor to the appropriate option and entering the desired value. Data are collected as a function of wavelength or time and can be scale expanded during real time acqui- sition for monitoring small absorbance changes under optimum conditions. Spec- tra can be displayed individually on a full- sized screen, in as many as six separate windows, or overlaid for direct comparison. Hitachi Instruments Inc., 44 Old Rid- gebury Road, Danbury, CT 06810, USA.ANALYTICAL PROCEEDINGS. AUGUST 1991, VOL 28 267 FTIR Spectrometers and Software Four new instruments for Fourier trans- form infrared spectroscopy are announced: the Galaxy Series 3000, 5000 and 7000 and the Research Series 1, together with the U-FIRST and Time Evolved Analysis software packages.The Galaxy Series 3000 spectrometers are optimized for applications in QA, QC and college laboratories and are available in near and mid-infrared models, each with 2 cm-' resolution. The Galaxy Series 5000 instruments provide a high level of flexi- bility in the analytical laboratory with 0.75 cm-' resolution. The Galaxy Series 7000 spectrometer features 0.4 cm-' resolution with optional 0.25 cm-' resolution for study of gas phase samples and other applications where high resolution is necessary. The Research Series 1 (RS/l) spectrometer covers the near and mid- infrared range from 25 000 to 400 cm-' and features a high intensity fluid cooled source and continuously adjustable, computer controlled iris aperture for complete optimization of experimental conditions.The U-FIRST software allows any operator to begin collecting and processing infrared spectra within minutes. In standard configuration it allows command input from function keys, mouse or command line entry. It includes all routine spectral evaluation methods. The FIRST time evolved analy- sis software for GC-FTIR provides full control of infrared spectral acquisition and evaluation of the resultant spectral data. In addition, optional TEA auto- mation packages provide full method storage, set-up and recall for the HP 5890 gas chromatograph and HP 7673A auto- sampler system.Mattson Instruments Ltd., Green Farm Road, Newport Pagnell, Buckingham- shire MK16 OAL. FTIR Spectrometer The Infrascan is a low-cost stand-alone instrument which is the ideal replacement for a dispersive infrared spectrometer. Operated from a single membrane, it is suitable for the teaching or factory sup- port laboratory. It can be used in harsh environments and has a large compart- ment for a wide array of accessories such as ATR, specular reflectance and liquid ATR. It is equipped with an RS232 port. Bio-Rad Microscience Ltd., Bio-Rad House, Maylands Avenue, Heme1 Hemp- stead, Hertfordshire HP2 7TD. Spectroscopy Sampling System The Model U-3410 ultraviolet-visible and near infrared spectroscopy sampling system is for large samples, typical types of which include specially coated optics, large glass and quartz plates, complex lenses and semiconductor wafers.The standard detector is an ultraviolet- visible-NIR integrating sphere which provides maximum sensitivity and light gathering for these demanding samples. Engineered modifications to the standard large sample compartment for customized applications are available in order to expand the size or include fully automated sample handling devices compatible with the spectrophotometer. Optional computer control provides increased flex- ibility, data acquisition and application- specific report generation. Hitachi Instruments Inc., 44 Old Rid- gebury Road, Danbury, CT 06810, USA. FTIR System The compact, hermetically sealed Ana- lect Diamond-20 features enhanced optics and one of the first applications of an integrated MS-Windows 3.0 software environment to FTIR.The software incorporates symbolic icons, interactive pop-up menus and on-line manual for help assistance. For example, a spec- troscopist can simultaneously display a developing sample spectrum in a corner of the screen, write a report in another window, call up a help screen in a third window, then perform a calculation in a fourth window. Laser Precision Analytical, 17819 Gil- lette Avenue, Irvine, CA 92714, USA. Atomic Absorption Software AA-Mate is a fully integrated, menu- driven, easy-to-use software and hard- ware package that records peak heights, graphs and calculates sample results, all at the push of a few PC buttons. The user selects the standards and blanks to use in the calculation and AA-Mate automati- cally selects the calculation method and updates the CUSUM.AA-Mate works on any AA instrument having analog output capabilities with any voltage between 0 and 1. It runs on IBM PC/XT/AT and compatibles with 640k RAM, and it stores data in ASCII file format. Software Excellence Inc., 700 North Milwaukee Avenue, Building 105 Suite 178, Vernon Hills, IL 60061, USA. Spectrofluorimeter The Shimadzu RF5001-PC scanning spec- trofluorimeter offers direct PC control for a wide range of applications including intracellular Ca2+, enzyme kinetics and ultrasensitive quantification. Combined with an extensive range of accessories, it enables the user to have an HPLC detec- tor one minute, a thermostatted stirred enzyme reaction the next and accurate quantification the next, with no need to change accessories.V. A. Howe and Co. Ltd., Beaumont Close, Banbury, Oxfordshire OX16 7RG. Liquid Chromatography-Mass Spec- trometry System The M-1000 LC/QMS features atmos- pheric-pressure chemical ionization Hitachi M-1000 LCIQMS268 ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 (APCI) and electrospray ionization (ESI). APCI offers high sensitivity, and a variety of ion-molecule reactions can be readily utilised for added sensitivity. Because ESI can produce multiple charg- ing of analyte species, high relative mol- ecular mass compounds can be analysed by using a nominal range analyser. As the M-1000 LC/QMS APIC interface accom- plishes ionization with the aid of a corona discharge under atmospheric pressure, the need for special traps such as liquid nitrogen is eliminated.Hitachi Instruments Inc., 44 Old Rid- gebury Road, Danbury, CT 06810, USA. Gas Chromatograph The GM 295 gas chromatograph is being used by gas suppliers in the United States to provide high purity gases for the semiconductor industry. It provides re- liable analysis of trace gas impurities in the ppb range. Gow-Mac Instrument Co. (UK) Ltd., Gow-Mac House, P.O. Box G13, Gill- ingham, Kent ME7 4HA. Liquid Chromatography Methods Development System The LC Analyst Expert Methods Deve- lopment System designed for computer aided chromatographic research is a com- bination of HPLC instruments and all the software necessary for developing sepa- rations. System components include the 620 quaternary pump, ISS-200 auto- sampler and LC-235 diode array detector. Also featured are a simple user interface with mouse control, sophisticated data handling, history file reports for complete documentation of methods and real-time changes, and automatic start-up and shut- down.A brochure is available. The Perkin-Elmer Corporation, 761 Main Avenue, Norwalk, CT 06859-0177, USA. Data Acquisition System for HPLC A multi-channel PC based data acqui- sition system is available. Its hardware consists of up to four channels of data acquisition and gradient pump control. Operating under microsoft windows, the software offers a wide range of calculation options, and results can be exported directly to spreadsheet applications, such as Excel, for customized reports. Sophis- ticated algorithms can automatically opti- mize integration.The system also allows on-screen editing of chromatograms for rapid method development. The software operates within GLP guidelines. A wide range of calibration routines are available. Applied Chromatography Systems Ltd., The Arsenal, Heapy Street, Mac- clesfield, Cheshire SKll 7JB. Autosampler and Derivatization System The 760/160 automatic sampling and de- rivatization system incorporates up to 160 samples, and as little as 5 p1 of sample is required. Capable of injecting from 1 to 250 1-11, the sample needle becomes part of the loop ensuring minimal sample loss. The unique vial shaker ensures excellent results with dilutions, standard additions and pre-column derivatization for amino acid determinations. Applied Chromatography Systems Ltd., The Arsenal, Heapy Street, Mac- clesfield, Cheshire SKll 7JB.Syringe for Headspace Sampler The CTC headspace sampler replaces the Carlo Erba HS250 autosampler. For this new instrument Hamilton have developed a special syringe equipped with a lateral orifice behind the scale, allowing flushing from the near side. The new 1002 syringe is available with a fixed needle (LTSN) or with a h e r tip (LT). The LT version can be fitted with a standard (gauge 2 2 point style 5) hypodermic needle. V. A. Howe and Co. Ltd., Beaumont Close, Banbury, Oxfordshire OX16 7RG. Software Image System The SW2000 software image system has been extended to give a more versatile approach to image analysis. It is capable of evaluating DNA or RNA ethidium bromide gels, protein coomassie blue or silver stained gels, autoradiographs and TLC plates.The package now performs a greater range of peak or band analysis to give a more varied arrangement of results. Ultra-Violet Products Ltd. , Science Park, Milton Road, Cambridge CB4 4FH. Gel Documentation System The GDS2000 gel documentation system has been extended to include the ability to visualise other gel media. A new filter specially designed for protein gels has been developed to improve the system and give sharper, more accurate results for protein gel imagery. The GDS2000 is now supplied with filters for DNA or RNA and the new protein filter as a standard package. The system can be used in conjunction with the SW2000 software package for analysis of all types of gel media.Ultra-Violet Products Ltd., Science Park, Milton Road, Cambridge CB4 4FH. Software for Metals Analysis TAP 2 TraceTalk software for deter- mining the concentrations of nine metals on the TraceLab trace element laboratory can run on any PC and contains standard methods for quantifying Cd, Cu, Hg, Pb, Sb, Se, Sn, T1 and Zn. Developed for pure metals solutions, the methods have been devised for concentrations below the 100 ppb level. These methods can be used as a basis for developing applications in a wide range of sample matrices. Radiometer Ltd., The Manor, Manor Royal, Crawley, West Sussex RHlO 2PY. Water Analyser The Model 1505 automated laboratory water analyser is capable of total organic carbon, purgeable organic carbon and total carbon measurement from 100 ppb to 2000 ppm.It uses a high temperature reaction system for the combustion of all organic species at 900 "C. Ionics UK Ltd. , Carrington Business Park, Carrington, Urmston, Manchester M314DD. Water Analysis System Metrohm have developed a comprehen- sive analysis system based on their 670 Titroprocessor, which gives precise and accurate information on pH, conduc- tivity, p and m values, total alkalinity, chloride, Mg, Ca and total hardness on a single sample in about 10 min. V. A. Howe and Co. Ltd., Beaumont Close, Banbury, Oxfordshire OX16 7RG. Silver Reclamation Service Ingold UK, part of Mettler-Toledo, is launching a service in the UK to reclaim pure silver used in industrial pH elec- trodes. For each electrode received Ingold will donate f l to charity plus the value of all the silver collected.Monies collected under the scheme will be donated to the RNLI, which has been supported throughout 1990 by other Mettler-Toledo schemes. Ingold, Mettler-Toledo Ltd., 64 Boston Road, Beaumont Leys, Leicester LE4 1AW. pH/ISE Meters The new Orion line of pH/ISE meters ranges from splash-resistant , rugged port- able models with true one-handed oper- ation to state-of-the-art benchtop pH/ concentration meters featuring autoblank correction, incremental techniques and dual electrode inputs. All meters feature enhanced capabilities for pH/ISE measurements. A brochure is available. Orion Research Inc., The Schrafft Centre, 529 Main Street, Boston, MA 02129, USA. Concentration Monitors A new range of instruments for monitor- ing and controlling solution concentration are microprocessor based and use elec- trodeless conductivity sensors.Both sol- ution temperature and percentage con- centration figures are continuously displayed. Percentage concentration is calculated from data held in memory which is unique to the chemical being monitored. Standard data are available.ANALYTICAL PROCEEDINGS, AUGUST LTH Electronics Ltd., Eltelec Works, Chaul End Lane, Luton, Bedfordshire LU4 8EZ. Karl Fischer Cell Conventional coulometric Karl Fischer cells in which the anode and cathode compartments are separated by a dia- phragm are prone to the formation of substances oxidizable by iodine, resulting in erroneous moisture determinations (Metrohm Information 3/90, Volume 19, pages 3-7).Metrohm have developed a cell which does not create these inter- fering substances; it is also a simpler approach which does not require a dia- phragm and uses a single reagent. V. A. Howe and Co. Ltd., Beaumont Close, Banbury, Oxfordshire OX16 7RG. Karl Fischer Volumetric Reagent Hydranal Composite 1 is a volumetric reagent capable of determining as little as 50 pg of water. The accuracy of Compo- site 1 has been demonstrated in tests carried out on chloroform samples. Of 10 samples tested, results showed a mean of 0.005 44% being achieved, with a standard relative deviation of only 4.3%. The new reagent is fast, gives stable end- points and is pyridine-free. Hoechst UK Ltd., Riedel-de Haen Technical Centre, Walton Manor, Wal- ton, Milton Keynes MK7 7AJ.Combined Measurement and Calib- ration Unit The Dulcometer is a measurement and calibration device capable of measure- ment and simulation over a pH range of 0-14 and redox 1000 mV. Self-calibration is carried out via its microprocessor at a high input resistance of 1OI2 Q. The control is via a small keyboard and data are displayed on a large LCD screen. The Dulcometer is supplied ready-to-use in a tough carrying case complete with buffers, cables, probes and a neck strap for hands-free operation. ProMinent Fluid Controls (UK) Ltd., Queens Drive, Newall, Burton on Trent, Staffordshire DEll OEG. Modules for Thermal Analysis A new motorised furnace has been intro- duced on all the TMA modules for the makers' SSC5200 thermal analysis system. Advantages include increased reproducibility of data, added safety and ease of use.Also available for the SSC5200 system is a horizontal differen- tial balance, adding to the thermogravi- metry-differential thermal analysis capa- bilities. The balance directs gas flow perpendicular to the weight detection direction to assure stable measurements by reducing the influence of gas flow, chimney effects and convection, and it allows simultaneous TGA and DTA test- ing from a single sample. 1991, VOL 28 Seiko Instruments USA Inc., 2990 West Lomita Boulevard, Torrance, CA 90505, USA. Scintillation Counting Cocktails Second-generation liquid scintillation counting cocktails exhibit improved safety while maintaining high counting efficiencies. Lumagel-Safe and Lumasafe cocktails are both classified as non-flam- mable, non-toxic and non-volatile.They have flash points of 150 "C and are based on diarylalkanes, which are readily bio- degradable. Lumasafe is for aqueous and non-aqueous samples, such as salt and buffer solutions, body fluids, acids and bases. Lumagel-Safe takes any sample accepted by classical universal cocktails without major changes in sample preparation. Both products are listed in a new 48-page LSC catalogue. Rhbne-Poulenc Laboratory Products, Liverpool Road, Eccles, Manchester M30 7RT. Particle Size Analyser Dry Powder Module The Coulter LS Series analyser's dry powder module (DPM) provides ease in evaluating particle size distributions of dry powders by laser diffraction. It handles both free-flowing and non-free- flowing powdered materials and elimi- nates concern over the effect of diluents on sample integrity.Sample analysis time is 30 s and, using a Coulter LS130, particles in the range 0.4-900 ym can be captured without changing lenses, con- figuration or range settings. Coulter Electronics Ltd., Northwell Drive, Luton, Bedfordshire LU3 3RH. Conical-bottom Centrifuge Bottles Nalgene conical-bottom centrifuge bottles, 175 ml capacity, for low and high speed rotors are available in three resins. The polyallomer bottle is translucent and has excellent chemical resistance. The polycarbonate bottle is transparent and offers excellent mechanical strength. The disposable polystyrene bottle is gamma radiation sterilized. Nalge Co., 75 Panorama Creek Drive, Box 20365, Rochester, NY 14602-0365, USA.Centrifuges and Accessories The compact, transportable Optima TLX ultracentrifuge, which operates up to 120 000 rev min-', provides benchtop convenience with the performance of the Optima L floor-standing models. The TLX uses standard wall current and can be operated under a fume hood. A full complement of rotors are available. The GS-6 range of centrifuges are available in both benchtop and kneewell designs. All are available with and without refriger- ation systems. The kneewell version can easily be moved. All the GS-6 centrifuges 269 can accommodate two fixed angle rotors, together with the GH-3.7 swinging bucket rotor, which can spin a wide range of tubes and bottles. The makers' Aerosolve canisters, designed for the containment of hazardous materials, are available for use with the buckets.A new re-usable 230 ml conical bottle, ideal for pelleting biological materials, cell membranes, sub-cellular organelles and bacteria, has been added to the makers' range. Avail- able in polypropylene or polycarbonate , the bottle has a polypropylene screw cap and moulded graduations, and it can be spun in Aerosolve cannisters. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Buck- inghamshire HP12 4JL. Freeze Dryer The Christ Alpha 1-4 is a benchtop freeze dryer which will condense up to 4 kg of ice in 24 h. A full range of accessories is available. V. A. Howe and Co. Ltd, Beaumont Close, Banbury, Oxfordshire OX16 7RG. Tube Furnace The UTF Mk. I1 large diameter tube furnace incorporates a framework in which the furnace assembly is supported at its gravitational centre.This permits the furnace to be set and firmly locked at any angle between the horizontal and vertical. The tubular work area of the furnace assembly has been designed to accept reaction tubes of up to 130 mm internal diameter and to provide maxi- mum operational temperatures of 1200 or 1600 "C, which can be profiled through the work area under the control of an external programmable module. Lenton Thermal Designs Ltd., Unit C2, Valley Way, Welland Industrial Estate, Market Harborough, Leicester- shire LE6 7PS. Tube Furnace for Use in a Glove Box A water cooled, high-temperature tube furnace has been developed to enable it to be located in the confines of a glove box.It has been designed to maintain its external temperature at a sufficiently low level to prevent damage to gloves. Exter- nal to the furnace assembly is a housing for the transformer required by the molybdenum disilicide heating elements, and a free-standing cabinet containing the furnace's programmable controller and overtemperature protection module. Lenton Thermal Designs Ltd., Unit C2, Valley Way, Welland Industrial Estate, Market Harborough, Leicester- shire LE6 7PS. Scanning Microscope The JSM-5400 digital scanning electron microscope is a general purpose instru- ment, suitable for fundamental research270 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 and production-line quality control. Easy to operate, it can be fitted with high accuracy WDS and EDS spectrometers for elemental analysis.It features high resolution to 4 nm and magnifications from ~ 1 5 to ~ 2 0 0 000. Operations from vacuum pumping to image observations and photography are completely automated. Jeol (UK) Ltd., Jeol House, Silver Court, Watchmead, Welwyn Garden City, Hertfordshire AL7 1LT. Mains Distribution System The Metrohm 615 mains distribution system can supply up to 5 or 6 different instruments from a single wall socket. In addition to acting as a distributor it isolates the apparatus from mains-borne interferences such as noise caused by switching peaks, etc. V. A. Howe and Co. Ltd., Beaumont Close, Banbury, Oxfordshire OX16 7RG. Software for Personal Computers EasyLims software for the personal computer offers large LIMS productivity to the smaller but growing laboratory.It runs on any suitable IBM PC or PS/2 computer. Based on microsoft windows, it is easy to use. With a powerful Point and Paint report generator, it includes in- tegrated spreadsheet, statistics and 3-D graphic capabilities. Single-user and network versions are available. A bro- chure is available. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Buck- inghamshire HP12 4JL. Storage Containers The BenchTidy storage container is manufactured from 3 mm thick clear acrylic, providing visible and functional storage of small laboratory and office items. Available in three convenient sizes (two, three and four compartment), the container has a hinged lid and special bumper feet to prevent slipping. Radleys, Shire Hill, Saffron Walden, Essex CBll 3AZ.Sharps Disposal Pouch The Biohazard sharps disposal pouch is made of solid paperboard which opens to an oval shape by folding in the bottom flaps. After inserting objects, such as needles, scalpel blades and discarded ampoules, the top flaps are closed and locked in place, ready for disposal. The steel wire, epoxy coated safety pouch stand provides a stable support. Radleys, Shire Hill, Saffron Walden, Essex CBll 3AZ. Benchtop Beta Shield The Nalgene U-shaped beta shield is made of durable, transparent, 10 mm acrylic. It can function as a stand-alone unit, a benchtop carrier transporting radioactive material in the laboratory or a waste container. It is featured along with other products in the 1991 Nalgene labware catalogue. Nalge Co., 75 Panorama Creek Drive, Box 20365, Rochester, NY 14602-0365, USA. Square Bottles The Nalgene square bottle has been introduced in a new 2 1 size in polycar- bonate and polyethylene terephthalate copolyester.Nalge Co., 75 Panorama Creek Drive, Box 20365, Rochester, NY 14602-0365, USA. Fluorinated Containers A new line of Nalgene fluorinated jerri- cans, transportation bottles and carboys have a fluorocarbon surface inside and outside to provide improved barrier properties, reducing solvent absorption and penetration. They are suitable for use with most acids, alkalis and aggressive organic solvents. Nalge Co., 75 Panorama Creek Drive, Box 20365, Rochester, NY 14602-0365, USA. Improved Specification for Acry lamide Acrylamide Grade 1 and acrylamide ‘Electran’ have been respecified to meet the highest quality requirements, while a new grade, Acrylamide Routine, has been introduced for less demanding requirements. Acrylamide 1 has been upgraded to create the new Grade 1- Molecular Biology Grade.Acrylamide ‘Electran’ has been respecified to improve the quality further and Acrylamide Elec- tran ‘Routine’ is a completely new specification. BDH Laboratory Supplies, Poole, Dorset. New Showroom for Analytical Supplies A new showroom and purpose-designed administration office has been opened in Little Eaton, Derby. A full catalogue is available showing the 4000 consumable lines and 2000 BDH chemical titles in stock. Analytical Supplies Ltd., Duffield Road, Little Eaton, Derby DE2 5DR. Stack Sampling Service To assist companies to comply with The Environmental Pollution Act and to assess their emissions, the National Occu- pational Hygiene Service, a registered charity, has recently expanded its stack sampling service.The on-site service is backed by extensive in-house laboratory support, including analytical research and method validation. The National Occupational Hygiene Service Ltd., Skelton House, Manchester Science Park, Lloyd Street North, Man- Chester M15 4SH. Literature Three brochures describe the MAT 95 Q mass spectrometer system, the TSQ 700 tandem quadrupole mass spectrometer for high performance GC or LC-MS- MS-DS and an electrospray system for the TSQ 700. Finnigan MAT Ltd., Paradise, Hemel Hempstead, Hertfordshire HP2 4TG. A brochure presents the Graphite Fur- nace Capacitively Coupled Plasma (GFCCP), which combines the advan- tages of graphite furnace atomic absorp- tion spectrometry and inductively coupled plasma atomic emission spec- trometry without the inclusion of their individual disadvantages.Aurora Instruments Ltd., 3031 Main Street, Vancouver, BC, Canada V5T 3G6. A brochure gives information on the ICP 2000 simultaneous plasma emission spectrometer. Baird Corporation Analytical Division, 125 Middlesex Turnpike, Bedford, MA 01730-1486, USA. A brochure gives details of the HP 8452A diode-array spectrophotometer. Litera- ture is also available on automated disso- lution testing with this instrument. Hewlett-Packard S.A., 150, route du Nant d’Avril, CH-1217 Meyrin 2, Geneva, Switzerland. Two brochures give information on chro- matography-mass spectrometry systems: ‘HP presents GC-MS for Every Lab’ and systems for target compound analysis’.Hewlett-Packard S.A., 150, route du Nant d’Avril, CH-1217 Meyrin 2, Geneva, Switzerland. ‘Highest-productivity GC-LC-MS The INCOS XL versatile benchtop GC- LC-MS-DS system and the ITS40 ion trap UltraTrace GC-MS-DS system are described in two brochures. Finnigan MAT Ltd., Paradise, Hemel Hempstead, Hertfordshire HP2 4TG. A product brief describes the use of optimization software for HPLC method development. Hewlett-Packard S.A., 150 route du Nant d’Avril, CH-1217 Meyrin 2, Geneva, Switzerland. Volume IX, Number 6, of the Supelco Reporter includes articles on 100 m Petro- col DH columns for petroleum analysis, ORBO-1000 sampling cartridges for sam- pling many airborne pesticides and poly-ANALYTICAL PROCEEDINGS, AUGUST 1991.VOL 28 27 1 chlorinated biphenyls in homes and public buildings, Supelclean LC Florisil tubes for quantifying PCBs in transformer oil, and Ambersorb adsorbents for removing volatile organic compounds from humid air. It also explains how gas pressure regulators work. Supelco Inc., Supelco Park, Bellefonte, PA 16823-0048, USA. Volume X, Number 1, of the Supelco Reporter features a new Petrocol EX2887 capillary column for extended simulated distillation analyses on heavier petroleum fractions. It also discusses Carboxen 1000 packing for the analysis of permanent gases, light hydrocarbons and light polar compounds. Other subjects include OMI- 1 indicating purifier tubes with Nanochem resin for semiconductor processes, PTE-5 QTM capillary columns for rapid screening of hazardous waste samples, and a thermal extraction system for quantification of leaking underground fuel tank hydrocarbons.Supelco Inc., Supelco Park, Bellefonte, PA 16823-0048, USA. A brochure gives details of a large range of low cost replacement HPLC source lamps. Lamps are available from the same companies which supply the HPLC detec- tor manufacturers, but at prices up to 50% lower. HPLC Technology Ltd., Wellington House, Waterloo Street West, Maccles- field, Cheshire SKll 6PJ. The Pyramid Chromatography Manager, a user-configurable data acquisition and analysis system, is described in a brochure. Axxiom Chromatography Inc. , 11988 Challenger Court, Moorpark, CA 93021- 7122, USA.A brochure gives details of the PeakTrac peak detector-autozero module. Axxiom Chromatography Inc., 11988 Challenger Court, Moorpark, CA 93021- 7122, USA. A data sheet describes numerous features and benefits of the Model U-2000 enzyme kinetics data system. Hitachi Instruments Inc., 44 Old Rid- gebury Road, Danbury, CT 06810, USA. A new series of books reports the most recent advances in the science and tech- nology of the low-temperature plasma. Volume 3, ‘Advances in Low-Tempera- ture Plasma Chemistry, Technology, Applications’, includes reports ranging from presentations of plasma science to descriptions of plasma-process appli- cations, such as the synthesis of advanced materials. Technomic Publishing AG, Mission- strasse 44, CH-4055 Basel, Switzerland. Two data sheets highlight instrumen- tation designed for Good Laboratory Practice compliance: ‘The PUS730 Series Ultraviolet-Visible Spectrometer in the GLP Environment’ and ‘Quality and Accreditation Standards: A Comparative Review’. Philips Analytical, York Street, Cam- bridge CB12PX. A data sheet describes how the MAX 5 portable combustion efficiency analyser can make it easy to maximize the efficiency of boilers, furnaces, fireboxes and any commercial or industrial combus- tion process. Teledyne Analytical Instruments, The Harlequin Centre, Southall Lane, South- all, Middlesex UB2 5NH. Literature describes the use of Ready Cap and Ready Filter solid scintillator prod- ucts. Ready Cap is used for counting soluble radioactive dose standards of the type found in receptor saturation and competition assays. Ready Filter can be used in place of conventional filters for separation of bound from free radioactive ligand in membrane or whole-cell recep- tor assays. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Buckinghamshire HP12 4JL. A brochure gives details of the Optima range of untracentrifuges and accessories, as well as the GS-6 centrifuges. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Buck- inghamshire HP12 4JL. ‘Focus on Synergy’, Volume 11, Number 1, features EasyLims, LAB Manager, HPLC System Gold, HPCE P/ACE systems, the DU-7000 Series ultraviolet- visible spectrophotometer and diagnostic reagents. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Buck- inghamshire HP12 4JL. A brochure details EasyLIMS software for the personal computer. Based on Microsoft windows, the software runs on any suitable IBM PC or PC/2 computer. Beckman Instruments Inc., 2500 Har- bor Boulevard, Fullerton, CA 92634- 3100, USA. A 1991 ‘New Product Supplement’ high- lights all recent additions to the Com- pany’s 1990 catalogue of electrical and electronic equipment. Livingston Hire, Livingston House, 2-6 Queens Road, Teddington, Middlesex TWll OLB.

ISSN:0144-557X    

DOI:10.1039/AP9912800266

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 27 1 Analytical Division Honours At its meeting held on May Sth, 1991, the Analytical Chemistry Silver Medals: Dr. Council of the Analytical Division J. Marshall (ICI C and P Division, approved the following recommendations Wilton) and Dr. J. K. Nicholson (Birk- from its Honours Committee. beck College, London). Nineteenth and twentieth Society for Twenty-third Analytical Division Dis- tinguished Service Award: Dr. A. H. Thomas (National Institute for Biological Standards and Control, London). Schools Lecturer for 1992/3: Dr. R. D. Snook (University of Manchester Insti- tute of Science and Technology).

ISSN:0144-557X    

DOI:10.1039/AP9912800271

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

272 ANALYTICAL PROCEEDINGS, AUGUST 1991, VOL 28 Robert Boyle Medal in Analytical Chemistry Nominations are invited for the award of the Robert Boyle Medal in Analytical Chemistry. It is a gold medal, awarded biennially, and is the Analytical Divi- sion’s most prestigious award to an analy- tical scientist working overseas. The Rules governing the award are as follows: 1. The award of the Robert Boyle Medal in Analytical Chemistry will normally be considered biennially by the Honours Committee, acting on behalf of the Council of the Analyti- cal Division of the Royal Society of Chemistry. 2. Members of the Honours Committee shall not be eligible for any of the awards within its remit during their period of service. 3. Candidates should normally be resi- dent outside the UK and the major part of the work cited for the award should have been done outside the UK.There is no restriction on nationality. 4. The aim of the award is to enhance the prestige of analytical science, particularly in the regard of scientists in other disciplines. This aim may best be fulfilled by making the award to a recognized analytical scientist rather than to someone, no matter how distinguished, in another field. 5. The merits of a particular candidate may be brought to the notice of the Honours Committee by or through any Member of the Council of theANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 273 Analytical Division by letter addressed to the President of the Division. The letter should be accom- panied by a supporting statement of the outstanding contributions made by the candidate.6 . The award shall be made on an over- all assessment of the candidate’s con- tribution to all aspects of analytical chemistrykience (research, practice, teaching, liaison between govern- ment service, industry and academia, promotion of and service to science through national and international bodies and institutions, etc.). Con- sideration will be given to the full impact of his or her work, which should have been recognized internationally. 7. The Honours Committee shall be at liberty to request from either candi- dates or sponsors additional infor- mation on any candidate recom- mended to it. 8. An award shall not be made if the attainments of the candidates cur- rently nominated do not reach the required standard. 9. The decision of the Council of the Analytical Division shall be final. 10. Any alterations to these Rules shall be subject to the approval of the Council of the Analytical Division. Recommendations for the next award should be made by or through a member of AD Council and then addressed to The Secretary, Analytical Division, The Royal Society of Chemistry, Burlington House, Piccadilly, London W1V OBN, by September 30th, 1991.

ISSN:0144-557X    

DOI:10.1039/AP991280272c

出版商:RSC    

年代:1991

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1991. VOL 28 273 New British Standards BS 490: Conveyor and Elevator Belting. Part 11. Methods of Test for Safety. Section 11.1 Laboratory Flame Tests. Section 11.4. Determination of Electrical Conductivity. BS 684: Methods of Analysis of Fats and Fatty Oils. Part 1. Physical Methods. Section 1.12. Determination of Dilatation. Part 2. Other Methods. Section 2.35. Analysis of Gas Chromatography of Methyl Esters of Fatty Acids. Section 2.45. Determination of Polar Compounds Content. BS 718: Density Hydrometers. BS 1545: Liquid Toilet Soap. BS 1715: Analysis of Soaps. Part 1. General Introduction, Sampling, and Test for Presence of Synthetic Anionic- active Surface Active Agents. Part 2. Quantitative Test Methods. Section 2.9. Method for Determination of EDTA Content.BS 1911: Hard Soap. BS 1912: Soap Flakes. BS 1913: Soft Soap. BS 1914: Toilet Soap. BS 2000: Methods of Test for Petroleum and Its Products. Part 40. Oxidation Stability of Gasoline (Induction Period Method). Part 105. Recovery of Bitu- minous Binders by Dichloromethane Extraction. Part 107. Sulphur in Petro- leum Products (Lamp Method). Part 182. Acidity (Inorganic) of Petroleum Pro- ducts (Colour Indicator Titration Method). BS 2646: Autoclaves for Sterilization in Laboratories. Part 2. Guide to Planning and Installation. Part 4. Guide to Maintenance. BS 3517: Methods for Thermal Shock Tests on Laboratory Glassware. BS 3762: Analysis of Formulated Deter- gents. Part 3. Quantitative Test Methods. Section 3.4. Method for Determination of Lower Molecular Cationic-Active Matter.BS 3908: Methods for the Sampling and Analysis of Lead and Lead Alloys. Part 9. Sulphur in Lead and Lead Alloys. BS 4129: Specification for Welding Primers and Weld-through Sealants, Adhesives and Waxes for Resistance Welding of Sheet Steel. BS 4146: Methods for Sampling Oilseeds. BS 4289: Methods for Analysis of Oil- seeds. Part 1. Preparation of Test Sample. BS 4376: Electrically Operated Blood Storage Refrigerators. Part 1. Specifica- tion for Closed Reach-in Types. BS 4405: Liquid Soap. BS 5350: Methods of Test for Adhesives. Part B8. Determination of Viscosity. BS 6068: Water Quality. Part 1. Glossary. Section 1.7. An Additional 47 Terms. Part 2. Physical, Chemical and Biochemi- cal Methods. Section 2.12. Determination of Phenol Index: 4-Aminoantipyrine (4- Aminophenazone) Spectrometric Meth- ods After Distillation. Section 2.38.Methods for the Determination of Total Chromium by Atomic Absorption Spec- trometry. Section 2.39. Method for the Determination of Sulphate Using Barium Chloride and Gravimetry. BS 6664: Flashpoint of Petroleum and Related Products. Part 5. Method for Determination of Flashpoint by Pensky- Martens Closed Tester. BS 6829: Analysis of Surface Active Agents (Raw Materials). Part 0. General Introduction. BS 7011: Consumable Accessories for Light Microscopes. Part 2. Slides. Section 2.2. Specification for Materials and Quality of Finish. Part 3. Cover Glasses. Section 3.2. Specification for Materials and Quality of Finish. BS 7079: Preparation of Steel Substrates Before Application of Paints and Related Products. Part 0. Introduction. BS 7118: Measurement of Fluid Flow: Assessment of Uncertainty in the Cali- bration and Use of Flow Measurement Devices. Part 1. Linear Calibration Relationships. BS 7392: Method for Determination of Distillation Characteristics of Petroleum Products.

ISSN:0144-557X    

DOI:10.1039/AP9912800273

出版商:RSC    

年代:1991

数据来源: RSC