ISSN:0144-557X    

DOI:10.1039/AP98926FX017

出版商:RSC    

年代:1989

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ANPRDI 26(5) 149-176 (1989) Proceedings of the Analytical Division of The Royal Society of Chemistry 149 Annual General Meeting of the Analytical Division 149 Reports of Meetings: Flow Analysis 150 Obituary 152 SUMMARIES OF PAPERS 152 Electrochemical Sensors 152 154 'Immunosensors Based Upon Direct Measurement of Surface Binding: Fundamental Chemical Limitations' by M. J. Eddowes 'ISFET-based Enzyme Sensors for Urea: Enzyme-modified ISFETs and Column-immo- bilked Enzyme Flow Injection Analysis' by G. K. Chandler, J. R. Dodgson and M. J. Eddowes 157 Research and Development Topics in Analytical Chemistry 157 159 'Flow Injection Determination of Sulphate in High Ionic Strength Media' by Andrew B. Marsden and Julian F. Tyson 'Laser Ablation System for Solid Sample Introduction Into the Inductively Coupled Plasma' by S. A. Darke, S. E. Long, C. J. Pickford and J. F. Tyson 161 Environmental Monitoring and Modelling 161 162 'Assessment of Hazards From Nuclear Facilities' by G. C. Meggitt 'Modelling of Radioactivity in the Environment-From Now to Eternity?' by David R. Williams 165 Equipment News 170 SAC 89: Workshops 170 Publications Received 171 Analytical Division Presentations 173 Conferences and Meetings 175 Courses 176 Analytical Division Diary Typeset and printed by Black Bear Press Limited, Cambridge, England May 1989 Analytical Proceedings CONTENTS

ISSN:0144-557X    

DOI:10.1039/AP98926BX019

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年代:1989

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ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 149 Reports of Meetings Flow An a I ysis Report on the Division meeting at the Scientific Societies’ Lecture Theatre, London February 8-9, 1989 It is often felt that a scientific meeting on a single topic generates more ideas and enthusiasm than a major congress cover- ing many subjects. This Flow Analysis meeting gave support to this notion and was a very successful scientific occasion. The programme was the last arranged in detail for the Division by Dr. Denys Coomber. He can be well pleased with this swansong and his lecturers (excluding the writer!) gave him excellent support by being uniformly immaculate time-keep- ers, good speakers and presenters of clear slides (and, in two cases, including very striking demonstrations). The four Ses- sion Chairmen also played important parts by encouraging useful and dynamic discussion after each lecture.Add to this the comfortable surroundings, the usual perfect organisation and pleasant buffet lunches, and you have a very congenial and stimulating two days. The lectures concentrated on Flow Injection Analysis (FIA). This technique was only introduced into the UK at the famous SAC Conference in Birmingham in 1977, and so has made much progress in a relatively short period. Recent advances in the field as a whole were highlighted by Professor Miguel Valcarcel of Cordoba, Spain, in an introductory lecture (his ninth lecture in a rapid 15-day tour of the UK), which presented a dazzling array of new ideas and applications. Inevitably, some of the innovations described raised questions that were not fully answered in the formal sessions, but this excellent lecture entirely served its purpose in providing a thought provoking and intensely interesting start.The interest was fully maintained by Professor Alan Townshend’s survey of the use of packed reactors in FIA: the ease and versatility of their application was very evident, Alan describing systems varying from very simple oxidation and reduction reactions in inorganic analysis to enzyme re-cycling methods. It has been a matter of some disap- pointment that FIA has not been more widely applied in “real world” analyses, especially in clinical chemistry, where the need for automation is so apparent. Ber- nard Rocks of the Royal Sussex County Hospital in Brighton (and one of five speakers at the meeting who are past or present researchers at Loughborough University) explained why FIA has not been used in many clinical laboratories, but also showed that the difficulties could be overcome by good instrument design and engineering.Like Dr. Fielden later in the programme, he emphasised the need for ultra-reliable computer controlled equipment. The first day’s programme finished with two more Loughborough presentations: Dr. Julian Tyson’s charac- teristically clear and thoughtful lecture highlighted the use of peak width measurements in FIA, exemplified in the area of atomic spectroscopy. His demon-150 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 stration of peak dispersion in an ordinary slide projector was a very striking one.Dr. Arnold Fogg made a wealth of important electrochemical applications of FIA very clear (even to me!), and his talk stimulated much discussion on “reverse FIA” and double peaks. Two papers on FIA in biochemistry started the second day’s proceedings, my own discussion of homogeneous drug - protein binding studies and hetero- geneous immunoassay methods being fol- lowed by a stimulating critical evaluation of enzyme and immuno-sensors by Dr. Mark Eddowes of Thorn - EMI. In each of these sensor types it was clear that flow methods offered at least partial solutions to problems such as reconciling sensor response time and sensitivity. Dr. Peter Fielden of UMIST then gave an excellent description of how FIA methods must be made more robust before they can be used in genuine industrial applications such as process and effluent monitoring and quality assurance. His own research had obviously contributed much in this area, and his comments on components of FIA hardware were of great value.The final session maintained our interest to the very end. Dr. Mike Har- riott’s description of his Belfast work on FIA - solvent extraction showed that the inherent difficulties could be overcome with care and patience. In the use of ion pairing agents such as Brilliant Green, the guiding hand of the President could clearly be seen, and the methods des- cribed were successfully applied to real samples, steels in this instance. Finally, Dr. Paul Worsfold introduced and demonstrated a concept that must have been new to many in the audience: microemulsions.These systems are a sort of half-way house between micelles and macroemulsions. They are optically trans- parent and quite stable, and obviously offer a wealth of analytical opportunities (not only in FIA), such as environmental effects on spectroscopic properties and enhanced solubility of non-polar mole- cules. So it was no surprise that most of the audience stayed to the very end of this fascinating meeting. Only one regret-is it not sad that a meeting on a very interesting topic, with lecturers that include most of the relevant UK research- ers as well as a leading analytical chemist from overseas (thanks again for organis- ing everything, Denys), can only attract 45-50 delegates? Small wonder that the Division is looking at attendance at its London meetings: what more can the members want? I can only urge those who did not make it to look out for the summaries to be published in Analytical Proceedings.J. N. MILLER Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire LEI 1 3 TU Winter Conference on Flow Injection Analysis: Orlando, Florida, January 5-7, 1989 Reflecting the increased interest, applica- tion and utilisation of Flow Injection Analysis (FIA) in areas extending from use in basic research, over routine appli- cations in chemical, clinical and phar- maceutical laboratories, to idon-line monitoring of industrial processes, several international FIA conferences and symposia have been organised and drawn attendance from more than 40 countries.Although a significant number of the more than 2200 FIA papers which have so far been published in interna- tional periodicals are the fruits of Ameri- can research groups, it is nevertheless true that FIA has been met with much less enthusiasm in the US than in Europe, and indeed Asia, where notably Japan and China are engaged in advanced and pro- lific research activities. This lack of interest or understanding of the potentials and capabilities of FIA was amply demon- strated last year at the “Flow Analysis IV Conference” in Las Vegas, USA, where less than one third of the contingent of delegates from 35 countries were Ameri- cans. In order to remedy this situation, Professors G. Christian and J. Ruzicka from the University of Washington, Seattle, and G. Pacey of Miami Univer- sity, Oxford, OH, decided to organise the first “Winter Conference on Flow Injec- tion Analysis,” which took place in Orlando, Florida, January 5-7, 1989.Aimed primarily at bringing together experienced FIA practitioners as well as novices from academia and industry, the conference was attended by some 50 persons, only a few of which came from overseas (Denmark, England and Japan). Yet, what was particularly rewarding for the organisers was the strong attendance of persons from the industrial field, the presence of which was not only reflected in the composition of the final pro- gramme, but also very much in evidence at the “Round Table” discussion which was held on the second day of the conference- Structurally, the meeting was divided into three sessions: ( a ) General Flow Injection Analysis; ( b ) General and Process FIA; and ( c ) FIA and Chromato- graphy, which altogether featured 21 lec- tures and 3 poster presentations. At hand were also three American exhibitors who displayed commercially available FIA equipment and auxiliaries (Alpchem , FTAtron and Alitea, USA). At the end of the meeting the enthused participants overwhelmingly suggested making the Winter Conference an annual event, the time of the first week of January being a period most convenient to the majority of the participants. The next meeting will hence be scheduled by the same organisers for 1990-in all probability again in Florida. ELO HARALD HANSEN Chemistry Department A, Bldg 207, Technical University of Denmark, DK-2800 Lyngby, Denmark

ISSN:0144-557X    

DOI:10.1039/AP989260149b

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年代:1989

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150 Obituary ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 John Aggett 1936-1989 Professor John Aggett, one of the Regional Advisory Editors of The Analyst, died on January 12th, 1989, after a distinguished career in Analytical Chemistry. For the most part, he served in what is now the University of Auckland, where he commenced as an undergraduate in 1954, graduating with First Class Honours and then a PhD in 1961. Having spent a few years as Research Officer with the Atomic Energy Commission in Australia, where he became an expert on solvent extraction processes, John returned to his alma mater in 1963. Amongst his many achievements was a Nuffield Foundation Fellowship, which he held with Professor Tom West at Imperial College in London and from which stemmed his interest in mechan- isms of atomisation and other aspects of atomic absorption analysis. A Fulbright Scholarship in 1984 permitted him to further his studies into trace element speciation in the environment.The Analytical Section, which was founded in the University of Auckland in 1957, was pioneered by John Aggett, who was responsible for directing, teaching and research. It is now the foremost Analy-ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 tical Section of any Department in New Zealand. He also set up a popular course in Environmental Chemistry. These two interests led him to co-found the New Zealand Trace Element Research Group in 1977. Throughout, he was deeply invol- ved in the improvement of professional standards in analytical laboratories based in industry.He conducted his research with enthu- siasm and flourish and, at the time of his death, was undertaking joint collabora- tion with a wide range of New Zealand industries, with mining groups, and with international groups such as ours in Car- diff. He was an active Regional Advisory Editor of The Analyst. John Aggett always emphasised the importance of the science underpinning the analytical che- mistry and his enthusiasm was a driving force for setting high standards. As a teacher, he was a mentor in the classical sense and encouraged undergraduates to work hard by providing them with a creative and stimulating work environ- ment. The author writes from experience as he followed on lecture courses researched and given by John Aggett and marvelled at the amount of painstaking research which had gone into researching the history and the fundamental prin- ciples underpinning each of his lectures.The foundations laid in both his research laboratory work and his undergraduate courses will have a profound influence on trace element speciation research in New Zealand and, indeed, in the international sphere, since many will remember his presence at the Bioavailability '88 Confer- ence in Nonvich last August. John had always been a keen sports supporter and, indeed, the first common ground he discovered between our groups was that we had trained Gareth Davies to degree level in Industrial Chem- istry at the same time as he represented 151 Welsh rugby on a trip to New Zealand! Although his health did not permit him to participate actively in such sports, he was an enthusiastic supporter.John was a modest and unassuming person who had great charm and who was a delightful and amusing companion, with an infectious sense of fun. He worked extensively on church and community activities and will be remembered for many years for the work he did for the Intellectually Handicapped Children's Society. We will miss John but, nevertheless, the firm foundations that he built within his undergraduate responsibilities, in his research projects, and in his community and family life will form a fitting tribute for many decades to come. He is survived by his wife, Faye, and by five children. DAVID R. WILLIAMS Analytical Applications of Spectroscopy Edited by C.S.Creaser, University of East Anglia and A.M.C.Davies, Institute of Food Research, Norwich This book provides a 'State-of-the-Art' review of the applications of the major spectroscopic techniques and will prove invaluable to researchers involved in this form of analysis. The book provides wide-ranging coverage of recent developments in analytical spectroscopy, and in particular the common themes of chromatography - spectroscopy combinations, Fourier transform methods and data handling techniques. Each section includes a review of key areas of current research, written by spectroscopists who have made major c?ntributions in their respective disciplines, as well as short reports of new developments in these fields. These common themes have played an increasingly important part in recent advances in spectroscopic techniques and emphasise the multidisciplinary approach of present research. 502 pages ISBN 0 85186 383 3 Price E47.50 ($99.00) To order or for further information, please write to: Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 IHN, UK. or telephone (0462) 672555 quoting your credit card details. We now accept Access/Visa/MasterCard/EuroCard. RSC Members are entitled to a discount on most RSC publications and should write to: The Membership Manager, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K.

ISSN:0144-557X    

DOI:10.1039/AP9892600150

出版商:RSC    

年代:1989

数据来源: RSC

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152 ANALYTICAL PROCEEDINGS. MAY 1989. VOL 26 Electrochemical Sensors The following are summaries of two of the papers presented at a Joint Meeting of the Electroanalytical Group and the Electrochemistry Group of the Faraday Division held on May 4th, 1988, in the Central Research Laboratories of THORN-EMI, Hayes, Middlesex. lmmunosensors Based Upon Direct Measurement of Surface Binding: Fundamental Chemical Limitations M. J. Eddowes THORN EM1 Central Research Laboratories, Dawle y Road, Ha yes, Middlesex UB3 1 HH There is currently considerable interest in the development of low cost, disposable biosensor systems, employing antibodies as the selective sensing agent. An effective system will seek to provide direct, quantitative measurement at low concentration with a rapid response time, employing a small volume of sample, without the need for sample pre-treatment or reagent addition.A basic strategy which might meet at least some of the above requirements is that of direct determination of the antigen (target analytej selectively bound at an antibody coated surface. A variety of methods for direct measurement of surface bound species based upon both electrical and optical effects have been considered.14 Whilst the choice of measure- ment method will determine, in part, the sensitivity of the system, its general performance will be dependent upon chemical factors determining the extent of binding. These chemical factors will include the binding affinity of the antibody for antigen, the rate of the surface binding reaction and the rate of transport of species from solution to the surface at which binding takes place. A considerable amount of information regarding each of these aspects of the system is available in the literature.It is therefore possible, with the help of relatively simple theoretical models,j to develop an under- standing of the fundamental limits to the direct binding measurement strategy which will subsequently aid its optimisa- tion, according to the requirements of any given application. Theoretical Treatment For the direct surface measurement method, the sensitivity and general system performance is determined by first, the relationship between the signal and surface coverage, and second, by the relationship between surface coverage and analyte concentration, the latter aspect being the primary concern of this treatment.The detection limit with respect to surface bound species of the physical measurement method therefore represents a fundamental constraint. For the pur- poses of this assessment, the value employed for the detection limit will be of the order of 0.1% coverage, in accordance with reasonable expectations of the capabilities of available direct methods. A second constraint is the volume of sample available which, in accordance with indications of clinical requirements, will be taken to be 100 1.11. Finally, rapid response has been specified as a requirement and a response time of the order of a minute will be taken as a further constraint. For any given application, where the constraints differ from those assumed.adjustment to the predictions based upon the theoretical treatment below will be required. Available Analyte versus Binding Site Density Assuming a sample volume of 100 1.11, it is a straightforward process to define the total amount of available analyte given its concentration in the sample. At a nanomolar analyte concen- tration, for example, the amount available will be 10-13 moles. Theoretical considerations,5 supported by experimental data,4 indicate a limiting surface concentration, Tllm, for an average sized protein analyte of 5 x lo-'* mol cm-2. Thus, if all the available analyte from a nanomolar solution bound to a 1 cm* detector area, 20% surface coverage would result. Given the detection limit of 0.1 in percentage coverage terms, assumed above, it is apparent that the amount of available analyte will limit the response at concentrations a little below nanomolar if a detector area of around 1 cm* is to be employed.Extension to the picomolar range will require either a detector area more of the order of 1 mm2 or a relaxation in the sample volume constraint. For optimum sensitivity it will be essential to target all the available analyte at the minimum detector surface area. Binding Equilibrium The surface binding equilibrium can be defined in terms of the dissociation constant, Kd, according to where [Ag] is the solution concentration of the antigen analyte, r is the surface concentration of bound species and the term in parentheses in the numerator represents the number of free binding sites. Rearrangement gives an expression for the surface coverage which is the familiar form of the Langmuir adsorption isotherm and is illustrated in Fig.l(a). It should be noted that, inANALYTICAL PROCEEDINGS. MAY 1989, VOL 26 153 equation 2, [Ag] represents the analyte concentration in solution after equilibration with the surface. If depletion of analyte from the solution has occurred, this equilibrium concentration may differ significantly from the initial starting concentration which is of interest.5 The coverage as a function of starting concentration, though having a similar form to that described by the Langmuir adsorption isotherm, will then be considerably depressed, as illustrated in Fig. l(b). The precise form of the equilibrium response curve will therefore depend upon the extent of analyte concentration depletion, which will itself be dependent upon factors such as the detector area, sample volume and the dissociation constant.By appropriate choice of these factors it should be possible to arrange for a suitable response curve, spanning the required measurement range. CJ z I I I I 0 2 4 6 8 10 Normalised antigen concentration [Agl/Kd Fig. 1. Equilibrium binding of antibody - antigen complex: A, where antigen is in excess and the initial antibody concentration is signifi- cantly lower than the dissociation constant for the complex; and B, where antigen is not in excess and the initial antibody concentration and dissociation constants are of a similar order of magnitude From the point of view of maximising surface coverage and hence the output signal, the importance of choosing a system with a low dissociation constant can be seen from equation 2.At the low concentration limit, where [Ag] << Kd, the adorption isotherm is approximately linear and of the form = ([Ag]/Kd)Tli,. Given the 0.1% surface coverage detection limit assumed for the physical measurement method this represents a detection limit in concentration terms of Kd/103. Available data6 on antibody - antigen affinity indicates a lower limit for the dissociation constant, Kd - M. Thus, for an antibody with optimum affinity a detection limit of 10-14 M is derived. However, unless the sample volume constraint is considerably relaxed, this detection limit is unlikely to be reached because of the limit of the total amount of analyte available, as discussed previously. Surface Binding Reaction Kinetics The rates of the surface binding and dissociation reactions are described in terms of the association rate constant, k,, and the dissociation rate constant, kd, according to v, = k,(Tli, - T)[Ag] .. . . . . (3a) vd = kdr . . . . . . . . . . (3b) Available experimental data on antibody - antigen binding rates6 indicate association rate constants of the order of 106 M - ~ s-I for protein antigens. The dissociation rate constants span a range, according to the dissociation constant, being given by kd = Kdk,. Thus, a value kd = s-* is derived for an antibody with a reasonable dissociation constant of 10-9 M . An integrated rate expression for the surface coverage as a function of time can be derived5 from equation 3.(4) From this the time to equilibrium, t > l/(k,[Ag] + k d ) , is derived and it can be seen that, for the values of the various parameters encountered in practice, the time to equilibrium will be excessively long, of the order of several tens of minutes. An indication of the initial rate of rise can be obtained directly from equation 3a. In percentage coverage terms at nanomolar concentration of antigen the rate of change will be of the order of 0.1% s-1. Given the sensitivity of the physical detection method this rate of change should be readily visible. Thus, whilst an equilibrium measurement method might be unfavourable owing to the long equilibration time, an initial rate of change method could provide both rapidity of response and adequate sensitivity.Mass Transport Rates Where reaction takes place at a surface the concentration of reactant will become depleted, locally, and the rate will therefore be reduced accordingly. The over-all surface reaction rate may then become dependent upon the rate of transport of species from the bulk of solution to the surface reaction site. The rate of surface adsorption controlled by diffusional mass transport of species has been studied5.7.8 both theoretically and experimentally. Experimental data relating to mass transport controlled antibody - antigen binding reactions at surfaces is also reported4 in the literature. The time to equilibrium for the diffusion controlled process is excessively long and, in any case, the equilibrium measurement has already been discounted because of the long equilibration time without mass transport limitations.It may be concluded that its transient nature and relatively slow rate make the diffusion controlled process inappropriate for the proposed rate of change measurement method. An effective rate of change measurement can be envisaged in which mass transport is convection assisted. This will both provide the maximum, time independent mass transport rate and serve to target the available volume at the minimum surface area. The increase in surface coverage with time and its linearity for convective as compared with diffusion controlfed mass transport is shown schematically in Fig. 2. Rapid transport rates can certainly be achieved in impinging jet9 or flow-through channel10 geometries, according to flow-rates and the flow system dimensions. However, it will be important to assess whether such a proposed convective flow dependent system can satisfy each of the sensitivity, sample volume and response time constraints simultaneously.In particular, it needs to be established whether there is sufficient volume to sustain an adequate flow-rate for the length of time necessary to develop the signal. It is first necessary to determine the magnitude of the rate constant of the surface process with which the mass transport process is linked. This will define the mass transport rate constant required to give the optimum response. The require- ments for and relative importance of sensitivity, minimum sample volume or speed of response will determine what is considered the optimum response in any given application. The effective surface rate, k R , in units of m s-1, is simply the product of the homogeneous bimolecular rate constant, k, and the limiting surface coverage, TI,,,, .Taking the typical values for these parameters indicated earlier gives a value for the surface rate constant, kR = 5 x m s- l . For optimum speed of response a mass transport rate constant, k D , as high as or higher than the surface rate constant, will be required, whilst for optimum sensitivity and minimum sample volume a slightly slower rate might be more advantageous. Taking a compro-154 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 al m E 0 / / / / 6. Constant rate of change / under convection control / / / / / / / / / A. Decaying rate of change under diffusion control V Time Fig.2. Schematic representation of the change of surface coverage as a function of time for: A, a system mass transport controlled by diffusion; and B, a system mass transport controlled by convection mise value for the required mass transport rate constant, kD = 10-5 m s-1, the required volume flow-rate for an appropriate flow system can be calculated. Assuming either an impinging jet configuration with a 1 mm diameter inlet nozzle or a point 1 mm along a 100 pm by 1 mm rectangular channel, a volume flow-rate of 5 p1 s-1 is calculated to be required to provide a mass transport rate constant, kD, of 10-5 m s-1. Given the proposed volume constraint of 100 pl this flow-rate can be sustained for 20 s and would give rise to roughly 1% coverage with a nanomolar concentration of analyte.Conclusions Assessment of the direct surface binding of antigen to an antibody surface has identified a number of limitations to the performance of the method when applied to immunoassay, subject to sample volume and response time constraints. There is an inevitable compromise between these constraints and the sensitivity requirement of the measurement system. Put simply, this means that if there is very little available analyte it will be difficult to bind a measurable quantity of it at a surface in a short time. Consideration of the rates of the elementary steps in the surface binding reaction indicate that mass transport will play an important role and that, in order to obtain a reasonable response time, an initial rate of change measurement method under a controlled convective flow regime offers some advantage.It is concluded that a measur- able signal can be obtained for a nanomolar concentration of analyte with a small sample volume (100 pl) within a response time of 20 s by using this initial rate of change measurement method. Dimensions of the order 0.1-1 mm for the convective flow system were assumed in making this estimate. It is to be stressed that the above consideration gives an approximate idea only of the likely performance of the system subject to the specified constraints. However, it is not anticipated that any significant improvement in performance as regards sensitivity is likely without significant relaxation of the sample volume and response time constraints.References 1. Janata, J., in Janata, J . , and Huber, R. J . , Edirors, “Solid State Chemical Sensors,’’ Academic Press, New York, 1985. 2. Newman, A. L., Hunter, K. W., and Stanbro, W. D., “Proceedings of the 2nd International Meeting on Chemical Sensors, Bordeaux, 1986,” ISBN 2-906257-00-1, 1986, p. 596. 3. Kronick, M. N., PhD Thesis. Stanford University, 1974. 4. Place, J. F., Sutherland, R. M., and Dahne, C., Biosensors, 5 . Eddowes, M. J., Biosensors, 1987/88, 3, 1. 6. Karush, F., in Litmann, G. W., and Good, R. A,, Editors. 7 . Delahay, P., andTrachtenberg, I., J . Am. Chem. SOC., 1957,79, 8. Delahay, P., and Fike, C. T., J. Am. Chem. Soc., 1958, 80, 9. Chin, D.-T., and Tsang, C.-H., J. Electrochem. Soc., 1978,125.10. Compton, R. G., and Unwin, P. R . , J . Electroanal. Chem., 1985, 1, 321. “Immunoglobulins,” Plenum, New York, 1978. 2355. 2628. 1461. 1986, 205, 1. ISFET-based Enzyme Sensors for Urea: Enzyme-modified ISFETs and Column-immobilised Enzyme Flow Injection Analysis G. K. Chandler, J. R. Dodgson and M. J. Eddowes THORN EM1 Central Research Laboratories, Dawley Road, Hayes, Middlesex U53 7 HH Potentiometric enzyme sensors, in which the pH change resulting from a reaction between an enzyme and its substrate is detected by either a pH electrode or ion-sensitive field-effect transistor (ISFET), have been described extensively in the literature.1 Traditionally, these devices consist of a membrane containing immobilised enzyme in direct contact with the pH sensing surface, giving a compact, self-contained device. The response is dependent on the physico-chemical parameters of the membrane,ZJ the most important of these being membrane thickness and enzyme loading. With increased thickness the membrane has a larger amount of enzyme available to catalyse the substrate reaction, and so will tend to give larger pH changes at the sensor surface, but the response is slowed by mass-transport effects within the membrane.Response time can be reduced by increasing the membrane permeability, but this can lead to physical weakness; a thinner membrane will give smaller pH changes for a given enzyme loading and short lifetime through loss of enzyme activity, although the response can be fast. Current theory gives a good description of the observed response provided that appropriate membrane parameters are assumed.3 Response times for such sensors are concentration dependent and typically have been reported as being around 90 s or more4; with an exceptionally thin (1 pm) spin-coated membrane a response time of -10 s has been achieved,5 but at the expense of sensitivity.The pH and buffer content of the sample have a strong effect on the sensor response1.3@ the pH change produced by the enzyme reaction depends on the buffer capacity of the solution, which is itself pH-dependent ; hence the response deviates from the logarithmic pH/[substrate] relationship seen in the absence of buffer. The pH and buffer content will vary between samples and therefore so will the pW[urea] calibration. A system has been proposed using feedback controlled coulometric titration to maintain a constant pH as the enzyme reaction proceeds.’ This gives a linear titration current/[urea] relationship and compensates for variation of the buffer capacity between samples, but as a thick membrane device it again suffers from a long response time.ANALYTICAL PROCEEDINGS, MAY 1989.VOL 26 1.0 0.8 155 - - An alternative approach is to use an unmodified pH sensor in a flow injection analysis (FIA) sy~tem83~ to monitor pH changes after reaction in a column containing immobilised enzyme. Column immobilisation offers the advantages of large area for reaction with little mass transport limitation, giving a fast response, and ease of reproducible fabrication of the separated components. A further advantage is that the dispersion inherent in such a system can be used to give a linear response and to reduce the effect on the response of variations in buffer capacity of the sample.Experimental Enzyme-modified ISFETs were produced using urease (Sigma, Type VI) immobilised in either poly(2-hydroxyethyl meth- acry1ate)hydrogel with various water contents, or in a BSA - glutaraldehyde cross-linked gel. The underlying devices were matched ISFET/MOSFET pairs with Ta205 pH membranes. The FIA system used a home-made 30 1-11 injection port and two Ta205 membrane ISFET pairs, before and after the enzyme column, to give a differential pH measurement. Column volumes were 100 pl (home-made, Perspex) or 300 1-11 (Omnifit); typical flow-rates were around 1 ml min-1.Urease was immobilised on silanised 50 ym controlled-pore glass, mesh 80 or 140 (Sigma), using BSA - glutaraldehyde coupl- ing10; the BSA - glutaraldehyde treated glass was loaded dry into the columns and urease was coupled in situ from a concentrated solution in approximately pH 7 phosphate buffer. Prepared columns were stored dry at 4 "C. The carrier stream and background buffer for urea calibration standards was 2 mM (total) phosphate buffer, pH approximately 6.86, prepared from 25-fold dilution of NBS equimolar phosphate standard, with 0.1 M KCI as an ionic strength adjuster. Column activity as a function of flow-rate was checked in constant flow experi- ments in which the pH change across the column was compared with that from complete hydrolysis of the standard with free enzyme.FIA experiments were then performed, using a flow-rate giving complete conversion. I,, 0 10 20 30 40 50 60 Time/m in Fig. 1. Sensor output dpH versus time. Samples of 25, 15, 5 and 2.5 mM urea added to 2 mM phosphate buffer, pH 6.86: 30 pl sample; flow-rate 0.88 ml min-l Results and Discussion The gel-immobilised enzyme-modified ISFETs were found to suffer from the problems mentioned above. In order to incorporate sufficient urease to catalyse urea in the clinical range (2-25 mM), and to counteract any fall-off in activity arising from the gel pH moving outside the optimum pH range for the enzyme, or the denaturing of the enzyme with time, a gel thickness of greater than 100 pm was required. This thickness was difficult to control precisely, yet had a strong effect on the response time.Hydrogels with low water content gave very long response times, while those with high water contents were too fragile to withstand an impinging flow of solution. The BSA - glutaraldehyde matrix was much easier to prepare but, being protein-based, was found to degrade easily through bacterial attack. The FIA system gave more promising results. Comparison of constant-flow experiments with complete reaction of standards with free enzyme showed that urea conversion in the columns approached 100% initially at moderate flow-rates (1 ml min-1) for both column volumes and glass meshes; the columns lost activity, apparently through physical washing-off of the enzyme, over a period of 4-12 h of continuous flow. Wet/dry storage up to 14 d at 4°C had no marked effect.Typical FIA calibration results for a 30 yl sample are shown in Fig. 1; response and recovery times are -30 s (independent of substrate concentration) and 4 min, respectively. Fig. 2 shows a calibration graph of FIA peak height against urea concentra- tion over the clinical range. The linearity arises from the effectively constant buffer capacity in this pH range of the reacted sample and carrier mixture, at the dilution (approxi- mately 25x) of sample arising from dispersion in the column. 1 0 5 10 15 20 25 Concentration of urea/mu Fig. 2. sample: flow-rate 0.88 ml min-1 FIA urea calibration: 2 mM phosphate buffer, pH 6.86; 30 pl In summary, it can be seen that the FIA approach avoids some of the problems associated with integrated gel-immobi- lised enzyme ISFETs.The response time is short, independent of substrate concentration, and could no doubt be reduced with optimisation of column enzyme loading and a reduction in size. The recovery time could be further reduced by accelerated pump-out. The response is linear, aiding accurate calibration. The enzyme lifetime is adequate for disposable-column appli- cations; the columns are relatively easy to make reproducibly and the operation of the system much less dependent on the precise conditions of fabrication than are gel-immobilised enzyme devices. References 1. See, for example. Eddowes, M. J., Pedley, D. G., and Webb, B. C., Sensors Actuators, 1985, 7, 233 and references cited therein. Eddowes, M. J . , Pedley, D. G..and Webb, B. C., Anal. Proc., 1986, 23, 152. 2.156 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 3. 4. Eddowes. M. J.. Sensors Actuators, 1987, 11, 265. See, for example, Miyahara, Y., and Moriizumi, T., Sensors Actuators, 1985, 7, 1; Kimura, J . , Kuriyama, T., and Kanawa. Y . , Sensors Actuators, 1986, 9, 373. Kuriyama, T., Nakamoto, S., Kanawa, Y . . and Kimura, J., “Proceedings of 2nd International Meeting on Chemical Sen- sors, Bordeaux, 1986.” 1986, pp. 568-571. Chandler, G. K., and Eddowes, M. J., Sensors Actuators, 1988. 13, 223. 5. 6. 7. 8. 9. van der Schoot, B. H., and Bergveld, P., Anal. Chim. Acta, 1987, 199. 157. RGiiEka, J.. and Hansen, E. H., “Flow Injection Analysis.” Wiley, New York, 1981. R8iiEka. J.. Hansen, E. H.. Ghose, A. K., and Mottola, H. A , , Anal. Chem., 1979, 51, 199. 10. Mosbach. K., Editor, “Methods in Enzymology,” Volume XLIV. “Immobilised Enzymes.” Academic Press, New York, 1976. ch. 10. I Eight Peak Index m - 1 - 1 , 66,000 spectra ... The Eight Peak Index of Mass Spectra is the largest printed index of mass spectral data in the world. It is an excellent aid for identifying unknown compounds and a convenient single point of entry to the various full mass spectral collections and mass spectral information appearing in the scientific literature. It contains data on the eight most abundant ions in 66,720 spectra, covering 52,332 compounds, and is indexed in three different ways for ease of use: M by molecular weight and formula by molecular weight and m/z by m/z of most abundant ion UK f 800.00 USA $1 850.00 Overseas €880.00 1 Special 30% Educational Discount! The Eight Peak Index of Mass Spectra is an invaluable reference source and to make it easier for educational establishments to purchase we are offering a 30% discount on the published price! Educational establishments will now be able to purchase the 3rd Edition for only: UK f560.00 USA $1295.00 Overseas f610.00 I 1 Credit Card Facilities Now Available! To make ordering even easier we now offer credit card facilities and aocept Access, Mastercard, Eurocard and Visa. For further information on the Eight Peak Index of Mass Spectra or to order, simply write to: ROYAL eB- SOCIETY O F CHEMISTRY Information Services Alison Hibberd Royal Society of Chemistry Thomas Graham House Science Park. Milton Road Cambridge CB4 4WF. UK Or telephone: (0223) 420066 quoting your crdir card Number I

ISSN:0144-557X    

DOI:10.1039/AP9892600152

出版商:RSC    

年代:1989

数据来源: RSC

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ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 Research and Development Topics Chemistry C R i Rz 157 in Analytical -PD S I t PD The following are summaries of two of the papers presented at a Meeting of the Analytical Division held on July 18-19th, 1988, in The Polytechnic, Plymouth. Summaries of thirty-three other papers appeared in the January and February issues. Flow Injection Determination of Sulphate in High Ionic Strength Andrew B. Marsden and Julian F. Tvson Depahment of Chemistry, Loughboiough University of Technology, Loughborough, LEl I 3TU Leicestershire The spectrophotometric determination of trace components in fine chemicals by flow injection (FI) techniques suffers from a number of practical problems which influence manifold design. Flow injection manifolds can be broadly classified into two types, those in which most of the inter-dispersion of injected material and reagent carrier stream is due to convection and diffusion processes arising from the laminar flow patterns (as typified by the single-line manifold), and those in which the degree of interdispersion is governed by mixing at confluence points (as typified by the multi-line manifold). Where there is a considerable difference in refractive index between the injected solution and the reagent carrier stream the former type of manifold is unsuitable, because of the large refractive index peaks which obscure the analytical signal.Although a similar problem is encountered with the second type of manifold when the injected material and the carrier stream have different refractive indices, this can be compen- sated for by matrix matching of the carrier stream.Other problems with mixing at confluence points can be tackled by the inclusion of a downstream packed bed reactor and pulse dampers. In this study previously developed ideas on manifold design132 were adapted for the determination of sulphate in water and in high ionic strength solutions. The methods chosen were a spectrophotometric method using the methyl thymol blue3 (MTB) - barium complex and a turbidimetric method using barium chloride in alkaline EDTA.4 Both methods were implemented on three-line manifolds. In the former method, either the decrease in absorbance of the Ba - MTB complex may be monitored or the appearance of free MTB. The decrease in absorbance of the Ba - MTB at 608 nm was followed.In alkaline solution, added via the third line in the manifold, the absorbance of the free MTB does not interfere. The use of alcoholic reagent solutions has been reported3 to increase the sensitivity of this determina- tion. Despite the additional difficulties of mixing of alcoholic solutions and aqueous solutions, known from previous investi- gations of the determination of chloride at low concentrations with a reagent containing a substantial proportion of methanol,2 this approach was used here. In the latter method the reagent (barium chloride solution) contains a small amount of polyvinyl alcohol (PVA) as an anti-flocculating surfactant. The third line merged a stream of alkaline EDTA to prevent the build up of precipitate in the flow cell and connecting lines.The increase in turbidity at 410 nm was monitored.158 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 0.1 A h I 600 s , Fig. 2. for three replicate injections of 10 p.p.m. sulphate Peaks obtained by the Ba - MTB spectrophotometric method ethanol. The sodium hydroxide solution was 0.036 M sodium hydroxide in 95% ethanol. In the turbidimetric method the reagent consisted of 5% (rnlV) barium chloride dihydrate solution with 0.05% (rnlV) of PVA added. The anti-flocculat- ing agent consisted of 0.3% (rnlv) EDTA (disodium salt) in 0.2 M ammonia solution. In the MTB method, an ion exchange micro-column was used to remove potentially interfering cations. This consisted of a 5 cm length of 2.3 mm i.d. glass tubing filled with Dowex 50-X 8 ion-exchange resin (BDH Ltd.) placed within the loop of the injection valve.Results and Discussion One of the greatest difficulties with the basic MTB system, was the considerable noise produced because of the rapid de- gassing of the ethanol - water solutions when they were mixed. Vigorous sparging of all solutions before use, and a lowering of the alcohol content of reagent solutions to 50% (VlV) reduced this noise. The insertion of a single bead string reactor of 20 cm length (SBSR) also helped reduce base-line noise caused by poor initial mixing.6 Typical peaks for the spectrophotometric method are shown in Fig. 2. A throughput of 15-20 samples h-* was achieved for the determination of sulphate in pure water, with a detection limit of a few mg 1-1.As pre-concentration of sulphate on an alumina column is possible, it may be feasible to extend the detection limit to sub-p.p.m. levels. Typical peaks for the turbidimetric method are shown in Figs. 3(a) and 3(b). The sensitivity of the method was much higher than the spectrophotometric method, and for the determination of sulphate in pure water the linear range of the system was 1.0-100.0 mg 1-1 with a detection limit of 0.45 p.p.m. The method was used for the analysis of a 3% (rnlv) caesium iodide solution [typical peaks are shown in Fig. 3(c)]. The calibration data over the range 1-8 mg 1-1 in this solution gave a slope of 0.559 k 0.045, an intercept of 0.045 k 0.232 and a correlation coefficient of 0.9996. The plus or minus terms are 95% confidence intervals.Thus, unlike some of the previously reported flow injection determinations of sulphate,5 a usable response was obtained down to 1 mg 1-1. Conclusion Of the two methods investigated so far, the turbidimetric method seems better suited for the determination of low levels of sulphate in high ionic strength media. Financial support for A. B. M. for this work by the SERC and BDH Ltd. (who generously supplied all chemicals) through the CASE scheme is gratefully acknowledged. References 1. Marsden, A. B., and Tyson, J. F., Anal. Proc., 1988, 25, 89. 2. Tyson, J. F., and Marsden, A. B., Anal. Chim. Acta, 1988,214, 447. 3. Madsen, B. C., and Murphy, R . J., Anal. Chem.; 1981,53,24. 4. Baban, S., Beetlestone, D., Betteridge, D., and Sweet, P., Anal. Chim. Acta, 1980, 114, 319.5. Krug, F. J., Zagatto, E. A. G., Reis, B. F., Bahia F"., O., Jacintho, A. O., and Jorgensen, S. S . , Anal. Chim. Acta, 1983, 145, 179. Reijn, J. M., Van der Linden, W. E., and Poppe, H., Anal. Chim. Acta, 1981, 123,229. RiiiEka, J., and Hansen, E. H., Anal. Chim. Acta, 1983, 145, 1. 6. 7. 240 s - 10-4Al J T 0.4 A - A+ Fig. 3. 3% (mlv) caesium iodide solution Peaks obtained for the turbidimetric method: ( a ) , 1 p.p.m. sulphate; (b), 10 p.p.m. sulphate; and (c), 10 p.p.m. sulphate inANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 159 Laser Ablation System for Solid Sample Introduction Into the Inductively Coupled Plasma S. A. Darke, S. E. Longt and C. J. Pickford Environmental and Medical Sciences Division, Harwell Laboratory, Oxfordshire OX I 1 ORA J.F. Tyson* Department of Chemistry, University of Technology, Loughborough, Leicestershire LEI I 3TU The weak link of an inductively coupled plasma (ICP) system is considered to be the inefficient method of sample introduction most commonly used, i . e . , solution nebulisation. The potential advantages that solid sample introduction methods offer over nebulisation make them attractive alternatives. Many methods of solid sample introduction for ICP have been developed but none to the extent that they are in widespread use. The combination of vaporisation by laser ablation and excitation by the ICP is one such method of solid sample introduction and has been used for both ICP and atomic emission spectroscopy (AES)1-3 and ICP mass spectrometry In this paper a laser ablation system will be described.It is based on a 2 J Nd - YAG laser and has been designed and constructed for use with ICP - OES and ICP - MS instru- ments. A study has been made of a number of parameters which affect the performance of the system. The application of the system to the analysis of some geochemical samples is discussed in this work. (MS) .4,5 Experimental Instrumentation A free running Nd - YAG laser (Spectron Laser Systems SL402, Rugby, Warwickshire) capable of producing a 200-ys pulse of 2 J maximum energy was used to ablate the solid samples in this laser ablation system. The sample cell was constructed from a cylindrical glass tube, 35 mm in internal diameter and 80 mm high, with tangential arms for gas inlet and outlet. The top of the cell was sealed with a plate-glass cover angled at 45" in order to eliminate reflections within the objective lens.The sample to be ablated was placed on a circular PTFE base, which was sealed with an O-ring. The base could easily be removed for sample changeover. The ablated material was carried along 2 m of connecting tubing to the plasma torch by an argon gas flow of 0.8 1 min-1. The initial experimental and developmental work for the laser ablation system was carried out by using a Model 2500 PlasmaTherm (Kresson, NJ, USA) inductively coupled plasma source unit. This was attached to a Spex (Metuchen, NJ, USA) l m focal length scanning monochromator fitted with a Czerny - Turner mounting and a holographic grating of 2400 lines mm-1. This, together with a Spex DPC2 digital pho- tometer and a Spectra-Physics (San Jose, CA, USA) SP4296 HPLC integrator were used for data collection and display.The analytical measurements on geochemical materials were carried out by using a commercially available ARL 3560 (Applied Research Laboratories, Crawley, Sussex) simul- taneous ICP-OES instrument and a PlasmaQuad (VG Iso- topes, Winsford, Cheshire) ICP-MS. Sample Preparation Four certified geochemical reference samples were used for the study, viz., SARM 1 (granite), SARM 2 (syenite), SARM 4 (norite) and SARM 5 (pyroxenite) (South African Bureau of * To whom correspondence should be addressed. t Present address: Technology Applications, US Environmental Protection Agency, Cincinnati, Ohio, USA. Standards, Pretoria, RSA). They were made into pellets by first mixing with a 1% (rnlV) solution of Mowiol (polyvinyl alcohol, Hoechst UK Ltd., Hounslow, Middlesex), followed by drying in a desiccator or an oven at 50 "C, and then pressing in a 1.5-cm die at 10-tons pressure. Yttrium and indium were added at the 100 pg g-1 level as internal standards. They were added as solutions together with the sample binder. Procedures Different laser ablation procedures were used for the ICP-OES and ICP-MS measurements. For ICP-OES, a single laser pulse was used to ablate material, which was transported to the plasma and resulted in a transient signal. With ICP-MS, in order to obtain a full scan, material was ablated repeatedly at 1.4 laser pulses per second for 1 min. The sample was moved during this time so that a fresh surface was presented to the laser for each pulse.The quadrupole mass spectrometer scanned the mass range continuously over the ablation period. Results and Discussion ICP-OES Measurements Table 1 shows the laser ablation ICP-OES results for a range of major and minor elements determined in SARM 5 . Either SARM 2 or SARM 4 was used for calibration, using the added internal standards to correct for any inter-sample ablation effects. The importance of closely matrix-matched standards is illustrated by the inaccuracy of the results when SARM 2 was used for calibration. SARM 4 and SARM 5 are of similar elemental composition and this is reflected in the much closer agreement between measured and certificate data. SARM 2 contains a high concentration of potassium compared with the other two standards.As this is the most obvious difference between the sample matrices, one possible explanation for the matrix effects observed is that the presence of easily ionisable elements has a modifying effect upon sample ablation, or excitations in the plasma. Table 1. Laser ablation ICP-OES measurements on SARM 5 . Standard deviations in parentheses. Number of replicates = 4 Measured concentration Element, Calibrated Calibrated Certificate YO with SARM 2 with SARM 4 value* A1 K Na Si Ba Mn Sr Ti Pg g-' 3.80 (0.47) 0.30 (0.01) 0.23 (0.02) 36.0 (1.4) 88. 820 22 870 .O (7.20) (14.0) (3.1) (87) 2.30 (0.28) 0.14 (0.006) 0.33 (0.03) 21.9 (0.82) 59 (4.8) 27.0 (3.6) 1710 (29) 1090 (110) 2.2 0.07 0.27 24.0 46 1700 32 1200 * Certificate of analysis, NIM-P, Pyroxenite SARM 5 , SA Bureau of Standards, Pretoria, RSA.160 /Eu (153) 1 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 ICP-MS Measurements ICP-MS measurements were made on SARM 1.A scan across the mass range encompassing the rare earth elements showed that it was possible to detect all that were in the sample by this technique. Europium, for example, is at mlz 153 (relative abundance 52.2%) and mlz 151 (relative abundance 47.8%) and is present at a concentration of 0.35 pg 8-1. Both of these isotopes were easily detected, suggesting that a limit of detection of less than 0.1 yg g-1 for europium is possible using this laser ablation ICP-MS system. Fig. 1 shows the linear relationship between isotope concen- 1200 1000 r I 800 c C 3 0 $ 600 2? Y Q, 400 a 200 ROYAL SOCIETY Of CHEMISTRV Informatm SerVlCeS trations and peak areas that exists for the rare earth elements in SARM 1 (only certified elements included).The graph is sufficiently linear (correlation coefficient = 0.9975) for any one isotope to be used and an internal standard for the others. Conclusions By use of the system constructed, laser ablation ICP-OES and ICP-MS can be used to make qualitative and semi-quantitative determinations of the elemental composition of geochemical samples. However, matrix effects are present which require standardisation to be made with closely matched materials. These matrix effects appear from the results to be related to the presence of easily ionisable elements. For a series such as the rare earth elements, the variation in sensitivity obtained with ICP-MS is sufficiently small to allow internal standardisation using one element to correct for sensitivity variations in the others.This work was supported by the Underlying Research Pro- gramme of the UKAEA. References 1. Abercrombie, F. N., Silvester, M. D., Murray A. D., and Barringer, A. R., in Barnes, R. M.. Editor, “Applications of Inductively Coupled Plasmas to Emission Spectrometry,” Franklin Institute Press, Philadelphia, PA, USA. 1978, p. 121. 2. Thompson, M., Goulter, J . E., and Seipcr, F., Analysr, 1981, 106, 32. 3. Carr, J . W., and Horlick, G., Specrrochim. Acta, Part B , 1982, 37, 1. 4. Gray, A. L., Analyst, 1985, 110, 551. 5. Arrowsmith. P., Anal. Chem., 1987, 59, 1437. AN INTRODUCTION TO APPLICATIONS OF LIGHT MICROSCOPY IN ANALYSIS By D.Simpson and W . G. Simpson, Analysis for Industry, Thorpe-le-Soken An Inirdu,mn 11. AppLraimonr 01 LIGHT MICROSCOPY IN ANALYSIS This new book reviews recent experience of the application of the light microscope in its various forms to a range of analytical applications. Light microscopy is one of the oldest basic techniques at the disposal of the analyst and is greatly undervalued and under used in the analytical laboratory. It remains a convenient, economical technique which should not be overlooked and can be of great value in the analysis of foods, pharmaceuticals, metals, plastics, water, agrochemicals, waste management, bacteriology and much more. The authors aim to encourage wide use of microscopy in actual practice and to remind analysts of its qualities and applications. Microscopists, analysts and students alike will gain much from the authors’ enthusiasm and this book should assist in extending the utility of the instrument in the future. Brief Contents: I Petrology and Mineralogy; Metals and Alloys; Plastics and Polymers; Surface Properties and Faults in Materials; Fibres, Paper and Textiles; Clinical and Biological Materials; Pharmaceuticals; Bacteriology and Microbiology; Moulds, Yeasts, Brewing and Distilling; Water Quality and Water Supplies; Foods and Spices; Health and Safety; Microscopy and Forensic Science. The book includes a bibliography, a listing of microscopy journals and an index. ISBN 0 85186 987 4 Hardcover 225pp Published 1988 Price f29.50 ($63.00) For further information, please write to: Royal Society of Chemistry, Sales and Promotion department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K. To Order, please write to: Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1HN. U.K. or telephone (0462) 672555 quoting your credit card details. We can now accept AccessNisal MasterCardIEurocard. RSC Members are entitled to a discount on most RSC publications and should write to: The Membership Manager, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K.

ISSN:0144-557X    

DOI:10.1039/AP9892600157

出版商:RSC    

年代:1989

数据来源: RSC

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ANALYTICAL PROCEEDINGS. MAY 1989. VOL 26 161 Environmental Monitoring and Modelling The following are summaries of two of the papers presented at a Meeting of the Analytical Division held on October 25th, 1988, in the Scientific Societies' Lecture Theatre, London W.1. Assessment of Hazards From Nuclear Facilities G. C. Meggitt Safety and Reliability Directorate, United Kingdom Atomic Energy Authority, Wigshaw Lane, Culcheth, Warrington WA3 4NE The potential hazards to the public and to the environment from nuclear installations arise from radioactivity released in postulated accidents and as a result of normal operations. These hazards are routinel) assessed by using a varietq of modelling techniques, supplemented by information obtained by direct monitoring where appropriate, in order to demon- strate that the installation ma) be operated safely. This process involves the assessment of the amounts of radioactivity which might be released to the environment under normal and accident conditions.The environmental impacts of these releases are then estimated by using environmental modelling methods. This paper outlines the way in which the environmental impact of releases to the atmosphere is assessed as part of the demonstration that risks posed by facilities have been reduced to levels that are as low as is reasonably practicable. Accidental Releases to the Atmosphere Atmospheric Dispersion The atmosphere is an extremely complex sqstem and buoyant material released into it will not only drift downwind but will also be dispersed across the wind by the action of turbulence.There are two sources of turbulence: thermal instability and the action of wind. In the atmosphere the temperature generally falls with increasing height. If this happens in such a way that the decrease in pressure and density are matched by the fall in temperature, a parcel of air displaced vertically then experiences no buoyancy forces and the atmosphere is said to be "neutral." If the temperature gradient is greater than this adiabatic lapse rate (ALR) a parcel of air displaced upwards will be lighter than its surroundings and will continue to rise: the atmosphere will be unstable. If the temperature gradient is smaller than the ALR the atmosphere will be stable. In unstable atmospheres any turbulence will be enhanced; in stable atmospheres it will be damped.The action of the wind in passing over the ground and any obstacles causes turbulence within the boundary layer of the earth's atmosphere; the amount of turbulence generated depends upon the windspeed and the roughness of the surface over which it passes. The interaction between the thermal effects and mechanical ones are complex but it has been found that the conditions can be divided into six categories on the basis of solar insolation, cloud cover at night and windspeed. The categories (known as Pasquill categories) can be used to estimate the vertical and horizontal spread of a plume of activity. The crosswind spreads of activity are found to be quite well represented by Gaussian distributions. The half-widths in the vertical and horizontal crosswind directions at particular distances downwind can be obtained, using the categorisation, from a combination of experimental data and theoretical considerations.There are a number of extensions of this basic scheme to take account of different ground roughness (which affects vertical dispersion) and the time period of the release (which modifies the horizontal dispersion). It is also possible to allow for other atmospheric features and for such things as the behaviour of hot plumes and interactions with building wakes. As the plume moves downwind material will be deposited from it on to the ground: should it rain material will be washed out. Models of these processes are applied in computer codes designed for atmospheric dispersion calculations.Radiation Exposures There are a number of pathways of radiation exposure from the released activity. The cloud of radioactivity is a source of direct radiation to people nearby as it passes. The exposure is transient and is, generally speaking, more important for the less severe hypothetical accidents, where noble gases form the greater part of material released. The other transient pathway is inhalation of activity from the passing cloud. This results in activity being taken into the body and being distributed and retained for periods of time which depend on the element concerned and its body chemistry. This radioactive material continues to irradiate organs of the body until it is excreted or undergoes radioactive decay. It is usual to calculate the radiation doses resulting over an entire lifetime from material inhaled during the accident by people in a number of age groups.Other routes of exposure result from the deposition of activity on the ground. The two most important of these are direct external irradiation and the ingestion of foodstuffs contaminated by the deposited activity. The first pathway is relatively simple to calculate but ingestion calculations require the modelling of the transfer of radioactivity through the food pathways. Among the more significant is the ingestion of radioiodine through cows grazing on contaminated land, the transfer of the element to milk and the consumption of the milk or its products. Health Effects Radiation exposures may affect the person exposed or his descendants.The individual exposed may suffer two type. of radiation effects. The first of these, which could only occur in extremely severe accidents, are acute and would arise only if a high threshold level of dose were exceeded. However, if this level were exceeded the effect would become progressively more severe as the dose increased until death became very likely. The other type of effects include cancer. The current hypothesis, based on extrapolation of the results of exposure to very high doses, is that any radiation dose, however small, may trigger the development of a cancer and the severity of the162 disease will be independent of the amount of radiation. The probability of the cancer being triggered will, however, depend on the radiation dose. It is considered that a radiation dose of 1 mSv will lead to a probability of about 0.001% of a fatal cancer of some kind developing. The induction of cancer is a stochastic process and it is believed that hereditary effects have a similar nature.Countermeasures If there were a release of radioactivity to the atmosphere then, if considered necessary, a number of countermeasures would be implemented. In the short term these might be, depending upon the severity of the accident, sheltering, the issue and consumption of stable iodate tablets (to prevent radioiodine accumulating in the thyroid gland), evacuation or the banning of certain contaminated foodstuffs. In the longer term, for the very severe accidents, it would be necessary to consider relocation of people.All of these measures would reduce the number of people who might suffer the acute effects of radiation or might have an enhanced risk of developing cancer later in their lives. Calculation of Impact The different stages of the calculation (dispersion, doses, countermeasures and health effects) are combined by com- puter programmes for each of the hypothetical accidents. For each defined accident, even if the amount of activity released is fixed, there will be a distribution of the number of casualties because of: firstly, the various atmospheric stability categories which might be present; and secondly, the different possible wind directions, when combined with a non-uniform popula- tion distribution around the site, leading to exposure of different numbers of people.The results of the calculations are typically presented in the form shown in Fig. 1, where the probabilities per unit time of various accidents occurring has been folded in. Routine Discharges to the Environment In order to obtain Authorisations for discharges of radioactiv- ity to the atmosphere, nuclear operators are required to assess the radiation doses which might arise from these discharges. The calculation proceeds using similar methods to those outlined above for accidents. There are, however, a few differences. While accidental discharges are generally assumed to take place over short periods, those from routine discharges are taken to be continuous and uniform. As a result the activity is spread in different directions according to the wind rose (rather than having a probability of being blown in a particular direction). The longer-term releases experience turbulence over much longer periods. The pathways of exposure are generally similar to those for the accidental case but there is, of course, no question of ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 countermeasures because doses are very much lower.Because the doses are low only the health effects which are postulated to be linearly dependent on dose (cancer and hereditary effects) need be considered. The annual limit on dose to members of the public employed by authorities is 1 mSv, corresponding to a fatal risk of the order of 10-5 per year. The dose to most exposed individuals is generally, in practice, a small fraction of this limit. 10-8 r 8 I 1 3 Y I" ' - 1 10' 102 103 Fig.1. Frequency distributions of early deaths from degraded core accidents per reactor year of operation. Curve numbers identify particular releases Number of early deaths These levels should be compared with those to which the public are exposed from natural background. Cosmic rays, radiation from activity in rocks and soils and that incorporated from natural sources into our bodies leads to average radiation doses of, on average, about 2 mSv per year. Almost one half of this comes from exposure indoors to the decay products of the naturally occurring radioactive gas radon. Conclusions The modelling procedures used in the assessment of the potential hazards from accident conditions and normal opera- tions at nuclear facilities have been outlined. The assessment methods are applied, in varying forms, to the whole range of nuclear facilities routinely in the course of demonstration that they can be operated safely.Modelling of Radioactivity in the Environment - From Now to Eternity? David R. Williams School of Chemistry and Applied Chemistry, University of Wales, Cardiff CF? 3XF Over and above natural background radiation, man, as part of there is the accidental incident from rather unpredictable the environment, is faced with two types of release of sources, such as the recent Chernobyl radioactive plume which radioactivity; first, there is the intentional slow release of very crossed Europe. small amounts of radioactivity over a large time scale from a In the former case, it is possible to set up many experiments specially constructed radwaste disposal vault, and secondly, to assess the exact material from which the packaging andANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 163 disposal vault will be constructed, to do exploratory drilling and analyses to assess the geosphere and the groundwater flows, and to set up both probabilistic and deterministic models in order to estimate the doses and risks to man over many thousands of years.For the latter sudden release of radiation, the best we can achieve is to set up a series of monitoring stations interlinked such that early warnings are obtained and planned evasive measures can be taken as appropriate. These two releases are summarised in the Fig. 1, indicating that modelling is not only a most useful asset to decision making but, in some instances, it is the only way forward.The disposal of radioactive waste is considered on time scales of thousands of years and involving concentrations of species way below those analysable by available techniques, both factors which cannot be subjected to life-size blank experiments involving non-radioactive species. Secondly, although much can be established from a retrospective study of Nagasaki, Chernobyl, etc., the uncertainty about the location, underlying cause and environmental circumstances associated with a future incident cannot be predicted and so, once again, a monitoring network that will continuously collect data for consequence modelling is essential. This network, known as RIMNET (Radioactive Incident Monitoring Network) has now been established in the UK.1 I Models 1 Slow release - Deterministic Models Data I I 4 Burst m Proba bi I istic Monitor, Model and Manage Programs Validation Fig.1. Two different aspects of radioactivity modelling: of planned protracted time scale radwaste disposal and of sudden incident monitoring and dose prediction Natural radioactivity has been well described in a range of publications and will not be discussed here, although it must be remembered that all the foregoing radiation considerations must be viewed against this natural background and the considerable variation that exists from place to place.2 The environmental consequences of radwaste disposal are quantifiable by a series of large computer models, which have been reviewed recently.3.4 Essentially, it is necessary to know, or to compute, the species present at each stage between disposal vault, waste packaging, backfill material and geo- sphere through to the biosphere.Solid, liquid and gaseous wastes are involved and are expressed in terms of physical chemistry parameters, such as solubility products, absorption coefficients, formation constants, etc. This data, extracted from databanks such as the one housed in Cardiff (-14 000 items), is combined with groundwater flow characteristics and site-specific details, such as the prevailing geology, the presence of humic and fulvic acids, etc. The output is a list of the radioactive species reaching man, albeit of future genera- tions, in 50, 500 or even 5000 years time and the probable risk (or dose) experienced assuming a “worst possible case” scenario.The main codes to be used in this assessment in the UK are based upon NAMMU, to be used by NIREX, and SYVAC, to be used by the DOE to assess the NIREX proposals.5-7 Recent versions of the latter (called TIME2 and VANDAL) incorpor- ate simultaneous isotope pathways and the cycle of ice ages.7 It is reassuring to note the large amount of effort that has gone into verifying the codes, into database comparisons, and into validating the models. An outstanding example of European Community collaboration in this respect is the CHEMVAL project which compares speciation databases present in the research laboratories of eight countries.8 Recognising that there are many conflicts of interests between waste producers, central government, local govern- ment and opponents to radwaste disposal sites, the Govern- ment has implemented the Best Practicable Environmental Option (BPEO) approach .9Jo Decisions are considered, taken and recorded (in the format of an audit trail) against the checklist shown in Table 1.10 Table 1.Check list for selecting a BPEO 1. Define the objective 2. Generate options 3. Evaluate the options 4. 5 . Select the preferred option 6. Review the preferred option 7 . Implement and monitor Throughout steps 1 to 7: maintain an audit trail Summarise and present the valuation Matching “hard” science to the “soft” politics (at govern- ment and opponent levels) is always exceedingly difficult but can be considerably assisted by the BPEO concept. Technol- ogy transfer from the waste disposal field is now occurring.Just as the space race had its high-tech spin-offs, so too radwaste disposal modelling is benefiting other aspects of civilisation. For example, non-radioactive waste is also being subjected to BPEO scrutiny and the models and databases are being employed for studies and predictions of non-radioactive toxic and hazardous wastes in the environment. A recent recommen- dation places such speciation-based decisions into the hands of local and regional authorities.11 3 t r e Fig. 2. Pattern of UK primary sites forming the skeleton monitoring under the RIMNET scheme for164 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 Recognising that the public has great difficulty in under- standing radiation, its units of measurement and dose-effect relationships and that, in the eyes of the public, waste and radioactivity are definitely NIMBY (Not In My Back Yard!) but, as far as monitoring is concerned, the same public ask WNIMBY (Why Not In My Back Yard?),’* the Government has set up a framework for monitoring radiation across the UK; this is called RIMNET.We recently undertook a survey of radioanalytical facilities in Wales on behalf of the Welsh Office.13 All instruments located in the Principality were listed. These involved hospi- tals, health authorities, industry (CEGB and Amersham plc), local authorities and educational institutes. There was a range of expertise on both the technical (equipment and sample handling) and scientific (survey planning and data interpreta- tion) fronts.Clearly, in the event of an incident such as Chernobyl, all of these facilities could be generating data in overdrive gear! Scaling-up this data to National level could lead to Government, press and public being swamped with data and interpretations of a wide range of qualities. Such consideration has led the Government to produce RIMNET, a national network of environmental radiation monitoring facilities based upon background monitoring sites on the skeleton of the locations shown in Fig. 2. The equipment and staff in these sites would be accredited, by training as necessary, to feed background levels by electronic mail into a central database facility (CDF). In the event of an incident being announced or detected by RIMNET, this skeleton could be fleshed out by expanding the amount of monitoring data collected by the locations indicated, and by bringing in supplementary accredited monitoring sites and facilities.The information received at the CDF would be assessed, bulletins prepared and regional and local authorities and the media informed. In addition, advice would be provided along the lines of restricting the consumption of certain foods, medical treatment, general advice, etc., as appropriate. It is pleasing to note that the system has already been set up and that the first dry run is scheduled for this autumn. It was Leonard0 da Vinci who remarked that “no human investigation can be called real science until it can be demonstrated mathematically.” This is never more true than in the field of radiation protection, where the long time scales, the extremely low speciation concentrations and the general complexities of the system render progress without a computer impossible.From experiences on the Government advisory committees on which I am privileged to serve,14 the impression is gained that the scientific knowledge of waste disposal and environ- mental monitoring is as good as that of any other country: the political will to implement varies, being somewhat tardy on the radwaste disposal front but enthusiastic on the monitoring network scene; the public perception of risk is sadly lacking and it is now the responsibility of all scientists in the field to liaise with interested persons in plain layman’s language. I am pleased to thank my colleagues in the applied chemistry speciation research group in Cardiff and also Government departments and industry for collaborating with our re- searches.The views expressed, however, are my own. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. References “Nuclear Accidents Overseas-the National Response Plan and Radioactive Incident Monitoring Network (RIMNET) ,” Department of the Environment, London, 1988. “Living with Radiation,” Third Edition, National Radiological Protection Board, Didcot, 1986, pp. 1-53. Duffield, J. R., and Williams, D. R., Chem. SOC. Reviews, 1986, 15, 291. Duffield, J. R., and Williams, D. R., Chem. Br., 1989, in the press. “NIREX Disposal Safety Programme,” NIREX, Didcot, 1988, “SYVAC ‘NC’ User’s Guide,” DOE SYVAC User Document, UD-SCI-2, First Edition, Department of the Environment, London.1985. Frizelle, C., New Scientist, 1988, October 15, 45. Read, D., and Broyd, T. W., Radiochim. Acra, 1989, in the press. Royal Commission on Environmental Pollution, “Best Practic- able Environmental Option,” 12th report, Cm 310, HM Stationery Office, London, 1988. Miles, J., Chem. Znd., 1988, 480. Health and Safety Executive’s Local Authority Enforcement Committee (HELA), cited in ref. 8. Page, R., Municipal Journal, 1987, 1493. Duffield, J. R., Griffiths, P. J. F., Robbins, D., and Williams, D. R., Report to Welsh Office, September, 1988, Ref. WEP5717713. Committee on Medical Aspects of Radiation in the Environ- ment, Department of Health; Radioactive Waste Management Advisory Committee, Department of the Environment; Radio- active Research and Environmental Monitoring Committee, Department of the Environment. pp. 1-24. SPECTROSCOPIC PROPERTIES OF INORGANIC AND ORGANOMETALLIC COMPOUNDS - VOLUME 21 Senior Reporters: G. Davidson, University ofNottingharn, and E.A.V. Ebsworth, University of Edinburgh This book reviews the recent literature published up to late 1987. Its Brief Contents are: Nuclear Magnetic Resonance Spectroscopy; Nuclear Quadruple Resonance Spectroscopy; Rotational Spectroscopy; Characteristic Vibrations of Compounds of Main-group Elements; Vibrational Spectra of Transition-element Compounds; Vibrational Spectra of Some Co-ordinated Ligands; Mossbauer Spectroscopy; Gas-phase Molecular Structures Determined by Electron Diffraction. ISBN 0 85186 193 8 Hardcover 525pp. Specialist Periodical Report (1988). Price E120.00 ($240.00) For further information, please write to: Royal Society of Chemistry, Sales and Promotion department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF, UK. To Order, please write to Royal Society of Chemistry, Distribution Centre,Blackhorse Road, Letchworth, Herb SG6 IHN, UK. or telephone: (0462) 672555 quoting your credit card details. We cannow accept Access, Visa, Mastercard & Eurocard. RSC Members are entitled to a discount on most RSC publications and should write to: The Membership Manager, Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridne CB4 4WF, UK. ROYAL SOCIETYOF CHEMISTRY Information Services

ISSN:0144-557X    

DOI:10.1039/AP9892600161

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS. MAY 1989, VOL 26 165 Equipment News Luminescence Spectrometers The Model LS-30 is a sensitive, rapid sampling luminescence spectrometer. Maximum sensitivity is ensured by a compact dual monochromator system. The illuminated flow cell is self-aligning and can be easily removed for mainte- nance. The peristaltic pump is controlled from the keyboard and samples can be measured manually or automatically using the optional 40-position auto- sampler. The PC controlled Model LS-50 is a versatile, high-performance , scanning instrument capable of measuring fluores- cence, phosphorescence, chemilumines- cence and bioluminescence data. It has the ability to analyse selectively many different types of sample and it is de- signed for accuracy of measurement, con- venience and ease of use.A comprehen- sive range of sample handling accessories is available. Many of these are computer controlled to automate sample handling for a wide range of applications. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Mass Analysis Systems The Compass concept is to provide com- plete solutions to gas analysis problems by designing optimised computer integrated mass spectrometer systems, the ideal system for each specific application being selected from a wide choice of the makers’ ion sources, quadrupole analysers, vac- uum and inlet systems and the com- prehensive PC 2000 series software suite, which can be augmented by customised software if required. Spectramass, Radnor Park Industrial Estate, Congleton, Cheshire CW12 4XR.Software for X-ray Spectrometry A new facility for automatic semi-quanti- tative analysis of totally unknown samples has been added to the X40 X-ray spec- trometry software package. Measurement is based on rapid scanning of the sample spectrum using a standard routine in X40. This includes the ability to switch parameters for optimisation of accuracy over different element ranges. After auto- matic background subtraction, peak searching and identification, elemental concentrations are calculated by means of the Criss XRF-11 fundamental paramet- ers program, which requires a minimum number of standards. Philips Industrial and Electro-acoustic Systems Division, 5600 Eindhoven, The Netherlands. Infrared Analyser LCIE approval to CENELEC specifica- tions EN50014 and EN50016 has been received for the purged PSA402 process infrared analyser. CENELEC EEx p approval allows thc PSA402 to be used in Zone 1 and Zone 2 hazardous areas and with group I1 gases.Gas, liquid and vapour measurements can all be per- formed by the 402, allowing components ranging from CO and C 0 2 to SOz, sol- vents, water vapour and water in solvents to be detected. Servomex Ltd., Crowborough, Sussex TN6 3DU. Monochromator An ultra-compact digital version of the Minichrom is available as a manually operated unit incorporating a high pre- cision sub-miniature stepping motor, Business Park, Basingstoke, Hampshire RG24 OWA. Software for Fourier Transform Infrared Spectrometry A major new software upgrade is announ- ced for the makers’ range of FT-IR spectrometers. The 4.30 issue of SPEC- TROMETER is designed for spectrometer control by any operator regardless of expertise.Included in the issue are full menu and command-line operation. All commands and parameters are linked to help messages. Available also is the facil- ity for detailed macroprogramming, including operator prompts, alarms and safeguards. Optometrics monochromator internal limit switches and a connector for direct hook-up to the CB-3 stepping motor controller. It can be purchased with a holographic or a ruled grating covering the following wavelength ranges: 180- 650,200-800,300-8OO nm and 750 nm-1.7 CLm. Optometrics (UK) Ltd., Unit D9, Cross Green Approach, Leeds LS9 OSG. Software for Near Infrared Spectrophotometery Following co-operation between Glaxo Central Analytical Development and the makers a new self-validating system has been designed for use by unskilled staff.Based on PRISM software and the InfraAlyzer, the system results in lower raw materials inventory costs, as checks can be carried out on incoming materials in 2-4.5 min. The concept encompasses fingerprinting , identifying and assessing the quality of raw materials, products and intermediates at each stage of a process, as required, to ensure uniform quality. Bran and Luebbe, Analysing Technolo- gies Division, Beechwood, Chineham Bio-Rad Microscience Division, 53-63 Greenhill Crescent, Watford Business Park, Watford, Hertfordshire WD1 8QS. Gas Chromatography Software New GPC-PRO software which can be used with any chromatography hardware, including dual channel RI and UV, viscos- ity or low angle laser light scattering detection, features peak broadening cor- rection and the ability to correct base-line points manually.Calibration can be car- ried out by using a series of narrow or broad distribution standards and it is possible to overlay a combination of these calibration curves to enhance compatibil- ity with samples. Viscotek Corp., 1032 Russell Drive, Porter, Texas 77365, USA. Gas Chromatographs Three instruments covering most levels of requirement in the detection of atmo- spheric and aqueous pollutants with the capability of also analysing simple sol- vents feature either thermal conductivity or FID detectors. The GM-1 is a basic166 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 routine instrument.The GM-2, for general laboratory work, incorporates a simple integral computer recorder cap- able of quantification. The GM-P has the same range of facilities as the GM-2 but is portable for field use. Gow-Mac Instrument Co. Ltd., Gow-Mac House, 6 Livingstone Circus, Gillingham, Kent ME7 4HA. Portable Gas Chromatograph The M200 system is a dual gas chromato- graph which will give precise analysis in a fraction of the time taken by conventional gas chromatographs. Columns, injectors and ovens are all incorporated in this 12-lb package. Independent temperature control from 30 to 200 "C gives the capacity to analyse a wide range of gases using a thermal conductivity detector. Environmental Monitoring Systems Ltd., Kingswick House, Kingswick Drive, Sunninghill , Berkshire SL5 7BH.PC Control of Gas Chromatographs Up to four Shimadzu GC-14A instru- ments can be directly controlled by a single IBM PC. Achieved by linking the computer with the chromatographs via their RS232C interfaces, this system faci- litates laboratory automation by enabling the remote programming of different analyses and the monitoring of key analy- tical parameters. The GC-14A instru- ments are suitable for use with capillary or packed columns and they feature a con- trol circuit which gives excellent oven temperature control, allowing operation close to room temperature. They can be fitted with FID, ECD, FTD, TCD and FPD detectors and they can be run with up to four sample injectors independently temperature controlled. The GC-8A series of chromatographs are designed for the smaller laboratory.Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH. Chromatography Columns The Petrocol DH fused silica capillary column offers an average of 400 000 plates for detailed analysis of hydrocarbons, resolving light hydrocarbons as well as rn- and p-xylenes under ambient starting temperatures. It resolves isobutylene and but-1-ene at sub-ambient initial temperat- ures. The Petrocol 3710 thick film glass capillary column, containing a 5 pm cross- linked methyl silicone film, satisfies all performance criteria of ASTM Method D3710 for simulated distillation of gasol- ine. It offers the potential for performing SIMDIS analyses with ambient starting temperatures.Supelchem UK Ltd., Shire Hill, Saffron Walden, Essex CBll 3AZ. HPLC Columns The Supelcogel C-611 column is espe- cially suited to the separation of mono- and disaccharides and sugar alcohols by ion exchange. It is stable over a pH range of 1-13 at temperatures up to 70 "C. The Supelcogel C-610 columns can resolve many mono- and diprotic acids and have efficiencies of at least 10000 plates with a stability of 1-13 pH. Supelchem UK Ltd., Shire Hill, Saffron Walden, Essex CBll 3AZ. HPLC Column System A cartridge system for 4 mm internal diameter columns offers improved effi- ciency and guaranteed reproducibility with ease of changing columns. A set of re-usable end-fittings, which can be used for 125 or 250 mm cartridges, can be employed with or without guard cart- ridges.Guard columns are only 4 mm long. The columns are available with most useful reversed phases. At introduction they will be available packed with Super- sphere, LiChrosphere and LiChrosphere- Select B (a phase designed for chromato- graphy of basic compounds) from E. Merck, Darmstadt. Other packings will be available later. Hewlett-Packard S.A. , Route Du Nant-d'Avril 150, P.O. Box CH-1217 Meyrin 2, Geneva, Switzerland. HPLC Analysis of Food Components and Additives A range of Shim-pack columns from Shimadzu can be used to separate the components of a variety of sugars and saccharides in standard saccharide solu- tions, honey, orange juice, wort and liquor. A stainless steel tube 4 mm in diameter and 25 cm long, the Shim-pack PNHZ-10/S2504 is packed with silica hav- ing a particle diameter of 10 ym and is chemically bonded with aminopropyl group.The Shim-pack PNH,-10 can be used in any mode of reversed-phase, normal-phase and anion exchange. Other Shim-pack columns for saccharide analysis include the SCR-1O1N and the ISA-07/ S2504. A data application sheet is avail- able. Dyson Instruments Ltd. , Hetton Lyons Industrial Estate, Hetton, Houghton le Spring, Tyne and Wear DH5 ORH. HPLC System System Gold QC I1 is preconfigured for automated chromatography using all iso- cratic and step-gradient techniques. It automates equilibration, elution and col- umn wash procedures for fast system start-up and shut-down. System Gold for the QC laboratory delivers smooth flow with reproducibility better than +O. 1% and built-in microchromatography flow- rates as low as 0.001 ml min-1.Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Bucking- hamshire. Liquid Chromatography Pumps The Series 250 LC pump is available in isocratic or binary versions, with the ability to upgrade the isocratic to pro- grammable binary. The 250 isocratic LC pump offers complete flow-rate range from 0.01 to 10 ml min-1, user selectable upper and lower pressure limits, pulse compensation system and automatic pump shut-off. The 250 systems allow the addition of auto-samplers, injectors, col- umns and data handling devices and they combine with the LC-135 and LC-235 diode-array detectors. Perkin-Elmer Ltd. , Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Automatic Sampling System The Model AS-100 HRLC automatic sampling system is electronically pro- grammable and offers high precision with a Multi-Mix capability and automatic washing. It can provide automatic injec- tions of up to 100 individual samples of any kind from volatile to viscous.Differ- ent sequences, volumes or temperatures can be programmed, and standards can be run in any order. A built-in solid-state refrigeration unit reduces spoilage of bio- logical samples. The Multi-Mix function enables the Model ASD-100 to perform automatic pre-column derivatisations. Bio-Rad Laboratories Ltd., Caxton Way, Watford Business Park, Watford, Hertfordshire WD1 8RP. Luminescence LC Detector The Model LS-40 is a programmable luminescence LC detector combining fluorescence , phosphorescence , chemilu- minescence and bioluminescence in one instrument.Using fluorescence detection, compounds can be detected down to the program level, while phosphorescence and chemiluminescence substantially increase the power of the technique. The integral printer and keyboard simplify operation and file keys provide method storage and recall. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Disposable Syringe Filters The new Anotop 25 Plus range builds on the success of the existing Anotop 25 series but delivers even better perfor- mance for sample preparation with the incorporation of a pre-filter, which forms an integral part of the compact unit and retains larger, extraneous matter prior to filtration through the Anopore mem- brane below.The Anotop 25 Plus range is available in 0.2,O. 1 and0.02 ym pore sizes. The 0.1 pm pore size Anotop 25 Plus has a specific application for mycoplasma remo- val in tissue culture work. Independent research has shown that these filters can remove contaminating species of mico- plasma from tissue cultures. Anotec Separations Ltd., Banbury, Oxfordshire.ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 167 TLC Sheets Empore TLC is a 3M technological materials development which combines inert PTFE fibres with chemically bonded silica particles from Analytichem into a flexible sheet for TLC. Available in a variety of bonded silicas, Empore TLC sheets are capable of handling an unli- mited range of samples and solvent systems and they have several times the capacity of a standard hard layer TLC plate.Spots can be cut or punched out for further analysis without having to resort to scraping. Jones Chromatography Ltd., New Road, Hengoed, Mid-Glamorgan CF8 8AU. Autosampler Vials Polypropylene vials for Waters 48-posi- tion WISP are non-ionic and so ideal for samples sensitive to possible ionic con- tamination or pH changes. A full range of caps and septa are available. The vials can be incinerated without opening or crush- ing. Polypropylene inserts (500 PI) are also available to fit all 4 ml screw top vials (including glass). HPLC Technology Ltd. , Wellington House, Waterloo Street West, Maccles- field, Cheshire SKll 6PJ. Ion Exchange Resins Molecular Biology Grade ion exchange resins are specially processed and certi- fied to ensure recovery of intact plasmid. Two types are available: AG 50W-X8 strong cation exchange resin, which gives same-day results in the removal of ethi- dium bromide and propidium iodide from plasmids, and AG501-X8, mixed bed resin, which is effective for rapid de- ionisation of formamide, glyoxal and PEG.Both are certified free of endo- and exonuclease and contain no ligase inhibi- tors. The Biotechnology Grade ion exchange resins have undergone process- ing and are certified to contain less than 100 microorganisms g-1. Bio-Rad Laboratories Ltd. , Caxton Way, Watford Business Park, Watford, Hertfordshire WD1 8RP. Gas Detection Systems The Surveyor range of fixed gas detectors and controllers are designed with the COSHH regulations in mind. The detec- tors for combustible, toxic or oxygen gases are BASEEFA approved and their fuel cell type sensors have lifetimes up to 2 years. The controller range extends from single-channel and four-channel units to multi-channel units.Servomex Ltd. , Crowborough, Sussex TN6 3DU. Oxygen Analyser The Model 9600 oxygen analyser system provides continuous monitoring of flue gas and features a maintenance-free micro-fuel cell sensor offering an absolute zero and an output linear to oxygen concentration; thus, no zero gases are required and atmospheric air can be used for calibration. The Model 9600 features three ranges of analysis: 0-5%, &lo% and 0-25% oxygen. Teledyne Analytical Instruments, The Harlequin Centre, Southall Lane, South- all, Middlesex UB8 5NH. Leak Detector Accessories New accessories for the portable HLT helium leak detector include the BP 100 “bombing” chamber for preparing small, sealed components, and the TP 100 test chamber into which the samples are trans- ferred for testing.For production line work the test cycle can be fully automated with the addition of the TC 100 test control electronics, which simply plug into the HLT 100. A new fast sniffer probe enables testing to be performed up to 50 m from the detector. Also available are a helium cylinder, pressure regulator and helium spray pistol. Balzers High Vacuum Ltd., North- bridge Road, Berkhamsted, Hertford- shire HP4 1EN. Titrator The AF7 Coulometric Karl Fischer titra- tor from LTE uses a new concept in reaction vessels, employing an ion-per- meable membrane to allow dual-speed high-volume runs at 20 mg min-1.Roth Scientific Co. Ltd., Alpha House, Alexandra Road, Farnborough, Hamp- shire GU14 6BU. Electrolyte Analysers The 600 Series of clinical electrolyte analysers combines advanced sensor tech- nology with minimal maintenance requirements. Units in the range include the 614, 634, 644 and the 664Fast Four analyser. All carry out measurements from serum, plasma, whole blood or urine. The 614 NdK and 634 CdpH analysers are ideal for paediatric and foetal applications and can accept samples as small as 35 1-11. Other options available with the 634 include the ability to report ionised calcium at any pH of the sample, corrected to the pH of 7.4, or the patient’s in vivo pH. The 644 Na+ K+, C1- and 664Fast Four Na+, K+, C1- and tCO, analysers are suitable for laboratories with a high sample throughput.Ciba Corning Diagnostics Ltd., Hal- stead, Essex, C09 2DX. Sodium Meter The pNa is a pocket sized sodium meter, which has an ion-selective electrode and an LCD display. It features four ranges: 23, 2.3, 0.23 and 0.023 g 1-1. UK Instruments Ltd., Happy Valley Industrial Park, Primrose Hill, Kings Langley, Hertfordshire WD4 8HZ. Bag-in-the-Box Packaging The bag-in-the-box packaging system, first introduced into the wine trade, is a practical method of storing and pouring liquids. It has now been introduced for chemical reagents. BDH buffer and AnalaR volumetric solutions, together with sodium hydroxide 40% mlV solution and water AnalaR, are currently available in bag-in-the-box packaging.BDH Ltd., Reagents Division, Broom Road, Poole, Dorset BH12 4”. Software for Particle C haracterisation Designed to expand the scope of the Galai CIS-1, the new software allows the re- liable measurement of concentration, size and shape of samples which may contain relatively few particles or cells. Roth Scientific Co. Ltd., Alpha House, Alexandra Road, Farnborough, Hamp- shire GU14 6BU. Thermal Analysis Equipment Roth Scientific have been appointed exclusive UK agents for the entire range .of thermal analysis products, including DSC, DTA, TGA and CALVET cal- orimetry manufactured by Setaram. The Setaram products cover a temperature range from -196 to +2400 “C. Roth Scientific Co. Ltd., Alpha House, Alexandra Road, Farnborough, Hamp- shire GU14 6BU. Software for Thermal Analysis New data acquisition software for the makers’ TRACE system, TRACE 3 Version 4, supports all the current thermal analy- sis techniques, including TG, DSC, DTA, TMA and STA.It is fully IBM compat- ible, operating on either PS/2 series or AT compatible machines, and it makes good use of the 640K of memory, hard disk and EGANGA graphic features available on PCS . Stanton Redcroft Ltd., Copper Mill Lane, London SW17 OBN.168 ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 Thermal Analysis System The makers' TA series of thermoana- lytical equipment is being expanded by the new TA4000 system, at the heart of which is the new TA T C l l processor. Also incorporated is the new DSC25 measuring cell, which can be used over a tempera- ture range of -20 to +750 "C and which, thanks to a sophisticated mechanism for opening and closing the furnace chamber, makes sample insertion simple.Me ttler Ins trumen te AG , CH-8606 Greifensee, Switzerland. Calorimeter The IKA C 4000 bomb calorimeter system has been developed on a modular style, the modules including a bomb and asso- ciated filling station,. a briquetting press, the C 4000 adiabatic measuring cell and a cooling water supply tank, computer con- trol module with documentation unit, a print-out facility and a Sartorius analytical balance. It will determine precisely the gross calorific values of solid and liquid substances. Sartorius Ltd., 18 Avenue Road, Bel- mont , Surrey SM2 6JD. Pump The EMP15/28 IV magnetic chemical pump utilises inverter drive to achieve pump impeller speed control and conse- quent response in discharge pressure or rate of flow.An impeller speed of approaching 8000 rev min-1 enables the pump to achieve a maximum pressure of 40 Ib in-2 and a maximum rate of flow of 40 1 min-1. The magnetic coupling elimi- nates potentially troublesome rotating seals. Totton Pumps Ltd., Southampton Road, Cadnam, Southampton SO4 2NF. Furnaces The Ultraspeed 1800 hand-built chamber furnace has been designed for a variety of applications, including those for which thermal cycling up to 1800 "C is required. It is currently available with a chamber capacity of 3 1, although it may be supplied in other, optional chamber sizes as user needs demand. Also announced is a new programmable tube furnace, the SRF Series, designed specifically for applications in superconductivity research.It offers a maximum operational temperature of 1600 "C and it has the ability for operation with controlled atmospheres, burn-off, flow metering, sample positioning and flame-failure detection, b.y means of which the hydrogen supply is shut off and replaced with nitrogen to effect purging. The SRF also features adaptability in meeting the precise dimensional and operational requirements of the application, including a customised work profile. Lenton Thermal Designs Ltd., 12-14 Fairfield Road, Market Harborough, Leicestershire LE16 9QQ. Rheometer A rotary/oscillatory rheometer, the Low Shear 40, designed for measurements on low viscosity and elastic fluids at low and very low shear rates, has two exchange- able measuring heads which provide for a wide measuring range and optimum sensi- tivity.Contraves Industrial Products Ltd. , Times House, Station Approach, Ruislip, Middlesex HA4 8LH. Dewpoint Meter The Series 3000 dewpoint meter is cap- able of monitoring critical humidity levels in, for example, an environmental cham- ber. It may be used to display either dewpoint or per cent. relative humidity. It has a total range from -75 to +85 "C dewpoint, providing an accuracy of better than k 0.3 "C dewpoint. Michell Instruments Ltd. , Unit 9, Nuf- field Close, Nuffield Road, Cambridge CB.4 1SS. Scanning Electron Microscope The JSM-5200, a scanning microscope with keypad control, has been designed for educational, quality control, or low- cost research purposes.Samples up to 51 mm across can be accommodated. Magnifications in 25 steps between 15 and 200 000 x can be achieved with resolutions to 5.5 nm. The JSM-5200 can be expan- ded for analytical work, options including an ED X-ray spectrometer, imaged pro- cessing and analysis. It also features a low accelerating voltage of 1 kV for non- coated specimens and a twin screen option for photography. A wide range of attach- ments are available. Jeol (UK) Ltd., Jeol House, Grove Park, Colindale, London NW9 OJN. Ultrasonic Cleaning Solutions More than 15 cleaning chemicals have been developed for use with the makers' range of ultrasonic Sonicleaners. They include solutions for cleaning all kinds of glass, metal and plastic apparatus. The makers offer to carry out trials and to make subsequent recommendations.Apollo Electronics, Westfield Resource Centre, Westfield Lane, South Elmsall, West Yorkshire WF9 2PU. Cleaning Agents Karafol Super from Neodisher is a vig- orous, strong-acid, powdery cleaning agent for use where difficult yet acid- soluble contaminations must be cleaned. Also available is Neodisher FA, a power- ful general cleaning agent for special laboratory and medical equipment wash- ing machines. Scientific Instrument Centre Ltd. , Unit 34D, Parham Drive, Boyatt Wood, East- leigh, Hampshire SO5 4NU. Thermostat The Hetotherm DT thermostat has been designed for temperature measurement of liquids in all types of baths. It has a continuously adjustable temperature range of from -50 to +110 "C, as well as five fixed temperatures of 25, 30, 37, 45 and 56 "C.Various versions can be supplied for use on standard baths, with or without built-in remote control cir- cuits, and HETO cooling baths. Paar Scientific Ltd. , 594 Kingston Road, Raynes Park, London SW20. Workstation Servers A computational server and a chemistry server adapted from the Titan graphics supercomputer can increase the process- ing power of networked high-end graphics workstations as much as ten times. Incor- porating one to four high-speed parallel vector processors, the Titan servers pro- vide peak processing performance of 64 MFLOPS and 64 MIPS. A single-proces- sor Titan server achieves 6.5 MFLOPS and a two-processor version 9.4 MFLOPS on the 64-bit 400 x 100 compiled Linpack benchmark. Ardent Computer Ltd., 694 North Row, Lloyds Court, Central Milton Keynes, Buckinghamshire MK9 3AP.Line Measurement System Philips' range of electron optical instrumentation for integrated circuit testing has been complemented by a new linewidth measurement system. Operat- ing on the Series 500 scanning electron microscopes, the system is designed to deliver repeatable measurements on materials used in wafer fabrication, ie., metals, oxides, resists and masks. Philips Scientific, York Street, Cam- bridge CB1 2PX. Protection Agent Neodisher IP Milch is a liquid agent for instrument care designed to be added to medical and laboratory washing machines and based on emulsified medicinal white oil. It protects against atmospheric corro- sion by adding a fine hygienic protective film to all instruments in the sterilising washing machine during the final rinse. The film is easily removed during the following wash, allowing the instruments to be properly sterilised afterwards.Scientific Instrument Centre Ltd., Unit 34D, Parham Drive, Boyatt Wood, East- 1-eigh, Hampshire SO5 4NU.ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 169 Kit for Analysis of Alkaline Phosphatase Isoenzymes The new Paragon Isopal Kit, in the Paragon agarose gel electrophoresis range, provides analysis of alkaline phosphatase isoenzymes in bone and liver fractions, intestinal and placental fractions and, with optional complementary reagents from the range, atypical variants. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Bucking- hamshire. Filter Units The first disposable, sterile filter units with a 90 mm diameter membrane (57.2 cm* filter area) and low protein bonding are announced.Nalgene Media-Plus filter units allow easy vacuum filtration of up to 1 1 of media with 20% serum, commonly used in hybridoma research laboratories. Nalgene Serum filter units provide vac- uum filtration of up to 500 ml of whole foetal bovine serum (FBS). Nalge Company, 75 Panorama Creek Drive, Box 20365, Rochester, New York 14602-0365. Complete Blood Analysis Systems A complete support package of quality control materials, sampling devices and data management systems now comple- ments the makers’ 200 Series of blood gas analysers. Extending this system concept are remote control and monitoring facili- ties and the option of linkage to co- oximetry for oxygen dissociation curve analysis.Ciba Corning Diagnostics Ltd., Hal- stead, Essex C 0 9 2DX. Automated Systems for Enzymatic Biochemical Analysis TrAAcs is a fully automated system for carrying out enzymatic tests. Using the TrAAcs system, laboratories are able to run up to 150 samples h-1, with up to 4 tests being carried out simultaneously. The system is based on colorimetric and ultraviolet detection down to 340 nm. Operator involvement is confined to placement of samples in the sample tray. Bran and Luebbe, Analysing Techno- logies Division, Beechwood, Chineham Business Park, Basingstoke, Hampshire RG24 OWA. Enzymes BsmA 1 and Bsr 1 are enzymes isolated from Bacillus stearothermophilus, and Ear 1 is isolated from Enterobactes aerogenos. All three are supplied in 100 and 500 units.The following enzymes are now being supplied in increased quan- tities: BamHl, Kpn 1, Nde 1, Nia IV, Pst 1 and Taq 1. A catalogue is available. CP Laboratories Ltd., P.O. Box 22, Bishops Stortford, Hertfordshire CM23 3DH. Literature New atomic spectroscopy application notes have been produced as follows. Fundamentals: The STPF Concept (Ref. 1.3E). Instrumentals: The Use of Tin(I1) Chloride and Sodium Borohydride for the Determination of Mercury with Amalga- mation Technique (Ref. 2.1E); Total Pyrolytic Graphite for Electrothermal Atomic Absorption Spectrometry (Ref. 2.2E). Industrial: Determination of Trace Elements in Diluted Boric Acid by Graphite Furnace AAS (Ref. 3.1E); Direct Determination of Trace Elements in Petroleum Products using Flame and Graphite Furnace AAS (Ref.3.3E). Environmental: Determination of Ar- senic using Graphite Furnace AAS and Zeeman Effect Background Compensa- tion (Ref. 4.1E); Determination of Cad- mium and Lead in Waste Water (Ref. 4.2E); Determination of Mercury in Air Using Atomic Absorption Spectrometry and the Amalgam Technique (Ref. 4.3E). Foodstuffs: Determination of Iron in Beer by Flame Atomic Absorption Spec- trometry following Acid Digestion of the Sample (Ref. 5.1E). Clinical Chemistry: Determination of Copper in a Trace Element Preparation (Ref. 6.1E); Fully Automatic Multi-Element Determination of Na, K, Ca and Mg in Serum Using the Model 2100 Flame Atomic Absorption Spectrometer (Ref. 6.2E). Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA.Details of the new Suprex SFE/SFC systems are described in the latest issue of Dyson Data, together with Chemical Data Systems range of specialist pyrolysis equipment and sample concentrators for gas chromatography. Also featured are the Shimadzu SPD-M6A photodiode array detector, the GCMS-QP2000 gas chromatograph - mass spectrometer system and an article on waste treatment monitoring using the Shimadzu TOC-500 total organic analyser. Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH. A 100-page monograph, “Screening and Confirmation of Drugs with Toxic-Lab TLC and Hewlett-Packard GCNS Systems,” presents step-by-step methods and procedures for analysis of 40 common drugs of abuse including antidepressants, benzodiazepine, pentazocine and tripelennamine .Hewlett-Packard S.A., Route du Nant- d’Avrill50, P.O. Box CH-1217 Meyrin 2, Geneva, Switzerland. Biotext (Vol. I, No. 3) features a new Supelclean DrugPak solid phase extrac- tion tube providing absolute metabolite recoveries greater than 85% for THC. It also discusses Supelcosil LC-18 and Supelcosil LC-DP columns for resolving and analysing steroidal components of oral contraceptives and anabolic steroids. Other articles feature a new RPLC column for improving resolution of important red blood cell nucleotides, and series connected Progel-TSK columns which optimise separations of different molecular weight lipoprotein fractions. Supelco Inc., Supelco Park, Bellefonte, PA 16823-0048, USA.Scientific Glass Engineering (UK) Ltd. have produced Issue No. 32 of their House Journal, SGE Topics. It covers the LS 3200 HPLC autosampler, HT5 high temperature stationary phase for capillary GC, and SGE’s new representative for the East of England. Scientific Glass Engineering (UK) Ltd., Potters Lane, Kiln Farm, Milton Keynes MKll 3LA. A brochure describes the Bio-Rad range of ion exchange resins, including their two new lines for biotechnologists and mol- ecular biologists, together with their analytical, technical and Aminex HPLC grade resins. Bio-Rad Laboratories Ltd., Caxton Way, Watford Business Park, Watford, Hertfordshire WD1 8RP. A brochure describes COMPASS systems for precision gas analysis. It provides information on systems for a range of applications, including environmental pollution monitoring, chemical process control, pharmaceutical quality assurance and residual gas analysis in high vacuums.Spectramass Ltd. , Radnor Park Indus- trial Estate, Congleton, Cheshire CW12 4XR. A brochure describes the series 9000 flue gas analyser systems, which optimise combustion efficiency and minimise exhaust emissions. Teledyne Analytical Instruments, The Harlequin Centre, Southall Lane, South- all, Middlesex UB2 5NH. The determination of the concentration of inorganic ions in tap water, using the technique of ion chromatography, is de- scribed in a brochure. The analysis uses the Shimadzu HIC-6A ion chromato- graph. Dyson Instruments Ltd., Hetton Lyons Industrial Estate, Hetton, Houghton-le- Spring, Tyne and Wear DH5 ORH.A brochure (Publication 5956-4182) de- scribes the HP enzymes kinetics system, showing how more reliable results can be obtained from fewer experiments. The system featured in the brochure has three main components: a software package dedicated solely to enzyme kinetics, the latest HP diode-array ultraviolet - visible spectrophotometer and an HP ultraviolet170 ANALYTICAL PROCEEDINGS. MAY 1989. VOL 26 - visible ChemStation. The system auto- mates the study of enzyme mechanisms from data acquisition through evaluation and model-fitting to the printing of results. Hewlett-Packard S.A., Route du Nant- d’Avrill50, P.O. Box CH-1217 Meyrin 2, Geneva, Switzerland. A catalogue covers the range of equip- ment for elemental, structural, molecular and electrochemical analysis available from Philips Analytical.It includes a wide range of spectrometry, electron micro- scopy, chromatography and spectropho- tometry equipment, as well as that for pH, conductivity and ion-selective measurement, and an automated labora- tory management system. Philips Industrial and Electro- Acoustic Systems Division, Building HKF 5600 MD Eindhoven, The Netherlands. A catalogue describes the Tacussel range of electrodes for titrators and measure- ment. Included are glass, metal, refer- ence, non-aqueous and ion-specific elec- trodes. Also covered by the catalogue are conductivity measuring cells, temperature compensating probes for critical measure- ment and the range of electrode cables that allow Tacussel electrodes to be used with most manufacturers’ instrumenta- tion. Roth Scientific Co. Ltd., Alpha House, Alexandra Road, Farnborough, Hamp- shire GU14 6BU. A brochure summarises the Klinger range of products including the following new items: a magnetic level gauge with BASEEFA approved transmitter and receiver, a range of asbestos-free sealing materials, Sealex PTFE joint sealant, packings and asbestos-free friction materials. Richard Klinger Ltd., Sidcup, Kent DA14 5AG. The EDT Analytical Digest describes the Chromajet electrochemical detector for HPLC, the QC 355 automatic pH meter, the Qualiprobe range of ion-selective electrodes and several other items. EDT Analytical Ltd., 14 Trading Estate Road, London NWlO 7LU. A booklet presents chromatograms that demonstrate a variety of advanced sep- aration methodologies using the Beck- man System 6300 and 7300 high perfor- mance amino acid analysers. Two expan- ded hydrolysate methods are discussed; they demonstrate improvement over pre- vious standard methods for the separation of complex hydrolysate mixtures from samples such as glycoproteins, connective tissue proteins, cell wall proteins, purified hormones and enzymes. Beckman, Progress Road, Sands Indus- trial Estate, High Wycombe, Bucking- hamshire. Severn Analytical Ltd. have recently introduced a training course for cus- tomers for their Coulochem electrochem- ical HPLC detector. Courses are held throughout the year and the fee for attendance covers instruction, accommo- dation, meals and comprehensive course material. Severn Analytical Ltd., Unit 2B, St. Francis Way, Shefford Industrial Park, Shefford, Bedfordshire SG17 5DZ. Axxiom Chromatography, suppliers of computer-based chromatography data systems, have added another European distributor to their network: Techlab GmbH, with offices in Cologne and Erke- rode, near Braunschweig. Axxiom Chromatography Inc., 36 Brunswick Road, Gloucester GL1 1JJ.

ISSN:0144-557X    

DOI:10.1039/AP9892600165

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

170 ANALYTICAL PROCEEDINGS. MAY 1989, VOL 26 Publications Received Petroanalysis '87. Developments in Ana- lytical Chemistry in the Petroleum Industry. Edited by G . B. Crump. Pp. x + 290. Wiley. 1988. Price 250. ISBN 0 471 91946 2. Introduction to Thermal Analysis. Tech- niques and Applications. Michael E. Brown. Pp. ix + 211. Chap- man and Hall. 1988. Price f17.50. ISBN 0 412 30230 6. Chemical Sensor Technology, Volume 1. Edited by Tetsuro Seiyama. Pp. xvi + 250. Elsevier. 1988. Price $150; Dfl285. ISBN 0 444 98901 3. Gas and Liquid Chromatography in Analytical Chemistry. Roger M. Smith. Pp. xiii + 402. Wiley. 1988. Price &60. ISBN 0 471 909807. Automatic Methods of Analysis. M. Valcarcel and M. D. Luque de Castro. Techniques and Instrumentation in Ana- lytical Chemistry, Volume 9.Pp. xii +ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 171 560. Elsevier. 1988. Price $131.50; Dfl250. ISBN 0 444 43005 9. Problem Solving with Microbeam Analy- sis. K. Kiss. Studies in Anulytical Chemistry 7. Pp. 409. Elsevier. 1987. Price $119.50; Dfl245. ISBN 0 444 98949 8 (volume); 0 444 41944 6 (series). Electron Capture Negative Ion Mass Spec- tra of Environmental Contaminants and Related Compounds. Elizabeth A. Stemmler and Ronald A. Hites. Pp. xvii + 390. VCH. 1988. Price DM128: f45. ISBN 0 89573 708 6 (VCH Publishers); 3 527 269045 (VCH Verlags- gesellschaft) . Ion Chromatography in Water Analysis. 0. A. Shpigun and Yu. A. Zolotov. Ellis Horwood Series in Analytical Chemistry. Pp. 188. Ellis Horwood. 1988. Price f32.50. ISBN 0 7458 0020 3 (Ellis Hor- wood); 0 470 21202 0 (Halsted Press). Soils Contaminated by Petroleum: En- vironmental and Public Health Effects. Edited by Edward J. Calabrese and Paul T. Kostecki. Pp. xiii + 458. Wiley Inter- science. 1988. ISBN 0 471 85106X. High Performance Liquid Chromato- graphy of Biopolymers and Biooligomers. Part B. Separation of Individual Com- pound Classes. 0. Mikes. Journal of chromatography Library, Volume 41B. Pp. xxi + 721. Elsevier. 1988. Price $189.50; Dfl360. ISBN 0 444 43034 2. Reviews on Immunoassay Technology. Volume 1. Edited by S. B. Pal. Pp. ix + 238. Macmillan. 1988. Price f40. ISBN 0 333 452852. Reviews on Immunoassay Technology. Volume 2. Edited by S. B. Pal. Pp. viii + 204. Macmillan. 1988. Price f40. ISBN 0 333 46849 X. Handbook of Inductively Coupled Plasma Spectrometry. Second Edition. M. Thompson and J. N. Walsh. Pp. xi + 316. Blackie. 1988. Price 250. ISBN 0 216 92264 X.

ISSN:0144-557X    

DOI:10.1039/AP989260170b

出版商:RSC    

年代:1989

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 171 Analytical Division Presentations At the Research and Development Topics in Analytical Chemistry Meeting, held on March 21st-22nd, 1989, in the National Institute €or Higher Education. Dublin, a number of presentations were made. Fol- lowing his Silver Medal Lecture, the sixteenth SAC Silver Medal was presen- ted to Dr. R. D. Snook. Later, at the conference dinner, the seventeenth and eighteenth Analytical Division Dis- tinguished Service Awards were presen- ted to Dr. G. B. Marshall and Dr. J. F. Tyson, respectively. Dr. R. D. Snook'(L) receives his Silver Medal from the President of the Analytical Division, Professor D. Thorburn Burns Dr. G. B. Marshall receives his Distinguished Service A ward from the President Dr. J. F. Tyson receives his Distinguished Service A wardlnfcymat ion Services CHEMICAL SAFETY DATA SHEETS Volume 1 - Solvents All solvents have hazardous properties, yet find ubiquitous use in industry and are among the most widely used chemicals in society.This important new book aims to cover every aspect of the hazards of these solvents, providing invaluable information in a concise but readable format, with full references for further investigation if required. Chemical Safety Data Sheets Volume 1 - Solvents provides up-to-date information on over 100 representative solvents. Included will be the full range of CHEMICAL, PHYSICAL AND BIOLOGICAL hazards likely to be encountered by their use, as well as safe handling, emergency precautions, safe disposal procedures and legislation governing their use regarding exposure, transportation and labelling, plus much more.it provides a concise overview of the related hazards of compounds, in a 1 ’ uniform style and is fully ‘indexed by chemical names, synonyms, class name, trade names and CAS Registry No., with a special ‘flash point’ index. Brief Contents: The data sheets are arranged in alphabetical order, and cover the following class headings: Glycols; Alcohols; Esters; Amines (including Nitro Compounds); Ethers; Chlorinated Hydrocarbons; Aromatic Hydrocarbons; Ketones. ISBN 0 85186 903 3 Softcover 300 pages Published 1989 Price S39.95 ($89.00) Volume 2 is scheduled for publication mid 1989 and will be entitled Main Group Metals and their Compounds. SOLVENTS IN COMMON USE: HEALTH RISKS TO WORKERS Solvents in Common Use Heail” Rskl 10 Workers This key handbook contains essential information on ten of the most commonly used solvents and is a must for safety officers and all workers in the EEC at risk from exposure to these solvents.The following information is given for every solvent covered: Chemical Abstracts name; synonyms and trade names; CAS Registry Number; NIOSH number; chemical and structural formulae; occurrence; spectroscopic data; measurement techniques; conditions under which the solvent is put on the market; storage, handling and use precautions; fire hazards; hazardous reactions; emergency measures in the case of accidental spillage; first aid; physio-chemical properties; toxicity; med ical/heal th surveillance; occupational exposure I imi ts.The ten solvents covered are: Acetone; Carbon Disulphide; Diethyl Ether; 1,4-Dioxane; Ethyl Acetate; Methanol; Nitrobenzene; Pyridine; Toluene; Xylene. .The information contained in this extremely useful book was compiled by an expert committee of the Royal Society of Chemistry for the Commission of European Communities. ISBN 0 85186 088 5 Hardcover 308pp Published 1988 Price E60.00 ($120.00) For further information, please write to: Royal Society of Chemistry, Sales and Promotion department, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K. To Order, please write to: Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1HN. U.K. or telephone (0462) 672555 quoting your credit card details.We can now accept AccessNisal MasterCard/Eurocard. RSC Members are entitled to a discount on most RSC publications and should write to: The Membership Manager, Royal Society of chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 4WF. U.K.ANALYTICAL PROCEEDINGS, MAY 1989, VOL 26 173 ROYAL SOCIETY OF C H E M ISTRY lnfor mat a n Services ISOTOPES: ESSENTIAL CHEMISTRY AND APPLICATIONS I1 Edited b y J R Jones, Unrversrty of Surrey ~~ Isotopes: Essentral Chemistry & Applications TI In the years mat have since me RSC published Isotopes: Essential Chemistry and Appricabons in 1980 there have been many changes and developments which warrant publication of this edition. This book covers the synthesis of a wide range of isotopically labelled compounds, the analytical methods used and many important applications.Contents: Organic Synthesis with Short-lived Positron-emitting Radioisotopes; Radioiodination Techniques; The Radiochromatography of Labelled Compounds; Modern Spectrometric Methods for the Analysis of Labelled Compounds; Localization and Quantitation of Radioactivitv in Solid Specimens Using Autoradiography; Isotope Shifts in NMR Sbectroscopy - Measurement and Applications; The Use of Stable Isotopes in Medicinal Chemistry; Radiopharmaceuticals; Isotopes in Molecular Biology; Industrial Applications of Radioisotopes. ISBN 0 85186 746 4 Softcover 272pp Special Publication No. 68 (1988) Price dE39.50 ($79.00) For turther intormation, please write to Royal Society of Chemistry. Sales and Promorion department. Thomas Graham House. Science Park. Milton Road. Cambridge CB4 4WF IJ K To Order, please write to Royal Society of Chemistry. Distribution Centre, Blackhorse Road. Letchworth. Herts SG6 1HN U K or telephone (0462) 672555 quoting your credit card details We can now accept AccffsNisal MasterCardEurocard RSC Mombors are entifled to a discount on most RSC publications and should wnte to The Membership Manager. Royal Soaety of Chemistry, Thomas Graham House, !Saence Park, Milton Road, cambndgeCB44WF U K

ISSN:0144-557X    

DOI:10.1039/AP9892600171

出版商:RSC    

年代:1989

数据来源: RSC