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SPECIAL ISSUE OF THE ANALYST MARCH 1984 The March 1984 issue of The Analyst contains 46 papers presented at SAC 83 - The 6th International Conference on Analytical Chemistry, held in Edinburgh, 17th-23rd July 1983. The papers presented cover the most important areas of analytical chemistry and provide a valuable overview of the conference. The March issue of The Analyst contains the 4 plenary lectures, as listed below, as well as 42 other papers presented. Plenary Lectures: Recent Developments in Fluorescence and Chemiluminescence Analysis - James N. Miller. Capillary Separation Methods: a Key to High Efficiency and Improved Detection Capabilities - Milos Novotny . Design and Application of Neutral Carrier-based Ion-selective Electrodes - W. Simon, E. Pretsch, W. E. Morf, D. Ammann, U. Oesch and 0. Dinten. Continuum Source Atomic-absorption Spectrometry: Past, Present and Future Prospects - Thomas C. O’Haver. Single Issue Price: RSC Members $10.00 ($18.50). Non-RSC Members $15.00 ($27.50). ORDERING: Yon-RSC members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 IHN, England. RSC Members should send their orders to: The Royal Society of Chemistry, Membership Officer, 30 Russell Square, London WClB 5DT. PAYMENT SHOULD ACCOMPANY ORDER.

ISSN:0144-557X    

DOI:10.1039/AP98421FX011

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年代:1984

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155 ANALYTICAL DIVISION DIARY Annual Reports on Analytical Atomic Spectroscopy VoI. 12 Methodology April, 1984 Edited by M. S. Cresser and L. C. Ebdon This volume reports on current developments Instrument Automation; Complete Instru- in all branches of analytical atomic emission, ments; New Commercial Instruments; absorption and fluorescence spectroscopy with references to papers published and New Methods; Detection Limits, Precision and lectures presented during 1982. Much of the Accu racy; St a nda rds a n d St a nda rd iza t io n ; information is in tabular form for ease of reference. . . Brief Contents Atomization and Excitation Applications Chemicals; Metals; Refractories and Metal Oxides, Ceramics, Slags, Cements; Minerals; Air Analysis; Water Analysis; Soils, Plants and Arcs, Sparks, Lasers and Low-pressure Dis- Fertilizers, Foods and Beverages; Body Tissues charges; Plasmas; Flames; Electrothermal and Fluids; Atomization; Vapour Generation; Hardcover 416pp 0 85186 697 2 Instrumentation Light Sources; Optics; Detector Systems; tkZui; Price f45.00 ($81 .OO) RSC Members f30.00 RSC members should send their orders to: The Royal Society of Chemistry, The Membership Officer, 30 Russell Square, London WClB 5DT. Non-RSC members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1 HN. The Royal Society of Chemistry Burlington House London W1V OBN

ISSN:0144-557X    

DOI:10.1039/AP98421BX013

出版商:RSC    

年代:1984

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ANPRDI 21(4) 127-156 (1984) April 1984 Hon. Secretary R. Sawyer Analvtical Proceedings - I Proceedings of the Analytical Division of The Royal Society of Chemistry AD President S. Greenfield Hon. Treasurer D. C. M. Squirrel1 Hon. Assistant Secretary D. I. Coomber, O.B.E. Hor). Publicity Secretary Dr. J. F. Tyson, Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire, LE11 3TU Secretary Miss P. E. Hutchinson Editor, Analyst and Analytical Proceedings P. C. Weston Senior Assistant Editors Assistant Editor Mrs. J. Brew, R. A. Young Ms. D. Chevin Publication of Analytical Proceedings is the responsi- bility of the Analytical Editorial Board: J. M. Ottaway (Chairman) L. S. Bark L. C. Ebdon A. G. Fogg A. C. Moffat "Exofficio members B. L.Sharp J. D. R. Thomas A. M. Ure *P. C. Weston *P. M. Maitlis J. Whitehead All editorial matter should be addressed to: The Editor, Analytical Proceedings, The Royal Society of Chemistry, Burlington House, Piccadilly, London, WIV OBN. Telephone 01-734 9864. Telex 268001. Advertisements: Advertising Department, The Royal Society of Chemistry, Burlington House, Piccadilly, London, W1V OBN. Telephone 01-734 9864. Analytical Proceedings (ISSN 0144-557X) is published monthly by The Royal Society of Chemistry, Burlington House, London, W1V OBN, England. All orders, accompanied by payment, should be sent to The Royal Society of Chemistry, The Distribution Centre, Black- horse Road, Letchworth, Herts., SG6 lHN, England. 1984 Annual Subscription price if purchased on its own: UKf53.00, Rest of World €56.00, US $106.00, including air speeded delivery.Air freight and mailing in the USA by Publications Expediting Inc., 200 Meacham Avenue, Elmont, N.Y. 11003. USA Postmaster: Send address changes to: Analytical Proceedings, Publications Expediting Inc., 200 Meacham Avenue, Elmont, N.Y. 11003. Second class postage paid at Jamaica, N.Y. 11431. All other despatches outside the UK by Bulk Airmail within Europe, Accelerated Surface Post outside Europe. PRINTED IN THE UK. @The Royal Society of Chemistry, 1984. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form, or by any means, electronic, mechanical, photographic, recording, or otherwise, without the prior permission of the publishers. Reports of Meetings North East Region The eighteenth Annual General Meeting of the Region was held at 7 p.m.on Friday, November llth, 1983, at the Scotch Corner Hotel, near Richmond. The Chair was taken by the Chairman of the Region, Mr. J. Vallance. The following office bearers were elected for the forthcoming year: Chairman-Dr. J. Newham. Vice-Chairman-Dr. A. Townshend. Honorary Secre- tary-Mr. C. L. Denton, 20 Bedford Road, Nunthorpe, Middlesbrough, Cleveland, TS7 OBZ. Honorary Treas- urer-Mr . M. Daniel. Honorary Assistant Secretary- Dr. R. Hutton. Members of Committee-Mr. J. G. Baber, Dr. A. C. Docherty, Dr. R. King, Dr. D. A. Leathard, Mr. G. E. Penketh and Mr. J . Vallance. Mr. F. C. Shenton and Mr. J. Whitehead were re-appointed as Honorary Auditors. Electtoanalytical Group The fourteenth Annual General Meeting of the Group was held at 1.30 p.m. on Friday, December 9th, 1983, at the Linnean Society, Burlington House, London, W. 1. The Chair was taken by the Chairman of the Group, Dr. H. Thompson. The following office bearers were elected for the forthcoming year: Chairman-Dr. H. Thompson. Vice-Chairman-Dr. A. G. Fogg. Honor- ary Secretary-Mr. A. E. Bottom, Kent Industrial Measurements Ltd., Oldends Lane, Stonehouse, Gloucestershire, GLlO 3TA. Honorary Treasurer-Dr. B. J. Birch. Honorary Assistant Secretary-Dr. J . P. Hart. Members of Committee-Dr. A. K. Covington, Dr. T. E. Edmonds, Dr. P. R. Fielden, Dr. M. L. Hitchman, Dr. J. D. R. Thomas (ex officio), Dr. A. Watson and Dr. E. C. Weller. Dr. R. M. Smith and Mr. J. G. Tillman were re-appointed as Honorary Auditors. 127

ISSN:0144-557X    

DOI:10.1039/AP9842100127

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年代:1984

数据来源: RSC

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PARTICLE SIZE ANAI.YSIS OF CONSTRUCTION MATERIALS 128 Particle Size Analysis and Pore Structure with Particular Reference to Construction Materials Surface Area of Powders by Air Permeability Measurements* T. P. Lees Cement and Concrete Association Wexham Springs Slough Berkshire SL3 6PL All of the early papers establishing permeability as a technique for measuring the surface area of powders (cements in particular) were published in the Journal of the Society of Chemical Industry some of them by members of the Road and Building Materials Group. Not only is this therefore an appropriate audience for a paper on the subject but the time is also appropriate because of the very recent publication of the revision of BS 4359 Part 2.1 Carman2.3 studied the flow of incompressible fluids through packed beds of powder and proposed the relationship which is known as the Kozeny - Carman equation.Because of the simplifying assumptions made Sv is strictly the “effective” permeability volume surface area (units m2imj) and will not necessarily have the same value as surface areas measured by other techniques. For convenience in this paper the correct terminology is implied by the simpler term surface area. K is the Kozeny constant and is normally taken to have a value of 5.0 for powders. Carman used liquids and recommended acetone for measuring cements. However cements have a wide particle size distribution (say 1-200 pm) and this made it difficult to form homogeneous beds by settlement from suspension; Carman also suggested that immobile adsorbed films of liquid on the surfaces of particles made the technique inappropriate for very fine particles (say <2 pm).Lea and Nurse? proposed air as the fluid and considered that its compressibility could reasonably be neglected. Their apparatus measured q the volume flow-rate of air through the bed of powder with a pressure drop flow meter previously calibrated to give a constant. C. such that q = - . ChZPL The pressure drop across the powder bed A p . was measured by a manometer filled w t h the same liquid as the flow meter manometer ( A p = hlpd). They considered that for cements which have a For the Lea and Nurse apparatus equation (1) becomes Anal. Proc. Vol. 21 The following are summaries of two of the papers presented at a Joint Meeting of the Particle Size Analysis Group and the Road and Building Materials Group of the SCI held onMarch 17th 1983 at the Society of Chemical Industry Belgrave Square London S.W.l.A summary of one of the other papers presented at the Meeting was published in the October 1983 issue p. 529. 7 . narrow range of densities the mass surface area. S, was more convenient i.e. S = - S V 9 Other workers have proposed that the rate of flow should be measured directly (e.g. with a bubble flow meter) making the apparatus independent of previous calibration. However. calculation is much simpler with the calibrated pressure drop flow meter which is essentially independent of atmospheric temperature and pressure and is to be preferred for apparatus in constant use.The results reported in this paper were obtained with this type of apparatus. Rigden5 and Blaine6 developed alternative apparatus based on measurement of the time taken for a constant volume of air to pass through the powder bed. Recently. Allen and Macsporran’ have shown that the Rigden equation is incorrect but in practice constant volume apparatus is usually used as a secondary method and is calibrated against known powders (e.g NBS SRM 114 which is traceable back t o a Lea and Nurse apparatus result). * This paper was first published in Chemistry and Industry. 1983. p. 632. PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS E = l - - I ALP where W is the mass of power (in kg). It is also used to calculate 5,. It can be shown that an error of 3(1 - E) 2E correct density.For example. an assumed density for Portland cement of 3 150 kg m-3 is often used. If the actual density is 3200 kgm-3 (error in density z = -1.5696) the calculated mass surface area will be 2.50% low for a porosity of 0.483 (the actual porosity for a target of 0.475). TABLE I z9/0 where E is the porosity calculated from the of k ~ Cross sectional area. A and height. L are constants in the Kozeny-Carman equation and additionally are used to calculate porosity. BS 4550 Part 38 specifies that the cell should form a powder bed 25.40 k 0.03 mm in diameter and 10.00 k 0.03mm high. Two cells each within these tolerances were used to measure the surface area of one cement. The nominal dimensions were used to calculate the mass of cement required to give a porosity of 0.475.The results (mean of 6 tests) for each cell were 316.9 mz kg-1 (s.d. of 1.91) for cell 1 and 314.9 m2 kg-1 (s.d. of 1.36) for cell 2. l n this particular instance statistical tests show that no significance is attached to the difference. However over a number of years it is obvious that on average cell 2 always produces lower results than cell 1. Careful measurement of the cells and the use of the actual dimensions in repeating and calculating the results gave the results shown in Table I. CELL DIMENSIOKS Diameter x 1Wim April 1984 The Powder Bed The first requirement of the method is the preparation of a uniform powder bed of accurately known dimensions and porosity. Porosity in this context is the ratio of the volume of interparticle voids to the total bulk volume of the powder bed.When the Lea and Nurse method was first adopted (in 1947) as a test method for Portland cement and the results used to establish compliance with a standard a fixed volume cell was specified to give a powder bed 25.4 mm in diameter ( A = 5.067 x lO-4m2) and 10 mm high ( L = 0.010 m). The measured density of the cement was used to calculate the mass of sample required for the bed to have a porosity of 0.475. Lea and Nurse had used a porosity of 0.492 in their original work4 and the reason for standardising on 0.475 has not been traced. The current British Standard for testing cement specifies a constant volume cell which produces a powder bed 25.0 or 25.4mni in diameter and 10.0mm high.A fixed porosity of 0.475 is specified. In other industries a wide variety of cells are used. In general. variable volume cells are preferred and the bed is compacted in increments which is claimed to give greater uniformity. It is necessary to measure the height of each bed accurately. Factors Affecting the Results Careless preparation of the powder bed often as a result of clumsy withdrawal of the plunger. causes most problems with the permeability method. However. this source of error will not be considered further because it can be eliminated by attention to detail. Powder density ps This is used to calculate the porosity of the bed. +z% in density leads to an error in S Cell dimensions .MeanS,,'m'kg-l . . . . . . 25.39 Crosssectionalarea.A x 10Vm' .. 5.063 Height.L X 10"m . . . . . . 10.03 . . . . . . 318.2 S.D. . . . . . . . . . . . . 1.84 It is obviously necessary to measure cell dimensions frequently and to take appropriate action if they outside the specified tolerances. 129 W Cell 1 Cell' 25.32 5.075 10.02 317.9 1.12 PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS 130 remove. T ~ B L E 11 Anal. Proc Vol 21 It has also been noticed that the variability of results is usually slightly more for cell 1 than for cell 2. This is possibly because the plunger for cell 1 is not such a good fit. allowing varying amounts of pou der to escape between the walls of the cell and the plunger which makes the plunger more difficult to h,lmm 5 0 1 0 Filter-paper support BS 4550 Part 3 specifies the use of a Whatman No 40 (or similar) filter-paper support When no powder IS present this gives a significant resistance to air flow that IS not corrected for The mean value of A p for the paper alone was obtained and IS compared in Table I1 uith that given by a Whatman No 41 paper Paper No 40 No 41 COMPARISON OF Alp VALUES Flow-rate (qim3 x s-l hZ/rnrn AplN m- 5 50 x lo-' 38 4 7 7 3 20 320 Surface areaim'kp-I ~~ 316.0 315.6 315.6 5 50 x 10-7 For the cement studied the results given in Table I11 should be expected if the resistance of the paper alone contributes to the observed pressure drop.TABLE 111 COMPARISON OF SURFACE AREA VALUES ~ Not corrected Corrected 318.0 Paper No.40 .. No.41 . . A number of tests were made using the two alternative filter-papers. and no systematic difference between the uncorrected results was observed. The theoretical effect increases when measurements are made at high porosities i.e. hl is small compared with h?. Measurements made under these conditions again showed no systematic differences in results for the two filter-papers (uncorrected). It is concluded therefore. that the flow resistance of the paper alone for the above levels at least does not contribute to the measured pressure drop across the powder bed. No explanation is offered for this anomaly. A related subject is the re-use of the filter-paper. Earlier editions of the British Standard test method specified that the paper should be changed after six tests.but in the 1978 revision this was altered so that a new paper should be used for each test. For the cement studied there was no systematic change in calculated S for up to ten usages of the papers. However. the change to the British Standard requirements was based on practical evidence and for accurate work it is recommended that a new paper be used for each determination. Compaction of the bed With the fixed volume type of cell used in the cement industry compaction of the bed is carried out in one operation. A number of tests were made where the cement was compacted in three or four layers; no differences in S values were observed. A test for bed uniformity is to compact by the normal operation.different masses of powder so that L i s changed. A series of tests were made where L was in the range 5-19 mm. The porosity of 0.475 was maintained as near as possible. No differences in calculated S were observed. Miscellaneous Different flow-rates of air had no effect on the results. Results were obtained over a range of ambient temperatures of 22-10°C and no effect was found. Preconditioning the powder by "fluffing" is advocated for some powders. With the cement studied this appeared to give a mean increase of approximately 2 m* kg-1. Powder technologists often recommend that sophisticated sampling techniques be used to prepare test portions. In this work all sampling merely consisted in taking random spatula-fulls of cement from PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS 131 TABLE IV EFFECT OF BED POROSITY Equation Cement Range of porosities A .. . . . . . . 0.376-0.552 0.420-0.553 0.382-0.548 r S = 457.5-284.3~ 0.986 S = 654.5-424.8~ 0.993 S = 453.1-304.6~ 0.992 S,= 916.8-348.2~ 0.951 D . . . . . . . . 0.458-0.604 . . + 8 6 k,r,d2RTinM 3PS,(1 - E ) 6k is the product of two constants and Carman fouada mean value for the product of 2.25 for a range of powders. Rather than attempting to solve this equation (a quadratic in S,) directly it is more convenient to evaluate the two terms separately and then combine them. The first term is identical to the Kozeny - Carman equation. i.e. April 1984 a mixed bulk. All the evidence is that this is a perfectly adequate method of sampling cement.However if the mixing has the same effect as “fluffing.” slightly higher results are obtained compared with less vigorously mixed samples. Kerosine (pL = 782 kg m-3) was used as the manometer liquid and hl and h2 were approximately 0.3m each. For these conditions the mean air pressure in the powder bed was approximately 3.4% higher than atmospheric. If air compressibility is taken into account the calculated results for S become approximately 1.7% higher. However the effect would be greater if for example mercury were to be used as the manometer liquid and differences in results between workers using different manometer liquids could be significant. Bed porosity It is recognised that the values obtained for surface area are different for different porosities.This has a technological significance because whereas BS 4550 specifies a porosity of 0.475 based on measured cement density ASTM C-204 specifies a porosity of 0.500 based on an assumed cement density of 3 150 kg m-3. Lea and Nursed used a poFosity of 0.492 because they found this was the average value readily achieved for various cements. Four cements were measured at a range of porosities and the relationships between calculated S and E shown in Table IV were calculated by least squares procedures. Slip flow The second term is B . . . . . C . . . . . . . The correlation coefficients are such that the linear relationships are highly significant and there are no obvious signs of plateaux on the lines. The slopes of the lines do not correlate with measured surface area.Carman9 suggested a correction to the porosity function to allow for adsorbed (stagnant) air films on the surface of particles. Schultzl(1 showed that by taking this stagnant air into account it is possible to arrive at what he calls “the effective surface area Sa‘’ and **the effective density pa’’ which are independant of porosity. The effective surface areas are considerably lower than the normally calculated values of S for all practical porosities. As an alternative to specifying a fixed porosity for all measurements it is possible to specify compaction at a standard pressure. Fixed compaction pressures are not suitable for use with fixed volume cells so the cement industry will probably continue to use a constant porosity.I t would be helpful if British Standards and ASTM (and other Standards) were consistent; a porosity of 0.500 would probably be the easiest to gain universal acceptance. However it would be better if this was based on the actual measurement of density rather than on assumed values. The Kozeny - Carman relationship (equation 1) is based on the viscous flow of air through the powder. It is considered that particularly for small particles andior low porosities some .‘slip‘’ occurs at the air - powder interface. Carman and Arne1111 have moposed an equation which takes this into account Ps 1 . . . . . . . . . . . . . PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS 132 S is then given as derive a relationship between S and & Anal.Proc. Vol. 21 When air is used (M = 0.029) at normal atmospheric temperature and pressure ( T = 293 K and P = 105 N m-z) viscosity 7 is 18 x 10-6N s m-2. These values together with the constants can be used to The cement industry for normal purposes ignores S and considers S k to be synonymous with S,. However for very fine powders the contribution of S becomes significant. For the four cements studied the appropriate values of surface area at a porosity of 0.500 are as shown in Table V. TABLE V SURFACE AREA CALCULATIONS FOR FOUR CEMENTS srn Cement B C D A Table VI were found. Sk TABLE VI s w . . 315 79 358 . . 442 155 528 . . 301 71 338 . . 743 427 985 The properties of cement D related to surface area are not likely to be adequately predicted from S k alone.The slip corrected values for the cements still vary with porosity. The relationships shown in SLIP FLOW CORRECTIONS TO SURFACE AREAS Equation . . S,=657.9-600.7~ 0.986 . . Sw= 1015.&974.5~ 0.997 . . Sw=638.&6O0.9s 0.990 . . S = 1719.7-1 469.0 0.995 Cement A B C D r In some industries slip corrected values are used as a matter of course. Conclusions Some of the factors leading to difference in results between operators have been studied for cements The variation of measured surface area with porosity leads to discrepancies between workers using different standard methods. Consideration should be given to using calculations based on taking slip flow into account particularly for fine powders.References 1. BS4359 “Methods for Determination of Specific Surface of Powder. Part 2 1982 Recommended Air Permeability Method,” British Standards Institution London 1982. 2. Carman P. C. J. SOC. Chem. Znd. 1938 57 225. 3. Carman P. C. J. SOC. Chem. Znd. 1939 58 1. 4. Lea F. M. and Nurse R. W. J. SOC. Chem. Ind. 1939 58 277. 5. Rigden P. J. J. SOC. Chem. Znd. 1943 62 1. 6. Blaine K. L. ASTM Bull. No. 112 1943. 7. Allen T. and MacSporran W. C. Powder Technol. 1982,33 195. 8. BS 4550 “Methods for Testing Cement Part 3 Physical Testing,’’ British Standards Institution London. 9. Carman P. C. ASTM Symposium “New Methods for Particle Size Determination,” American Society for Testing and Materials Philadelphia PA USA 1947 p. 24. 10.Schultz N. F. Znt. J. Min. Proc. 1974 1 65. 11. Carman P. C. and Arnell J. C. Can. J. Res. 1948 26 128. 133 PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS April 1984 English Clays Lovering Pochin & Co. Ltd. St. Austell Cornwall PL25 4DJ Improved Methods of Particle Size Analysis K. J. Burr Introduction Particle size is a strictly controlled parameter for the products mostly china clay or calcium carbonate that we supply and this necessitates a large number of routine tests (of the order of 100-200 per day) at each of the production quality control laboratories and at the central research laboratory. Manual methods using gravity sedimentation techniques have proved slow labour intensive and subject to operator error. No commercial particle sizer was available that met the criteria of giving results in terms of percentage by mass finer than or coarser than a given size (equivalent spherical diameter) and of being capable of handling large numbers of samples.We have therefore developed two pieces of equipment in-house one known as ASTRA to measure the “percentage finer” values to within about 170 and the other known as ULTRA to measure “percentage coarser” values to within 0.170 mainly for small amounts in the tail of the particle size distribution. Measurement of “Percentage Finer” The principle of ASTRA is the same as that of the Andreason technique in which a sample is taken of the initial homogeneous deflocculated suspension and a further sample is taken after a given period of sedimentation and at a fixed depth below the surface so that all particles greater than the required size have fallen below the sample point.The ratio of suspension solids concentrations gives the required result directly. Suspension concentrations are measured by using an X-ray absorption technique in which samples are extracted by a vacuum system and a vertically driven sampling tube into a measuring cell with a plutonium-238 X-ray source positioned on one side and an X-ray detector on the other. Sedimentation cylinders containing the test samples are placed in a cylindrical water-bath which can be rotated to bring each cylinder in turn to the sampling position. Up to twenty samples can be handled at a time. An initial sampling run is made with the samples being stirred by means of a rotating magnet under the water-bath and magnetic followers in each cylinder.A second sampling run is made after the desired sedimentation time at the conclusion of which the results are calculated and printed. A third and fourth sampling run may also be made for determinations at one or two other (finer) sizes if desired. The sequence of operations which includes sample cell rinsing between samples and standardisa- tion measurements with water in the cell is controlled automatically by a built-in single board microcomputer. The only manual operations required are the preparation of the sample suspension to approximately 6% mlV solids concentration and initialising the equipment for the required measurement via a numerical keyboard. The use of a microcomputer also enables many other facilities to be provided to facilitate operation and maintenance.The duration of the test run is mainly determined by the duration of sedimentation. For a 2-pm test 20 samples can be tested in 2.25 h. As well as providing a rapid reliable result with the minimum of operator effort the equipment effectively extends working hours as a run can be initiated at the end of the day and results will be ready next morning. This is particularly true for say 1-pm tests which normally take a full working day. The size range is arranged to be about 1-5 pm but can be extended in either direction by changes in sample extraction depth and programme software. One limitation of the equipment is that erroneous results may be given if the sample is a mixture of minerals which are not uniformly distributed throughout the size range due to possible differences in X-ray absorption coefficients.Measurement of “Percentage Coarser” The ULTRA equipment uses the principle of successive sedimentation and decantation of material remaining in suspension the sedimented material being re-suspended homogeneously after each decantation except the last in which the sedimented material is re-suspended in a small volume of water and the solids concentration determined. Comparing the calculated mass of residue with the initial mass of solids in the sample gives the (approximate) percentage coarser than the size of interest The accuracy of the results depends among other factors on the number of decantations performed as only a proportion of undersize material is removed each time.134 PARTICLE SIZE ANALYSIS OF CONSTRUCTION MATERIALS Anal. Proc. Vol. 21 The equipment has many similarities to the ASTRA but the main difference is that suspension concentration is determined by using a commercial digital density meter (the DMA 40 manufactured by Anton Paar Austria) through which the samples are pumped. The reason for not using the X-ray absorption technique is that the coarse residues are normally not kaolinite as is the bulk of the sample but quartz mica and felspar in unknown proportions and hence of unknown X-ray absorbence. Their densities are however much less disperse than their X-ray absorption coefficients so errors introduced by suspension density measurement are small.Tests can be made on up to 20 samples at a time with 4-15 decantations in the size range 5-20 pm. As results are very dependant on the number of decantations performed an automatic correction is applied for the amount of undersize material remaining in the residue. This correction is based on a measurement of the suspension concentration just above the residue before the last decantation and a measurement of the percentage coarser than half the cut size (as the correction is dependant on particle size distribution). For each sample three results are printed; an uncorrected percentage coarser a percentage coarser corrected for an infinite number of decantations and a percentage coarser than half cut size. Typical test times are 2.25 h for 20 samples measuring Yo > 10 pm with 4 decantations; and 4 h for 20 samples measuring YO > 10 pm with 10 decantations.Trials on Laser Particle Size Analysers Although both the above pieces of equipment are rapid in terms of sample throughput they are not as fast as might be desirable for single sample measurements to be used for close production control. Laser-based particle size analysers have the facility for providing extremely rapid measurement so an investigation into their use with china clays has been undertaken. There are two limitations to the light scattering principle on which the available equipment is based as far as we are concerned. Firstly the equipment is based on the measurement of spherical particles whereas china clay particles are disc shaped so that their projected diameter is far from the equivalent spherical diameter.We require results in terms of equivalent spherical diameter as most of our particle size selection production processes are based on either gravity or centrifugal sedimentation. Secondly the laser system cannot detect the presence of very fine particles (below 1 pm or 0.2 pm depending on equipment) of which there are an appreciable number in most products and measurements are required as a cumulative percentage finer. However it is possible to make (largely empirical) corrections for both of these effects to obtain results in the desired form. The correction equation is as follows M k . d d- F-Mf P d = F. Mf - . 1 +- 100 where Pd is the 740 < size d (equivalent spherical diameter) M k . d the laser derived YO < size k X d where k is shape factor F the fines correction factor (constant for type of sample) and Mf the laser derived < YO sizef (fis fairly small typically 1 pm). The denominator is a normalising factor to bring all results back to 100% total. Tests were made on the Microtrac (Leeds and Northrup) and the CILAS granulometer. Agreement between corrected results and Sedigraph (Micromeritics) results were quite good over the size range 1-10 pm. Optimum correction coefficients vary with type of sample but appeared to be invariable with time (over a period of 5 weeks) for samples from a given product stream. For single point measurements (percentage finer than 2 pm) agreement between corrected results and sedimentation tests was within 1.5% root mean square difference for the majority of sample types with about 300 samples being tested. It is felt therefore that it is possible to obtain meaningful results in the required form by application of the above corrections.

ISSN:0144-557X    

DOI:10.1039/AP9842100128

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

April, 1984 Pyrolysis PYROLYSIS 135 The following is a summary of one of the papers presented at a Joint Meeting of the Chromatography and Electrophoresis and Thermal Methods Groups held on September 14th, 1983, at the Scientific Societies’ Lecture Theatre, 23 Savile Row, London, W . l . Determination of a,fi-Unsaturated Compounds Formed by a Burning Cigarette R. R. Baker, H. F. Dymond and P. K. Shillabeer Group Research and Development Centre, British - American Tobacco Company Ltd., Southampton, SO9 1 PE Tobacco is a complex mixture of over 900 components. During its combustion in a burning cigarette temperatures up to about 950 "C are generated, and oxygen levels between zero and 21%, together with an intricate gas-flow pattern, are observed. These conditions result in the formation of a smoke aerosol in which over 3 800 substances have so far been identified.l.2 The interior of the burning zone of the cigarette is oxygen-deficient and hydrogen-rich.As air is drawn into the cigarette during a puff, oxygen is consumed by combustion with carbonised tobacco and the simple combustion products carbon dioxide, carbon monoxide and water are formed in the combustion region.2 Temperatures in this region vary between approximately 700 and 950 "C during a puff. Immediately downstream of the combustion region is a pyrolysis - distillation region, where the temperatures are between about 200 and 600°C and which is still oxygen deficient. The majority of smoke products are generated in this region by a variety of mechanisms. As these products are drawn downstream during a puff, condensation into an aerosol phase occurs. Cigarette smoke thus consists of aerosol particles and a vapour phase.Relationships between various tobacco constituents and smoke products are complex and difficult to resolve. However, a number of studies using radiolabelling3 and pyrolysis47 techniques have been made to elucidate particular reaction paths. a$-Unsaturated compounds are found in the vapour phase of smokes13 and several of these, especially propenal, are known lachrymators and irritants. In order to investigate their levels in cigarette smoke, and aspects of their generation, the analytical method described in this paper has been developed. Smoke Production and Collection The delivery of products in cigarette smoke depends, inter a h , on the way in which the cigarette is smoked.In order to compare the deliveries of particular smoke products amongst different cigarettes, the cigarette is smoked on a smoking machine using a standard set of internationally agreed parameters; a 35-cm3 puff of 2 s duration is taken every minute. The pressure - time profile of the puff is bell-shaped. In the work described here the aerosol particles in cigarette smoke were removed by passing the smoke through a Cambridge filter, which is a disc made of interwoven glass fibres and typically 58 mm in diameter by 1.4 mm thick. The remaining vapour phase, which contains the a,&unsaturated compounds, was collected either by passing through two ethanol bubble traps in series at -78 "C, or, more preferably, through a glass chromatography column.The column contained Chromosorb G, 60-80 mesh, wetted with a 1 : 1 mixture of ethanol and water, and was constructed to have a minimum dead volume. It absorbed the a$-unsaturated compounds. For the collection of smoke under machine-smoking conditions, two cigarettes were smoked through each of four ports of the smoking machine. The Cambridge filter pads were changed between cigarettes to minimise potential reaction of the a,o-unsaturated compounds with products in the aerosol particles. For the pyrolysis studies, 1 g of tobacco was pyrolysed in a silica tube (220 mm X 8 mm i.d.) placed in a small furnace, under non-isothermal conditions (mean heating rate of 3.5 K s-l) with the appropriate atmosphere continuously passed over the tobacco. The inlet gas flow to the pyrolysis tube was kept constant at 3.33cm3s-1 and a platinum/platinum - 13% rhodium thermocouple was placed in the centre of the tobacco in order to monitor its temperature directly.Smoke collection was carried out as described above. A total of six pyrolysis experiments were carried out, three with argon flowing over the tobacco, and three with a mixture of 10% V/V oxygen in argon. For each gas mixture three experiments were performed, with the products released over the temperature ranges 25400,25400 and 25-950 "C.136 PYROLYSIS Anal. Proc., Vol. 21 Analysis The a,P-unsaturated compounds were separated from the other vapour phase components by their specific base catalysed reaction with thiols.14715 With butanethiol the reaction is: RCH=CRlCHO + C4H9SH+RCH-CHRICHO SC4H9 The addition compounds were then separated by gas - liquid chromatography.Immediately after smoking or pyrolysis, the column containing the smoke vapour phase was removed from the smoking machine or pyrolysis tube and eluted with water. A pre-determined volume of the eluate was collected and the butanethiol added. After shaking for 15s, sodium hydroxide solution was added to the tube and re-shaken. It was essential that the column was eluted and the butanethiol added as quickly as possible after smoke production in order to prevent loss of the a$-compounds by reaction with other vapour phase smoke constituents. It was also essential to add the sodium hydroxide solutior 3er the butanethiol in order to prevent polymerisation of the propenal. The reaction mixture was heated at 5540°C for 30min, cooled and then partitioned with dichloromethane containing an internal standard for the subsequent gas-chromatographic analysis.After separation of the two layers a sample of the dichloromethane layer was injected on to a gas chromatograph. The gas-chromatographic separation of the addition compounds was achieved by using a glass column packed with 5% polyethylene glycol 20M on Chromosorb G (HP) under temperature programmed conditions. The system was calibrated with the addition compounds formed from freshly distilled a, P-unsaturated compounds. Results and Discussion The levels of some a,P-unsaturated compounds in the mainstream smoke from three plain (non-filter) cigarettes containing three types of tobacco are given in Table I.The levels of virtually all of the compounds are substantially higher from the cigarette containing flue-cured tobacco. As the sugar content of flue-cured tobacco is much higher than that of air-cured (typically 15% and almost 0%, respectively), it is tempting to conclude that the @unsaturated compounds are formed by decomposition of the sugars. Indeed, pyrolysis studiesl”l8 have shown that propenal and other carbonyls such as acetaldehyde and acetone can be formed from the thermal decomposition of glucose, fructose and sucrose. However, direct studies in which carbon-14 labelled D-glucose and sucrose were added to a cigarette, and the resultant carbonyls analysed, could not detect either propenal or but-Zenal incorporating carbon-14 in the products.19 Furthermore, analysis of the smoke from a series of cigarettes containing either cellulose as the smoking material, or tobaccos previously extracted with various solvents, indicated that propenal and other vapour-phase carbonyl components were produced mainly from cellulose, hemicellulose and lignin and not from extractable sugars.20 Pyrolysis studies18 have indicated that the decomposition of these carbohydrates produces propenal and other carbonyls.TABLE I LEVELS OF a, P-UNSATURATED COMPOUNDS IN MAINSTREAM CIGARETTE SMOKE* Smoke delivery/pg per cigarette Product Pro enal 2-I& thylpropenal But-2-enal But-3-en-2-one 3-Methylbut-3-en-2-one Pent-3-en-2-one Pent- 1 -en-3-one Propenenitrile 2-Methylpropenenitrile But-Zenenitrile Formula CH2 = CH .CHO CH2=C(CH3).CH0 CH,CH=CH.CHO CH3COCH=CHZ CH&OC( CH3)=CH2 CH3COCH=CHCH3 CH3CH2COCH = CH2 CH2= CH. CN CH2=C(CH3)CN CH,CH=CHCN Flue-cured tobacco 92 17 37 86 18 22 8 17 3 6 Air-cured tobacco 35 6 17 38 7 9 3 16 3 8 Blended? tobacco 71 15 21 55 10 13 4 13 3 6 * Plain cigarette, 70 mm long and 25 mm in circumference. t Mixture of 70% flue-cured and 30% air-cured tobacco.April, 1984 PYROLYSIS 137 The total amounts of propenal formed during the non-isothermal pyrolysis of flue-cured tobacco under a variety of conditions are given in Table 11. When the pyrolysis atmosphere was 100% argon, the product was formed by the thermal decomposition of tobacco components; in the presence of oxygen in the pyrolysis atmosphere, tobacco combustion would also be occurring.In an argon atmosphere, three quarters of the propenal was released at temperatures below 400°C. This corresponds to the temperatures in the pyrolysis - distillation zone in the burning cigarette. In the presence of oxygen almost twice as much propenal was generated, again below 400°C. Thus, in a burning cigarette, propenal is produced by both thermal decomposition and combustion processes. The lower yields of propenal for pyrolysis in oxygen up to 600 and 950 “C (Table 11) were probably due to losses represented by gas phase oxidation of the propenal. TABLE I1 PRODUCTION OF PROPENAL DURING PYROLYSIS OF FLUE-CURED TOBACCO HEATED AT 3.5 K s-1 Temperature Propenal yield/ Pyrolysis atmosphere range/”C pg g- tobacco Argon 25-400 42 25-950 56 Argon Oxygen - argon i 1 + 9 I Argon 25-600 47 Oxygen - argon 1 + 9 25-400 82 Oxygen - argon 1 + 9 25-600 74 25-950 72 Thus, based on these and the other cited studies, it is concluded that, in a burning cigarette, propenal is produced from tobacco components such as cellulose, hemicellulose and lignin by both thermal decomposition and combustion mechanisms, at temperatures generally below 400 “C.However, it should be borne in mind that the propenal yield from the mainstream smoke of a flue-cured cigarette (92 pg per cigarette, containing 1 g of tobacco) is higher than the pyrolysis yield in oxygen (82 pg g-l of tobacco). Inside the actual burning cigarette, conditions must exist and processes must be occurring which cannot be entirely reproduced in isolated pyrolysis experiments.1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. References Dube, M. F., and Green, C. R., Recent Adv. Tob. Sci., 1982, 8, 42. Baker, R. R., Prog. Energy Combust. Sci., 1981, 7, 135. Jenkins, R. W., Jr., Comes, R. A . , and Bass, R. T . , Recent Adv. Tob. Sci., 1975, 1, 1. Green, C. R., “Recent Advances in the Chemical Composition of Tobacco and Tobacco Smoke,” Proc. Hecht, S. S . , Schmeltz, I., and Hoffmann, D., Recent Adv. Tob. Sci., 1977,3, 59. Chortyk, 0. T . , and Scholtzhauer, W. S., Beitr. Tabakforsch., 1973,7, 165. Baker, R. R., J . Anal. Appl. Pyrol., 1983,4,297. Grob, K., Beitr. Tubakforsch., 1965, 3,243. Grob, K., Beitr. Tabakforsch., 1966, 3, 403. Grob, K., J . Gas Chromatogr., 1965,3, 52. Laurene, A. H . , Lyerly, L. A., and Young, G. W., Tob. Sci., 1964, 9, 150. Newsome, J. R., Norman, V., and Keith, C. H . , Tob. Sci., 1965,9, 102. Williamson, J . T . , and Allman, D. R., Beitr. Tabakforsch., 1966, 3, 590. Beesing, D. W., Tyler, W. P., Kurtz, D . M., and Harrison, S. A., Anal. Chern., 1949, 21, 1073. Testa, A . , and Joigny, C . , Ann. Tabac, 1972, 1, 67. Fargerson, I. S., J . Agric. Food Chem., 1969, 17, 747. Katd, K., Agric. Biol. Chem., 1967, 31, 657. Burton, H. R., in Shafizadeh, F . , Sarkanen, K. V., and Tillman, D. A . , Editors, “Thermal Uses and Grager, F. L., Nedlock, J-. W., and Martin, W. J . , Carbohydr. Res., 1971, 17, 335. Kaburaki, Y., Shigematsu, H . , and Kusakabe, H . , Sci. Pap. Cent. Res. Inst. Jpn Tob. Salt Corp., 1969,107, I73rd Am. Chem. SOC. Symp., 1977, 426. Properties of Carbohydrates and Lignins,” Academic Press, New York, 1976, p. 275. 135.

ISSN:0144-557X    

DOI:10.1039/AP9842100135

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

138 COMPUTER AIDS IN CHEMISTRY Anal. Proc., Vol. 21 Computer Aids in Chemistry The above was the title of the Analytical Division Symposium at the RSC Autumn Meeting. The following are summaries of six of the papers presented at the Symposium, which was held at the University of Swansea on September 20th-22nd, 1983. Determination of a,fi-Unsaturated Compounds Formed by a Burning Cigarette R. R. Baker, H. F. Dymond and P. K. Shillabeer Group Research and Development Centre, British - American Tobacco Company Ltd., Southampton, SO9 1 PE Tobacco is a complex mixture of over 900 components. During its combustion in a burning cigarette temperatures up to about 950 "C are generated, and oxygen levels between zero and 21%, together with an intricate gas-flow pattern, are observed. These conditions result in the formation of a smoke aerosol in which over 3 800 substances have so far been identified.l.2 The interior of the burning zone of the cigarette is oxygen-deficient and hydrogen-rich.As air is drawn into the cigarette during a puff, oxygen is consumed by combustion with carbonised tobacco and the simple combustion products carbon dioxide, carbon monoxide and water are formed in the combustion region.2 Temperatures in this region vary between approximately 700 and 950 "C during a puff. Immediately downstream of the combustion region is a pyrolysis - distillation region, where the temperatures are between about 200 and 600°C and which is still oxygen deficient. The majority of smoke products are generated in this region by a variety of mechanisms. As these products are drawn downstream during a puff, condensation into an aerosol phase occurs.Cigarette smoke thus consists of aerosol particles and a vapour phase. Relationships between various tobacco constituents and smoke products are complex and difficult to resolve. However, a number of studies using radiolabelling3 and pyrolysis47 techniques have been made to elucidate particular reaction paths. a$-Unsaturated compounds are found in the vapour phase of smokes13 and several of these, especially propenal, are known lachrymators and irritants. In order to investigate their levels in cigarette smoke, and aspects of their generation, the analytical method described in this paper has been developed. Smoke Production and Collection The delivery of products in cigarette smoke depends, inter a h , on the way in which the cigarette is smoked.In order to compare the deliveries of particular smoke products amongst different cigarettes, the cigarette is smoked on a smoking machine using a standard set of internationally agreed parameters; a 35-cm3 puff of 2 s duration is taken every minute. The pressure - time profile of the puff is bell-shaped. In the work described here the aerosol particles in cigarette smoke were removed by passing the smoke through a Cambridge filter, which is a disc made of interwoven glass fibres and typically 58 mm in diameter by 1.4 mm thick. The remaining vapour phase, which contains the a,&unsaturated compounds, was collected either by passing through two ethanol bubble traps in series at -78 "C, or, more preferably, through a glass chromatography column.The column contained Chromosorb G, 60-80 mesh, wetted with a 1 : 1 mixture of ethanol and water, and was constructed to have a minimum dead volume. It absorbed the a$-unsaturated compounds. For the collection of smoke under machine-smoking conditions, two cigarettes were smoked through each of four ports of the smoking machine. The Cambridge filter pads were changed between cigarettes to minimise potential reaction of the a,o-unsaturated compounds with products in the aerosol particles. For the pyrolysis studies, 1 g of tobacco was pyrolysed in a silica tube (220 mm X 8 mm i.d.) placed in a small furnace, under non-isothermal conditions (mean heating rate of 3.5 K s-l) with the appropriate atmosphere continuously passed over the tobacco.The inlet gas flow to the pyrolysis tube was kept constant at 3.33cm3s-1 and a platinum/platinum - 13% rhodium thermocouple was placed in the centre of the tobacco in order to monitor its temperature directly. Smoke collection was carried out as described above. A total of six pyrolysis experiments were carried out, three with argon flowing over the tobacco, and three with a mixture of 10% V/V oxygen in argon. For each gas mixture three experiments were performed, with the products released over the temperature ranges 25400,25400 and 25-950 "C. Trends in Laboratory Instruments with Microcomputers M. Hewins Pye Unicam Ltd., York Street, Cambridge, CB1 2PX The major change made in laboratory instruments in the last decade has been the incorporation of microprocessors, giving new facilities for control and operation.Typically these give: more printed results and experimental details; more information about the instrument; less staying with the instrument to change valves or temperature at set times; and the possibility of making several measurements of, for example, wavelength simultaneously. It is in these control facilities that major developments are occurring and will continue for some time to come. During the last 10 years users and manufacturers have been exploring the benefits and limitations of microcomputing and identifying the optimum mix of facilities. The importance of this can be appreciated if you turn to 1905 and the infant motor car industry. Mass production was unknown but hundreds of small “garage shops” were making cars.Most had four wheels, but the similarities stopped there: some had steering wheels, some tillers; some had hand-brakes on the right, foot-brakes on the left; some had fixed throttles, others had dashboard throttles. The design elements were present but no combination had emerged that was suitable for the average person. Laboratory instruments are in the same position today, with the design elements present but no stabilised architecture linking them. This talk looks at the design elements and their stabilisation. Changes so Far Elements have emerged in the last decade in increasing numbers and complexity as computing power increases. Integrators, which have halved in cost in the last decade, have increased several-fold in capability, providing a group of elements that is going to become important for the control of instruments.Early integrators gave area counts only, but now they detect a peak automatically, look for base lines and separate small peaks from the shoulders of big peaks; an example of this type is the Philips CDP1. Later integrators have added further elements to the list with statistical calculations, storage of data, alternative methods of peak area measurements, etc. Data processing (DP) provided the first group of design elements but the major role of the microprocessor is in direct instrument control. Things began simply with, for instance, a solvent programmer, produced during the late 1970s, which used a processor to control the switching period of a valve admitting varying proportions of two solvents to a liquid chromatography pump.This simple function has now become a small part of the PU4002 pumping system, which controls the pump motor, balances out fluctuations in pumping rates and solvent mixes due to pressure, compensates for solvent compressibility, provides safety cut outs and many other features. It is a typical example of the way in which more and more complex functions are being put under processor control to self-correct changes. In other control applications, such as the Philips Series 304 chromatograph, the processor has replaced functions previously carried out in hardware. Here, three ovens have different requirements and each has a different degree of control and accuracy, typically k0.570.The ovens cool or warm as appropriate, and control calculations are performed once in every second. In this manner, very precise control of the ovens can be achieved at accurate temperatures and for very accurate analyses. Today Where are we now in facilities for instrument control? Most of the elements identified carry out existing tasks in new ways, giving a more reliable instrument or a less expensive product. The major developments are not here, however, but in facilities that give more control than was previously possible, allowing tasks to be performed more reliably and efficiently. The CDPl integrator saved the time of writing down the results by printing them. Later integrators draw the chromatographic trace and label the peaks.The pumps and chromatographs are not quite so clever but give error messages, failure warnings, etc. These design elements are here to stay and new ones are appearing.April, 1984 COMPUTER AIDS IN CHEMISTRY 139 Data handling and direct instrument control are still frequently performed in separate boxes but now both can be controlled through a single keyboard and display unit. Data handling is becoming recognised as an integral part of the instrument and its control. Experimental conditions and DP parameters are part of the same method or analytical recipe. A new design element is the storage of these recipes within the instrument itself, and their automatic use according to, for example, the number of the sample in the automatic sample handler. Here instrument control links the sample directly to analysis conditions and data processing. This reduces errors in that less hand setting of numbers and parameters is required.Control is extended further by adding to the printing of results and graphs a complete report of the analysis conditions and a statement of any faults or departures from the set conditions. The possibility of errors is again reduced and less time is required to run the analysis and write reports. Other new design elements found in these instruments are storage of raw data, storage of results, new calculations, facilities for users’ own calculations and linking of the instrument to other computers. All provide for greater control of the instruments, making possible changes in instrument parameters in direct response to results, for example, switching a valve or calling a different method into operation when a certain result is found.Where Next? The above facilities are found in today’s instruments, at least as accessories. Perhaps not each one in every instrument, but certainly most of them. In tomorrow’s instrument they will be commonplace. The next major change will be in the area of the user interface. At the moment entering information into some microprocessor-controlled instruments is a little difficult, as the interface is difficult to use and shows little architectural stabilisation. It is a little like the typewriter before QWERTY. One likely change to the interface will be an increasing use of graphics. Pictures are clearer than words, graphs are easier to interpret than tables of results (and they can be overlaid for comparisons) and control can be via icons (small pictures representing an activity).Another major change will be in the area of decision making. As data processing becomes part of the control loop, instruments will become self optimising, seeking out the optimum balance of parameters to meet some particular criterion. This development will bring large improvements in efficiency and reduced analysis times. Finally, quite radical changes may come about because microprocessors make possible instruments that could not be controlled previously. One example is the array spectrophotometer, such as the Philips PU4021. Prior to the appearance of microprocessors it was impossible to make simultaneous measurements at more than two different wavelengths.It is now entirely practical to stream measurements from a whole spectrum simultaneously into the instrument, thus making possible an entirely new analytical technique. Different examples will emerge over the years to come of instruments not previously possible, particularly as techniques improve for correlating and reading the mass of data produced by array devices. Simulation and Modelling in Chemical Analysis D. Betteridge BP Research Centre, Chertsey Road, Sunbury-on- Thames, Middlesex, 7W16 7L.N Computer simulation and modelling are widely used as aids to understanding or the solution of engineering and management problems, but their use in the analytical laboratory has been limited. The three separate problems discussed below illustrate the value of the approach to analytical problems.Optimisation of an Autoanalyser Erni and Muller applied a non-linear programming method to the optimisation of the determination of nitrogen and phosphorus by continuous flow analysis.' The approach was to construct a block diagram of the system in which all of the relevant flow-rates, changes in concentrations and the passage of reactants through the analyser were clearly marked. Appropriate mass and flow balance equations were then written down to give two basic equations and eleven sets of constraints. A few experiments were conducted to provide reasonable values for constants in the equations and then the whole was subjected to a standard calculation employing non-linear programming.This resulted in the prediction of optimum conditions, which were different from those currently used. Experiments were carried out under the new set of conditions and a 10-fold improvement in sensitivity was obtained.140 COMPUTER AIDS IN CHEMISTRY Anal. Proc., Vol. 21 Thus, the combination of modelling, non-linear programming and a few experiments enabled an optimisation to be carried out more efficiently than by the conventional univariate approach. Application of Queueing Theory to the Analysis of Throughput of Samples Vandeginste has made a thorough study of the analysis sample throughput in a large spectroscopic laboratory.2 The object was to see if queueing theory could explain the pattern of analysis time and lead to improvements in efficiency.Queueing theory assumes a steady-state condition of samples, with constant values for the mean of the interval between the arrival of samples and the analysis time. The inter-arrival time is assumed to follow a Poisson distribution. There are a number of simple equations, derived from the theory, which enable one to calculate the basic items of useful information, such as mean time spent by a sample in the system, the mean number of samples waiting for analysis, the analyst utilisation factor, etc.3 Vandeginste was able to show that the passage of samples through a large spectroscopic laboratory fitted one of the standard queueing models and to suggest ways of improving the sample throughput. The study showed that the balance between analysts being underworked and overworked is easily disturbed.He also showed that the theory can be applied to the consideration of several different sampling strategies by making use of data which is readily to hand in well organised laboratories. A simulation program has been prepared and this permits the manager to play useful computer games, in which the effects of altering parameters such as mean analysis time, number of analysts, etc., can be evaluated visually. Simulation of Flow Injection Analysis Recently a random walk (Stochastic or Markovian chain) model of flow injection analysis has been used to simulate the dispersion and reaction of sample during flow injection analysis.4 The model assumes a plug of a given number of molecules, whose position in the tube is randomly allocated.Then, during the course of a simulated second, each molecule moves first by laminar flow and they by a random step. At the end of the operation, the new positions of each molecule are calculated and the process is repeated. As an extension, the chances of chemical reaction can be calculated and so both physical and chemical kinetics are incorporated in the model. When displayed as a computer simulation it stirs the imagination and has proven most effective in concentrating the mind on the intricacies of the mixing process in FIA. Conclusions These diverse examples, and our own experience over the last year, lead to the conclusion that the understanding and improvement of analytical methods and procedures may follow from the application of computer aided modelling and simulation.References 1. Erni, P. K., and Muller, H. R., Anal. Chirn. Acta, 1978, 103, 189. 2. Vandeginste, B. G. M., Anal. Chirn. Acta, 1979, 112,253. 3. Lapin, L. L., “Quantitative Methods for Business Decisions,” Second Edition, Harcourt Brace Jovanovich, 4. Betteridge, D., Marczewski, C. Z., and Wade, A. P., unpublished results. New York, 1981, Chap. 23. Computers as an Educational Resource Philip Barker Department of Computer Science, Teesside Polytechnic, Cleveland Developments in science and technology take place with ever increasing rapidity. Indeed, most people are familiar with the information explosion that is characteristic of research within each of these areas of human endeavour. In 1982, the UK government sponsored a campaign to promote “Information Technology” as a means of solving some of the problems associated with the generation, storage, handling and dissemination of information. Promoting the widespread use of computers and sophisticated electronic communication systems was a central issue in this promotional campaign.April, 1984 COMPUTER AIDS IN CHEMISTRY 141 Education is also primarily concerned with the generation, storage and dissemination of information and knowledge. It would therefore seem quite natural to assume that computers (and information technology generally) might play an important role within the various teaching and learning processes that take place within an educational system.This is indeed so. The computer is finding an increasing number of applications as an educational resource at all levels of instruction, ranging from primary teaching through to advanced university degree courses and a wide variety of industrial training applications.1 Nowadays, CAL (Computer Aided Learning) and CBT (Computer Based Training) are two popular acronyms that are often used to describe activity within this area.Originally, only very large computers (or mainframe systems) had the processing speed to support interactive CAL and CBT applications. Today, however, minicomputers and micros are also extensively used. Indeed, much of the development work that is currently taking place is intended to support microcomputer based CAL. The range of instructional techniques for which the computer is used includes: drill and practice; inquiry based learning; intelligent tutoring; dialogue generation; problem solving; expert system usage; gaming; and simulation.These basic techniques can be employed in order to implement a wide variety of teaching and learning strategies. The way in which a CAL author utilises these will obviously depend upon the nature of the subject matter to which they are applied and the educational objectives that are to be realised. Computer programs (or courseware) that are used for teaching purposes can embody just one or several of these techniques. As an instructional resource the computer can be used in two basic ways: either stand-alone, or, in combination with one or more ancillary instructional devices, A successful application of the latter approach requires that the additional teaching resources are appropriately interfaced to the computer that is used to control them.The sophistication of the devices that have been used in this type of situation varies quite considerably. Between them they are able to provide facilities for: simple static image display (via a slide projector); animated presentations (using a video disc); sound generation (from a voice synthesiser); and the creation of life-like simulations that closely model real situations. When several teaching aids of this type are interfaced into a suitable computing system it is possible to construct extremely sophisticated multi-media workstations (or learning centres). These enable the production of amicable, high band width human - computer interaction environments in which each individual student or trainee may optimise hidher activities to meet specific needs.Courseware Development From what has been said above it is easy to deduce that computer based learning systems contain two fundamental types of building block: hardware and software. Hardware to support multi-media instructional technology is now at an advanced state of development. Unfortunately, the same cannot be said for the courseware that is needed to drive and control these systems. Many of the control programs that are available are extremely primitive. Indeed, in many instances their design has completely ignored the important ergonomic aspects of both author - computer and student - computer interaction, These limitations make it difficult both to generate and to use CAL (and CBT) courseware in an effective way, Generally, two basic software development approaches are used to generate courseware for use with CAL systems.Some authors employ conventional programming languages in order to code their instructional scheme; others use a special type of code generation facility known as an author language.* A variety of CAL author languages now exist; typical examples include IPS, PILOT, STAF and MICRO TEXT.^ The advantages of these types of tool are: they are usually easy to learn; they provide greater author productivity; they avoid the complexities of conventional programming languages; they offer powerful pattern matching primitives; they contain many useful facilities for generating educational dialogues; and they provide special student monitoring facilities. Unfortunately, rapid advances both in authors’ requirements and in instructional technology frequently make particular implementation versions of these languages out of date and, therefore, difficult to use.This is particularly so in the case of multi-media instructional technology. In order to investigate the problems associated with courseware development for use in multi-media instruction we have been designing and implementing an experimental authoring facility called MUMEDALA. 3 This is a frame-based language designed for use in an advanced microcomputer-based workstation. This is able to communicate with other local and remote computers via a communication network. The workstation contains a variety of different devices for the presentation of information (random access slide projector, video disc, video tape, speech synthesiser, audio tapes) and the acquisition of information from the author or student (for example, a keyboard, a touch pad, sound142 COMPUTER AIDS IN CHEMISTRY Anal. Proc., Vol.21 analysis equipment, proximity sensor, a bit pad, a MICROPAD and interfaces to effect the control of teaching rigs). Facilities are provided to enable the CAL author to create frames, store them and, subsequently, indirectly supervise the way in which they are presented to a student. Undoubtedly, one of the most interesting features of this system is the video disc that is used to provide both static images and animation. An added attraction is the ability to combine computer generated static teletext graphics with images retrieved from the video disc.This enables many novel instructional techniques to be implemented. Unfortunately, the use of this type of equipment is not without its difficulties.4 Two major problems currently exist: video disc production and the design of suitable linguistic primitives that give the courseware author facile control of this type of medium. The MUMEDALA system is currently being used to address problems in this latter category. Future Directions Undoubtedly, the future directions that developments in CAL will take will be significantly influenced by the current advances being made within information technology generally. Several areas of information technology are now emerging as important building blocks for the future.5 Most prominent amongst these are: computer networks, video technology and artificial intelligence (AI) techniques. The important developments within computer networking originate from two sources, viz., research into Local Area Networks (LANs) and the experience being gained with satellite transmission systems (to enable global communication). Together these are likely to provide a communication infrastructure that will be particularly well suited to the development of sophisticated open learning systems.The potential importance of video technology stems from the ease with which this medium can be used to capture and store details of events that are of interest to us. Possible roles for the laser-based optical video disc system within education have already been hinted at.Ways in which digital processing and transmission techniques are likely to influence this medium remain to be seen. A1 techniques will provide us with two important developments: advanced methodologies for modelling students, their behaviour and student - teacher interaction; and the application of expert system technology for the creation of knowledge bases that can subsequently be used to drive computer-based teaching machines through the use of highly intelligent student - computer interfaces. Conclusion Within science education computers have a particularly important role to play. At present we are only scatching the surface of what might be achieved through appropriate use of the resources that are currently available. Within the next decade, computer based education is likely to take significant strides forward.No doubt progress in this area will promote much thought about new approaches to education. The future role of teachers and the function of our institutions of education will undoutedly be topics for much heated debate. References 1. 2. 3. Barker, P. G., and Yeates, H., “Introducing Computer Assisted Learning,” Prentice-Hall International, Englewood Cliffs, NJ, USA, 1984, to be published. Barker, P. G., and Singh, R., “Author Languages for Computer Based Learning,” Br. J . Educ. Technol., 1982, 13, 167. Barker, P. G., “MUMEDALA-An Approach to Multi-Media Authoring,” Paper presented at the 4th Canadian Instructional Technology Conference, Winnipeg, Canada, 1983; Br. J . Educ. Technol., 1984, in the press.4. 5. Barker, P. G., “Video Disc Programming for Interactive Video,” Wireless World, 1983, 89, 44. Barker, P. G., Wireless World, 1983, in the press. Teaching the Use of Microcomputers in Chemical Instrumentation B. P . Levitt Department of Chemistry, Imperial College of Science and Technology, London, SW7 2AZ The Chemistry Microprocessor Unit forms part of the Department of Chemistry at Imperial College. Its main function is to design and construct microcomputing and interfacing equipment within theApril, 1984 COMPUTER AIDS IN CHEMISTRY 143 Department, especially for research in electroanalytical chemistry. It is responsible, in co-operation with the Imperial College Computing Centre, for the post-experience course that is described in this paper.Microcomputers in Chemical Instrumentation This course originated in response to a request from the Laboratory of the Government Chemist for a course at Imperial College on the use of microcomputers in chemical and allied laboratories. The development of a universal interface system designed by Dr. N. Goddard and particularly suitable for both research and teaching purposes was supported by a Department of Industry contract sponsored by the Laboratory of the Government Chemist; the development of the course itself was supported by a contract from the National Computer Centre under the MAP (Microprocessor Application Programme). Hardware design and development, under the first contract, occupied about a year (1979-80) and construction of ten work stations and course development a further year (1980-81).The first course was held in November, 1981. The Universal interface system, designed and built by Dr. Goddard, has been described in papers elsewhere. It consists of a microprocessor-controlled rack, which accepts specialised interface boards, e.g., analogue to digital conversion, digital to analogue conversion, timer - sequencer, electrochemical boards, a.c. mains and 12-14 volt d.c. switching. The special feature of this system is its control by high level language (BASIC) instructions; the experimenter does not need to programme in machine code or, in fact, to be proficient in the details of interfacing. Similar, if less elaborate, systems are now becoming available commercially. Ten work stations have been set up for the course, each with a universal interface rack system and a Research Machines RML 3802 microcomputer with twin disc drives.The latter is provided by the Imperial College Computer Centre’s Microcomputing laboratory. The course is designed to attract research personnel from industry and Government laboratories, including those with no previous computing experience. It runs for 5 full days, the maximum time for which personnel are likely to be released. An economic charge (excluding development costs) is made, currently &390 including the course manual and lunch, but not accommodation. Only twelve 45-min periods are devoted to lectures, the remainder of the course being spent in the microcomputing laboratory gaining “hands-on” experience. An important theme in the course is an emphasis on the economics of computerisation, especially the high cost of software as opposed to hardware: “never make it if you can buy it.” The course manual is an important document for a commercial course of this type.Word processing techniques are essential as the rapidly changing technology requires updates for almost every course. The 250-page manuals are photocopied by a local firm and cost about &12 per copy. They contain full lecture notes, which enables a high rate of information transfer, and also a shortened version of the RML BASIC Manual, with the addition of the interface commands. There are also full instructions and notes for the laboratory work, including listings of programmes. Supplying ready written programs was first introduced to save the time required for inexperienced students to construct them in BASIC.Students first run the programmes and then modify them to change the experimental conditions. Somewhat to our surprise, we have found that this is a more effective way of teaching students the structure of programmes which control experiments. The lectures start with an introduction on the most economic use of microcomputers. They then describe the organisation of storage and transfer of information in a microcomputer to and from the random access memory and programme execution, but machine code programming is not included. The lectures continue with a description of interfacing standards, electromechanical interfaces, interface and conversion devices, timing interrupts and real-time operations, case histories, programming languages and programming design and future trends in hardware interfacing.A lecture is also devoted to non-experimental uses of microcomputers, e.g., for word processing, report generation, accounting, stores and data bases. The laboratory work, after an introduction to the RML microcomputer and BASIC, continues with exercises in digital input and output, digital to analogue conversion, analogue to digital conversion and signal filtering, followed by two simple chemical experiments, vit., acid - base titration and cyclic voltammetry. The course also includes two seminars. The first is on users’ previous experience in the use of micros and the second is a wind-up discussion with the course lectures at the end of the course.The course is advertised in Chemistry in Britain, New Scientist, Personal Computing World, etc. The sixth commercial course is now in progress. Nearly all of these courses have been over-subscribed,144 COMPUTER AIDS IN CHEMISTRY Anal. Proc., Vol. 21 although the current one has only 14 out of a maximum of 20 participants (two per work station). In addition, two courses were given in January 1983, sponsored by the SERC Chemistry Committee for SERC chemistry research students. The first course, for which all expenses were paid by SERC, was very heavily over-subscribed. Even the second course, for which a fee of f50 was charged, was also fully subscribed. At least 125 participants outside IC have taken the course. The next one is scheduled for March 1984 and we shall continue these courses unless, or until, demand falls.The course would be equally applicable for workers in life sciences and medicine and we may well change the orientation towards these fields. Microcomputing in the Undergraduate Chemistry Laboratory Course Although Imperial College’s computing facilities are accessible by chemistry undergraduates from the time that they arrive in the College, their first formal training is a two-week compulsory FORTRAN course on the CDC mainframe computer in their second year. A few third year students, especially those specialising in physical chemistry, also use microcomputing techniques. Next year, our first year students will use three BBC micro work stations. They will first familiarise themselves with the use of the BBC micro without programming it themselves.We have written a general purpose data acquisition and handling programme that is menu driven. Later in first year and in the second year, they will use this programme to acquire and process data from simple first and second year experiments. Eventually, we envisage that all first year students will teach themselves the elements of BASIC as a preparation for the second year computing course. The BBC was chosen for its reliability, good keyboard and excellent version of BA~IC (functions and sub-routines, IF . . . THEN . . . ELSE. . . structure), and good graphics. The built-in analogue to digital converter can be directly connected to the 0-1 V output provided by many instruments for a potentiometric recorder without interfacing.The major deficiency is the very limited amount of memory left for a programme when using a disc and graphics. Cassette operation is too unreliable and too slow for undergraduate use. Our work station consists of a BBC model B with disc upgrade (&500), single disc drive (&300), black and white monitor (f100) and Epson printer (E300). The general purpose data programme will accept data entered as numbers from the keyboard as well as voltages and times measured by the micro. Subsequently, the data points can be listed and modified. Scaling and transformation of the points, including logarithms, exponentials and powers, and first differences are provided. Some or all of the values can be plotted out on the screen and peaks integrated.Any plot from the screen can be copied to the Epson printer. The programme provides the statistics of the X and Y value separately and of the best straight line. Memory considerations limit the number of data points to 200 X , Y values or 400 X values. The minimum voltage acquisition cycle time appears to be about 30 ms. Whereas this is not a serious restriction for undergraduate experiments, it may well be significant for research applications. Experiences with Undergraduates and Micros C. A. Wellington and K. Ahmad Department of Chemistry, University College of Swansea, Singleton Park, Swansea, SA2 8PP First Year Early in the era of cuts in university education the pressure on staff time had increased and it was realised that unless alternative but equally valid forms of teaching were introduced the quality of help given to undergraduates would diminish.This was particularly true in the first year undergraduate laboratories, where the number of students was large and the students inexperienced. It seemed possible that an inexpensive microcomputer could alleviate the pressure. Experience with computer- aided teaching in the Open University had indicated that in a laboratory situation where the pro- grammes were of direct benefit to the processing of the results the use of computer terminals was very popular, but that in a situation where the assistance offered by the computer was not directly necessary to the pursuance of the Course or project, the use made of the computer was minimal. Necessity is a good driving force; we are all lazy by nature.In a laboratory situation, and as long as the memory size is sufficient, microcomputers can often be a distinct advantage over terminals to mainframe computers where time sharing or down-time can poseApril, 1984 COMPUTER AIDS IN CHEMISTRY 145 unexpected problems. The programmes we have used have been interactive with the user and related directly to the experiments that the students are expected to perform in the laboratory. Prior to entering university most students have only had a very limited experience of quantitative chemical analysis, often restricted to volumetric analysis. Even in the latter, calculations of the required result proves difficult for many. With x new undergraduates facing y different calculations, the staff can face xy incorrect experimental accounts each week and withx > 140, xy is a very large number.Moreover, it is often the case that the same error is repeated by many of the students. In the programmes developed here students are required to input their experimental results to the microcomputer, which then checks, often in several stages, the correctness of their calculations. When these are incorrect they are encouraged to think logically through their calculations and to recalculate them. Only in extrernis does the programme recommend that they seek the aid of a human demonstrator. The procedure has proved extremely popular. New undergraduates do not have to embarrass themselves before university staff, who are relieved the tedium of repeatedly working through the same interpretive difficulties with many students and are thereby relieved to teach other aspects of analytical procedures effectively. Not only are analytical experiments, such as the spectrophotometric analysis of iron, accomplished more easily, but the analysis of atomic spectra ( e .g . , of H atoms), thermochemical experiments, etc., are covered in this way. Present undergraduates have from time to time remarked “We could not have done the experiment if it were not for your computer,” ignoring the hordes of earlier students who did indeed succeed, albeit perhaps with a better student - staff ratio. That they are proficient after being helped with the microcomputer is the assurance that students and staff gain from the present approach.Subsequent Years In physical or analytical chemistry experiments in the second and third year students plot functions of the experimental data which should result in linear graphs. The appraisal of the results is usually in terms of linear regression (least squares) analysis of these plots. While hand calculators allow this analysis, few give the student the standard deviation of the slope, because the necessary correlation coefficients are not calculated. Here a microcomputer is most useful and some programmes show the graph on the screen as the data is entered and give all the necessary standard deviations as the successive data points are inserted. This gives the student an excellent appraisal of the quality of the experimental work. However, it seems that an important point has been neglected, namely, the correct weighting of the data.Rigorous Least Squares Analysis The correct approach to the weighting of data has been discussed by Wentworth’ following Deming.2 In performing a least squares analysis of their linear graphs students usually go no further in the standard programmes than assuming unit weighting of each data point and assuming all of the error is in the ordinate values of the points. Deming,z quoted by Wentworthl has pointed out that, while y (andx) data points which correspond to an exponential equation y = a exp(bx) may each have the same unit weighting, such data are usually treated by taking logarithms and plotting logloy against x and then treating the log y values as having unit weighting.The neglect of the factor (2.303y)Z not only distorts the results for a and b but also invalidates the reciprocal matrix. Wentworthl discusses the way in which correct weightings of each point should be assessed and how these can be computed, giving a fully worked example for non-linear equations. 1 It is not difficult to write computer programmes to analyse properly data in which both variables are weighted. These should not be too large for a microcomputer. Such programmes should be more widespread in use, especially in analytical chemistry. One such rigorous analysis of analytical data (for kinetic experiments) involved the writing of a suitable computer programme.3 In this paper the internal variance was assessed by considering the errors for each experimental operation, and compared with the external variance that displayed by the reproducibility of the results.A comparison of these variances is an excellent pointer to the correctness of the design of the experiment. Gas and Liquid Chromatography These two important techniques in analytical chemistry are often introduced in sample experiments in the first year laboratories. In second and third year laboratories it is possible to develop procedures for the optimisation of analyses by gas chromatography (GC) and HPLC. The application of plate146 COMPUTER AIDS IN CHEMISTRY Anal. Proc., Vol. 21 theory and the introduction of the window diagram approach4 for the optimisation of performance has brought important rationalisations to the practice of chromatography.The optimisation in GC has usually involved the use of the relative volatility parameter CY [(VB - V,)/(VA - Vo) where VA and VB are the elution volumes of solutes A and B, respectively, and Vo is the void volume of the column]. The optimum mixture of two packings can be found by injection of the solutes on to two separate columns containing each packing, plotting the particular coefficients for each solute against the volume fraction of liquid phases on the column and then plotting the relative volatility of pairs of solutes against the volume fraction of liquid phase.4 Such operations can be easily computed on a microcomputer. This is a very good approach in GC, where Vo << VA (and VB) but in HPLC, Vo can be similar in magnitude to VA and/or VB and then the window diagram in terms of the separation factor S[SAB = (VB - V J ( VA + VB)] is preferable.5 Moreover, S does not require the determination of Vo, often difficult in HPLC.Plate theory gives, without assumption, 2R,/NJ = S, where R, = chromatographic resolution (for 6u, “base-line” separation, R, = 1.5) and N is the number of theoretical plates required. For the optimisation of HPLC, S can be plotted against the variable parameter(s) and the highest value of S relates to the minimum value of N+ and results in the best separation. For several solutes S , of the most difficult separable pair (i, j ) must be plotted to obtain a window diagram. When more than one parameter is involved three dimensional S , plots are involved and these can often be effectively displayed using the superior graphics of the mainframe computer. A suitable computer program used to produce Fig.1 is available.6 Microcomputers such as the BBC can be fitted with terminal emulator ROM and they become very suitable colour terminals for interfacing with the maillframe computer. %Ba 12.0 3.50 _. 6.00 0 Fig. 1. S-Window optimisation for the separation of catecholamines on ODS as a function of pH and of propan-1-01 percentage by volume. 1 . 2. 3. 4. 5. 6. References Wentworth, W. E., J . Chem. Educ., 1965, 42, 96 and 162. Deming, W. E . , “Statistical Adjustment of Data,” John Wiley, New York, 1943; also published by Dover, Wellington, C. A . , J . Chem. SOC. A, 1969, 2584. Laub, R. J . , and Purnell, J. H . , J . Chromatogr., 1975, 112, 71. Jones, P., and Wellington, C.A . , J . Chromatogr., 1981, 213, 357. Ahmad, K . , Ph.D. Thesis, University of Wales (Swansea), 1983. New York, 1943.April, I 984 COMPUTER AIDS IN CHEMISTRY Application of Kalman Filters to Analytical Chemistry 147 T. Lilley Exploratory Methods Group, BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex, TW16 7LN The Kalman filter is a mathematical tool used by control engineers for estimating signals in the presence of noise.1.2 It is a first order recursive filter, which means it uses only the last estimate (filtered output) and the present (raw data) input to make the next estimate (output). This has two implications: firstly, estimates can be made in real time and so any corrective measures can be made immediately; and secondly, systematic, random or transient changes in the signals can be modelled for.In chemical analysis it has been used to improve signal to noise ratios in multi-component analysis,3 for on-line drift compensation4 and signal resolution enhancement5-7 and deconvolution.8 Kalman filtering has also proved of value in smoothing chromatographic data (Fig. 1). Fig. 1. Above: noisy chromatogram. Below: chromatogram Kalman filtered using a moving average model. The filter is capable of estimating one or more parameters simultaneously and these can be constants, e.g., concentration of species in multi-component spectra, or variables, e.g., base line drift or fitting of unknown peak shapes. The filter uses least-squares techniques to fit the noisy data to models provided by the user and these are created by a set of coefficients that are input into the algorithm. Unlike regression techniques the Kalman Filter has two models, the system model and the measurement model. The system model Fig. 2. Above: noisy chromatogram with transient peak. Below: Kalman filtered chromatogram with self correcting routine to prevent oversmoothing of transient peaks.148 EQUIPMENT NEWS Anal. Proc., Vol. 21 defines how the parameters themselves change. It allows the parameters to be constants or variables, but it also enables a random corpponent to be included. This last feature means unknown and transient signals can be catered for. The measurement model defines the relationship between the parameters and the measurement, for example, if the parameter is a concentration and the measurement is a spectrum then the system model is a constant and the measurement model is a series of absorbances. A confidence interval of the estimate is given by the mean-square error, which is an integral part of the algorithm, the square-root of which is the standard deviation. The operation of the Kalman filter is very flexible. The same algorithm can be used for a variety of models produced simply by changing a few coefficients. A moving average (random) model can be applied to smooth noisy signals (Fig. 1). The degree of smoothing obtained depends on a single coefficient, which reflects the magnitude of the random component. A simple self-correcting routine can be employed which retains peak height for transient peaks (Fig. 2). The determination of components in the spectra of mixtures can be achieved using good (high signal to noise) reference spectra of each component in the measurement rnodel.3.4 It is also possible to model simultaneously for base line drift4 and sinusoidal interferences, which can then be corrected on line. References 1. 2. 3. 4. 5 . 6. 7. 8. Kalman, R. E., J . Basic Eng., 1960, 82, 371. Bozic, S. M., “Digital and Kalman Filtering,” Edward Arnold, London, 1979. Poulisse, H. N. J . , Anal. Chim. Acta Comput. Tech. Optim., 1979, 112, 361. Poulisse, H. N. J., and Engelen, P., Anal. Lett., 1981, 13, 1211. Seelig, P. F., and Blout, H. N . , Anal. Chem., 1976, 48, 252. Seelig, P. F., and Blout, H. N., Anal. Chem., 1979, 51, 327. Brown, T. F., and Brown, S . D., Anal. Chem., 1981, 53, 1410. Rutan, S. C., and Brown, S . D., Anal. Chem., 1983, 55, 1707.

ISSN:0144-557X    

DOI:10.1039/AP9842100138

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

148 EQUIPMENT NEWS Anal. Proc., Vol. 21 Equipment News Spectrophotometer The Lambda 7 is a microcomputer-controlled, ratio recording, double-beam ultraviolet - visible instru- ment. It can scan at up to 1440 nm min-’ and can handle spectra with sharp absorbance bands, for example pyrene, at maximum scan speeds. It has an integral RS232C interface for connection to a laboratory com- puter. When coupled to the maker’s Model 3600 data station or Model 7500 professional computer it can be controlled using the PECUV software package. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire, HP9 1QA. Analysis System Based on the maker’s PU8600 ultraviolet - visible spectrophotometer, the system enables small-batch assays to be automated. The measurement conditions for up to ten different assays can be stored.Up to 100 samples can be loaded in the automatic sample changer. Pye Unicam Ltd., York Street, Cambridge, CBl 2PX. Software for Emission Spectroscopy CESPEC 8E enables the maker’s modular emission spectrometer systems to include Hewlett-Packard’s Model 9816 desk-top computer. Capabilities include the calculation of calibration functions and inter-element corrections by regression, systems checks and plotting of profiles by integration, transmission of results and messages to remote peripherals, and quality checks. Pye Unicam Ltd., York Street, Cambridge, CB1 2PX. Atomic Absorption Spectrophotometer The Shimadzu AA646 microprocessor controlled atomic absorption - flame emission instrument features a dual frequency simultaneous photometric system that ensures a high signal to noise ratio.V. A. Howe & Co. Ltd., 12-14 St. Ann’s Crescent, London, SW18 2LS. Atomic Absorption Furnace The GFA-4 furnace consists of a graphite tube, electric- ally heated with adjustable inner and outer gas purge, which is surrounded by a further graphite tube and held by two water-cooled blocks. The power supply is microcomputer controlled. Semi- and fully automatic injection systems are available. V. A. Howe & Co. Ltd., 12-14 St. Ann’s Crescent, London, S W 18 2LS. Spectrophotometer The Shimadzu MPS-2000 is a multi-purpose ultraviolet - visible microprocessor controlled instrument. It features a dual-face end-on detector system and a saturation-free pre-amplifier system. There are three optional programming attachments, including an inter- face for the HP85F computer.V. A. Howe & Co. Ltd., 12-14 St. Ann’s Cresent, London, SW18 2LS. Spectrophotometer The Bausch and Lomb Spectronic 1001 talks to its operator through its alphanumeric display. It has a wavelength range of 190-950 nm. The microprocessorApril, I984 EQUIPMENT NEWS 149 control system can store up to thirty pre-formulated tests. Ten standard programmes are available. Gallenkamp, P.O. Box 290, Technico House, Chris- topher Street, London, EC2P 2ER. Fixed Wavelength Detector The uvMonitor D enables ten different measurements to be made in the range 214-550 nm (254-nm standard). It features drop-in filters and snap-in lamps for manually operated instrument capable of the determi- nation of inorganic and organic species.Dionex (UK) Ltd., 1st Floor, The Parade, Frimley, Camberley, Surrey, GU16 SHY. Air Monitoring Station The AP 300 E series system allows the initial selection of two or three parameters and the incorporation of additional measurements and data acquisition at a later time. The parameters offered are carbon monoxide, oxides of nitrogen, ozone, hydrocarbons, sulphur diox- ide and dust analyses, together with automatic calibra- tion systems, standard gas generators, meteorological parameters and data acquisition. Horiba Instruments Ltd., 5 Harrowden Road, Brack- mills, Northampton, NN4 OEB. Sulphur and Chlorine Analyser The MESA 200 is a dedicated instrument for the measurement of total sulphur and chlorine content of petroleum products.wavelength conversions. It is fitted with the Max N high pressure fluid cell. Typical noise levels are 1 X absorbance units peak to peak (dry). House, High Street, Stone, Staffordshire, ST15 8AR. Laboratory Data Control (UK) Ltd., Milton Roy HPLC Packing NOVA-PAK CI8 is a reverse-phase packing that can separate acidic, neutral and basic compounds. It is available in 15 cm steel columns and in 10 cm Radial-PAK cartridges for use in the maker's RCM-100 and Z-Module radial compression units. Waters Associates, 324 Chester Road, Hartford, Northwich, Cheshire, CW8 2AH. Electrochemical Detector Cells for HPLC The new cells, made by ESA, include the 5011, which has one coulometric electrode and one amperometric electrode. Detection of catecholamines as low as 500 fg with a signal to noise ratio of 8 to 1 has been reported.The 5012 uses a single coulometric porous graphite electrode and a wall-jet design electrode. Severn Analytical, 36 Brunswick Road, Gloucester, GL1 1JJ. Syringes The Hamilton 7000 series are designed for rapid injection of minute volumes. The total syringe capacity is in the needle. V. A. Howe & Co. Ltd., 12-14 St. Ann's Crescent, London, SW18 2LS. Fraction Collector The Buchler LC-100 automatic unit can hold up to 100 test-tubes or 36 scintillation vials in removable racks. It operates in ambient temperatures down to 0 "C. Gallenkamp, P.O. Box 290, Technico House, Chris- topher Street, London, EC2P 2ER. Ion Chromatograph The QIC Ionochrom analyser is a single-channel, Horiba Instruments Ltd., 5 Harrowden Road, Brack- mills, Northampton, NN4 OEB.Ion Selective Monitors The EIL 8080 Series consists of three monitors, the 8081, 8082 and 8086, designed for the continuous measurement of fluoride, ammonia and nitrate levels in drinking water and for river water monitoring and sewage works applications. Kent Industrial Measurements Ltd., Analytical Instruments, Hanworth Lane, Chertsey, Surrey, KT16 9LF. Calcium Buffer and Indicator BAPTA [ 1,2-bis(2-aminophenoxy)ethanc-NNNN- tetraacetic acid] has a Ca*+ affinity insensitive to pH changes around 7. It provides rapid Ca2+ buffering and enables the direct measurement of Ca2+ by ultraviolet spectroscopy. BDH Chemicals Ltd., Broom Road, Poole, Dorset. Surface Analysis System A computer controlled electronics package is available for use with the LHS 10 multi-method systems.150 PUBLICATIONS RECEIVED Anal.Proc., Vol. 21 Leybold-Heraeus Ltd., 16 Endeavour Way, Durns- ford Road, London, SW19 8UH. Balances A comprehensive range of Shimadzu balances and weighing systems is announced. These include the EB series of electronic balances. V. A. Howe & Co. Ltd., 12-14 St. Ann’s Crescent, London, SW18 2LS. Peristaltic Pumps The Buchler range of four constant flow pumps is designed to permit easy insertion of a continuous length of tubing even while the pump is running. The pumps feature a nylon ribbon between the rollers and tubing to reduce tubing wear. Gallenkamp, P.O. Box 290, Technico House, Chris- topher Street, London, EC2P 2ER. Diluter - Pipetter The Shimadzu DIP-1 is a computer controlled digital instrument.It will dilute a sample on dispensing in a dilution ratio set on a digital dial. Dyson Instruments Ltd., Sunderland House, Station Road, Hetton, Houghton-le-Spring, Tyne and Wear, DH5 OAT. Pipetter Tip The Maxi Tip moulding tool has been re-designed to fit a wider range of pipetters than before. Hughes and Hughes Ltd., Elms Industrial Estate, Church Road, Harold Wood, Romford, Essex, RM3 OHR . Ashing Furnace The series ECF furnace is supplied in three standard chamber sizes and has a maximum operational temper- ature of 1200 “C. There is a choice of two-term (P+D) or three-term (PID) temperature control instrumenta- tion. A full-segment temperature programmer is a standard option. Lenton Thermal Designs Ltd., 12/14 Fairfield Road, Market Harborough, Leicestershire, LE16 9QQ.Literature A leaflet describes the IonPac membrane reactor, which is used with the maker’s post column reactor and a Series 2OOOi ion chromatograph. Dionex (UK) Ltd., Eelmoor Road, Farnborough, Hampshire, GU14 7QN. A brochure gives details of the Neslab series of bath - circulators, which offer temperature control to kO.01 “C and better over the range from -80 to +loo “C. Jencons (Scientific) Ltd., Cherrycourt Way Industrial Estate, Stanbridge Road, Leighton Buzzard, Bedford- shire, LU7 8UA. A brochure describes Haake temperature controllers, which can be used with various Haake circulators. Gallenkamp, P.O. Box 290, Technico House, Chris- topher Street, London, EC2P 2ER. A publication, 570231L, Moisture Determination by Karl Fischer Reagent, is available. Reference is made to two pyridine-free solutions for use with the Karl Fischer method of determining the water content of organic compounds. BDH Chemicals Ltd., Broom Road, Poole, Dorset. A book, Optical Techniques, price 25, is available and includes contributions by Professor Anders Thore and Tim Rawlins. Ultrolab Ltd., P.O. Box 75, Broadway, Bebington, Wirral, L63 5RQ. A brochure covers a range of water test kits and pH indicator papers. Camlab Ltd., Nuffield Road, Cambridge, CB4 1TH. Thermal Analysis Software “Isothermal” software can be used with the maker’s DSC-2C and DSC-4 differential scanning calorimeters. Applications include oxidative induction time analysis, isothermal curing and isothermal recrystallisations. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire, HP9 IQA.

ISSN:0144-557X    

DOI:10.1039/AP9842100148

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

150 PUBLICATIONS RECEIVED Anal. Proc., Vol. 21 Publications Received Methods for the Examination of Waters and Associated Materials. Standing Committee of Analysts (to Review Standard Methods for Quality Control of the Water Cycle); Department of the Environment, National Water Council. HM Stationery Office. The Bacteriological Examination of Drinking Water Supplies 1982. Reports on Public Health and Medical Subjects No. 71. Pp. xiv + 122. 1983. Price f6.30. ISBN 0 11 751675 9.April, I984 PUBLICATIONS RECEIVED 151 Extractable Metals in Soils, Sewage Sludge-treated Soils and Related Materials 1982. Pp. 17. 1983. Price f2.75. ISBN 0 11 751689 9. Acute Toxicity Testing with Aquatic Organisms 1981. Pp. 67. 1983. Price f4.90. ISBN 0 11 751672 4. Assessment of Biodegradability 1981.Pp. 104. 1983. Price 27.50. Environmental Radioanalysis. H. A. Das, A. Faanhof and H. A. van der Sloot. Studies in Environmental Science, Volume 22. Pp. iv + 296. Elsevier. 1983. Price $83 (USA & Canada); Dfl195 (Rest of World). ISBN 0 444 42188 2. Topics covered include Principles of NAA and Prompt Technique, Principles of Radiotracer Studies, Sampling Pre-concentration and Decontamination, Analytical Criteria, Water, Biological Materials, Silicates and Coal. Gas Chromatographic and Associated Methods for the Characterization of Oils, Fats, Waxes and Tars. 1982. Pp. 59. 1983. Price f6.30. ISBN 0 11 751677 5. Instrumentation for Environmental Monitoring. Vol- ume 1, Radiation. Lawrence Berkeley Environmentul Instrumentation Survey. Second Edition.Robert J. Budnitz, Anthony V. Nero, Donnie J . Murphy and Robert Graven. Pp. xxii + 1130. Wiley- Interscience. 1983. Price f142.50. ISBN 0 471 86880 9. Part I introduces units, sources and effects of radiation, discusses basic detection methods and describes the measurement of alpha, beta, gamma and X-radiation. Part I1 discusses, in more detail, sources of anthro- pogenic radiation: nuclear power plants, nuclear spent- fuel reprocessing and mining and milling. Part I11 describes the measurement of specific radionuclides. Methods of Seawater Analysis. Second, Revised and Extended Edition. Edited by K. Grasshoff, M. Ehrhardt and K. Kremling. Pp. xxviii + 419. Verlag Chemie. 1983. Price DM140. ISBN (Verlag Chemie) 3 527 25998 8; (Verlag Chemie International) 0 89573 070 7.The chapters in this book cover the following topics: Sampling and Sampling Techniques; Filtration and Storage; Determination of Salinity; Determination of Oxygen; Determination of Hydrogen Sulphide; Deter- mination of Thiosulphate; Determination of pH; Deter- mination of Alkalinity and Total Carbonate; Determi- nation of Nutrients; Determination of Trace Metals; Determination of the Major Constituents; Determina- tion of Organic Constituents; and Automated Chemical Analysis. Chromatographic Analysis of the Environment. Second Edition, Revised and Expanded. Edited by Robert L. Grob. Pp. x + 724. Marcel Dekker. 1983. Price SwFr251. ISBN 0 8247 1803 8. The 16 chapters in this book are divided into six sections: A, Chromatographic Theory and Environ- mental Sampling; Part B, Air Pollution; Part C, Water Pollution; Part D, Soil Pollution; Part E, Waste Pollution; and Part F, Other Chromatographic Tech- niques Applied to Environmental Problems.Chemical Sensors. Proceedings of the International Meeting on Chemical Sensors, Fukuoka, Japan, Septem- ber 19-22, 1983. Edited by T. Seiyama, K. Fueki, J. Shiokawa and S. Suzuki. Analytical Chemktry Symposia Series, Volume 17. Pp. xvi + 775. Elsevier. 1983. Price $144.50 (USA & Canada); Dfl375 (Rest of World). ISBN 0 444 99638 9. Treatise on Analytical Chemistry. Part 1. Theory and Practice. Second Edition. Volume 10. Section I. Mag- netic Field and Related Methods of Analysis. Edited by Philip J. Elving, Maurice M. Bursey and I. M. Kolthoff. Pp. xxx + 533. Wiley-Interscience.1983. Price f61.75. ISBN 0 471 89688 8. Topics covered are NMR : Principles and lH Spectra, NMR : I3C Spectra, ESR Spectroscopy, Nuclear Quad- rupole Resonance Spectroscopy, Secondary Ion Mass Spectrometry and Mossbauer Spectroscopy. Methods of Enzymatic Analysis. Third Edition. Volume 111. Enzymes. 1: Oxidoreductases, Transferases. Edited by Hans Ulrich Bergmeyer, Jiirgen Bergmeyer and Marianne Grassl. Pp. xxvi + 605. 1983. ISBN 3 527 26043 9 (Verlag Chemie); 0 89573 233 5 (Verlag Chemie International). Over 60 chapters comprise this comprehensive contri- bution to the ”Methods of Enzymatic Analysis” series, divided into several sections that include Methods for Isoenzyme Analysis, Oxidoreductases: Dehydro- genases Acting on COOH Groups, Oxidoreductases Acting on Groups Other than COOH, Transferases for One-Carbon Groups and Ketonic Residues, Acyltrans- ferases and Glycosyltransferases, Aminotransferases and Phosphotransferases.“AnalaR” Standards for Laboratory Chemicals. Eighth Edition. Edited by D. J. Bucknell. Pp. xxviii + 897. BDH Chemicals for AnalaR Standards. 1984. Price f24. ISBN 0 9500439 4 X. The latest edition of “AnalaR Standards’’ contains about 410 monographs, of which 70 appear for the first time. Included this time are a series of materials of importance in biochemical and clinical analysis. Annual Reports on Analytical Atomic Spectroscopy, Volume 12. Reviewing 1982. Edited by M. S. Cresser and L. Ebdon. Pp. xii + 404. The Royal Society of Chemistry. 1983. Price 245; $81. ISBN 0 85186 697 2; ISSN 0306 1353. ARAAS is a handbook of current practice and recent advances in instruments and methods in the form of critical annual reports. It contains chapters on Atomiza- tion and Excitation, Arcs, Sparks, Lasers and Low- Pressure Discharges; Plasmas; Flames; Electrothermal Atomization, Vapour Generation; Instrumentation, Light Sources, Optics, Detectors, Instrument Control, Complete Instruments, New Commercial Instruments; Methodology, New Methods, Detection Limits, Preci- sion and Accuracy, Standards and Standardization; Applications, Chemicals, Metals, Refractories and152 ANALAR GOLDEN JUBILEE Metal Oxides, Ceramics, Slags, Cements, Minerals, Air Analysis, Water Analysis, Soils, Plants and Fertilizers, Foods and Beverages, and Body Tissues and Fluids. Anal. Proc., Vol. 21

ISSN:0144-557X    

DOI:10.1039/AP9842100150

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

152 ANALAR GOLDEN JUBILEE Anal. Proc., Vol. 21 Phases, Biomedical Analysis, Other Differential Migra- tion Methods of Separation, Optimization, Natural Products, Column Efficiency and Peak Resolution, Thermodynamics of Retention, Pharmaceuticals, Detection and Instrumentation, Ion Chromatography, Ion Exchange and Ion Pair Chromatography, Reversed Phase Chromatography, Combined LC - MS, Novel Detection Methods and Stationary Phases. In addition to the above there will be a trade exhibition and an extensive social programme. For further information contact Professor Csaba Horvhth, Department of Chemical Engineering, Yale University, Mason Laboratory, P.O. Box 2159, Yale Station, New Haven, CT 06520, USA. Environmental, Forensic and Archaeological Micro- scopy July 11-12, 1984 Conferences and Meetings Principles of Automation and Applications of Robotics May 9-10, 1984, London A meeting on the above topic will be organised by the Automatic Methods, Microchemical Methods and Spe- cial Techniques Groups of the Analytical Division and the Microcomputer and Microprocessor Group of the Royal Society of Chemistry and held at The Scientific Societies’ Lecture Theatre, 23 Savile Row, London, W.l.The first day of the meeting will be devoted to automated analysis, and the second to robotics. The cost of the meeting will be f60 to RSC members (f80 to non-members); the closing date for registration is April 27. For further details contact Dr. C. J. Jackson, Occupa- tional Hygiene Laboratory, 403 Edgware Road, Lon- don, NW2 6LN. Eighth International Symposium on Column Liquid Chromatography May 20-25, 1984, New York, NY, USA This symposium will be held in the Penta Hotel, New York.It is intended to celebrate 20 years of modern liquid chromatography and to act as a forum for reporting on the latest advances. The topics for the sessions will be Nucleic Acids and Their Constituents, Preparative Liquid Chromatography, Measurement of Physico-chemical Data, Environmental, Food and Forensic Analysis, Bonded Stationary Phases, Proteins, HPLC with Small Dimension Columns, Size Exclusion Chromatography, Biopolymers, Supercritical Fluid Chromatography, Analysis of Peak Profiles and Band Dispersion, Chiral Separations, Polar Stationary As part of the Micro 84 meeting the above symposium will be organised by the Royal Microscopical Society.Its purpose will be to explore the role of various microscopical techniques in investigating and charac- terising environmental, forensic and archaeological materials. A framework of invited papers will provide the basis for interchange of ideas concerning the most appropriate microscopical technique for tackling indi- vidual problems in these related fields. The invited lectures will be as follows: “The Automated SEM and Environmental Studies,” R. S. Lee; “The Use of STEM for Environmental Investigations,” F. D. Pooley; “Automatic Particle Analysis in Forensic Science ,” R. Keeley; “The Role of Optical Microscopy in the Study of Ancient Ceramics,” D. Peacock; and “The Role of SEM and X-ray Spectrometry in the Study of Ancient Materials,” M.S . Tite. Further details and registration forms are available from The Administrator, Royal Microscopical Society, 37/38 St. Clements, Oxford, OX4 1AJ. Antibody Combining Sites and their Exploitation in Cellular Studies September 3-6, 1984, Guildford At the 9th International Subcellular Methodology Forum the above will be the main topics, with distin- guished U.S. and European scientists contributing (and U.S. Army support). There will be consideration of membranous and biomedical aspects, including the localisation of tumour antigens and neuroreceptors. The venue will be the University of Surrey, at which accommodation will be available. Information from Dr. E. Reid, Guildford Academic Associates, 72 The Chase, Guildford, Surrey, GU2 5UL. SAC 86 July 20-26, 1986, Bristol The SAC 86 International Conference and Exhibition on Analytical Chemistry, organised by the Analytical Division of the Royal Society of Chemistry, will be held at the University of Bristol. For details of the confer- ence apply to Miss P. E. Hutchinson, Royal Society of Chemistry, Analytical Divison, Burlington House, Pic- cadilly, London, W1V OBN.

ISSN:0144-557X    

DOI:10.1039/AP984210152b

出版商:RSC    

年代:1984

数据来源: RSC

摘要:

April, 1984 ANALYTICAL DIVISION DIARY Analytical Division Diary 153 APRIL Monday to Thursday, 16th to 19th: Exeter RSC Annual Chemical Congress: Analytical Division Symposium on The Analyst in Court. Opening Address by R. F. Coleman. Theophilus Redwood Lecture: “Forensic Analysis: Much Ado About Next to Nothing,” by R. L. Williams. April 17th- “Recent Investigation of Fungal Toxins,” by B. Caddy. “Toxicology’s Challenge to the Analyst,” by I. Sunshine. “Chemical Identification of the Locus: Strategies and Significances,” by W. J. Tiistone. “Forensic Science Evidence-Considerations of Objectivity,” by H. H. Bland. “Forensic Testing and Individual Liberty: the Analyst on Trial,” by P. G. W. Cobb. April 18th- “Regulatory Analysis by the Public Analyst and Official Agricultural Analyst,” by A.J. Harrison. “Judgement: A Gamble by Interpretation Out of Fact,” by P. 0. Dennis. “Meat products-Interpretation of Proximate and Other Analyses,” by C. H. S. Hitchcock. “Chemical Microscopy,” by W. C. McCrone. “The Independent Consultant as Civil Forensic Scientist and Referee,” by Diana Simpson. “Regulatory Analysis, the View of the Official Referee and Revenue Analyst,” by R. Sawyer. April 19th- Title to be announced by The Hon. Mr. Justice Forbes. “The Development of Statutory Methods of Analysis and Sampling for Foodstuffs,” by R. Wood. “Use Reference Samples Rather Than Reference Methods,” by H. T. Delves. “Quality Assurance in Reference Laboratories: Analytical and Sampling Problems,” by N. T. Crosby. “Analytical Quality Assurance in Public Analysts’ Laboratories,” by D.W. Lord. The University, Exeter. Registration is necessary. Cost f46 to members of RSC, f80.50 to non-members, E9.20 to student, retired and unemployed members, and E l 1 .SO to accompanying persons. Contact: Dr. J. F. Gibson, Royal Society of Chemistry, Burlington House, London, W1V OBN. (Tel. 01-734-9971). MAY Wednesday and Thursday, 2nd and 3rd: Glasgow Scottish Region and Automatic Methods Novel Instrument Design in Atomic Spectro- scopy. This symposium will attempt to highlight some recent developments in instrument design for atomic spectrometry and indicate possible future trends in this field, Through a combina- tion of informal discussions and lecture presen- tations it is hoped that those attending the meeting will discover some “new ideas” which may be of potential use in their own labora- tories.Wednesday, 2nd, 7 p.m.- Informal discussion and display of poster papers. Thursday, 3rd, 10 a.m.- Plenary Lecture-“Grating or Fourier Transform Spectrometers: Which and Why?” by A. P. Thorne. “New Developments in Nebulizers, Chambers and Torches for ICP - OES,” by B. L. Sharp. “Some Thoughts on Making the Best Use of Conven- tional Pneumatic Nebulizers in Flame Spectro- scopic Analysis,” by M. S. Cresser. “Microcomputer Controlled Background Correction for ETA - AES and ETA - continuum source AAS,” by D. Littlejohn, J. Marshall, J. Carroll, J. M. Ottaway, T. C. O’Haver and J . M. Harnly. “Recent Advances in ICP Source Utilisation and Sample Introduction,” by R. D. Snook. “Recent Developments in Inductively Coupled Plasma Instrumentation,” by N.Barnett. Royal College Building, University of Strathclyde, George Street, Glasgow. Registration is necessary. Cost &20 to RSC members, f30 to non-members and &6 to students. Contact: Dr. Janet Warren, Department of Forensic Science, University of Glasgow , Glasgow. (Tel. 041-339-8855, Ex. 574). Group. Thursday, 3rd: Southend East Anglia Region and Chromatography and Electrophoresis Group, jointly with The Essex Section of the RSC. Information. Speakers to include: N. W. Bristow, I. Carrington, D. P. Leworth and P. C. Weston. College of Technology, Southend. Contact: Dr. D. Simpson, Analysis For Industry, Factories 2/3, Bosworth House, High Street , Thorpe-le-Soken, Essex, C016 OEA. (Tel. 0255-861714).[continued on p. 154154 ANALYTICAL DIVISION DIARY Anal. Proc., Vol. 21 Analytical Division Diary, continued May, continued Wednesday and Thursday, 9th and 10th: London Microchemical Methods and Automatic Methods Groups, jointly with the Microcom- puters and Microprocessors Group of the RSC. Principles of Automation and Applications of Robotics. Wednesday, 9th- Session I: Principles of Automated Analysis Keynote Lecture-“The Why, When and Wherefore of Automation in Analysis,” by D. C. M. Squirrell. “Principles of Automation,” speaker to be an- nounced. “Design of Instruments for Automated Analysis,” by M. Ford. “Implementation of Automated Analytical Systems in Industry,” by Professor Loechst. Session 11: The Approach to Automation-Case Studies Keynofe Lecture-“How Automation Has Changed Over the Past 10 Years,” by D.R. Deans. “Does In-House Development Still Have a Role in the 1980s?” by K. J. Leiper. “Commercializing the In-house Development- SIMSLIN (a continuously recording dust sampling instrument),” by M. J. Leck. “Contract Automation-the Development and Modification of Instrumentation for Automatic Spectrometric Titration.” by Professor J . M. Otta- way and G. Cooksey. “The Co-operative Approach With an Instrument Manufacturer-ATD 50 (an automated thermal desorption unit for gas chromatography) .” by R. H. Brown and F. Banyard. “The Role of the Commercial Manufacturer-The Smaller Company’s Approach to the Development of a Marketable Product.” by D. Hendry. “Where Do We Go in the Next 10 Years.” by Professor D.Betteridge. Discussion on “Automated Chemical Analysis-Can the Lessons of the Past 10 Years Provide a Reliable Pointer to the Future,” introduced by D. G. Porter. Thursday, 10th- Session 111: Principles of Robotics Reviews from experts on the following topics: “Geometrics and Current Devices.” “Sensors. ” “Computer Languages for Robot Control.” “Integrating the Robot with the Total System.“ Session IV: Applications of Robotics This session will contain a series of short talks by some 8-10 present users of robot arms and will endeavour to provide a practical view of the problems and benefits of introducing robotic arms. The session will include a panel discussion. Speakers will include staff from the following firms: AERE, BP, Glaxo and LGC. Scientific Societies Lecture Theatre, 23 Savile Row (entrance in New Burlington Place), London, W.1. Registration is necessary. Cost f35 to RSC members, f50 to non-members and f25 to students or retired members, for one day; f60, f80 and $40, respectively, for two days. Contact: Dr. C. J. Jackson, Health and Safety Executive, Occupational Medicine and Hygiene Laboratories, 403 Edgware Road, London, NW2 6LN. (Tel. 01-450-8911, Ex. 227). Thursday, loth, 5.30 p.m.: Pontypridd Western Region Chemometrics or Computers Helping Chemists. Speaker: Professor D. Betteridge. Polytechnic of Wales, Pontypridd. Contact: Mr. F. W. Sweeting, Wessex Water Authority, Bristol Avon Division, P.O. Box 95, The Ambury, Bath, BA1 2YP. (Tel: 0225-313500, EX. 385). Thursday, 15th: Hull North East Region.Persistence in Analytical Chemistry. Speaker: G. Nickless. The University, Hull. Mr. C. L. Denton, 20 Bedford Road, Nun- thorpe, Middlesbrough, Cleveland, TS7 OBZ. (Tel. 0642-315721). Wednesday, 16th: Loughborough Electrophoresis Group. Midlands Region and Chromatography and Inorganic Ions in Chromatography. Speakers to include: M. Cooke and M. Masters. University of Technology, Loughborough. Contact: Dr. D. Simpson, Analysis For Industry, Factories 2/3, Bosworth House, High Street, Thorpe-le-Soken, Essex. C016 OEA. (Tel. 0255-861714). [continued on p . 155April, 1984 ANALYTICAL DIVISION DIARY 155 Analytical Division Diary, continued May, continued Wednesday, 16th, 10.30 a.m.: Daresbury North West Region and Radiochemical Methods The Facilities of the Daresbury Laboratories of the “Introduction to the Nuclear Structure Facility,” by Tour of Nuclear Structure Facility. “Introduction to the Synchrotron Radiation Source,” by N. Greaves. Tour of Synchrotron Radiation Source and asso- ciated facilities. Science and Engineering Research Council , Daresbury, Nr. Warrington. Registration is necessary. Cost &3 to RSC members, &5 to non-members and free to students and retired members. Contact: Dr. A. Dyer, Department of Chem- istry and Applied Chemistry, University of Group. SERC. G . W. A. Newton. Salford, Salford, N5 4WT. (Tel. 061-736- 5843, Ex. 575 or 505). Wednesday, 23rd, 10.30 a.m.: Sunbury South East Region and Special Techniques Quantitative NMR. BP Research Centre, Sunbury. Contact: Mr. J. Huddleston, AERE, Building 10.2, Instrumentation and Applied Physics Division, Harwell, Oxfordshire, OX1 1 ORA. (Tel. 0235-24141, Ex. 2030). Group. Thursday, 24th: Birmingham Midlands Region, jointly with the Royal Statis- Statistics in Chemistry. The University, Birmingham. Contact: Mr. H. E. Brookes, 35 Dunster Road, West Bridgford, Nottingham, NG2 6JE. (Tel. 0602-231769). tical Society.

ISSN:0144-557X    

DOI:10.1039/AP9842100153

出版商:RSC    

年代:1984

数据来源: RSC