ISSN:0144-557X    

DOI:10.1039/AP98522FX029

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

August 1985 Health and Safety in the Chemical Laboratory - Where do we go from here? Analytical Proceedings Proceedings of the Analytical Division of The Royal Society of Chemistry 'The Analysis of Solid Samples by Atomic-emission and X-ray Fluorescence Spectrometry' CONTENTS 229 Editorial 230 Honorary Publicity Secretary's Column 23 1 1984 RSC Awards 232 Summaries of Papers 232 'Applications of Thermal Methods in Catalysis' 236 245 Equipment News 250 Analytical Division Distinguished Service Award (Rules) 250 Conferences and Meetings 25 1 Course 252 Analytical Division Diary This publication provides an overview of health and safety developments in the chemical laboratory and workplace, and will provide essential reading for anyone involved in these ANPRDI 22(8) 229-252 (1 985) areas.Brief Contents: Accident and Dangerous Occurrence Statistics in the United Kingdom; Morbidity and Mortality Studies; Economics of Health and Safety Measures; Procedures and Statistics in France; Professional Negligence, Liability and Indemnity; The System in the United States of America; The System in the United Kingdom; The System in the Federal Republic of Germany; Hazards of Handling Chemicals; Hazards of Apparatus, Equipment and Services; Managing People; What Standards Should We Use? Conflict of Safety Interests with Legislation; The Protection of Workers Exposed to Chemicals: the European Community Approach; Recommendations Arising from the Symposium. Special Publication No. 57 Softcover 206pp 0 85186 945 9 Price f16.50 ($30.00).RSC Members f12.00 ~ ~~ Ordering: Non-RSC Members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 1 HN, England. RSC Members should send their orders to: The Royal Society of Chemistry, Membership Officer, 30 Russell Square, London WC1 B 5DT. The Royal Society of Chemistry Burlington House, Piccadilly London W1V OBN Electronically typeset and printed by Heffers Printers Ltd, Cambridge, England ... 111 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Environmental Chemistry VoI. 3 Disposal and Utilization of Sewage Sludge Possible Consequences of Sewage Sludge Disposal and Senior Reporter H. J. M. Bowen A review Of the literature published UP to the end of Utilization and the Need for Monitoring 1982.Inorganic Deposits in Invertebrate Tissues Metal Deposits Ligand Binding Silica Deposition Urates Specialist Periodical Report (1984) Hardcover 153pp 0 85186 775 8 Price f41.00 ($74.00) RSC Members f27.00 RSC Members should send their orders to: The Royal Society of Chemistry, Membership Officer, 30 Russell Square, London WC1 B 5DT Non-RSC Members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts SG6 7 HN, England. Brief Contents: Tropospheric Ozone Ozone Sources in the Unpolluted Troposphere Photochemistry of the Clean Troposphere Ozone Distribution in the Troposphere Sinks of Ozone in the Unpolluted Troposphere Tropospheric Ozone Budget Ozone Formation and Destruction in Polluted Air Elevated Ozone Levels Biological Effects of Ozone Analytical Techniques The Environmental Chemistry of Organotin Com pou nds Toxicological Patterns of Organotins Analysis of Organotins at Environmental Levels Modes of Entry into the Environment Aqueous Chemistry Transformations in the Environment Degradation of Organotin Compounds Determination of Heavy Metals in Sewage Sludge Analysis of Sewage Sludge Selected Procedures for Sludge Analysis The Royal Society of Chemistry Burlington House Piccadilly London W l V OBN

ISSN:0144-557X    

DOI:10.1039/AP98522BX031

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 229 Ed it oria I International Congress of Pure and Applied Chemistry The 30th Congress of Pure and Applied Chemistry is to be held in Manchester from Sunday September 8 to Friday Sep- tember 13, 1985, and is being organised by the Royal Society of Chemistry on behalf of IUPAC, the International Union of Pure and Applied Chemistry. It is the fourth time that the Congress has been held in Britain and the first time it has been held outside London. The Open- ing Ceremony will take place on Monday, during which the Congress will be for- mally opened by Lord Todd and the Congress Plenary Address given by Professor Sir George Porter. Manchester has been a centre of pure and applied chemistry for more than 200 years and many famous scientists, such as John Dalton, James Prescott Joule, Wil- liam Henry Perkin, Arthur Lapworth, Frederic Kipping, Sir Robert Robinson, Sir Edward Frankland, Sir William Pope, Lord Rutherford, Michael Polanyi, Lord Todd and Sir Ewart Jones have been associated with the City.It is one of the major centres of chemical industry in Europe and the area includes three uni- versities and a polytechnic. It is highly appropriate, therefore that the City should host this congress. In April, 1982, the Analytical Division received an invitation to participate in the organisation of the Congress and first discussions took place in a Programmes Committee meeting in June of that year. It was interesting to note that although analytical science had not been selected as a symposium subject in the 1983 Congress in Cologne it featured prominently in the three previous Congresses in Vancouver, Helsinki and Tokyo, when the subjects chosen included the application of analy- tical chemistry in biology and medicine, instrumental methods of analysis, trace analysis and methodology for the charac- terisation of materials.The recommendation by Programmes Committee that there should be four symposia covering the whole week was accepted by the Analytical Division Council and the Organising Committee and a detailed programme of lectures was assembled. Dr. D. I. Coomber and Dr. C. J. Peacock were appointed as Divi- sional Representatives to the Organising Committee and their work in developing the Programme and liaising with the Committee is gratefully acknowledged. The first symposium, entitled New Instrumental Methods of Analysis, con- sists of the following papers.Solid State Organic Mass Spectrometry Using the Laser Microprobe, by D. M. Hercules (Pittsburgh), Analytical Microwave Spec- troscopy-Now or Never? by J. F. Alder (Manchester), Some Laser Based Analy- tical Techniques, by C. Grey-Morgan (Swansea), Some Recent Work in Atomic Fluorescence, by S. Greenfield (Lough- borough), Novel Detection Systems for Flow Injection Analysis, by P. J. Wors- fold (Hull), Flow-through Detectors Based on Chemically Modified Elec- trodes, by G. Johanssen (Lund) and Prac- tical Applications of ICP - MS in a Multidisciplinary Laboratory by J. S. Hislop (Harwell). This Symposium will take place on Monday and Tuesday morning and the next Symposium on Advances in Auto- matic Methods (to include Microcomput- ers) will follow on Tuesday afternoon and Wednesday morning.Papers will include Spectroscopic Methods, by G. Horlick (Alberta), New Approaches to Data Handling and Presentation in Gas Chro- matography, by D. R. Deans (Cleve- land), Applications of Robotic Principles to Laboratory Automation, by T. B. Pierce (Harwell), Artificial Intelligence and Analytical Chemistry, by D. Bet- teridge (Middlesex) , Microcomputer Applications in Spectroscopy, Chromato- graphy and Kinetic Determination, by H. Pardue (Indiana), and Robotics and Flex- ible Chemical Analysis, by L. A. Gifford (Manchester). The section on Biotechnology- Analytical Applications will take place on Thursday and will consist of the following papers. Enzyme Probes for Determining Inhibitors, by C.Tran-Minh (St. Etienne), Recent Advances in Non- isotopic Immunoassays, by J. N. Miller (Loughborough), Some Analytical Appli- cations of Enzymes, by A. Townshend (Hull), Analytical Affinity Chromato- graphy, by P. D. G. Dean (Cambridge), and Bioanalytical Techniques in Forensic Science by P. G. W. Cobb (Aldermaston). The final symposium on Environmental Analysis will by presented on Thursday afternoon and Friday morning. L. Kosta (Ljubljana) will talk on Changing Priori- ties in Analytical Monitoring of the Aquatic Environment, J. Savory (Virgi- nia) will discuss Monitoring of Toxic Metals in Haemodialysis Patients, A. R. Ware (Kent) will talk on Methods of Measuring Environmental Radioactivity and G.Nickless (Bristol) will present the final paper on Persistence (Pesticides and Metals) and Analytical Chemistry. Programmes such as these have, of necessity, to be arranged well in advance of the date of the meeting and to enable up to date developments to be included poster presentations in each of the sec- tions have been invited. As an indication of the interest shown in the Symposia, fifty poster presentations have been offered to date. Each of the other Divisions of the Society has organised a programme of lectures covering the whole week and there will clearly be much to tempt analysts away from their own programme of meetings. Of particular interest to analysts is a programme organised by the Electrochemistry Group of the Faraday Division and the Electroanalytical Group of the Analytical Division. It is entitled New Electrochemical Sensors and sub- jects covered include Fundamentals, Gas Sensors, Ion Selective Electrodes, Inte- grated Devices and Biosensors. An attractive programme of social events has been arranged, including a concert by the Halle Orchestra, visits to the Lake District, Derbyshire Peak Dis- trict, Sheffield and Chatsworth House, Gawsworth Hall, Snowdonia, Wedgwood Pottery, Chester, York, Quarry Bank Mill, Castlefield and Blackpqol illumina- tions. A Civic Reception will be held on Monday, Section Receptions on Tuesday and the Congress Dinner on Thursday. A most interesting, stimulating and rewarding week is assured for the 1500 delegates who have already registered for the Congress and to those who will be registering in the future. J. WHITEHEAD

ISSN:0144-557X    

DOI:10.1039/AP9852200229

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

230 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Honorary Publicity Secretary’s Column There are still a few copies of the second edition of the glossy brochure bending the shelves in my office. Ten thousand copies of this A4-sized four-page colour glossy explanation of what analytical chemistry is and what analytical chemists do were printed last October. They are aimed primarily at sixth-form students but are probably understandable by a wider range of the student population. If you would like some copies for any kind of activity involving chemistry and young people, just let me know. It doesn’t have to be specifically an RSC sponsored event. One major outlet for these brochures is the schools lecture programme. Professor Alan Townshend is touring the country presenting “Trace Analysis-An Illumi- nated Discussion ,” hopefully in every Region of the Analytical Division.Most of these lectures will be run in conjunction with a local teachers’ centre who will circulate schools with the details, but additional publicity would not do any harm. So if you have offspring involved in a school or college science society in a location near the venue of the schools lecture in your Region, then perhaps they could pass on a copy of the notice of the meeting to the teacher in charge. As the lecture is part of the Regional lecture programme, you will receive details of the lecture as part of the normal Divisional publicity mail shots. Those of you in Regions already visited by Professor Townshend can look forward to having next year’s lecture “Potential Sense in Analytical Chemistry,” to be given by Dr.J. D. R. Thomas of UWIST. Group Liaison and Policy Committee has been considering the reasons for attendance at meetings and concluded, not surprisingly, that it is the topic of the meeting that is the most important con- sideration rather than the weather, time of year, etc. The Committee asked Coun- cil to consider setting up a working party to consider all aspects of the Group structure. There do seem to be some subject areas not covered by an appro- priate group, such as molecular spec- trometry, surface analysis, etc. If you have any thoughts that you would like passed on to Group Liaison and Policy Committee, then let me know. The Analytical Methods Committee and the Association of Official Analytical Chemists are exploring possible collabor- ation.At present this will involve an exchange of information and avoidance of duplication of work. The next edition of the methods book is recovering, in the capable hands of Colin Watson, from the set back of Dr. Harold Egan’s untimely death. Whatever the final format of this new edition, it will certainly be more comprehensive than the previous edi- tions. The AMC Sub-Committees on “Nitrogen Factors” and “Statistical Methods” are well into their stride. The former, under the Chairmanship of Professor R. A. Lawrie (Professor of Food Science and Head of the Depart- ment of Applied Biochemistry and Food Science at Nottingham University’s School of Agriculture), aims to assess the validity of the over-all nitrogen factor for comminuted pork of 3.45 (dating from 1961) when applied to the analysis of modern cured pork products, which may be prepared from specific locations in the carcase. The Statistical Methods Sub- Committee, under the Chairmanship of Dr.M. Thompson (lecturer in Analytical Geochemistry in the Department of Geol- ogy at Imperial College) is getting to grips with the experimental design of co- operative studies and the protocol for evaluating the results of such studies. Further information concerning the recent activities of the AMC and its Sub-committees can be obtained from the Divisional Council’s Annual Report (published in April, 1985). Requests for more detailed information or offers of help with collaborative studies should be directed to the AMC Secretary, Mr.J. J. Wilson (c/o Burlington House). Any donations to the AMC Trust Fund should be addressed to Dr. D. I. Coomber, also care of Burlington House. In addition to losing Harold Egan, the analytical community suffered the further loss of another distinguished and energetic member with the death of Professor Gordon Kirkbright. Tributes more eloquent than I am capable of have already been paid to this unique analytical scientist, so just let me gently remind you that the Association of British Spectro- scopists, in conjunction with Gordon’s colleagues from the Department of Instrumentation and Science at UMIST, the Society for Applied Spectroscopy and the Analytical Division of the RSC, is establishing an appeal fund for a bursary to help promising young analytical scien- tists of any nation to attend conferences or places of learning to further their education.Cheques should be made pay- able to “The Association of British Spec- troscopists Trust (GFK Appeal)” and sent to Dr. J. F. Alder, DIAS/UMIST, P.O. Box 88, Manchester M60 1QD. This September is going to be a busy month if you like going to conferences. The major event is, of course, the IUPAC Congress in Manchester from the 9th to the 13th. There will be analytical sessions on “New Instrumental Methods,” “Auto- mated Methods,” “Environmental Analy- sis,” “Analytical Applications of Biotech- nology” as well as a joint Analytical/ Faraday Division Symposium on “New Electrochemical Sensors.” The Congress is preceded by Flow Analysis 111, the third International Conference on Flow Analy- sis, organised by the Midlands Region at Birmingham University from September 5th-8th.Particle Size Analysis 85, from September 16th-20th in Bradford, com- pletely overlaps Analyticon 85, which runs from the 17th to the 19th in London. Future major Divisional meetings include the RSC Annual Congress at Warwick University from April 8th-llth, 1986, when the Divisional theme will be “New Spectroscopic Sensors and Techniques.” As an added attraction, Professor G. Hieftje will present the 1986 Theophilus Redwood lecture. The Division’s major event of 1986 will be the SAC 86/3rd BNASS Conference at Bristol from July 20th-26th. This will be a joint conference on Analytical Chemistry and Atomic Spectroscopy, run in conjunction with the Spectroscopy Group of the Institute of Physics, and will have similar formats to previous SAC and BNASS (Biennial National Atomic Spectroscopy Sympo- sium) events.The format will be three lecture streams on the Monday and Tues- day and two on the Thursday and Friday, devoted to topics other than atomic spec- troscopy, with two streams on the Thurs- day and Friday on atomic spectroscopy. The Wednesday will be given over to update courses (“Recent Advances in Electrothermal Atomisation,” “Diode Array Detectors,” “Ion Chromato- graphy” and “Robotics and Microproces- sors for the Analytical Laboratory”), the exhibition and the opening of the atomic- spectroscopy sessions. As with previous conferences in the series, there will be poster sessions, discussion sessions, industrial visits, an accompanying persons programme and, naturally, some social events.Divisional Group participation will be strong and several of the sessions will have been organised by the appro- priate subject group. There will be top quality plenary and invited lecturers from all over the world and a large number of the world’s leading analytical chemists will be present. Altogether an event not to be missed, so mark the week in your diary now. The Division is planning a full pro- gramme of meetings for 198516, starting with a meeting on October 23rd, 1985, “Burning Topics in Analysis ,” concerning analytical aspects of fires (their investiga- tion and prevention), and featuring Professor Bishop’s L. S. Theobald Lec- ture “Fire in Flight.’’ “Newer Analytical Techniques in the Fermentation Indus- tries” will be discussed on DecemberANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 231 12th, 1985, and “Tracers in Analysis” on February 5th, 1986.The 1986 R. and D. Topics meeting will be held at Birkbeck College on April 15th-16th. The Divi- sion’s Symposium at the Bath Autumn Meeting from September 23rd-25th, 1986, will be concerned with “Enzymes and Antibpdies.” Analytical chemists will be participat- ing in the British Association meeting at Strathclyde in the shapes of Professor Ottaway, Professor Townshend, Profes- sor A. F. Fell and Dr. B. Caddy on the morning of August 29th, 1985. The Automatic Methods Group is organising two major meetings early in the 1985/6 session. The first of these concerns the “Automated Analysis of Ions in Solution,” September 25th-27th, 1985, at York University. The major sessions will tackle “Spectrophotome- tric,” “Electroanalytical,” “Conventional Chromatographic” and “Combination Chromatographic Methods” and there will be an exhibition of equipment. The second meeting deals with “The Inte- grated Approach to Laboratory Automa- tion,” October 23rd-25th, 1985, at Fern- down in Dorset. The topics to be addressed include “Analytical Instrumen- tation ,” “Robotics ,” “Information Management Systems” and “Laboratory Staffing and Design.” Again, there will be an exhibition and demonstration of appropriate hardware and software. Further information on any of the above items can be obtained, in the first instance, from Miss P. E. Hutchinson, Secretary of the Analytical Division, Royal Society of Chemistry, Burlington House, Piccadilly, London W1V OBN. J. F. TYSON

ISSN:0144-557X    

DOI:10.1039/AP9852200230

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 231 1984 RSC Awards Two of the 1984 RSC Awards went to analytical chemists: the award for Analy- tical Separation Methods, sponsored by Roche Products, was given to Dr. M. B. Evans of Hatfield Polytechnic; and the award for Chemical Analysis and Instrumentation, sponsored by Perkin- Elmer, was given to Professor R. K. Harris of the University of Durham. The awards were presented at a cere- mony held in Burlington House on June 5th. Our photograph shows (L-R) the President of the Analytical Division (Mr. P. G. W. Cobb), Professor R. K. Harris, Dr. M. B. Evans and the President of the Royal Society of Chemistry (Professor R. 0. C. Norman). Brief Contents: Chemical Biographies; Chemical Education and Chemical Institutions; Recent Developments Introduction; in the History of Chemistry Edited by C.A. Russell This book is intended primarily to inform chemists of recent progress in the history of chemistry. It originated from an initiative of the Historical Group of the Royal Society of Chemistry who for some considerable time had been aware of a rising surge of interest amongst chemists in the history of their subject. Yet there was also considerable frustration in obtaining reliable and up-to-date information, in understanding recent trends and in perceiving the relevance to specific problems of some of the less obviously ‘chemical’ writing of the last few years. Those with whom the Group was in touch included chemistry teachers wishing to introduceperhaps only occasionally-historical elements into their school curricula.Chemistry to 1800; General and Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Analytical Chemistry; Biochemistry; Instruments and Apparatus; Industrial Chemistry; Chemistry by Location in Western and Central Europe; Appendix I Periodicals for the History of Chemistry; Appendix It Some Useful Addresses; Author Index; Subject Index: People; Subject Index: Themes. Hardcover 344pp. ISBN 0 85186 917 3 Price f27.50 ($36.00) RSC Members f12.00 Others who expressed both interest and frustration were members of university and polytechnic chemistry departments, chemists in industrial research and those who had taken early or normal retirement. These are the readers for whom this book has been published, although it is hoped that professional historians of science may also find it to be of interest and value in its general surveys of the literature. Ordering: Non-RSC Members should send their orders to: The Royal Society of Chemistry, Distribution Centre, Blackhorse Road, Letchworth, Herts. SG6 lHN, U.K. RSC Members should send their orders to: The Royal Society of Chemistry, Assistant Membership Officer, 30 Russell Square, London, WC1 B 5DT.

ISSN:0144-557X    

DOI:10.1039/AP9852200231

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

232 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 The Analysis of Solid Samples by Atomic-emission and X-ray Fluorescence Spectrometry The following is a summary of one of the papers presented at a Joint Meeting of the North East Region and the Atomic Spectroscopy Group held on October 17th, 1984, at the Central Laboratories of Tioxide UK, Stockton-on-Tees. An Overview of Solid Sampling Analysis H. Hughes Consultant (Metallurgical Analysis), 7 Rowan Avenue, Guisborough, Cleveland TS 14 8DR This paper served as an introduction to the meeting. Several aspects of development and application had been selected for discussion and some of these were the subject of individual papers presenting the techniques in more depth. Developments in analytical application generally result from two sources, improvements in the design and performance of instrumentation and developments in techniques to exploit the potential offered by improved instrument performance.Both these facets are discussed in the two separate sections of the paper which deal with atomic emission and X-ray fluorescence. Atomic Emission The evolving needs of optical emission, in particular with the advent of ICP excitation as a technique applied routinely, have been reflected in instrument development. Wide dynamic ranges of calibration, background correction requirements and wavelength coverage up to 850 nm to include alkali metals such as potassium have influenced spectrometer design. The manu- facturers have responded to meet demands and this is typified, for example, by the recent Philips introduction of the PV 8050 series of optical emission spectrometer systems.In this series the standard wavelength range covers 165-485 nm, giving the best possible dispersion to separate problematical overlaps in general applications, with an optional long wavelength exten- sion to cover up to six elements in the 530-850 nm range. This is illustrated in Fig. 1. Automatic background correction using a stepping motor slit drive is also optional for ICP systems, whilst other features such as individual slit assemblies to reduce cross-talk between adjacent lines by the use of light guides improves the limits of detection. Extended measuring capabili- ties facilitate 4 x 106 dynamic ranges and other accessories, such as programmable roving detectors , allow further flexibil- ity in support of a fixed spectrometer configuration.Such developments by the manufacturers support the user in maximising the effectiveness of application and the latter play their part in developing optical emission for a wider application. There is little doubt that atomic-emission spectrometry has received an impetus from developments in the last 5 years or so after a period relatively in the doldrums in industrial applica- tion. This belief is illustrated in the following sections. Spark Excitation Whilst this technique continues to be the workhorse in many areas of metal production I have selected one area for review. This is the case where an element can be present in two forms and speciation is necessary to separate these forms.In steel, this can be true of many elements, such as carbon, boron, phosphorus, aluminium and carbide forming elements, for example titanium and vanadium. For production purposes, in 1. Constant low-pressure argon zone 2. Temperature controlled zone 3. Analytical gap of excitation stand 4. Entrance lens 5. Switchable mirror (cylindrical for ICP system) 6. Light from ICP mirror optics or second excitation position 7. Entrance slit (motorised displacement with automatic background 8. Exit slit plate 9. Concave primary grating correction option) 10. Exit slit on long wavelength side of entrance slit 11. Light guide 12. Photomultiplier Long wavelength extension 13. Plane secondary grating 14. Long wavelength exit slits and photomultipliers Programmable scanning channel option 15.Angled plane mirror 16. Exit slit 17. Filter turret 18. Switchable light guide 19. Tie bar 20. Position reading head Fig. 1. Optical system of the PV 8050 seriesANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 233 Philips I’ I 12 I 13 I 14 I 5 , 16 , 17 Als = f Ix (when Ix constant) 7 I Tirne/s AIT = fZlx Fig. 2. Analysis of soluble and insoluble aluminium particular, it is important to separate total aluminium into the matrix solid solution form (soluble aluminium) and the insoluble aluminium where aluminium is present as oxide and/or silicate inclusions in the steel. A previous paper’ reviewed some of the developments reported from Japan to adapt the spark emission method to carry out this analysis. Whilst Imamura and Fukui2 described a method based on the pulse-height analysis of the light produced from individual sparks, Onodera et al.3 described a method where two consecutive integrations were made and the difference in light intensities between the two was related to the insoluble aluminium present.The latter method had the advantage that no expensive add-on equipment was required to conventional optical-emission spectrometers. The Institut de Recherches de la Siderurgie Francaise (IRSID) has investigated the technique further and Wittmann and Wiilay4 have described this work. They demonstrated that the difference between the two intensities (taken between 0 and lo00 pulses and between 3000 and 4000 pulses) was the result of the removal of insoluble aluminium under the action of the spark, leaving the soluble aluminium to be measured in the second integration.This is illustrated in Fig. 2. Data in the paper compared optical- emission and atomic-absorption results for the determination of soluble aluminium in the presence of insoluble aluminium varying between 0.0005 and 0.0033%. Agreement was very good. Philips have investigated the technique and modified it on the basis of their findings. Ronksleys established that when the insoluble aluminium content was high, instances were identified when the insoluble aluminium was not totally removed in the first integration and the modification was to take seven integrations of 3 s and critically examine each one to establish when the intensity became constant. This method is also illustrated in Fig. 2, and allows the determination of insoluble and soluble aluminium in steels with total aluminium contents up to 0.2%..\pplication to other elements is possible when the additional information is required for other elements for metallurgical reasons, and boron and titanium are high on the list of priorities to be developed. Low-pressure Discharges Glow discharge lamp The lamp has been the subject of much investigation and development for two possible applications: in bulk analysis and to profile variations in surface composition. The principle of the lamp was summarised in a recent paper.6 Basically, the sample forms the cathode of the lamp and a negative glow is maintained at a pressure of 6 Torr of argon. In bulk analysis, the lamp’s potential for application was clearly illustrated and the advantages were identified, particularly ease of calibration using binary samples.6 Although further work has been reported recently in the latest ARAAS volumes the technique has yet to make a real impact in metal analysis, particularly ferrous analysis.In surface analysis it has made much more impact. Com- pared with Auger, ESCA, SIMS, etc., it is much simpler to apply and operate on a routine day to day basis, although it does not have the same scope for depth resolution as those techniques. Again, in a paper already referred to,l its potential application to measure surface composition profiles is illus- trated for de-carburisation in steel surfaces, following the processing of ingots or slabs into plate or sheet. Other papers, one by Koch et al.,7 which also described the lamp’s application to measure contamination profiles on the surface of processed steel, and the other by Ohasi et d . , 8 who used a preliminary discharge technique to limit the initial unstable intensity profile to 1 nm (10 A), enabling depth profile measurements from the upper surface to 100nm to be made, illustrate practical applications of the technique. Other conference papers by Droog and Osawa have respectively illustrated day to day application of the lamp in a steel plant, to measure the surface contamination of processed steel, and the in-depth profiling of galvanised steel. Hollo w-cathode lamp Like the glow discharge lamp the hollow-cathode lamp has not made the impact expected at one time. It is possible that other techniques now provide the limits of detection and sensitivity required for solid sample analysis.Papers by Buzaai-Gyorfi, however, illustrated the lamp’s application to the analysis of small amounts of carbide inclusions extracted from steel (for chromium, manganese, molybdenum, silicon and vanadium)g and the analysis of the rare-earth elements cerium, dyspro- sium, lanthanum and ytterbium in steel. 10 In the latter instance the hollow cathode discharge tube was water-cooled. Inductively Coupled Plasma Several interesting methods for solid sampling prior to the introduction into a plasma have been reported. One of these produces an aerosol by sparking, which is then swept into an ICP torch by using argon. Hirokawa and Takadall illustrated its application to aluminium alloys and a calibration graph including high silicon contents using reference samples was illustrated.Other workers have described direct solid sample introduc- tion into an ICP using a graphite rod. A Russian conference paper claimed a detection limit of approximately 10-11 g when dry residues of solution aliquots (10 pl) on graphite rods were introduced. Kirkbright and Snookl2 have also reported the application of a similar technique.234 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Finally, in this interesting section, laser ablation as a precursor to ICP analysis has been the subject of work by several authors. Carr and Horlickl3 used a ruby laser in the normal and Q-switching modes. The best results were obtained in the normal mode for the analysis of aluminium alloys and brass with relative standard deviations of 5 and 3.3%, respectively.Ishizuka and Uwamino14 also used a ruby laser to investigate steel, brass, aluminium alloys and titanium alloys. Again, performance was better with the normal mode of laser operation and Table 1 summarises the relative standard deviations and limits of detection (3 a) for elements in steel. Table 1. Rsd and LD (3 a) for elements in steel Element Y O deviation, O/O detection, p.p.m Concentration, Relative standard Limit of A1 0.02 4.6 2 c o 0.15 3.1 0.6 Cr 0.69 3.8 1 c u 0.10 8.6 0.3 Mn 0.25 4.6 0.3 Ni 0.32 3.3 1 V 0.31 11.0 1 Thompson et aZ.15 also interfaced a laser ablation cell and an ICP torch with flexible PVC tubing. X-ray Fluorescence This technique followed optical emission into general applica- tion with a time gap of approximately 10 years and develop- ment and application has followed the same two paths of improved instrument design and performance and the refine- ment of analytical procedures to overcome problems identified in application.Dealing first with instrument development, progress in X-ray tube design and the manufacture of a range of single crystals and detectors has contributed much to the per- formance of present-day instruments and practical detection limits in actual samples for XRF now compare very favourably with atomic-absorption and ICP when the dilution involved in sample preparation is taken into account. This is illustrated in Table 2. Table 2. Practical detection limits (p.p.m.) in mineral analysis Element AAS ICP XRF As 20 10 2 c o 5 2 5 c u 2 5 5 Mn 5 5 20 Mo 2 30 2 Ni 5 5 5 This is a continuing process, as typified by the latest Philips update of their sequential and multi-channel PW 1400 and PW 1600 series, the PW1404 and PW1606.Features include compact configuration, high-efficiency generators to reduce energy costs, new sealed detectors and faster counting poten- tial. Above all, however, is the relentless effort to improve performance for light element analysis (fluorine and below), an area where XRF has suffered disadvantages compared with other techniques. Two developments in particular are worthy of discussion, multi-layers and dual-anode tubes. Multi-layers are artificial crystals produced by depositing alternate very thin layers of heavy and light element atoms on a silicon substrate.Values of 2 d in the range 4 1 2 nm (4G120 A) are possible in practice, making them ideal for light element analysis. Barbee and Schiller16 report success in producing high PW1400-PXI PW 1404-PX1 > v) C PW1400-TIAP t r .- al Sc tube .- (47 p.p.m.1 2 x c > PW1400-TIAP Rh tube (64 p.p.m.1 PW141O-ADP (142 p.p.m.1 Magnesium, % - Fig. 3. ment development (detection limits shown in parentheses) Improvement of magnesium (in steel) analysis with instru- quality multi-layers and sensitivity gains by a factor of between 3 and 5 are reported for light elements in the range magnesium to oxygen compared with a thallium AP crystal. The PW 1404 incorporates such a crystal in its configuration, the PX-1 with a 2 d spacing of 5.1 nm, now produced exclusively for Philips.Its effect on sensitivity and limit of detection is illustrated in Fig. 3, taking the analysis of magnesium in cast iron as an example. The same figure also illustrates clearly the effect of continuous instrumental developments on performance. Another monochromator, the PX-2 (2d spacing 12nm) offers the possibility of considerable improvement in the analysis of carbon and boron. Fig. 4 illustrates this with a calibration for carbon in steel. PX-2, in fact, provides sensitivities between 5 and 10 times better than lead stearate and like PX-1 the excitation benefits of a scandium tube for light elements are fully exploited. 0.27 t > v) 0) c .- .- E 0.22 x > E I I 0.5Q 0.75 0.17 0.25 Carbon, YO Fig. 4. monochromator) Calibration graph for carbon in steel (scandium tube, PX-2 Reference to the scandium tube highlights progress in X-ray tube technology.A previous paper17 illustrated the improve- ment in excitation for light elements below calcium in the periodic table using a scandium tube. Upwards in the table beyond vanadium, however, a rhodium anode tube is much more efficient compared with scandium. Although fluores- cence yield is not such a problem for higher atomic numbers a combination of two anodes to maximise fluorescent yield is an attractive proposition. Philips have achieved this with the dual-anode tube (DAT). The anode of the new type of tube consists of a layer of scandium or chromium (most effective for light element fluorescence) deposited on a layer of rhodium,ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 235 molybdenum or gold (most effective for heavy elements).At comparatively low voltages (again most effective for light element excitation) the dual-anode tube functions as a conven- tional scandium or chromium tube, whereas at higher voltages the rhodium, molybdenum or gold radiation is produced to give more efficient excitation of the heavy elements. The comparative intensity yield for individual and combination anodes is illustrated in Fig. 5. This type of tube is now available for instruments such as the PW 1404. 5 4 - gl$3 2 1 0 Fig. 5 . 10 20 30 40 50 Atomic number (2) ComDarative sensitivitv of chromium. rhodium. scandium and dual anode (c‘hromium - go1d)‘side window X-ray tubes In the area of application, the understanding and correction of inter-element effects and the development of sample preparation methods (particularly to overcome mineralogical effects in oxide materials) have ensured that technique development has kept pace with instrument development.As a result, day to day levels of performance have reached a very high standard and the remainder of the paper illustrates this. The development of mathematical models with a-factors based on absorption theory by Traill and Lachance,’* de Jongh19 and Rasberry and Heinrich*() have enabled calibration graphs over wide ranges of composition, and techniques for preparing stable Li2B407 glass beads, in the instance of oxides, has ensured accurate and reproducible results. The exploitation of microprocessors and minicomputers for instrument operation and data processing has also been an integral part of development.Table 3 illustrates long-term performance achievements over a period of 5 months in the instance of feldspar analysis. During this period eleven new samples were prepared using lithium tetraborate . The over-all long-term precision and the accuracy following a-corrections were excellent. Table 3. Long-term reproducibility-feldspar analysis Oxide SiOz A1203 CaO K20 NazO Chemical, X-ray, Precision 69.64 69.67 0.07 16.44 16.42 0.04 O/O O/O (0) 0.18 0.16 0.0004 9.66 9.70 0.014 3.19 3.20 0.011 Likewise for steel analysis, the correction procedure makes analysis over a wide range of calibration a practical possibility. Table 4 illustrates the accuracy possible for alloy steels.The residual mean errors without a-correction are listed to illus- trate the extent of the problem, together with those following correction when the mean error has been reduced to a very low level. Table 4. Accuracy of X-ray analysis of alloy steels Range, Element Yo Si 0-1.4 Mn 0-2.1 Cr 0-25 Mo 0.2.5 Ni 0-25 Ti 0-0.5 RMS, % without &-correction 0.014 0.036 0.86 0.017 0.40 0.005 RMS, Yo with a-correction 0.01 1 0.018 0.063 0.012 0.039 0.006 In conclusion, reference has already been made to the use of computers for instrument operation and data processing, and reference should be made to the concept of automated laboratory management, where the data from the various atomic-emission, X-ray fluorescence, atomic-absorption, com- bustion and classical methods can be transmitted, edited, stored and evaluated on a long-term basis in a central computer.With the throughput of a laboratory in our present scale of operation it would be impossible to cope with the amount of information generated. Hopefully, the paper has presented an overview that is exciting and augurs well for the future of solid sample analysis. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. References Hughes, H., Analyst, 1983, 108, 286. Imamura, N., and Fukui, I . , “XXI CSI,” Cambridge, 1979, Abstract No. 225. Onodera, M. , Nishizaka, K., Saeki, M., and Sakata, T., Nippon Steel Tech. Rep. Overseas, 1977 (91, 73. Wittmann, A., and Willay, G., “Proceedings of the 36th Chemists’ Conference, BSC Teesside Laboratories,” British Steel Corporation, Middlesbrough, 1983, p. 83. Ronksley, B . , Personal communication. Hughes, H., Metall. Muter. Technol., 1981, 569. Koch, K. H., Kretscmer, M., and Grunenberg, D., Mikrochim. Acta, 1983, 11, 225. Ohasi, Y., Furunushi, Y . , and Taunoyama, K., Tersu To Hagane, 1983,69, 1344. Buzaai-Gyorfi, A., Acta. Chim. Hung., 1983, 113, 279. Buzaai-Gyorfi, A., Acta. Chim. Hung., 1983, 113, 285. Hirokawa, K., and Takada, K., Nippon Kinzoku Gakkaishi, 1983,47, 507. Kirkbright, G. F., and Snook, R. D., Appl. Spectrosc. , 1983,37, 11. Carr, J. W . , and Horlick, G . , Specfrochim. Acfa, 1982,37B, 1. Ishizuka, T., and Uwamino, Y., Specrrochim. Acta, 1983,38B, 519. Thompson, M., Goulter, J. E., and Sieper, F., Analyst, 1981, 106, 32. Barbee, T. W., and Schiller, E., AZP Conf. Proc., 1981,75,131. Hughes, H . , Metall. Muter. Technol., 1984, 137. Lachance, G. R., and Traill, R. J., Can. Spectrosc., 1966, 11,43 and 63. de Jongh, W. K., X-ray Spectrom., 1973, 2 , 151. Rasberry, S. D., and Heinrich, K. F. J . , Anal. Chem., 1974,46, 81.

ISSN:0144-557X    

DOI:10.1039/AP9852200232

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

236 ANALYTICAL PROCEEDINGS. AUGUST 1985. VOL 12 Applications of Thermal Methods in Catalysis The following are summaries of six of the papers presented at a Joint Meeting of the Thermal Methods Group and the Surface Reactivity and Catalysis Group of the Faraday Division held on November Zlst, 1984, i n the Scientific Societies Lecture Theatre, London, W.l. Applications of Thermal Analysis Methods to the Study of Catalysts G. C. Bond Department of Chemistry, Brunel University, Uxbridge Methods of Preparing Heterogeneous Catalysts The chemistry used for preparing heterogeneous catalysts will be illustrated with reference to supported metals. Here a low concentration (0.1-20"/o m/m) of metal is formed in a highly dispersed state on the surface of a support. which is typically a high surface area porous oxide (y-A1203.SiOz, etc.). Activated carbon or graphite and low area supports (such as a-A1203). as well as many other materials, can be used. When the active phase is well dispersed. a large fraction of the metal atoms is situated at the surface of the particles and these are accessible for catalysis. Some approximate benchmarks are that for a diameter of 10 nm, the dispersion (i.e., the fraction of atoms at the surface) will be about 10%. and to achieve 100% dispersion the size has to be reduced to about 1 nm. 1 The presence of the support also allows the incorporation of other components, P . g . , promoters. Preparative methods can be subdivided into those where the support and the active phase (or their precursors) are co-precipitated, and those where the active phase (or its precursor) is deposited on a pre-formed support.Co- precipitation is easily applied when the support and active phase precursors can be precipitated from solution as hydrox- ides. Thus. for example, addition of base to a solution of Ni(N03)? and Al(N03)3 results in the formation of the mixed hydroxides. and calcination to the oxides followed by reduction of Ni?+ to the metal affords the active catalyst. The active phase precursor can be precipitated on to a suspension of the support; a particularly useful way of achieving this is to generate OH- ions uniformly throughout the solution by the thermal decomposition of urea at t30-100"C. In this way Ni(OH)? can be deposited on to silica. for example; drying. calcination and reduction complete the process.A commonly used method is to fill the pores of the dry support with a solution of the salt of the active metal. then to dry, calcine if desired and finally reduce. This initial procedure is known as impregnation. The method is widely applicable, and control over the location of the active phase in the support granule is possibly by choice of drying conditions. metal salt and competitive adsorbates. Finally, most oxidic supports have a layer of OH- groups at their surfaces, and these may dissociate either as acids or bases; the resulting ions can be exchanged with either anions or cations of the active metal. giving a highly dispersed precursor phase. The product is filtered, washed, dried and reduced. Catalytic activity for elements in the metallic state chiefly resides in Groups 8 and 1B of the Periodic Classification and most of these twelve metals find use in industrial catalysed processes. In addition to the supports already mentioned, amorphous and crystalline solid acids (such as silica - alumina and zeolites) are finding increasing use.as are various spinels. UB8 3PH Promoters usually have basic character ( e . g . . K + . Na+. MgO, La,03) and are added to impart thermal stability or to improve resistance to poisoning. Calcination and reduction are commonly used steps. and are those most usefully studied by thermal analysis. Methods of Thermal Analysis Thermal analysis involves heating the specimen at a constant rate and observing some change in the specimen or its surroundings.The simplest change in the specimen to monitor is its mass: this is thermogravirnetric analysis (TGA). Buoyancy correc- tions are needed for quantitative work. Measurement of the temperature of the specimen in relation to that of a reference informs us whether an exothermic or endothermic reaction is occurring; this is differential thermal analysis (DTA). As a refinement, the rate of evolution or absorption of heat can be measured by a balancing electrical input to maintain specimen and reference at the same temperature; this is differential scanning calorimetry (DSC). Changes in the surroundings can be followed by analysing the gas atmosphere around the specimen. If this involves analysis of gases released, we speak of evolved gas analysis (EGA), whereas if it involves measuring the hydrogen consumed in a reduction step, it is temperature programmed reduction (TPK). It is also possible to study the change in catalytic activity with temperature either by gas analysis or by measuring the heat evolved.Thermal analysis can be applied either qualitatively (i.e.. as fingerprinting or as an aid to identification), or quantitatively (i.e., measuring enthalpy change. hydrogen consumed, etc.). Kinetic information. such as activation energy. can be derived by varying the heat rate. but great care, and control over sample size and shape, heating rate. gas flow-rate. etc.. needs to be exercised if reproducible results are to be obtained. Some Applications of Thermal Analysis to Catalysis Studies TPR can be used to determine the number of different reducible species at the precursor stage.If. however, two peaks are observed. this may also signify that a single species is being reduced in two steps (t.g.. Cult + Cu+ + Cu"). The alternatives can often be distinguished by varying the concen- tration of the active phase; if the relative areas of the two peaks change, one has two distinct species. An example of this is provided by VO, - Ti02 catalysts. At low vanadium concentra- tions there is a single peak at about 450°C due to VO, ions forming a monolayer on the support. while for concentrations greater than about .1?* a second peak is observed' (T,,,;,, -600 "C), which corresponds to crystalline V2Oi.ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 TPR has also been used to study the reduction of bimetallic catalysts with a view to establishing whether or not the two components become alloyed; care has, however, to be used in interpreting the results.TPR of RuC13 and C U ( N O ~ ) ~ co- impregnated on to silica shows3 two peaks, which, by varying the Ru : Cu ratio, can clearly be assigned to the reductions of the two salts. Notwithstanding this, the two metals are found to be alloyed. Oxidation then converts the alloy to a mixture of RuO2 and CuO, reduction of which shows only one TPR peak, but the metals are now not alloyed. Obviously, the number of peaks seen does not permit valid predictions about the structure of the resulting catalyst. A further example of how one may be misled by TPR results is provided by the system H,PtCl, - V205.The platinum salt is reduced to Pt" a little above ambient temperature. There then follows (1W-175 "C) an extensive hydrogen consumption which is not accompanied by any loss of mass in TGA; only above 200 "C does a mass loss occur. The hydrogen uptake is, in fact, due to the formation of a hydrogen vanadium bronze H3.4VZO5, which has a limited range of stability and dehydrates to v 2 0 3 . 3 . Both TPR and TGA were needed to solve this problem.4 One final example illustrates the limitations of a single technique. Metal chlorides are often used as precursors, and it is usually assumed that hydrogen uptake as seen by TPR will correspond to the hydrogen chloride evolved. This is some- times not the case, as the HCl may chloride the OH groups on the support surface and be difficult to remove.This is 237 particularly so with titanium dioxide, where measurement of the hydrogen chloride evolved has shown that it continues to be formed well above the point at which the reduction of the metal salt is complete.5 The important conclusion is that the use of a single method can be grossly misleading, and that the amount of information acquired increases more than in proportion to the number of methods used. Indeed, one could propose the First Law of Thermal Analysis as stating that "the amount of information obtained is proportional to the number of interactions possible between the methods used." For n methods the number of pairwise interactions A, is given by the formula i = n - 1 References 1. Bond, G. C., J. Mol. Catal., to be published.2. Bond, G. C., Perez Zurita, M. J . , and Tahir, S. F., unpublished work. 3. Bond, G. C., and Xu Yide, J. Mol. Catal., 1984,25, 141. 4. Bond, G. C., Duarte, M. A., and Alcock, G. A., unpublished work. 5 . Bond, G. C., Rajaram, R. R., and Wakeman, J., unpublished work. The Use of Temperature Programmed Methods in Selection of Methanation Catalysts 1. J. Kitchener, N. D. Parkyns and S. B. J. Scott British Gas Corporation, London Research Station, Michael Road, London S W6 2AD Since the introduction of temperature programmed reduction (TPR) by Robertson and McNichol,' the technique has been used extensively in these laboratories2 and played an important role in elucidating the structure of nickel - alumina co- precipitated catalysts .3 More recently, we have been engaged in a programme of developing methanation catalysts, which combine high activity with a resistance to deactivation by high-temperature sintering. The choice of catalysts for further development is made by exposing up to 50 catalysts at a time to a standard sintering test, after which they are examined by several techniques.Some estimate of the relative activity remaining after this test is required so that the best formulation can be selected for further testing. In order to obtain this information we have devised two new methods, called temperature programmed methanation (TPM) and step-temperature programmed methanation (STPM), respectively. Temperature Programmed Methanation (TPM) The technique of TPM is very similar to that of TPR and the apparatus is practically identical.1.2 The hydrogen - argon reduction gas used in TPR is replaced by a hydrogen - carbon dioxide (1 + 9) mixture. Hydrogen is consumed according to the equation Accordingly, the katharometer responds directly to the extent of reaction. Typical TPM curves are shown in Fig. 1. Typical programming rates are 10-30 "C min-1; the final temperature need not exceed 600 "C. The shape of the curve as shown in Fig. 1 A is typical for a freshly reduced, unsintered catalyst where the catalytic activity is very high. The limit of hydrogen consumption is set by thermodynamic equilibrium, as shown in the broken line at the COZ + 4H2-+CH4 + 2H20 . . . . ( 1 ) ---- ---- 3000 \ Theoretical ". maximum '. .- s 1000 I i1 0 consumption \ 200 400 600 Tern peraturePC Fig. 1.Typical TPM curves for nickel catalysts. A, Freshly reduced, unsintered catalyst; B, C, D, different catalysts previously exposed to sintering conditions top of the figure. The initial temperature where hydrogen consumption is first detectable and the slope of the first part of the curve are governed by the activity of the catalyst, but as the curve approaches the thermodynamic limit, it levels off and then falls with further increase in temperature. The reason for the final increase is discussed below. The TPM curve never actually reaches the thermodynamic limit for reasons discussed elsewhere.4 After sintering, all catalysts lose their activity to some extent. This is represented by curves B-D, which show the range of TPM curves encountered in practice.The information may be used in two ways. First, an analysis can be made of the first part of the curve, assuming that the TPM apparatus is an integral reactor; in this way, activation energies can be derived238 8 6 - 8 S 0 .- - P 4 - w al S 0 I“ 2 - 0 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 - ----_ - - Theoretical 1. maximum I that are comparable to those obtained by conventional kinetic studies.4.5 More generally, however, the catalysts can be grouped arbitrarily into classes. A hydrogen consumption is chosen at about half the maximum normally obtained (about 1250, see broken line in Fig. 1) and the temperature at which this is attained is noted. We find that catalysts that achieve this consumption at 350 “C or less (letter “a” in Fig. 1) have high activity on testing under simulated commercial conditions, those requiring a temperature of up to 400°C (letter “b” in Fig.1) have an adequate activity, while those requiring over 500 “C (letter “c”) are unlikely to be sufficiently active for practical use. Step Temperature Programmed Methanation (STPM) Simple TPM curves are analysed on the assumption that hydrogen consumption is solely due to methanation (equation 1) and ignores the possibility of the reverse CO-shift reaction Furthermore, the catalyst is likely to be hotter than the nominal temperature because of the heat evolved in methana- tion. This is shown by a displacement of the curves to lower temperatures when the temperature is lowered again. Apart from this, the TPM curves are reversible. Another feature that leads to uncertainty in the accuracy of the curves arises because the hydrogen consumption is measured after water has been removed from the gas stream.This causes the stream velocity to decrease in a way that is dependent on the extent of reaction. The time delay before measuring the hydrogen signal at a nominal temperature is thus continuously altering. For these reasons, a semi-continuous programme was adopted where the methanation reaction was held at a series of stepwise increasing temperatures, the technique being accord- ingly named step-temperature programmed methanation (STPM). Steps of 20°C are used. Because it was felt useful to analyse the gas stream to determine methane, the steady state at each temperature step allowed the use of gas chromato- graphy, thus replacing the non-specific measurement of the thermal conductivity of the effluent gas in TPM. Accordingly, the concentration of methane in the gas stream is now used to monitor the progress of methanation, as shown in Fig.2. CO,+H2+CO+H2O . . . . (2) 0 100 300 500 700 Temperature/”C STPM curves for same catalysts as in Fig. 1 Fig. 2. The use of GC analysis at each step necessarily means that there are more data to be handled. Furthermore, when the gas analysis is completed, some signal needs to be sent to the temperature control unit in order to increase the temperature further. To handle all this extra load, we have incorporated a dedicated microcomputer (Commodore PET), which also prints out the curves of methane concentration against temperature.STPM curves (Fig. 2) are quite straightforward to interpret. The curves A-D represent the same catalysts as Fig. 1. One can see that the most active catalyst (A) produces not only the most methane but shows its peak of maximum production at the lowest temperature. The peak value represents the relative activity of the catalyst quite unambiguously. It will be seen that all of the the curves tend to converge to a common curve above 500”C, clearly because of the limitation of thermodynamic equilibrium. In other words, there is no distinction in activity between the worst and the best catalysts above 600 “C or so: all are equally active. STPM does also demonstrate clearly the increasing part that the reverse CO-shift equation plays.2 Carbon monoxide formation begins at 300 “C and rises steadily with temperature. Most catalysts fall on the same curve, as the reaction is very facile and structure-insensitive and nickel is a good catalyst for it.Yields are thus governed by thermodynamics, not by catalyst activity. The formation of carbon monoxide does confirm the composite nature of the TPM curves and the concomitant consumption of hydrogen accounts for the secondary rise at higher temperatures. Comparison of TPM and STPM for Catalyst Evaluation We have used both techniques extensively and found a good correlation between the rather empirical property of tempera- ture for bringing the consumption of hydrogen to a given level in TPM and the more direct maximum production of methane in STPM, so that both techniques can be used with confidence for evaluating catalyst activity. TPM apparatus is much cheaper to build but the time taken to obtain the curves is little different from STPM so that there is no great gain in productivity. The use of the microcomputer, implicit in STPM, does have the great advantage that the data can be readily processed and presented in a form for direct use.In the end, the relationship between predictions of activity derived from TPM and STPM and the performance of the catalyst under commercial methanation conditions has to be established experimentally. Nonetheless, we have found these temperature programmed techniques to be invaluable for speeding up the process of developing catalysts of acceptable commercial performance. 1. 2. 3. 4. 5 . References Robertson, S.D., McNichol, B. D., de Baas, J. H., Kloet, S . C., and Jenkins, J . W., J . Catalysis, 1975, 37, 424. Burch, R., Flambard, A. R., Day, M. A., Moss, R. L., Parkyns, N. D., Williams, A., Winterbottom, J . M., and White, A., in Poncelet, G., Grange, P., and Jacobs, P. A , , Editors, “Prepara- tion of Catalysts 111,” Elsevier, Amsterdam, 1983, p. 787. Puxley, D. C., Kitchener, I. J . , Komodromos, C., and Parkyns, N. D., in Poncelet, G., Grange, P., and Jacobs, P. A., Editors, “Preparation of Catalysts 111,” Elsevier, Amsterdam, 1983, p. 237. Isiakpere, S . E., Kitchener, I. K., Komodromos, C., Lam, C. W., and Parkyns, N. D., in Hirsch, L. H., Editor, “Proceed- ings of the International Gas Conference 1983,” Government Institute Inc., Rockville, MD, USA, 1983, p.482. Lam, C. W., British Gas Corporation, London Research Station, unpublished results.ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 239 Use of Thermal Analysis Techniques in Research on Methanation Catalysts Julian R. H. Ross Department of Chemical Technology, Twente University of Technology, P. 0. Box 217, 7500AE Enschede, The Netherlands This paper illustrates the kind of information that can be obtained in the study of any catalyst system using thermal analysis techniques. Particular attention is given to the sort of information which can be obtained with thermogravimetry (TG) and differential scanning calorimetry (DSC). The co- precipitated nickel - alumina catalyst system (used, among other things, for the methanation of carbon monoxide) is discussed as an illustration of the methods.TG can be used to study the calcination and reduction of the catalyst as a function of the conditions under which the catalyst was prepared or pre-treated; it can also be used to determine the active metallic area after reduction under various conditions. The differential scanning calorimeter is used both to study the calcination of the catalyst and also to determine the kinetics of the methanation reaction before and after ageing of the reduced catalyst in steam - hydrogen mixtures. It has also been used to determine the conditions under which the rate of the methanation reaction becomes controlled by internal and external diffusion. Experimental The catalysts were prepared either by co-precipitation1 or by a sequential precipitation method.2 In the former method, concurrent addition of sodium carbonate and a solution of the nitrates of nickel and aluminium to a vessel containing water was carried out at such a rate that the pH remained constant, normally 7.0; a series of materials was also made in which lanthanum was included in the precipitate by adding lan- thanum nitrate to the nitrate solution.The sequential method involved first the precipitation of alumina, then the addition (when appropriate) of lanthanum nitrate and, finally, the precipitation of nickel. Precipitation was again carried out by the simultaneous addition of a solution of sodium carbonate. The subsequent steps in the preparation of an active catalyst involve the calcination of the precipitate to bring about the decomposition of the hydroxy compound formed on precipita- tion and the reduction of the oxidic phase so formed.Variables studied which have an effect on the calcination step have included the effect of precipitation conditions, the nickel to aluminium ratio in the Precipitate and the presence of a variety of possible promoters added to the precipitation solutions or added directly to the precipitate.s5 These variables also have an effect on the reduction and ageing of the catalyst, as does the temperature of calcination.3.6 The majority of the work was carried out with equipment supplied by DuPont de Nemour Inc., the 990 controller, the 951 TG cell and the 910 High Pressure DSC cell being used. Suitable gas-flow systems were used for the control of the various atmospheres used, these including argon, hydrogen and pre-mixed carbon monoxide and hydrogen. The TG system was modified slightly to allow all of its volume to be effectively and rapidly flushed out by the gases in use; the DSC was evacuated by a rotary pump between different gas mixtures.Early DSC experiments were carried out by using a Perkin-Elmer DSC lB, again using controlled atmospheres.7 Additional supporting data were obtained by using conven- tional adsorption equipment [total (krypton) and metallic (hydrogen) areas], flow reactors, X-ray diffraction (XRD) and scanning electron microscopy (SEM). 1-6 Results The unpromoted precipitate is found to be a mixed hydro- carbonate compound with general formula Ni,Al,(OH),- C03.nHz0, which resembles the mineral takovite in struc- ture.’ The nickel and aluminium ions both exist in the “brucite layer” of the material while the carbonate ions and the water of crystallation both exist in “interlayers” between the brucite layers.Under suitable conditions, other anions such as nitrate (low pH of precipitation) or chloride (precipitation from the chlorides) may be substituted for the carbonate ions. A variable nickel - aluminium ratio is possible; for hydrothermally-treated samples, the range is 2-3, but wider ranges are possible if the precipitate is not crystallised by the hydrothermal ageing process. Decomposition of the precipitate occurs in two distinct steps. The first, at about 180°C, corresponds to the loss of water of crystallisation, and the second, at about 4OO0C, to the loss of the hydroxy groups and the carbonate or other ions.The use of either TG or DSC gives characteristic decomposition patterns for each material. When only one phase is present only two peaks are observed in the DTG or DSC traces, but the presence of other phases at high or low nickel contents can readily be seen (Fig. 1). Analysis of the TG curves allows the composition of the precipitate to be calculated. The curves can also be used as fingerprints to show the purity of the material prepared. Evolved gas analysis can be used (quadrupole MS) to identify the species produced during the decomposition. 0 200 400 600 0 200 400 600 Temperatu re/”C Fig. 1. Comparison of DTG and DSC profiles for decomposition of various precipitates. ( a ) , Ni : A1 = 0.5; (b), Ni : A1 = 1.5 The reduction process also depends on the various para- meters involved in the preparation. It can be followed very satisfactorily by using the TG method.The differential results (DTG) are very similar to those obtained with the TPR Method. The TG approach also has the advantage that the results are entirely quantitative; the mass loss on reduction can often be used to determine or check the metallic content of the catalyst. We have used the method successfully in this connection to determine the amount of the active component absorbed in an alpha-alumina matrix when the coprecipitate is deposited by the hydrolysis of urea in the pores of the matrix.8 The position of the peak maximum in the DTG results is also an indication of the degree of interaction between the alumina and the nickel of the catalyst.As a rough rule of thumb, the more difficult the sample is to reduce, the greater the interaction and the more stable the final material. Thus, the DTG results show240 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 that a material with a nickel t o aluminium ratio of 3, calcined at temperatures between 450 and 6OO”C, is more difficult to reduce than samples with higher nickel contents, and there is a correlation between the stability and the peak maximum with samples of increasing nickel to aluminium ratio. If calcination is carried out at too high a temperature (e.g., 1000 “C), then phase separation occurs to give NiO and NiA1204; this is clearly discernable from the DTG reduction curves, there now being two peak maxima, one at about 500 “C, corresponding to the NiO phase, and the other at about 850 “C, corresponding to the reduction of NiA1204.The TG system can also be used to obtain a rough estimate of the metallic areas of the reduced catalysts. The samples are reduced in the TG and are then cooled in argon to 100°C; carbon monoxide is then added to the gas stream and the instantaneous mass increase is measured. This is assumed to correspond to carbon monoxide chemisorbed on the nickel surface. Areas calculated from this rapid method are in good agreement with those obtained by the more time-consuming volumetric hydrogen adsorption method.2 The use of DSC for the measurement of the kinetics of catalytic reactions, in particular methanation, was first des- cribed by Beecroft, Millar and Ross in 1976.7 The method has the advantage over the use of DTA in some reactions that the signal of the DSC gives directly the rate of evolution of heat during the reaction at the surface of the catalyst particle.With nickel catalysts, the reaction is effectively 100% selective for methane under most conditions and thus the rate of reaction can be calculated directly from the rate of evolution of heat, using the enthalpy of the reaction (H” = -210kJmol-* of methane formed). Arrhenius plots of the data can be construc- ted and the behaviour of various catalysts can be compared very rapidly; a number of samples can be studied per day. Only small amounts of catalyst are used (about 1 mg) and this allows one to compare the activities of different parts of the same sample.Our experience of the preparation of Ni - A1203 samples is that results from different batches of the same sample are reproducible within 5% and different preparations of the same composition and preparation conditions are reproducible to better than 10%. In practice, we reduce the catalyst in a separate system (either TG or a separate tubular reactor, which can be used for larger samples) with tempera- ture programming to the final temperature and then deactivate the sample in either a water saturated nitrogen atmosphere or a nitrogen atmosphere containing a trace of oxygen; if deactiva- tion is not carried out, the samples can be pyrophoric when exposed to the atmosphere prior to transfer to the TG system and re-reduction.DSC is also used to determine the activities of the samples after steam sintering in the presence of hydrogen, a test used in attempting to determine the probable stability of the samples under steam reforming or methanation conditions. More recently, the technique has been used to study samples with high nickel to aluminium ratios of 9 and 20. These materials are much less stable than those with a ratio of 3, but the activities of samples with Ni to A1 = 9 were very high as long as calcination and reduction were carried out at relatively low temperatures. Recent work has also involved the comparison of samples containing nickel, aluminium and lanthanum prepared by co-precipitation and by sequential precipitation .*-9 The results show that the co-precipitation method gives more stable materials, particularly at low lanthanum contents, and that there is a much greater chance of retention of impurities in the precipitates if there is lanthanum present than if the material contains only nickel and lanthanum; the presence of impurities such as sodium nitrate is clearly evident in the DTG traces of the calcination step if the samples are not dried at 100°C and then re-washed before calcination.The DSC method has been used in other laboratories, in particular in the group of L. L. van Reijen in the Technical University of Delft, with which we have collaborated for some time. They have recently shown how the DSC can be used to examine diffusion limitations in methanation with nickel - aluminium catalysts. With powdered samples, they found that external diffusion limitations became important at about 550 K but that with a single pellet of material there was a region of internal diffusion limitation between about 450 and 550 K.1” 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. References Kruissink, E. C . , van Reijen, L. L., and Ross, J . R. H., J . Chem. SOC. Faraday Trans. I , 1981,77,649. Gelsthorpe, M. R., Lippens, B. C., Ross, J . R. H., and Sambrook, R. M., in Portela, M. F., Editor, “Proceedings of the 9th Iberoamerican Symposium on Catalysis, Lisbon, 1984,” Iberoamerican Society of Catalysis, Lisbon, 1984. Alzamora, L. E., Ross, J . R. H . , Kruissink, E. C., and van Reijen, L. L., J . Chern. SOC. Faraday Trans. 1 , 1981,77, 665. Gelsthorpe, M. R., Mok, K. B., Ross, J. R. H., and Sambrook, R.M., J . Mol. Catal., 1984,25,253. Gelsthorpe, M. R., Lansink-Rotgerink, H . , van Ommen, J . G., and Ross, J. R. H., to be published. Kruissink, E. C., Alzamora, L. E., Orr, S., Doesburg, E. B. M., van Reijen, L. L., Ross, J . R. H . , and van Veen, G., in Delmon, B . , Grange, P., Jacobs, P. A . , and Poncelet, G., Editors, “Preparation of Catalysts 11,” Elsevier, Amsterdam, 1979, p. 143. Beecroft, T., Millar, A . W., and Ross, J . K. H.,J. Caral., 1975, 40,281. Mok, K. B . , Ross, J . R. H . , and Sambrook, R. M . , in Poncelet, G., Grange, P., and Jacobs, P. A . , Editors, “Preparation of Catalysts 111,” Elsevier, Amsterdam, 1983, p. 237. Lippens, B. C., Fransen, P., and Ross, J . R. H., to be published. van Reijen, L. L., Hakvoort, G . , and van der Klugt, V ., “Proceedings of the 9th Iberoamerican Symposium on Cataly- sis,” Lisbon, 1984. Study of Polymerisation Catalysts by Pressure Differential Scanning Calorimetry-the Effect on the Oxidative Stability of Polyethylene Terephthalate D. C. Harget, J. N. Leckenby” and W. J. Sichina Du Pont UK Ltd., Wedgwood Way, Stevenage, Hertfordshire Polyethylene terephthalate (PET) is the most widely used polymer in the manfacture of fibres for textile use. Many properties of polyester fibres are dependent on the resin “recipe,” which includes copolymers, such as diethylene glycol or adipic acid, polymerisation catalysts, optical brighteners, etc. These additives can affect the thermo-oxidative stability of the PET resin. The concept of oxidative stability is important to fibre producers as a polymer with a low stability can undergo a drop in its relative molecular mass during the spinning process and is also more prone to the formation of gels.This can lead to a variety of problems, including discolouration, high plugging rates, broken filaments, texturing problems, etc. An increase in the oxidative stability of PET can be achievedANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 12 g 10 0) t 8 - 2 4 - I 3 -0 6 - + c. 0 O - k - 2 - 0 24 1 - I 100 p.p.m. Ca I 10 p.p.m. Ca ,'-----' by two means. An antioxidant can be added or the standard polymer additives can be selected such that, in addition to their normal functions, they also promote oxidative stability. In order to evaluate the effectiveness of various additives with regard to oxidative stability, differential scanning col- orimetry (DSC) is an extremely effective technique as the oxidation process is accompanied by a significant heat of reaction.' The high sensitivity of DSC makes possible the use of small samples.DSC has been used successfully to study the oxidation of a wide variety of products, including lubricants,* greases,3-4 fats and oils,5 polyolefinscs and rubbers.9 To distinguish clearly between stabilities resulting from various resin formulations, the DSC conditions need to be optimised. This can be achieved in three ways: firstly, testing with a particle size which has a large surface to volume ratio; secondly, scanning at low heating rates; and thirdly, increasing the partial pressure of oxygen. In the latter instance the Du Pont Pressure DSC, which is usable to 7 MPa (lOOOp.s.i.g.), is particularly amenable to such studies.Procedure While the experimental conditions will depend to some extent on the stability of the particular resin studied, the following pressure DSC (PDSC) procedure is perfectly general. PDSC parameters Sample size Temperature program 8 mg ground resin Isothermal for 5 min at 150°C Heat at 5"Cmin-1 from 150°C to 300 "C Dry 0 2 at 5.5 MPa (800 p.s.i.g.) 50 ml min- 1 Atmosphere Gas flow-rate The PET resin should be ground to produce a particle size of approximately 0.25-0.40 mm. The ground resin should be filtered between two sieves of 20 and 30 mesh size. The particles remaining in the 30-mesh sieve should be retained for testing. The ground resin is then placed in a tared aluminium sample pan, weighed, and covered with a lid.Five holes are punched in the upper lid using a pointed instrument. The sample is next placed in the PDSC cell at ambient temperature. The cell is closed and prepared for preparation, which begins with purging by pressurising the cell to 0.34 MPa (5Op.s.i.g.) with the reactive gas. The gas is discharged by opening the exit valve at the rear of the cell. The cell is again pressurised to 0.34 MPa (50 p.s.i.g.) and a flow of 50 ml min-1 maintained through the cells for 30s. With the exit valve closed, the cell is pressurised to the operating pressure 5.5 MPa (800 p.s.i.g.) with the dry oxygen and a flow of 50 ml min-1 maintained through the cell. The sample is next heated to a temperature of 150 "C and maintained for 5 min to drive off any 2o I -4 -8 160 1 180 200 220 240 260 280 300 TemperaturePC Fig.1. oxygen atmosphere DSC trace obtained by heating a PET resin in a pressurised surface moisture. Following the isothermal hold at 150 "C, the resin is heated at 5 "C min-1 from 150 to 300 "C. An oxidation exotherm will be observed at approximately 225°C. The oxidation onset temperature is then taken as a measure of the stability of the resin. Discussion Shown in Fig. 1 is a typical trace obtained by heating a PET resin in a pressurised oxygen atmosphere. The trace shows that an exotherm occurs at approximately 255 "C. Polymer- analytical investigations indicate that this exothermal enthalpy effect is accompanied by strong degradation of the polymer.' Following the initial exothermic degradation, the polymer undergoes simultaneous melting and degradation and con- tinues to degrade when heated above the melt.This results in a distinctive undulatory thermogram, which can be used to characterise polyester resins with regard to their oxidative stabilities. Shown in Fig. 2 is a comparison of the stabilities of two PET resins which contain varying levels of a calcium ester inter- change (EI) catalyst. As can be seen, the resin containing the greater amount of the calcium catalyst exhibits a higher degree of oxidative stability, as evidenced by its higher oxidative onset temperature. 160 200 240 280 320 Temperatu re/"C Fig. 2. Effect of calcium on oxidative stability of PET resins. Sample size, 16.1 mg; heating rate, 5 "C min-*; atmosphere, oxygen at 5.5 MPa Displayed in Fig.3 is a comparison of the stability traces obtained for two PET resins, one of which contains an antimony polymerisation catalyst, and the other a calcium catalyst. The results show that the resin containing the calcium 16 ! \ Calcium -8 180 200 220 240 260 280 300 320 Temperatu rePC Fig. 3. calcium or antimony polymerisation catalysts Comparison of stability traces for two PET resins containing242 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 additive is significantly more stable, as reflected by its higher onset temperature and a smaller initial oxidative exotherm. Other ester interchange catalysts, such as zinc and man- ganese, have been observed to decrease the oxidative stability of PET.' Thermal analytical studies have shown that increasing the concentration of diethylene glycol (DEG) significantly decreases the stability of PET.' 18' 16 I I I 1 I I 160 200 240 280 320 Ternperatu re/"C Fig.4. Oxidation exotherm with curve subtraction for PET resin containing 100 pg g-1 of calcium catalyst. Sample size, 16.1 mg; heating rate, 5°C min-l; pressure, 5.5 MPa If desired, the melting component of the oxidation thermo- gram can be subtracted out, resulting in a trace showing only the exotherm associated with the oxidative degradation of the resin. This can be carried out by running a fresh sample under the same conditions described above except with a dry nitrogen atmosphere. The results in both oxygen and nitrogen should be normalised with respect to the sample mass by using the File Modification program.This is most easily achieved by dividing all of the data points by the respective sample masses. The normalised data from the nitrogen run can then be subtracted from the data obtained in oxygen using File Modification. This results in the generation of a new data file showing the effects of oxidative degradation only. This is shown in Fig. 4 for a PET resin containing 100 pg g-1 of a calcium catalyst. 1. 2. 3. 4. 5. 6. 7. 8. 9. References Zimmerman, H., Becker, D., and Schaaf, E., J . Appl. Poly. Sci., 1979, 35, 183. Levy, P. F., Nieuweboer, G., and Semanski, L. C., Thermo- chim. Acta, 1970, 1, 429. Blaine, R. L., Am. Lab., 1974, 6 , 18. Du Pont Thermal Analysis Applications Brief No. 41. Du Pont Thermal Analysis Applications Brief No.48. Du Pont Thermal Analysis Applications Brief No. 40. Howard, J . B., Polymer Eng. Sci.. 1973, 13, 429. Frank, H. P., J. Polym. Sci., Symposium No. 57, 1976, 311. Ponce-Velez, M. A., and Campos-Lopex, E., J. Appl. Polym. Sci., 1978, 22, 2485. Constant Rate Thermal Analysis for Catalyst Activation M. H. Stacey ICI plc, New Science Group, The Heath, Runcorn, Cheshire The aim of this paper is to review the strengths of the constant rate thermal analysis (CRTA) technique' relative to the conventional techniques of DTA, TGA, EGA, TPR and TPD, etc., for the study of gas - solid reactions such as those involved in catalyst activation (calcination and reduction). First, I propose that CRTA is best utilised for the detailed study of reaction kinetics and the preparative-scale production of active catalysts having well defined, reproducible histories.It thus allows the sound correlation of their properties in subsequent use with precisely defined preparative conditions. Conventional thermal analysis (DTA, etc.) is only useful for quick screening to establish what reactions occur and not for determining detailed kine tic be haviour . Secondly, I define the essential difference between DTA, etc. (where a linear temperature rise is always used and all other kinetically important parameters are uncontrolled), and CRTA (where a constant rate is maintained throughout a reaction by varying the temperature using an automatic feedback loop). The following aspects will be reviewed: theory; practice (design of equipment); use (examples from my own work).Theory For a gas - solid reaction, the most general form of rate equation is where f(a) is a function defining the variation in reaction interface area with conversion (a), a is the fractional conver- sion to product and Pi, Pi are partial pressures of reactant and/or product gases at the reaction interface. In conventional DTA, etc., Tis a linear function of time, but all of the other factors vary continuously as the reaction proceeds; consequently, use of peak-shape analysis for diag- nosis of kinetics is nearly always useless. In CRTA the reactant or product gas(es) are removed from the reactor at a fixed number of mols-1 and their partial pressure(s) in the reactor are maintained constant. Hence, both d d d t and g(Pi, Pj .. .) are held constant throughout the reaction. It follows that OC f(a) e-EIRT which means that the form of f ( a ) determines what shape of temperature profile will be produced. A variety of common forms off(&) yield profiles which are either isothermal, always increasing, or show a minimum. Such profiles are diagnostic of the type of nucleation and growth kinetics. In order to determine E independently of f(a) at least two runs are needed utilising different gas removal rates (but the same gas partial pressures). These may be achieved in a single run by including a regularly switched gas removal rate control. From the AT values at each alteration of daldt [where f(a) is constant] a value of E can be calculated to within f5% precision. In order to apply these design targets in practice several options are possible.In order for the differential rate equation to be valid there should be no significant temperature or pressure gradients external or internal to the solid particles and the reactant or product gas purge rate from the reactor should be kept constant. The first condition (well mixed reactor) is achievable in any of three different ways. Firstly, use of microscopic samples (relying on gaseous - solid heat and gas diffusion), as in ideal DTA; secondly, use of thin static layers ofANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 243 solid and slow reactions’; and thirdly, use of agitated beds of solid (fluidised bed reactor) as in our laboratory. It is practical also in our version of CRTA to work at moderately high rates where each particle has within it a concentration gradient; hence the diffusion limited regime is accessible to investigation as well as the chemical reaction limited regime.This possibility is favoured by large particles, high rates and low external partial pressures, while, con- versely, chemical reaction rate control is favoured by small particles and low rates (i.e., low temperatures). Practice We have chosen a small fluidised bed reactor with a capacity of up to 20g to provide the good mixing and heat transfer necessary for preparative-scale CRTA. Particles are generally 50-250 pm in diameter for good fluidisability. The oven is a fan circulated hot air oven. Purge-rate and gas partial pressure control were provided by constant flow helium supply (which also fluidised the solid) and by a katharometer detector and a dew-point hygrometer.In this way the effluent gas could contain one other gas in addition to water vapour, so allowing the study of basic salt decompo- sitions [e.g., hydrozincite Zn5(OH)6(C03)2] .2 Alternatively, when studying reductions of supported metal oxides, a 5% hydrogen - nitrogen supply was used for purging the reactor. Both gas supplies were switchable between high and low flows (settable at any chosen values). The feedback control loop was implemented by interfacing a microcomputer to the whole system. Control of flow- switching, carrier gas selection, data logging and data process- ing were also performed by the microcomputer. The software implementation allowed easy choice of alternative, conven- tional temperature programmed schedules as well as the desired CRTA mode.A decomposition at 10 mbar product partial pressure would typically take 15-20 h. Uses of Preparative CRTA The various types of behaviour that we have found are taken from a range of examples drawn from our own work on catalysts. Dehydration of Aluminium Hydroxides (Gibbsite and Boeh- mite) Temperature profiles for constant rate are isothermal, indi- cating a constant area interface. Activation energies have been determined and rates are retarded by the gaseous water produced. Decomposition of Hydrozincite and Malachite3 These basic carbonates illustrate the need for dual detectors (dewpoint for water and katharometer for carbon dioxide plus water). They also demonstrate simultaneous evolution of carbon dioxide and water in a 1-step mechanism (hydrozincite) and a 2-step mechanism (zincian malachite).The interface area behaviour is dependent on the crystalline morphology. The rates of decomposition are unaffected by carbon dioxide or water partial pressures. Reduction of Experimental Supported Copper Catalyst This technique illustrates the process Both the evolution of water and the consumption of hydrogen are determined. A nucleation - growth temperature profile has been found. The rate is retarded by water vapour. MO + H2+ M + H20 Reduction of Experimental Nickel Catalyst This again illustrates a nucleation - growth temperature profile, but at a much higher temperature. Conclusions The CRTA method can be applied in practice to make useful amounts of catalysts with well defined, reproducible prep- aration histories.The kinetic equation’s form and parameters can be accurately determined and may be useful for the design of large-scale processes. References 1. 2. Stacey, M. H., in Dollimore, D., Editor, “2nd European Rouquerol, J., J . Thermal Anal., 1970, 2, 123. Symposium on Thermal Analysis, Aberdeen 1981 ,” Heyden, London, 1981, pp. 408-12. Stacey, M. H., “10th International Symposium on the Reactiv- ity of Solids, Dijon, 1984,” Elsevier, Amsterdam, 1985, in the press. 3. Cryostatic Cell for the Study of Low Temperature Chemisorption and Temperature Programmed Desorption A. G. Mitchell and R. W. Joyner BP Research Centre, Chertsey Road, Sunbury-on-Thames, Middlesex Tw16 7LN Chemisorption studies and temperature programmed desorp- tion (TPD) are useful techniques for studying the interaction of gases with a catalyst surface.These studies, however, are usually carried out at temperatures greater than ambient. 1 Therefore, information on weakly held states, with heats of adsorption of t60kJmol-1 is lost. There are instances where information on these states may have significance in catalytic studies, i.e., carbon monoxide adsorption on copper, or hydrogen on platinum. Both instances exhibit AHads at and below 60 kJ mol-1. An apparatus has been developed, based on an Oxford Instruments cryostat, that is capable of chemi- sorption and TPD in the range 77-670 K. The construction and performance of this instrument will be described and results will be discussed for the chemisorption of carbon monoxide on supported palladium catalysts.Experimental The design of the cryostatic cell is illustrated in Fig. 1. The Cryostat (Oxford Instruments Ltd., Oxford, Model DN 1710) has a liquid nitrogen reservoir that feeds the copper heater block with a controllable flow of nitrogen coolant. A wound electrical heating element supplies heat to the heater block via a temperature controller (Eurotherm Ltd., Worthing, Model 812). The cryostat has been modified by changing the heating element and platinum resistance thermocouple arrangement to cope with a larger temperature range (77-670K) than was originally specified (77-500 K). The temperature can be held at any level between 77 and 670 K or temperature programmed at a rate between 0.1-20Kmin-1.The pyrex reactor cell (Fig. 1) allowed a flow of carrier gas over the 1 ml catalyst bed at atmospheric pressure. The catalyst244 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 bed temperature was monitored by a chrome1 - alumel thermocouple situated in the centre of the bed. The carbon monoxide chemisorption experiments were operated in a pulse mode.2 A thermal conductivity detector (TCD) as part of a gas chromatograph (Pye Unicam Ltd., Cambridge, Model 204), detected non-adsorbed or desorbed carbon monoxide. A helium carrier gas (30 ml min-1) was used in all experiments. The catalysts were prepared by the impregnation of PdCl;! solution on to the supports, followed by evaporation to dryness and then reduction with hydrogen at 573K; 10% mlm palladium - graphite, 5 mlm palladium - y aluminium oxide and 5% mlm palladium - silica catalysts were prepared with nitrogen BET surface areas of 500, 300 and 280m2g-1, respectively.N2 exhaust valve Sorption Pump Copper heater block Table 1. Dispersion (from X-ray diffraction) and CO chemisorption data of Pd catalysts Sample Dispersion, YO Co/Pd,* 10% Pd/C 60 0.65 5% Pd/Si02 30 0.70 5% Pd/A1203 40 0.70 * Co/Pd, = molecules Co/molecules Pd at surface. Discussion The first set of experiments were conducted on the support materials to establish if they contributed to carbon monoxide chemisorption at sub-ambient temperatures. The graphite and aluminium oxide exhibited considerable CO adsorption between 113 and 183 K (=3 x 10-5 mol g-1 of CO). The silica chemisorbed <10-6 mol g-1 of CO in this temperature region.The choice of chemisorption temperature for the palladium catalysts is thus restricted to that above which the CO desorbs from the support (in this instance 180 "C). The two TPD peaks observed for CO on Pd (Fig. 2) are in good agreement with the single crystal LEED work of Conrad et al.3 The higher temperature peak accounted for a CO : Pd surface ratio of exactly 0.5. Conrad et al. found that CO adsorbed with a 2 x 1 structure on Pd, giving a 0.5 monolayer coverage. Further coverage can be achieved but with a much lower AHads caused by carbon monoxide repulsive interactions. Pt resistance TIC Fig. 1. The cryostat and reactor design -200 The experiments were conducted as follows: reduction with hydrogen at 573 K for 2 h; flow switched to helium at 573 K for a further 2 h; cooled to chemisorption temperature (113 K to study support effects, 183K to study carbon monoxide - palladium interactions); carbon monoxide pulses introduced as 6.7 x 10-6 mol aliquots every 5 min; pulsing stopped after saturation of the catalyst; TPD at 10 K min-1 to 373 K. Powder X-ray diffraction line broadening was used to determine the palladium dispersion. Results The amount of carbon monoxide chemisorbed and TPD data are given in Table 1. The heats of adsorption (AHads) have been calculated by equating the following rate ( R ) expression at equilibrium: - P -- (Mi?+ Rabsorption = (1 - 0) 3 10' Rdesorption = exp (-AHadslRT) where 8 is the CO monolayer coverage, P the pressure in torr, M the relative molecular mass of CO (28), T the temperature in kelvin and R the gas constant (8.314 J K-1 mol-1). The supports, carbon, silica and aluminium oxide, all adsorbed carbon monoxide below about 183 K, therefore the carbon monoxide on palladium experiments were conducted at this temperature. The TPD spectra (Fig. 2) exhibited two peaks on all the supported palladium catalysts at 263 and 493K. These correspond to heats of adsorption of 55 and 120 kJ mol-1, respectively. 0 200 400 Tem peratu re/"C 15 60 105 160 AHlkJ mol-' Fig. 2. Temperature programmed desorption spectra; carbon monoxide on supported palladium catalysts The TPD spectra and the amount of CO chemisorbed on the Pd were virtually independent of the support used. Conclusions A chemisorption and TPD cell has been built and demon- strated to achieve stable and programmable temperatures in the range 77-670 K. Significant chemisorption - physisorption occurs on the supports below about 180 K, which swamps any effect on the supported metal. The study of CO adsorption on various supported, well dispersed palladium catalysts was therefore limited to >180 K. The amount of carbon monoxide chemisorption and TPD spectra were in good agreement with published single crystal data. References 1. 2. 3. Falconer, J. L., and Schwartz, J . A., Catal. Rev. Sci. Eng., 1983, 25, 141. Sarkany, J., and Gonzalez, R. D., J. Catal., 1982, 76, 75. Conrad, H., Ertl, G., Koch, J., and Latta, E. E., Surf. Sci., 1974, 43, 462.

ISSN:0144-557X    

DOI:10.1039/AP9852200236

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 245 Equipment News Atomic Absorption System The Model 3030 system for flame, furnace and hydride applications is controlled from a single keyboard with software defined function keys, and an information centre. Analytical method development is simplified by the software. An unlimited number of methods are stored on floppy disc. The analyst need only select the element; the software sets up the condi- tions for analysis and these are displayed on the information centre. The robotic arm of the furnace autosampler is totally computer controlled; it samples, dilutes and injects standards and samples, having first generated its own standards from a single solution. The stabilised tempera- ture platform furnace provides inter- ference-free analyses.Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Atomic Absorption Spectropho- tometer Furnace The GFA-4A graphite furnace for the Shimadzu AA-670 instrument can store up to 9 methods in a battery buffered memory and each of these can have up to 9 programmed steps, including ramping. Also featured are light temperature moni- toring, a temperature calibration function and an optional autosampler, which allows sequential multi-element analysis for up to 8 elements. V. A. Howe and Co. Ltd., 12-14 St. Ann’s Crescent, London SW18 2LS. Spectrophotometers The Shimadzu UV240 ultraviolet - visible instrument has been developed by add-on accessories, including an advanced colour measuring system using the micro- computer interface, a Hewlett Packard HP 85 personal computer and an integrat- ing sphere attachment. In addition to the uncorrected reflection curve and usual data, sample number information, Tristi- mulus values and standard values are also printed out. It is then possible to have colour difference values, calculation of values for up to three illuminants, A, C, Ob5 and corrected values at 5-mm inter- vals. The UV260 instrument also facili- tates optimum colour measurement and its inbuilt display unit offers quick and clear result presentation.The MPS-2000 is a multi-purpose recording spectropho- tometer. Its applications include measurement of translucent tissues, trans- parent dyestuffs and opaque samples, such as paper, powders and cloth. Its sample compartment is large enough to accommodate large samples such as camera lenses.V. A. Howe and Co., Ltd., 12-14 St. Ann’s Crescent, London SW18 2LS. Spectroscopy Software The SPECTRAFILE-IR and SPECTRAFILE-UV are available on the Apple IIe and IBM PC micros. The Apple IIe version of SPECTRAFILE-IR offers advanced data han- dling, spectral storage and search and programmed instrument control. The new IBM PC version offers full colour graphics. SPECTRAFILE-UV features a full range of data manipulation routines for UV spectroscopy. Heyden and Son Ltd., Spectrum House, Hillview Gardens, London NW4 2JQ. Software for Multidimensional Spectroscopy Using PETLS, a software program for the makers’ Series 7000 professional com- puter, data from luminescence spectro- scopic analysis of complex mixtures, such as oils, can be presented as a three- dimensional map of the mixture or as a contour plot. The software also enables specific data to be obtained at any user- defined point in the matrix.Examples of uses are identifying oils and the source of oil spills, monitoring environmental pol- lution, examining biological and bio- chemical samples and monitoring the luminescence decay of phosphors. The program can also be used to present data from HPLC using an ultraviolet or flu- orescence detector and from gas chromat- ography using a Fourier transform infrared spectrometer detector. It can also present kinetic data monitored by infrared, ultraviolet or luminescence spectroscopy. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Spectrometer Plasma I1 is an inductively coupled plasma emission spectrometer combining the analytical flexibility of a sequential ICP instrument with the speed of a simul- taneous system. Over 70 elements can be determined in a variety of sample mat- rices at the rate of 50 elements min-1.Its software will decide which parameters will produce the best results for an analy- sis. While the instrument is generating results the next analysis can be set up. Spectral data and calibration curves can be displayed in real time during an analy- sis, while data are formatted to the printer and floppy disc for hard copy and archi- ving. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Spectrometer The Jobin-Yvon Q500 mobile elemental analyser is a portable spark spectrometer intended for use in metals quality control and warehouse stock management appli- cations. The operator uses a hand-held spark gun to excite the sample.The software compares the spectral intensities with those of known standards and indi- cates by means of red or green lights whether the metal is within specification or not. EDT Research, 14 Trading Estate Road, London NWlO 7LU. Spectrophotometer The Novaspec is a simple visible spectro- photometer operated by means of only four keys. It features automatic wavelength calibration at switch-on and microprocessor controlled selection of correct filter combinations. LKB Instruments Ltd., Nuclear Instru- ments Division, 232 Addington Road, Selsdon, South Croydon, Surrey CR2 8YD. Tablet Dissolution Analysis The L3DA, a completely automated system for tablet dissolution studies, con- sists of the makers’ Lambda 3 ultraviolet - visible spectrophotometer, a Model 3600 data station, a six cell changer and DISSOLUTION software, which controls the entire system, logs data and prints results in a choice of seven different formats.Methods, including standard and base line data, are stored on floppy disc and can be retrieved at a later date. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Gas Chromatograph New options and accessories are announ- ced for the Model 8300 instrument. A programmable temperature vaporiser (PTV) is an addition to the range of split - splitless and on-column capillary injectors. It provides both split and split- less operation.Samples are injected into a cold environment. A new option adds raw data re-integration to the data processing system. Following an analysis, the chro- matogram can now be re-examined, inte- gration parameters changed, re- calibrations carried out and, if necessary, the process repeated until the most suit- able parameters are determined. The sensitive and specific Hall detector can now be installed. The specification of the standard Model 8300 has been enhanced. Four-ramp temperature programming with full automated bleed compensation for both packed and capillary systems is standard over the temperature range from -80 to +5OO0C. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA.246 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Gas Chromatograph The new high-temperature version of the Mega Series instrument will characterise heavy petroleum residues up to straight chain carbon number 128 and waxes up to carbon number 70.This new version is capable of programming wide-bore col- umns and ovens up to 450°C and there is new software for the instrument’s data processor. The instrument uses automatic on-column injection. Erba Science (UK) Ltd., Headlands Trading Estate, Swindon, Wiltshire SN2 6JQ. Flame Photometric Detector A new detector for the makers’ Sigma 2000 gas chromatograph is sensitive to sub-nanogram amounts of sulphur and phosphorus compounds. Being 10 000 times less sensitive to hydrocarbons than to sulphur compounds, it offers high selectivity. It allows operation up to 400°C and is simple to use as a conven- tional flame-ionisation detector.Employ- ing a standard FID amplifier, it can be retrofitted to existing Sigma 2000 instru- ments. Its applications include pollution monitoring of ambient air and furnace stacks, analysing sulphur and phosphorus in pesticide residues, sulphur compounds in crude and refined gas, petroleum pro- ducts, cigarette smoke and physiological fluids. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Automatic Injection Devices One-shot samplers are available in two models, the Model 941, which can inject into either the front or rear injection port, and the Model 940, which allows injection only into the port above which it is mounted. Both models are suitable for packed and capillary columns and are ideal for use with the makers’ Network.The operator needs only to position a sample vial and press a start button. Because the sample volume is accurately and reproducibly measured the external standard method becomes more attrac- tive. Packard Instrument Ltd., 13-17 Church Road, Caversham, Reading, Berkshire RG4 7AA. Chromatography Software A new version of the makers’ GCDS chomatography data system software is announced. It runs on the Apple micro- computer and its features include the ability to acquire 250 peaks and 5500 data points, an HPLC option allowing simul- taneous data collection whilst controlling three pumps and gradient programs and an auto facility which allows fully auto- matic operation of the system, even set- ting up different methods for each sam- ple.U-SCI Ltd., Winstanley Industrial Estate, Long Lane, Warrington WA2 8PR. Microbial Identification System The HP5898A automated system identi- fies bacteria, yeasts, moulds and other microbes, frequently to the sub-species level. Composed of an HP7670 series automatic sampler, an HP5890A gas chromatograph, an HP3390 series inte- grator and an HP9000 series 200 desktop computer with various peripherals, the system automatically injects, sequences and chromatographs samples, handles system calibration and generates reports. After performing chromatographic analy- sis of cell wall lipids, the system refer- ences the resultant chromatogram against the software library to provide identifica- tion. Hewlett Packard Ltd., Miller House, The Ring, Bracknell, Berkshire RG12 1XN.Beer or Lager Gravity Determination The coupling of the makers’ PU 4500 gas chromatograph to a Paar Scientific DMA 55 density meter provides a method of automating original gravity determina- tions in beer and lager. The original gravity value is calculated using the PU 4810 computing integrator with its BASIC programming facility. Pye Unicam Ltd., York Street, Cam- bridge CB1 2PX. HPLC Systems A series of modular systems is announ- ced. Included are solvent delivery systems ranging from single-piston pumps to pul- seless units with a precision of 0.3% of the specified flow-rate, detectors for both HPLC Solvents A range of high purity solvents is avail- able. Alkaline and acidic impurities are kept at very low levels and non-volatile residues are below 3 p.p.m.All the solvents have a maximum water content of 0.05% with the majority at 0.01%. Literature is available. May and Baker Ltd., Liverpool Road, Barton Moss, Eccles, Manchester M30 7RT. HPLC Packing for Protein and Peptide Separations Based on rigid polystyrene/DVB, the new wide pore reversed-phase packing, PLRP-S 30081, has been designed to utilise the enhanced selectivity of the phenyl surface for separating a wide range of proteins. The column has a pH capabil- ity of 1-13 and wide solvent compatibility for use on both isocratic and gradient elution. Polymer Labs Ltd., Essex Road, Church Stretton, Shropshire SU6 6AX. Vial Designed for use with the Waters 96 vial autosampler, the new vial offers the possibility of using one vial with micro- sample capacities and with two sealing options.It is designed with a taper allow- ing the use of a small sample, up to 1 ml, the amount needed being less than 100 pl. The neck top is stretched with a flange offering the option of a polythene plug or a self sealing crimp cap. Chromacol Ltd., Glen Ross House, Summers Row. London N12 OLD. Industrial Process Computer The ITB 120 can receive data from a variety of instruments including pH met- LDC modular HPLC systems filter and continuously variable ultra- violet and visible absorbance, refractive index, fluorescence, electrical conductiv- ity and amperometric detection, and units for integration and data reduction. Laboratory Data Control (UK) Ltd., Milton Roy House, High Street, Stone, Staffordshire ST15 8AR. ers, viscometers, flow or level meters and its modular design permits up to 128 inputs to be accommodated.It operates using instructions externally keyed in via the touch sensitive alphanumeric key- board. It can be used with the makers’ density meters. It is especially suited to process and quality control applications.ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 247 Paar Scientific Ltd., 594 Kingston Road, Raynes Park, London SW20 8DN. Water Monitoring System This portable system has an underwater probe designed for fast water profiles, fixed depth monitoring and for mud measurements. Depth rated to 1500 m, the unit measures, prints and stores data from over seven parameters, including pressure, conductivity, temperature, sal- inity, dissolved oxygen, pH and redox.Each parameter can be digitised and scanned every 29 ms. The device is manufactured by Idronaut . Eiva Ltd., Haslemere House, Lower Street, Haslemere, Surrey GU27 2PE. Detachable Cable Electrodes These electrodes feature screw fittings accepting cables terminated with BS Coaxial, French, BNC, DIN, USA stan- dard and combination and many other types of connector. They can be used with the makers' and most other leading makes of pH meter. The range includes a micro- combination pH electrode for small vol- ume samples or centrifuge tubes, stan- dard combination pH electrodes for general applications, a plastic bodied combination pH electrode, a rapid response standard electrode for labora- tory use and a reference electrode for research applications.Kent Industrial Measurements Ltd., Oldends Lane, Stonehouse, Gloucester- shire GLlO 3TA. Ion Analyser The capability of the Delta 150 instrument has been extended by the addition of the multi-electrode measuring facility previ- ously available only with the Delta 155. When used with the five electrode station accessory, the Delta 150 can now analyse sequentially for up to five different ion species in a single sample. Stored calibra- tion data eliminate the need for recalibra- tion when switching between electrodes. Corning Medical and Scientific, Corn- ing Ltd., Halstead, Essex C 0 9 2DX. Nitrogen Oxides Analyser The Model 4000 analyser is designed for the continuous measurement of oxides of nitrogen. Using vacuum operation and a chemiluminescent reaction, it has a rapid response time, providing 95% of the required reading in less than 1.5 s.Vac- uum operation offers increased measur- ing sensitivity over its eight ranges, and a heated inlet system prevents condensa- tion of the sample gas. Signal Instrument Company Ltd., Stan- dards House, 1 Doman Road, Camber- ley, Surrey GU15 3DW. Automated Sample Preparation The Hamilton Microlab M diluter - dispenser has been used as a basis for a new sample preparation system employ- ing a proprietary balance and connecting the instruments through a suitably programmed Epson Hx-20 microcom- puter. The approximate amount of sam- ple is placed on the balance, which registers the mass and feeds this through the computer. The latter calculates the amount of liquid required to reach a desired concentration and instructs the Microlab M to dispense this amount.The system is suitable for use with balances with RS232 interfaces. V. A. Howe and Co. Ltd., 12-14 St. Ann's Crescent, London SW18 2LS. Haematology Analyser The Contraves Autolyzer 801 system offers up to 16 parameters including lymphocytes and platelets from whole blood or pre-dilutions. Seventy-five results h-1 can be achieved even when pathological bloods are being measured and three volume distribution curves are available. No supplementary vacuum system is required and no cyanide or liquid mercury are used. Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire. Clinical Instruments and Reagents The Cellsampler 880s automatically pre- pares all dilutions necessary for electronic cell counting of red cells and platelets.It works with both venous and capillary blood and features an automatic washing device which cleans the measuring system between samples. It can take samples through the stoppers of closed Vacu- tainertubes. Only 200 yl of venous blood or 20 pl capillary blood is needed. Also available are a range of reagents for IL and Corning equipment, such as blood gas analysers, electrolyte analysers, flame photometers and chloride, calcium and carbon dioxide analysers. The Virgo - IPA therapeutic drug monitoring assays offer fast, accurate results with the advan- tages of non-isotopic methodology. Kits are available for gentamicin, theophyl- line, tebramycin, phenytoin and pheno- barbital.The assays can be adapted to most automated analysers or simple spec- trophotometers. Ultrolab. ity of potable water. It can be set up on a bench, requires only 2 1 of water and gives a result within 100 h. Testing may be carried out by BNF staff or the equipment can be purchased outright. BNF Metals Technology Centre, Grove Laboratories, Denchworth Road, Wantage, Oxfordshire OX12 9BJ. Surface Area Analyser The Micromeritics Flowsorb I1 2300 can be used for single, multi-point, total pore volume and chemisorption measure- ments. It permits analysis of specific surface areas from 0.01 m2 g-1 to over 1000 m2 g-1 and pore volumes from 0.005 cm3 can be measured. A wide range of sample cells enables analysis of differing materials and a single point surface analy- sis can be accomplished in less than 10 min.Coulter Electronics Ltd., Northwell Drive, Luton, Bedfordshire LU3 3RH. Thermoregulator The Braun Thermomix 1442D uses digital read-out for control and operating tem- peratures. Its control range is -30 to + 150 "C and it will maintain temperatures to within 0.01"C. Although designed as part of a modular system for use with the makers' range of water-baths and re- frigeration units, it can be used as a free-hanging unit for any bath. FT Scientific Instruments Ltd., Station Drive, Bredon, Tewkesbury , Gloucester- shire GL20 7HH. Centrifuge The J2-21M/E microprocessor economy centrifuge features programmable con- trols and d.c. drive. Its memory can store up to 10 programs, and there is a choice of acceleration and deceleration rates.It also features digital logic for time, speed and temperature settings. It can spin a total of 14 of the makers' rotors. Measurement of Aggressivity of Waters The BNF electrochemical cell offers a rapid means of determining the aggressiv- .~.. - _ _ _248 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire. Feeders for Spinning Rimers Triton TM1 electromagnetic vibrating variable feeders provide essential uniform feed and complete hopper discharge for the Microscal range of spinning rifflers used in the analysis of free flowing and recalcitrant powders. The TM1 is moun- ted on rubber feet and has a steel base and Computer Aided Laboratory Management The CALM package offers fast and sim- ple acquisition of data from up to 40 sources, quick presentation of routine or ad hoc reports and the ability to commun- icate with other computer systems and management personal computers running packages such as Lotus Symphony.Milequip Laboratory Computer Systems, Northgate House, 19 London Road, Gloucester GL1 3EZ. Triton TMI electromagnetic vibrating variable feeders cast aluminium trough with silver hammer finish. It has a maximum output of 70 kg h-1 (tested on dry sand). The Triton Engineering Co. (Sales) Ltd., Kingsnorth Industrial Estate, Wot- ton Road, Ashford, Kent TN23 2LB. Heat -s hrink Tubing This tubing is made from PTFE and is supplied in an expanded state. On the brief application of heat it shrinks, mould- ing itself around irregular shapes to form a completely sealed protective jacket for components that will be subject to tem- peratures up to 500°F and exposed to shock, moisture, corrosive chemicals, abrasion or chafing.A folder, “The Source ,” is available. Zeus Industrial Products Inc., c/o Mal- colm Leybourne, Roggersdorfer Str. 13, D-8150 Holzkirchen, West Germany. Energy Dispersive Analysis System An enhanced version of the 9100 series of analysers, the 91OO-LX, is announced. The enhancements include complete applications software, an imaging tech- nique for acquisition and presentation of X-ray and microscopy signals, standard- less EDS measurement techniques, soft keys allowing one-keystroke operation, the ECON series of detectors for elemen- tal detection down to boron and a unique spectrum display system.EDAX International, P.O. Box 135, Prairie View, IL 6(X)69, USA. Laboratory Interface and Software for Computer The DAQRW data acquisition system is a general purpose interfacing module for the makers’ Series 7000 professional com- puter. The package includes the hardware and software necessary to perform ana- logue and digital input and output. The DAQ17000 library acts as an interface between the hardware and high level programming languages, so that analysts can write programs in FORTRAN or BASIC to accomplish such tasks as connecting the Series 7000 to analytical instruments, controlling and monitoring experiments and implementing the graphics capability of the Series 7000. DMS 7000 and GRAPH 7000 are general purpose software pro- grams for the Series 7000.DMS 7000 provides general data ’ management capabilities. One of the primary uses of GRAPH 7000 is the construction of calibra- tion graphs. Perkin-Elmer Ltd, , Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Amplifier NF Instruments of Japan have introduced their Model 5610 two-phase lock-in amplifier, which features a wide fre- quency range from 10 Hz to 100 kHz, a choice of modes to allow the operator to choose between large dynamic reserve and high output stability, five automatic setting functions (range, sensitivity, mode, phase, frequency or combinations of these), IEEE 488 interface and optional RS232C interface, two digital displays plus a bar graph display and a full range of filters. EDT Research, 14 Trading Estate Road, London NWlO 7LU.Oscilloscope The 1425 is a digital storage, 20 MHz, dual trace oscilloscope, which can func- tion as a real-time instrument as well as a digital storage instrument for both tran- sient capture and high-speed storage of repetitive signals. It offers automatic measurement of time and voltage via on-screen cursors and alphanumeric read- out as well as an optional waveform processor. Gould Electronics Ltd., Roebuck Road, Hainault, Ilford, Essex IG6 3UE. Literature A new ICP Bulletin describes the deter- mination of eight toxic waste metal lea- chates: arsenic, barium, cadmium, chro- mium, lead, mercury, selenium and silver. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. An application bulletin, “Rapid and Re- producible Injection on to Microbore Columns,” describes the problems that can be met by chromatographers with the new generation of microbore columns.Packard Ins-trument Ltd., 13-17 Church Road, Caversham, Berkshire RG4 7AA. A general products brochure describes Nermag gas chromatograph - quadrupole mass spectrometer instruments, including the R10-1OC research instrument, the R10-10s electron impact (upgradeable) system, the R10-1OT dedicated electron impact-only instrument for routine use and the R30-10 tandem MS - MS. Infor- mation is also given on various options (HPLC, FAB, solid probe, etc.) and the associated GC - MS data systems SIDAR. Dorand Electronics Ltd., DELSI Instrument Division, Allens Lane, Ham- worthy, Poole, Dorset. A brochure describes the Contalab com- puter controlled laboratory reactor that can operate round the clock without supervision.The reactor assembly is equipped with a 11 reaction vessel, a reflux condenser and a stirrer. Measure- ments that can be made are the tempera- ture inside the reactor and in the jacket, the internal pressure in the reactor, pH and mass on balance. The temperature range is from -30 to +200”C. Contraves Industrial Products Ltd., Times House, Station Approach, Ruislip, Middlesex HA4 8LH.248 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Beckman Ltd., Progress Road, Sands Industrial Estate, High Wycombe, Buck- inghamshire. Feeders for Spinning Rimers Triton TM1 electromagnetic vibrating variable feeders provide essential uniform feed and complete hopper discharge for the Microscal range of spinning rifflers used in the analysis of free flowing and recalcitrant powders.The TM1 is moun- ted on rubber feet and has a steel base and Computer Aided Laboratory Management The CALM package offers fast and sim- ple acquisition of data from up to 40 sources, quick presentation of routine or ad hoc reports and the ability to commun- icate with other computer systems and management personal computers running packages such as Lotus Symphony. Milequip Laboratory Computer Systems, Northgate House, 19 London Road, Gloucester GL1 3EZ. Triton TMI electromagnetic vibrating variable feeders cast aluminium trough with silver hammer finish. It has a maximum output of 70 kg h-1 (tested on dry sand). The Triton Engineering Co. (Sales) Ltd., Kingsnorth Industrial Estate, Wot- ton Road, Ashford, Kent TN23 2LB.Heat -s hrink Tubing This tubing is made from PTFE and is supplied in an expanded state. On the brief application of heat it shrinks, mould- ing itself around irregular shapes to form a completely sealed protective jacket for components that will be subject to tem- peratures up to 500°F and exposed to shock, moisture, corrosive chemicals, abrasion or chafing. A folder, “The Source ,” is available. Zeus Industrial Products Inc., c/o Mal- colm Leybourne, Roggersdorfer Str. 13, D-8150 Holzkirchen, West Germany. Energy Dispersive Analysis System An enhanced version of the 9100 series of analysers, the 91OO-LX, is announced. The enhancements include complete applications software, an imaging tech- nique for acquisition and presentation of X-ray and microscopy signals, standard- less EDS measurement techniques, soft keys allowing one-keystroke operation, the ECON series of detectors for elemen- tal detection down to boron and a unique spectrum display system.EDAX International, P.O. Box 135, Prairie View, IL 6(X)69, USA. Laboratory Interface and Software for Computer The DAQRW data acquisition system is a general purpose interfacing module for the makers’ Series 7000 professional com- puter. The package includes the hardware and software necessary to perform ana- logue and digital input and output. The DAQ17000 library acts as an interface between the hardware and high level programming languages, so that analysts can write programs in FORTRAN or BASIC to accomplish such tasks as connecting the Series 7000 to analytical instruments, controlling and monitoring experiments and implementing the graphics capability of the Series 7000.DMS 7000 and GRAPH 7000 are general purpose software pro- grams for the Series 7000. DMS 7000 provides general data ’ management capabilities. One of the primary uses of GRAPH 7000 is the construction of calibra- tion graphs. Perkin-Elmer Ltd, , Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. Amplifier NF Instruments of Japan have introduced their Model 5610 two-phase lock-in amplifier, which features a wide fre- quency range from 10 Hz to 100 kHz, a choice of modes to allow the operator to choose between large dynamic reserve and high output stability, five automatic setting functions (range, sensitivity, mode, phase, frequency or combinations of these), IEEE 488 interface and optional RS232C interface, two digital displays plus a bar graph display and a full range of filters.EDT Research, 14 Trading Estate Road, London NWlO 7LU. Oscilloscope The 1425 is a digital storage, 20 MHz, dual trace oscilloscope, which can func- tion as a real-time instrument as well as a digital storage instrument for both tran- sient capture and high-speed storage of repetitive signals. It offers automatic measurement of time and voltage via on-screen cursors and alphanumeric read- out as well as an optional waveform processor. Gould Electronics Ltd., Roebuck Road, Hainault, Ilford, Essex IG6 3UE. Literature A new ICP Bulletin describes the deter- mination of eight toxic waste metal lea- chates: arsenic, barium, cadmium, chro- mium, lead, mercury, selenium and silver. Perkin-Elmer Ltd., Post Office Lane, Beaconsfield, Buckinghamshire HP9 1QA. An application bulletin, “Rapid and Re- producible Injection on to Microbore Columns,” describes the problems that can be met by chromatographers with the new generation of microbore columns. Packard Ins-trument Ltd., 13-17 Church Road, Caversham, Berkshire RG4 7AA. A general products brochure describes Nermag gas chromatograph - quadrupole mass spectrometer instruments, including the R10-1OC research instrument, the R10-10s electron impact (upgradeable) system, the R10-1OT dedicated electron impact-only instrument for routine use and the R30-10 tandem MS - MS. Infor- mation is also given on various options (HPLC, FAB, solid probe, etc.) and the associated GC - MS data systems SIDAR. Dorand Electronics Ltd., DELSI Instrument Division, Allens Lane, Ham- worthy, Poole, Dorset. A brochure describes the Contalab com- puter controlled laboratory reactor that can operate round the clock without supervision. The reactor assembly is equipped with a 11 reaction vessel, a reflux condenser and a stirrer. Measure- ments that can be made are the tempera- ture inside the reactor and in the jacket, the internal pressure in the reactor, pH and mass on balance. The temperature range is from -30 to +200”C. Contraves Industrial Products Ltd., Times House, Station Approach, Ruislip, Middlesex HA4 8LH.

ISSN:0144-557X    

DOI:10.1039/AP9852200245

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

250 ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 Conferences and Meetings Chromatography of Ions September 3 and 5, 1985, London and Manchester The fourth annual Dionex Symposium will be held at two venues: Imperial College, London, on September 3 and UMIST, Manchester, on September 5. The papers to be given include “Mem- brane Technology or Everything you Wanted to Know About Membrane Sup- pression but Did Not Like to Ask.” In addition, several users will be reading papers on their own ion chromatography application. For further information contact Dionex (UK) Ltd., Eelmoor Road, Farnborough, Hampshire GU14 7QN. Flow Analysis I11 September 5-8, 1985, Birmingham The full scientific programme of this meeting, which will take place at the University of Birmingham, is now avail- able.The speakers will be J. RQiitka, G. Johansson, A. Townshend, P. J. Wors- fold, B. 0. Ranger, K. S. Johnson, E. Pungor, K. K. Stewart, J. F. Tyson, F. J. Krug, F. Ingman, B. Karlberg, C. J. Patton, K. T6th, C. Riley, W. E. van der Linden, J. Vanderslice, P. Hoagensen, M. Gisin, L. Gorton, R. C. Schothorst, J. N. Miller, D. C. Johnson, W. Frenzel, Zhao-Lun Fang, M. Burguera, E. H. Hansen, M. Valcarcel, G. E. Pacey, J. F. van Staden and M. Whitfield. In addition two poster sessions will be held. For further information contact Dr. A. M. G. Macdonald, Department of Chemistrv. The University, P.O. Box Pollution Monitoring and Control This meeting will be held in the Eurotel. October 29-31, 1985, Wembley The increasingly important area of pollu- tion monitoring and control is to be covered by a show-within-a-show at Wembley Conference Centre. Promoted alongside the established and successful exhibition and conference, Test + Trans- ducer, the event will highlight instrumen- tation already partly covered by the main show and in which a significant portion of the near 5500 audience has an active interest and involvement.Test + Trans- ducer deals with measurement sensors of all types plus instrumentation for test, analysis and control. It includes environ- mental equipment, gas analysers and noise and vibration monitoring devices. The product guide for Pollution Moni- toring and Control includes air quality monitors, boiler and furnace instrumenta- tion, composition analysers, effluent instrumentation, filters, flue gas analys- ers, internal combustion engine exhaust monitoring, moisture detectors, noise instrumentation, nuclear radiation detec- tors, particle size analysers, pH meters, sampling systems, vibration detectors and instrumentation.The audience will be drawn from all branches of industry, i.e. electronic, electrical and mechanical engineers responsible for research, design, production and maintenance. For further information contact Trident International Exhibitions Ltd., 21 Plymouth Road, Tavistock, Devon PL19 8AU. Monitoring in Industry November 12-13, 1985, Antwerp, Bekium 363, Birmingham, B15 2TT: - The sessions will be on Occupational Exposure Limits, General Aspects of Monitoring, Practical Aspects of Moni- toring Techniques and Recent Develop- ments and Applications of Monitoring Techniques in Industry and the Point of View of Users.For further details contact Monitoring in Industry, c/o K.VIV, Jan van Rjswijck- laan 58, B-2018, Antwerpen, Belgium. Anatech ’86 April 22-24, 1986, Noordwijkerhout, The Netherlands This symposium, which is to be sponsored by the Royal Netherlands Chemical Society and FECS, will be held at the Leeuwenhorst Congress Centre. It is aimed at an interdisciplinary audience of industrial and academic analytical chem- ists and those involved in process control and process analysis. The scientific pro- gramme will consist of invited plenary lectures, keynote lectures and submitted research papers. The invited lectures will deal with state of the art analytical tech- niques already successfully applied in process analysis, sampling procedures and sampling strategy, selection of analy- tical procedures and instruments with regard to optimum process control and new analytical techniques of possible interest for process control.For information on the symposium contact Professor W. E. van der Linden, Laboratory for Chemical Analysis, Department of Chemical Technology, Twente University of Technology, P.O. Box 217, NL-7500 AE Enschede, The Netherlands.ANALYTICAL PROCEEDINGS. AUGUST 1985, VOL 22 111 CAC May 2629, 1986, Lerici, Italy An international conference on chem- ometrics in analytical chemistry and opti- misation will be held at Villa Marigola in Lerici, Italy, on May 26-29, 1986. The conference is being organised under the auspices of the Analytical Division of the Italian Chemical Society and of the Chemometrics Society.Topics will in- clude: application and development of techniques for design; optimisation and evaluation of analytical procedures and results; application of chemometrical techniques (pattern recognition, opera- tions research, information theory, artifi- cial intelligence, robotics, etc.) in analy- tical chemistry with a special reference to food chemistry and clinical chemistry; computerised signal and data processing; education in chemometrics. The program will include invited plenary lectures and submitted research papers. Papers are to be refereed for publication in a special issue of Analytical Chimica Acta. Further information can be obtained from Professor M. Forina, Istituto di Analisi e Tecnologie Farmaceutiche ed Alimentari, Via Brigata Salerno (ponte), 1-16147 Genova, Italy.XXV Colloquium Spectroscopicurn Internationale June 21-26, 1987, Toronto, Canada The XXV Colloquium Spectroscopicum Internationale will be held at the Hilton Harbour Castle, Toronto. The meeting is sponsored by the Spectroscopy Society of 25 1 Canada, the Society for Applied Spectro- scopy (USA) and the National Research Council of Canada. The core of the scientific program will consist of two plenary lectures, by Nobel Laureates Dr. Gerhard Herzberg and Professor Arthur L. Schawlow, and about thirty-five invited lectures by young scientists. The other lectures will be selected from sub- mitted abstracts. There are no plans for poster sessions. The invited and submit- ted presentations will be based on recent research, rather than reviews of past work. A second circular with a call for papers will be published in Spring 1986. Anyone wishing to receive additional information on the Colloquium should contact Mr. L. Forget, Executive Secretary CSI XXV, National Research Council, Canada, Ottawa, Canada K1A OR6.

ISSN:0144-557X    

DOI:10.1039/AP985220250b

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

ANALYTICAL PROCEEDINGS, AUGUST 1985, VOL 22 25 1 Course 11th Annual AOAC Spring Training Workshop and Exposition April 27-30, 1986, Seattle, WA, USA The 11th Annual Association of Official Analytical Chemists Spring Training Workshop and Exposition will be held at the Stouffer Madison Hotel, Seattle, Washington. A NASA astronaut and other outstanding speakers will open the meeting. The technical programme offers the following sessions for chemists and microbiologists interested in methodol- ogy and equipment pertaining to the analysis of food, fertilizers, feed, drugs, cosmetics and the environment: “The Leading Edge,” a series of presentations on what is new in methodology and which discusses liquid chromatography (LC), gas - liquid chromatography (GLC), gas chromatography - mass spectrometry (GC - MS), atomic-absorption spectro- photometry (AA), inductively coupled plasma spectrometry (ICP), molecular spectroscopy, ion chromatography, flow injection techniques, computers and mi- crobiological methods; “Working Smart ,” a series of presentations on problem solving in key analytical areas, LC, AA - injection techniques, molecular spectro- scopy, ion chromatography, microbiol- ogy, and robotics; discussion workshops and analytical updates in critical areas such as pesticides, food, drugs, microbiol- ogy, feeds, fertilizers and the environ- ment; and poster sessions on a variety of subjects.The meeting will also feature a scientific exposition with the latest in analytical equipment and services. For further information on this meeting contact Mike Wehr, Oregon Department of Agriculture, Laboratory Services Divi- sion, 635 Capitol Street NE, Salem, OR ICP, GC - MS, automated analysis - flow 97310, USA.- ROYAL SOCIETY OF CHEMISTRY: ANALYTICAL DIVISION A Meeting on CHEMICAL CONSULTANCY-A NEW BEGINNING! The East Anglia Region of the Analytical Division is holding a one-day meeting with the above title on Wednesday October 2nd, 1985, at the Warren Spring Laboratory in Stevenage, Hertfordshire. The meeting will be of interest both to existing consultants and t o those who intend to ’set themselves up’ in the field. Further details, etc., can be obtained from Mr. B. W. Woodget, Division of Chemistry, The Hatfield Polytechnic, P.O. Box 109, Hatfield, Hertfordshire. Tel. No. Hatfield (07072)-79586.

ISSN:0144-557X    

DOI:10.1039/AP9852200251

出版商:RSC    

年代:1985

数据来源: RSC