摘要:

Proceedinas - ~ cof the Analytical Division ofThe Chemical SocietyCONTENTS161 Summaries of Papers: AnnualChemical Congress161 'History of Analytical Chemistry'187 'Modern Methods of Speciation-Characterisation of ChemicalSpecies'192 Equipment News196 Correspondence197 Analytical Division DistinguishedService Award197 SAC Silver Medal198 Robert Boyle Essay Awards198 Guide to Spectral Data198 CS Autumn Meeting198 CourseVolume 14 No 7 Pages 161-198 July 197PADSDZ 14(7)161-198(1977)ISSN 0306-1 396July 1977PROC EEDINGSOF THEANALYTICAL DIVISION OF THE CHEMICAL SOCIETYOfficers of the Analytical Divisionof The Chemical SocietyPresidentD. W. WilsonHon. SecretaryP. G. W. CobbSecretaryMiss P. E. HutchinsonHon. Treasurer Hon.Assistant SecretariesJ. K. Foreman D. I . Coomber, O.B.E.; D. C. M. Squirrel1Editor, ProceedingsP. C. WestonProceedings is published by The Chemical Society.Editorial: The Director of Publications, The Chemical Society, Burlington House, London, W1 V OBN.Telephone 01 -734 9864. Telex 268001.Subscriptions (now members): The Chemical Society, Distribution Centre, Blackhorse Road,Letchworth, Hem., SG6 1HN.Non-members can only be supplied with Proceedings as part of a combined subscription with The Analystand Analytical Abstracts.Q The Chemical Society 1977Annual Reports on AnalyticalAtomic SpectroscopyVOLUME 5,1975This comprehensive and critical report of developments in analytical atomicspectroscopy has been compiled from over 1550 reports received fromworld-wide correspondents who are internationally recognised authorities inthe field and who constitute the Editorial Board. In addition to surveyingdevelopments throughout the world published in national or internationaljournals, a particular aim has been to include less widely accessible reportsfrom local, national and international symposia and conferences concernedwith atomic spectroscopy.Paperbound 276pp 82"x 6" f 15 (CS Members f9)(Still available: Vols. 2-4 covering I 972 to 1974)Obtainable from : The Chemical Society, Distribution Centre,Blackhorse Road, Letchworth, Herts., SG6 1 H

ISSN:0306-1396    

DOI:10.1039/AD97714FX021

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

Vol. 14 No. 7 July 1977 of the Analytical Division of the Chemical Society ANNUAL CHEMICAL CONGRESS The Annual Chemical Congress of The Chemical Society and The Royal Institute of Chemistry was held at University College London from March 28th to April lst, 1977. Two Symposia were organised by the Analytical Division and summaries of seven of the papers given at Symposium A, History of Analytical Chemistry, and of two of the papers presented at Sym- posium B, Modern Methods of Speciation-Characterisation of Chemical Species, are presented below.The Sixth Theophilus Redwood Lecture by Dr. D. R. Deans will appear in full in a forthcoming issue of Proceedings. History of Analytical Chemistry The following are summaries of seven of the papers presented at the Annual Chemical Congress on March 30th, 1977.The History of Analytical Chemistry in America R. Belcher Department of Chemistry, Frankland Building, University of Birmingham, P.O. Box 363, Birmingham, B15 2TT When I was invited to present one of the Bicentennial Lectures at the Pittsburg Conference last year1 on “200 Years of Anglo-American Analytical Chemistry,” I found to my surprise that not only had a history of Analytical Chemistry in the United States never been prepared, but also that very few of my American colleagues could supply me with the necessary informa- tion.The first reference provided by Ferenc SzabadvAry in his classic book “The History of Analytical Chemistry”2 is 1864, when Woolcott Gibbs described the first method of electro- gravimetric analysis.If we consider fundamental contributions to analytical chemistry this date is probably correct, although Alter’s observations on analytical spectroscopy (1854) also deserve consideration. Chemical analysis, however, had been practised in some form or other in the earliest colonial times. The first Governor of Connecticut, John Winthrop, Jr., the first American to become a Fellow of the Royal Society, was among many other things a mineralogist.He must, therefore, have had some interest in the chemical compo- sition of the various minerals which he collected and later presented to The Royal Society. We know that in the latter half of the 17th century (1672) Leonard Hoar wrote to Sir Robert Boyle,l our own greatest analytical chemist of classical times, describing the laboratories he proposed to have built at Harvard University in order to teach chemistry.Some form of chemical analysis would have been an essential part of such a course. In the earlier years of the American colonies very few people in England foresaw the great future that lay ahead. One man who had some foresight was a certain Sir Winston Churchill, an impoverished officer in the Guards who had fought for Charles I against the Puritans.He was the ancestor of his more famous namesake. In 1675 he wrote “those far-off distant regions, now become a part of us and growing apace to be the bigger part in the sun-burnt Americas. ”3 Various industrial processes had been in use from the earliest times, such as the production 161 Accordingly, it is hoped that this history will be a useful contribution.162 HISTORY OF ANALYTICAL CHEMISTRY Proc.AnaZyt. Div. Chem. SOC. of wood-tar, glass making, brewing, potash production and tanning. Although it may have been crude, some form of quality control would have been essential. E. F. Smith,4 in referring to the immediate post-revolution pxiod, states, “Many of the leading chemists were devoted to mineralogy.They discovered new methods of anaZysis* and brought to light many interesting species.” On the other hand, in 1892 G. C. Caldwel15 in his retiring Presidential Address to the American Chemical Society speaks somewhat disparagingly of this period. In this address, “The American Chemist: His Past and Present,” he refers to some of the papers published in the late 18th century and those of the early 19th century. He states that they consist mainly of arguments between Priestley on the one hand and Mitchill and Woodhouse on the other, on the phlogiston theory. He says, “What meagre showing this is when we consider that on the other side of the ocean we find the names of such chemists as Lavoisier writing on the greatest variety of chemical subjects.” He con- siders that nothing important was done in America during the first two decades of the 19th century and he has a poor opinion of the first papers that appeared in the early volumes of the American Journal of Science.Only in the 1840s does he consider that original work in chemistry was carried out. He refers to chemists such as W. B. and R. E.Rogers, J. L. Smith, C. U. Sheppard, J. W. Draper, T. S. Hunt, E. N. Horsford and W. Gibbs. He goes on to say that at this time about 20% of the papers described the analysis of minerals and waters and ten papers were concerned with analytical chemistry (showing that he differentiated chemical analysis from analytical chemistry). Presumably, these ten papers describe some original contributions to the subject.Caldwell refers to each decade in turn and it is interesting to note that in the 70s he observes that analytical chemistry was very much more prominent in the work of this particular decade than at any time before it. In the 80s a new chemical journal appeared, i.e., The JournaZ of Analytical Chemistry. This journal started publication in 1887 but ceased to exist six years later when the Editor and Publisher Edward Hart became Editor of the Journal of the American Chemical Society.It is probably true that little of great originality was forthcoming at that time either in general or analytical chemistry and it is interesting to note that one present-day chemist considers that Priestley had an inhibitory effect on the progress of American chemistry. Before his arrival in America, the American chemists tended to be anti-phlogistonists. Priestley kept them arguing for years when they might have been pursuing more fruitful investigations.On the whole, I think the late 18th and early 19th centuries were fruitful periods. Thomas Jefferson, the third President of the United States said in 1785: “Chemistry is among the most useful of sciences, and big with future discoveries for the utility and safety of the human race.” A number of text-books were published by American chemists during the latter part of the 19th century.Before 1800 British books were not favoured, but early in the 19th century British books by Accum, Henry, Black, Thomson, Parkes and Mrs. Marcet were reprinted. The Chemical Society of Philadelphia was founded in 1792.One of its earlier objectives was a collection and analysis of minerals and ores. It issued what is the earliest known publication of a chemical society in America. Thomas Peter Smith, at the age of 20, in 1797 delivered a lecture to the Society on a history of chemistry. It was decided to publish this as a pamphlet. Apart from student societies at the Universities of Glasgow and Edinburgh, this was the first chemical society and it existed for about 10 years.I t was followed by the Columbian Chemical Society which, unfortunately, had a very short existence. I have referred to these and later chemical societies previous1y.l Undoubtedly, the formation of such societies must have stimulated American chemistry and it is during this period that contributions began to be made.For example, in 1802 Robert Hare invented the oxy-hydrogen blowpipe. It is said that the first mineral analysis of any importance made in America was of the mineral chondrodite. The analysis was carried out by Langstaff who noted that it contained fluorine, a fact that the great Berzelius had failed to observe.Other names concerned with the analysis of minerals are Vanuxen, Torrey and Gorham. One finds conflicting statements about the early state of analytical chemistry. I believe that Caldwell is a little hard on the early American chemists. Thus, there were books by Rush, Mitchill and Woodhouse. * R.B.’s italics.July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 163 There are several accounts in the 19th century of the analysis of minerals and waters, described in papers published in the Transactions of the American Philosophical Society.I have referred elsewherel to the analysis of “Chalybeate Waters” by Dr. John D. Normandie. This is said to be the earliest published chemical contribution from the USA (1768). Later in the 19th century J. Madison, in a letter to the astronomer Rittenhouse, describes his tests on what he calls “Sweet Springs.” It is interesting to note that to test for iron he uses a solution of nutgalls.This is the same test for iron used by Pliny in the 1st century AD and is believed to be the first example of the use of a chelate compound in analytical chemistry. In 1789 Dr. Robert McCauslin analysed “an earthy substance” found near Niagara Falls.He concludes that it is “a combination of an acid with a calcareous earth.” Professor Emmett, who occupied the Chair of Chemistry of the University of Virginia, in 1824 published a number of analytical papers. Some of the titles are as follows: “On Iodide of Potassium as a Test for Arsenic”; “Bromine and Iodine in Kanawha Salts”; and “Upon the Solvent a:id Oxidating Powers of Ammoniacal Salts.” In the same period J.W. Bailey published “a test for nitric acid,” and “a test for sulphur by Playfare’s nitro-prusside.” James C. Cutbush, who was a member of the Columbian Chemical Society and President for a time, was Professor of Chemistry at West Point. He published several papers, among which may be mentioned “On the Composition and Properties of Greek Fire.” In 1813 he published “Philosophy of Experimental Chemistry,’’ in 2 volumes.He has a paper listed in the “Memoirs of the Columbian Chemical Society” entitled “On the Oxy-acetite of Iron as a Test for Arsenic.” William J. McNevin wrote a number of papers on the examination of minerals and natural waters. J. T. Bowen (1803-28) studied extract of purple cabbage as a test for acids and alkalis.He was succeeded in the Chair of Chemistry in Nashville by J. Troost, a Dutchman, who had come to the USA in 1810. Troost was a mineralogist and he studied the composition of meteoric bodies. A book on “Practical Chemistry” by John Redman Coxe published in Philadelphia in 1818 contains a very extensive section on analysis. An English edition of Fresenius’s “Qualitative Analysis” was published in New York in 1844.Volume 50 of the American Jounzal of Science, published in 1845, has a comprehensive index for the first 49 volumes. There are many references to the analysis of ores and minerals and also to adulteration. I t is probable that the methods for analysis used at that time followed European practice. I t seems, therefore, that Caldwell’s criticism of the early American chemists was not justified.They showed great activity in analysing ores, minerals and waters during the latter part of the 18th century. They were among the first to accept the new French theories and they probably led the world in promoting organised societies. It is true that this bounding vitality appeared to burn itself out after the collapse of the Columbian Chemical Society, but American chemists soon recovered from this setback and new names began to appear on the scene.For the remainder of this paper I shall refer to the work of a few selected American chemists. He also published a paper on the common blowpipe. He is also credited with the oxy-acetite of iron paper. James Curtis Booth Booth (1810-88) is generally considered to have been the first American industrial chemist.He was a pupil of Woehler and was said to have been the first American student to study analytical chemistry in Germany. He studied also for a time in England. In 1836 he established in Philadelphia a laboratory for instruc- tion in chemical analysis and applied chemistry, which is said to have been the first training made available in chemical analysis.Many American chemists, who later became famous, studied a t this laboratory. He also served as melter and refiner at the US Mint and was analyst for many chemical industries. Booth devised the nickel alloy from which the 1 cent coins of 1856 were made ; these replaced the large copper coins used before that time.He also introduced the bronze coinage alloy. During his term of office, gold was discovered in California and he devised the methods of refining for the large amounts of bullion which came to the Mint. He later worked with Gustav Magnus. Booth analysed ores of iron, nickel and other metals.164 HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Div. Chem. SOC. The first precision balances to be used in America were made by Robinson of London, but apparently none of these models has survived, even in museums.A balance used by Booth (Fig. 1) and on show at the Philadelphia Adacemy of Natural Sciences has recently been described by J. T. .Stock.6 Apparently, Booth must have had this specially made. Stock remarks that “It’s design is a mixture of naivet6 and ingenuity.” He concludes that the unknown maker was an excellent workman but had no special knowledge of balances.Fig. 1. Balance associated with J. C. Booth. Benjamin Silliman, Jr. The first regular University laboratory courses in chemical analysis were started at Yale in 1842 by Benjamin Silliman, Jr. His famous father, who had studied with Frederick Accum in London, and who started the American JournaZ of Science in 1818, persuaded the authorities later to set up a School of Science a t Yale University.Silliman Jr. was appointed Professor of Technical Chemistry and J. P. Norton, Professor of Agricultural Chemistry. I have mentioned elsewhere the difficult circumstances under which these courses were started.l This laboratory was first called the Yale Analytical Laboratory but later it was re-christened the Sheffield Scientific School after J.E. Sheffield who became its benefactor. J. Lawrence Smith Smith graduated in Medicine, but while on a walking tour he happened to visit Liebig a t Giessen and became his first American pupil.* From that moment his main interest became chemistry. His studies covered a wide field and included the composition of spermaceti, soils and minerals.He was probably the first to separate barium and strontium as the chromates. Smith’s method for the decomposition of silicates for the determination of the alkalis was published in 1871 and is still used. He examined the weight equilibrium of platinum and showed the importance of the nature of the surface on the time to equilibrate.He recommended sodium bisulphate instead of the potassium salt for the fusion of corundum because the melt was much easier to dissolve. * A number of American chemists studied under Liebig. Details can be found in an interesting paper It is interesting to record part of the account given by Horsford of his daily At 7.00 another by Ropp on After lunch by H. S. Van Klooster.7 routine.crystallography. the afternoon was spent in the laboratory until 6.30 p.m.” “He attended a lecture by Fresenius on sugar a t 6.15 a.m. Laboratory work started a t 8.15 and a t 11.05 Liebig lectured until 12.30.July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 165 He discovered a new mineral which he named Liebigite. Smith spent several years in the Turkish Empire exploring its mineral resources.Oliver Woolcott Gibbs Gibbs (Fig. 2), who graduated from Columbia University, worked as Assistant to Robert Hare for a period. He went abroad to study chemistry in Germany under Rammelsberg, then under Rose and finally under Liebig. He returned to the USA in 1848 and was appointed Professor of Chemistry at the City University, New York, and later Rumford Professor at Harvard.2 Although it seems that Luckow studied this independently and simultaneously, Gibbs was the first to publish.Besides copper, Gibbs determined nickel, silver and bismuth and, as peroxides, lead and manganese. It is for this contribution that Gibbs is generally remembered, but he made many other substantial contributions to analytical chemistry which appear to have been overshadowed by his work on electrogravimetric analysis.For example, he studied the contamination of lead molybdate. He recommended various fusion mixtures for silicate analysis ; among these were potassium hydrogen fluoride and potassium hydrogen sulphate. He recognised that magnesium co-precipitates seriously on calcium oxalate. He studied the determina- tion of magnesium and phosphate as the magnesium ammonium phosphate precipitate and preferred microcosmic salt as the precipitant.He studied extensively the basic acetate separation. He worked out a method for the determination of manganese in which the final weighing form was manganese pyrophosphate. He investigated methods for the separation of platinum metals, rare earth metals and many others.Gibbs also devised a special filter. It is interesting to note that in a text-book published in 19138 Gibbs has 26 references, J. Lawrence Smith has 10 and Chandler only has two. There are no references to Booth or any of his predecessors.* Gibbs was the first to describe electrogravimetric methods of analysis. He also studied the composition of ammonium molybdophosphate. Gooch has 33.Fig. 2. Woolcott Gibbs (1822-1908). Charles Frederick Chandler In my Bicentennial Lecture at the Pittsburg Conference1 I described Chandler’s early life I stated then that it appeared that Chandler * A. A. Blair, the author of that excellent book “Chemical Analysis of Iron,” first published in 1888, So obviously he was one of the heirs of It may be noted that Pregl based his gravimetric micro-method for phosphorus Blair, however, states that he got it from a Mr.Wood, who and his training under Woehler in Germany. used the address, “Laboratory of Booth, Garrett and Blair.” Booth’s Laboratory. in organic compounds on “Blair’s Method.” in turn got i t from a “Mr. J. H. Nichols of the Homestead Works.”166 HISTORY OF ANALYTICAL CHEMISTRY proc. AnaZyt. Dzv.Chem. soc. was the first Professor of Analytical Chemistry in the world (1859) and so far nobody has contradicted me. Chandler probably had more influence on American chemistry in general than any other American chemist during the last half of the 19th ~ e n t u r y . ~ He learned his analytical chemistry as private assistant to Professor Heinrich Rose. He had the oppor- tunity to study with some of the greatest scientific minds of the age, but it was from Heinrich Magnus that Chandler learned the art of the experimental lecture, of which he became one of the greatest exponents.His former mentor C. A. Joy appointed him as janitor at Union College, but he was able to serve as Joy’s assistant simultaneously. When Joy resigned, Chandler was appointed Assistant Professor and to the full Professorship in 1859.Chandler was a man of tremendous energy. He was not only a superb teacher but he never missed an opportunity to emphasise the importance of chemistry in all branches of everyday life, e.g., public health, agriculture, trade and industry. He organised a chemical society a t Union College, the membership of which was open not only to students but also to those in industry and, indeed, to anyone who was interested.The opening meeting of 1861 was addressed by Professor Charles Joy. He discussed the rise of organic chemistry, spectral methods of analysis and other topical subjects. A later lecturer was a Professor H. Townsend, who lectured on “Spectral Analysis.” Some of the papers were published in various journals, including the London Chemical News and The Scientz9c American.Un- fortunately, this society disappeared after Chandler left Union College to take up an appointment at The School of Mines, Columbia College. The Trustees of Columbia College had been reluctant to sponsor this new Department. Chandler, however, had the vision to foresee the great possibilities arising from the chaos of the Civil War. He stated, “A nation can only be great if its industry is great.Its industry can be great only if it is built on a sound technical base in which chemistry is one of the main foundation stones. I want to help build that foundation.” Chandler put all his efforts into his work and soon began to gain fame for the College. His reputation as an assayer spread rapidly.In 1868 he devised a new system of assay weights known thereafter as the assay ton weight, which simplified and revolutionised the method of evaluating the noble-metal content of ores, bullions, slags, etc. The New York College of Pharmacy, which was in financial straits, asked Chandler if he would lecture on chemistry one night each week. There would be no salary, but he would have an allowance of $400 for experimental apparatus and lecture materials.Chandler thought it over and then decided it was his duty to see that pharmacists had a thorough education for “the people’s lives are in their hands.” He put new life into the College of Pharmacy in his characteristic fashion. Chandler made contributions to public health and his study of lead in city water supplies and its physiological effects is a classic.He also showed the great possibilities of applying chemical knowledge in industry. In 1870 Chandler and his brother founded a journal, The American Chemist. Unfortunately, although successful in its objectives it was a financial failure. After 5 years of struggling they decided that if it survived it must have the editorial and financial support of a great number of chemists. It was this that led eventually to the formation of the American Chemical Society.The first proceedings of the new Society were published in The American Chemist. This arrangement continued for 2 years, when the journal was suspended to make way for the Journal of the American Chemical Society, which appeared in 1879.Chandler made many contributions in industry and his work covered water supplies, foods, coal and water gas, sugars, metallurgy, paints, lubricants, etc. To solve the many problems that confronted him he developed new analytical methods and new experimental apparatus. Among these may be mentioned the assay ton weights, a universal flash-point apparatus, the Chandler photometer, the Chandler-Baum6 hydrometer scale, a sludge-metering device and a flow meter.Always ready to provide knowledge from his great experience, Chandler was exceptionally generous to young people. Often he worked without payment. His whole life and career are an object lesson to us in this more materialistic age. Chandler must have been one of the most versatile chemists of all time. He was a first-class teacher and lecturer, an outstanding research worker and he made contributions in many different areas of applied chemistry.A t the age of 19, in 1856, he returned to America. They are still used in assay laboratories.J d y , 1977 HISTORY OF ANALYTICAL CHEMISTRY 167 He was a brilliant organiser and was not only the driving force behind the foundation of the American Chemical Society but also of the Chemists Club, which still exists in New York.Conclusion Notable contributions to analytical chemistry were made by many other American chemists during the last century. For example, the work of Wormley a t the University of Pennsylvania on the microchemistry of poisons, P. T. Austen (Rutgers University), who is credited with the discovery of ash-free filter-papers,* and H.C. Jones (University of Balti- more) who devised the Jones Reductor. The great contributions of S. A. Gooch (Yale University) in all fields of classical analysis were of outstanding importance during the latter part of the last and early part of the present century. His famous crucible was still in use in the years prior to the 2nd World War.I have referred to other distinguished American analytical chemists of the last century and of the present century in my Bicentennial Lecture, but I consider that one of the most notable contributions is that of Alter, a Pennsylvanian physician, which was published in 1854. Alterlo?l1 states, “The spectrum emitted by an element differs from all others in its number of bands, intensity, and position, so that the element can be identified simply by observa- tion.. . . By the use of a prism it is possible that the elements of the stars and the earth can also be identified.” Alter determined the spectral lines of the individual elements in the visible region and published this in the form of tables. I have not been able to obtain Alter’s original paper, but it seems as though he showed that alloys can be identified by their spectral lines.A useful account, which covers the first quarter century, is to be found in the paper by Olsen.12 My main concern has been to cover the earlier periods in the history of American analytical chemistry, for details are much more difficult to track down. There is still a good deal of work to be done in this direction and I hope that my pioneering efforts will stimulate others in America, who are better placed than I am, to follow up some of the earlier papers published in the American Journal of Science and to examine some of the early American books on chemistry.I do not intend to refer to American analytical chemistry during the 20th century. There is still a great deal to be discovered.1 . 3. 4. 5. 6. 7. 8. 9. 10. 1 1 . 12. 3 I. References Bclcher, R., Analytica Chinz. Acta, 1976, 86, 1 ; Chemy Brit., 1976, 12, 387. SzabadvAry, F., “The History of Analytical Chemistry,’’ Pergamon Press, Oxford, 1966. Caccia, B., Gold Bull., 1976, 9, 91. Smith, E. F., “Chemistry in America,” Appleton, New York, 1914. Caldwell, G. C., J . Am. Chem. SOC., 1893, 14, 331.Stock, J. T., J . Chem. Educ., 1976, 53, 497. Van Iilooster, H. S., J . Cheun. Educ., 1956, 33, 493. Xellor, J . W., “A Treatise on Quantitative Inorganic Analysis,” Griffin, London, 1913. Hixson, A. W., J . Chem. Educ., 1955, 32, 499. A41tcr, D., Am. J . , 1854, 18, 55. Alter, D., Aun. J . , 1855, 19, 213. Olsen, J. C., J . Chewi. Educ., 1927, 4, 506. From Assaying to Analytical Chemistry: How an Art Became a Science F.Szabadvary Mzisritm f o r Science and Technology and the Technical University, Budapest, Hungary For many years the qualitative assaying of industrial and agricultural products was adequately performed only by the organs of sense and by practical experience, although for some special materials, e.g., gold, qualitative and quantitative analytical methods were available even centuries ago.The term “chemical analysis” was used first by Robert Boyle, but it came * I t appears that Fresenius made this discovery independently and one year earlier.168 HISTORY OF ANALYTICAL CHEMISTRY Proc. AnaZyt. Diu. Chem. SOC. into common use only in the 19th century, before which such knowledge was called “ars probandi” (art of assaying).In the 17th and 18th centuries qualitative and gravimetric methods were developed in order to obtain information mainly on minerals, ores and mineral waters. At the end of the 18th century titrimetric methods gained importance in the textile industry, where their purpose was the qualitative testing of textile ingredients. In titrimetry absolute values were not calculated, but rather arbitrary empirical values were determined.For a long period the gravimetric method involved the weighing of the reduced pure metal content of the compound, although Marggraf referred to the fact that the amount of silver can be calculated from silver chloride. Bergman summarised in a table the number of parts of a precipitate that correspond to 100 parts of each individual metal.The pioneer of stoicheiometric calculations and even of the word “stoicheiometry” was Jeremias Benjamin Richter in about 1790. He determined analytical equivalent weights, but inaccurately. However, the term equivalent weight was used firstly by Wollaston, who in 1814-1816 published the first book to include logarithmic analytical calculations and developed the first analytical slide-rule.Titrimetric standard solutions containing equivalent weights were sugges- ted by Andrew Ure for general usage in 1839, but they became widespread only after the intro- duction and extension of the meter system, chiefly owing to the work of Friedrich Mohr (1856). In the last century analytical chemistry was entirely a descriptive science, producing only formulae, while nothing was known of the reasons for the phenomena that occurred.Observations made in the field of electrochemistry, affinity and examination of solutions were gathered by Wilhelm Ostwald, who established a new and independent branch of science, physical chemistry, which became the common “grammar” of the different fields of chemistry. With this discipline he was the first to provide a theoretical explanation of several phenomena in analytical chemistry, e.g., formation of precipitates, indicator changes and end-point titrations, and he introduced the concepts of solubility product and dissociation constant.His fundamental book entitled “Die wissenschaftlichen Grundlagen der analytischen Chemie” was published in 1894, and only a year later it was reprinted in several other languages, including English and Hungarian.The discovery of the hydrogen electrode and potentio- metric titration contributed greatly to the further development of the theory of titrations. At the beginning of this century Szily, Friedenthal, Sorensen, Salm, Noyes and Bjerrum made outstanding contributions to the more detailed elaboration of the theory of acid - base titrations, while that of redox titrations is due mainly to Peters, Clark, Michaelis and Kolthoff. Although the analytical methods of absorption and emission spectroscopy had been used since the middle of the last century, their theoretical explanation was possible only after the theory of atomic structure had been elucidated.PAS of the Past Miss J.D. Peden Formerly Public Analyst for Somerset County Couutcil, Taunton, Somerset The need for our profession to be born was demonstrated by a German chemist called Frederick Accum, over 150 years ago. He acted as assistant to Sir Humphrey Davy, set up his own laboratory in Soh0 and published, in 1820, information about the state of the nation’s food. Lead in wine, vitriol in gin, chromates in confectionery and cyanides in custard were just some of the results of ignorant and fraudulent adulteration carried out at that time.It took 30 years to set up an Analytical Sanitary Committee, largely by the efforts of the Editor of The Lancet, and here the great name is that of Sir Arthur Hill Hassall, who practically was the Committee. The microscope was his chief tool and his books of drawings are now very valuable; his findings were published in The Lancet and did confirm many of the accusations.Chemistry was necessary when he examined coloured sweets, though. In 101 mixed bagfuls, for instance, he found 59 cases of colouring with lead chromate, 12 with red lead, 6 with mercuric sulphide, 11 with Prussian blue and 9 with copper arsenite. The Committee reported that adulteration was widespread and not only, therefore, was health in danger, but public morality was tainted and the commercial character of the nation was being lowered both at home and abroad.July, 19 7 7 HISTORY OF ANALYTICAL CHEMISTRY 169 All Public Analysts know that shortly afterwards came the first Act in the world for “Preventing the Adulteration of Articles of Food and Drink.” This Act permitted the appointment of Public Analysts, but did not insist, so very few came into being until the improved (but not perfect) Act of 1872.Somerset, for instance, ordered that “One First Class Analyst” be appointed, in 1874, and William Walter Stoddart, “a person professing competent Medical, Chemical and Microscopic knowledge,” was chosen, at a salary of El00 a year with E50 extra for “making and sustaining a suitable Laboratory.” Candidates were not numerous, for analysis had been confined to university and college staff, with a mere handful of private consultants, so local authorities often told their Medical Officers that they could easily take on this additional chore, although they had had no chemical train- ing as such.Dr. Letheby was one exception, being Medical Officer and qualified Public Analyst to the City of London as well as Lecturer on Medical Jurisprudence to the London Hospital. August 7th, 1874, is the historic date in this story, when 25 Public Analysts met at the City Terminus Hotel in Cannon Street, London. The prime movers were six men: Alfred Henry Allen, August Duprd, Charles Heisch, Theophilus Redwood, Thomas Stevenson and George Wigner.Seventy-seven men, who held 110 appointments between them, had been invited and the majority had expressed interest. The group had really met to explore the faults of the 1872 Act and to criticise them in detail, but the most important decision was to form an Association for “the purpose of mutual assistance and co-operation.” Dr.Redwood took the Chair and became the first President when the Society of Public L4nalysts was created. He was PA for Middlesex and Professor of Chemistry to the Pharma- ceutical Society. The main tasks, as they saw them, were: to define “adulteration”; to establish the normal composition of foods; to agree on food standards; to develop agreed methods of analysis; to consider the 1875 Act, then imminent; to educate members in the legal side of the work.A long and detailed definition of the word “adulteration” was finally agreed on and then, after all their efforts, the word was dropped from the title of the new Act, which was now the Sale of Food and Drugs Act. Nearly all existing PAS had joined the Society by December and regular meetings to present papers were being held in 1875.These were at first published in Chemical News, owned by Mr. (later Sir) William Crookes, but Council decided that the Society should publish its own journal, free to members and 3/6 a year to non-members, to be called simply The Analyst. The second President of the Society of Public Analysts, August Duprd, wrote the first paper in the first issue of The Analyst, in March 1876, on “The Examination of Whisky.” He was actually the Official Analyst of Explosives to the Home Office and examined many home-made bombs, then called “infernal machines,” during the Sinn Fein outrages of 1882.Other papers show the wide variety of subjects and the versatility of the Analysts. Duprd wrote on “Copper as a Normal Constituent of Plant and Animal Tissues,” Winter-Blyth on “The Poisons of the Cobra” and “The Albuminoids of Cheese,’’ Hehner on “The Excretion of Potassium Chlorate,” Allen on ‘:The Assay of Carbolic Powders,” and Wigner on “The Analysis of Cleopatra’s Needle.” G.W. Wigner of London was one of the younger members, then in his thirties, whose remarkable energies really started the Society.He ran a large commercial and consulting practice apart from his duties as PA. He was also Chemist to the Thames Conservancy and a competent chemical engineer, advising on the design of manufacturing plant. He was to die in 1883, at the age of 42, after a few months in office as President. Meanwhile, in 1877, the Society received international recognition when it was con- sulted by the German Government through their Commissioner, Dr. Rottenburgh.Germany was preparing to follow our lead in the way of food legislation; a list of 27 questions was submitted and duly answered in the second volume of The Analyst. Some of the early members were themselves German in origin, notably Otto Hehner, who had the distinction of serving on Council for 44 years (from 1880 to 1924, when he died of malaria in South Africa).He was one of Dr. Hassall’s assistants, to begin with, at his laboratory in Ventnor and later he became a partner in London. He published a large number of papers over the years. In those early days the grosser forms of food adulteration were still found on occasion and (Dr. Hassall was among those present.)170 HISTORY OF ANALYTICAL CHEMISTRY Proc.Analyt. Div. Chem. SOC. there were prosecutions for tea containing Prussian blue and china clay, for saltpetre in jam, chalk in milk and plaster in muffins, with oddities like mushroom ketchup made from pigs’ liver. PAS then tended to take a very idealistic stand; food should be as nature produced it and all additives were adulterants, but the real needs of large-scale manufacture caused them to modify those views, although the emphasis still is, and always will be, on food safety.It was Hehner who was then leading a crusade against the use of all “anti- septics,” as preservatives were then called. He quoted the results of tests on boric acid and formaldehyde, for instance, carried out on Public Analysts, young children and pigs, apparently in that order.Another member, Dr. Paul Vieth, was chemist to the Aylesbury Dairy Company before he went back to Germany in 1892 to be the Director of the State Research Institute. He kept in touch with the Society of Public Analysts until the First World War, which broke many ties. It sounds odd to read that he gave a paper to the London Farmers’ Club, flourishing in the 1880s.In 1884 there was an International Health Exhibition, and the Society was asked to provide an exhibit of unhealthy foodstuffs. They now had difficulty in finding the almost obsolete sweets yellow with lead chromate and cayenne pepper red with vermilion, but had no trouble in finding examples of pickles and peas “greened” with salts of copper, because this remained a legal practice until 1925. The Institute of Chemistry organised a 2-day Conference on Food Analysis and Professor Odling, the President of the Institute, declared “how largely the public was indebted to the labours of those many gentlemen who undertook so ably the office of Public Analyst.” “Labmrs” seems to be the right word, for it sometimes appears that the Analysts had to struggle against the magistrates as much as the offenders.For instance: a case against alum in flour was dismissed, as “aluminium might have come from another source, such as dirt or clay,” which presumably were acceptable; and a case against putrid shrimps was dismissed because the inspector had tasted them and survived. However, the publican who sold “British Brandy,” an artificial spirit, coloured and flavoured, when the real thing was called for, was convicted, although even he appealed on the grounds that, compared to French Srandy, his preparation was much more wholesome. Another test case was lost on the grounds that baking powder was not a food within the meaning of the 1875 Act.Analysts were also concerned for the safety of the public who used a wide range of other contaminated commodities, noting the frequent use, for instance, of copper arsenite to colour wallpaper, the backs of playing-cards and green candles.The President of the Society of Public Analysts in 1884 was Alfred Hill of Birmingham and he was followed by A. H. Allen of Sheffield and of Allen’s “Commercial Organic Analysis.” The next President was Matthew Algernon Adams of Kent, in 1889.He “enjoyed an extensive practice as a specialist in ophthalmic surgery, but loved his Laboratory better than his consulting-room.” The Society at that time had just under 200 members, 161 ordinary members, 26 associates and 10 honorary members, including Chevreul of Paris, Hofmann of Berlin and Fresenius of Wiesbaden. Allen had been in office when the Pure Beer Bill was introduced into Parliament, but this proved, alas, an abortive measure.Hehner protested that added water was no adulterant if beer was a nondescript article, and Analysts did a lot of work on the detection of hop substitutes, such as quassia. It is interesting to remember that the really Old English drink was ale, made from malt and water only, and there was severe criticism in the 15th century of those who added “an unwholesome sort of Weed, called a Hopp.” Thanks largely to the efforts of PAS, it was fairly safe to eat most foodstuffs by this time, and even medicines had advanced a little from the hey-day of the patent proprietary remedies.There were, for instance, Morrison’s Universal Pills, two to be taken at bedtime in a glass of lemonade for the prevention of insanity and old age, and Parr’s Life Pills, which were stated to cure both constipation and diarrhoea.Such products were being checked, in every sense of the word, a century ago, although PAS did not always succeed in the Courts. So prosecutions failed for: Castor Oil Pills with no castor oil (plea of “trade practice”) ; Paregoric with no opium (claimed to be sold as a substitute) ; Arsenical Soap with no arsenic (the bench held that arsenical soap would have been a drug, as stated, but soap free from arsenic was not a drug-case dismissed). He made history by being the first effective PA to be appointed under the original Act of 1860, One of the great characters in the Society was Charles Alexander Cameron of Dublin.July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 171 when he was only 30 years old. He was Medical Officer of Dublin and became Sir Charles Cameron for “improving the dwellings of the working-classes” ; he was Professor of Chemistry to the Royal College of Surgeons, the chief authority on agriculture and PA for the greater part of Ireland. He became President in 1893 and was a wonderful host for Meetings in Dublin, being a famous after-dinner speaker; he died in 1921, aged 90. It was in his Presidential year that the Institute of Chemistry set up its examination system for the purpose of qualifying chemists, and the famous “Branch E” for Public Analysts started 3 years later, although not officially recognised by the Local Government Board until 1900. The earlier Dinners sound very jolly affairs, with everyone taking part in the entertain- ment. Muter played the piano, Sykes played the fiddle and Hehner and Vieth sang German songs. James Baynes from Hull told anecdotes, Heisch gave humorous recitations and the President provided champagne. Another famous and versatile member was John Newlands of the Law of Octaves, who first postulated the periodic nature of the elements in 1863, before Mendeleef published his Table. He had served as a soldier in Italy, under Garibaldi, and was equally known as chemist, philosopher and poet. And so I must end this appraisal of the pioneering work of the PAS of the past, but not without a tribute to those who are the PAS of the present. Cameron also presided over the first formal Dinner of the Society.

ISSN:0306-1396    

DOI:10.1039/AD9771400161

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 171 Irish Contributions to Analytical Chemistry D. Thorburn Burns Department of Analytical Chemistry, The Queen’s University of Belfast, Belfast, B T 9 5AG I t is necessary to define the terms Irish chemist and Irish chemistry. The first Royal Charter of the Institute of Chemistry of Great Britain and Ireland refers to the profession as “Analytical and Consulting Chemistry.”l The charter of 1949 re-defined chemistry and chemist in wider terms.This expression raises problems of multi- nationality as many chemists worked abroad. The Irish origin of one of the most famous, Robert Boyle, is often overlooked.2 Irish could also quite reasonably refer to work carried out in Ireland. Both classes were included by Desmund O’Raghallaigh3 and by Partingt~n.~ The second problem is how to select from the many.O’Raghallaigh3 cites 60 Irish chemists of note, many of whom made contributions to analytical chemistry. Examples from both classes of Irish chemist have been selected on the basis of their contri- butions, interest as people, connections with Institutions and with the Institute1 of Chemistry. The history of the departments of chemistry of Irish universities, except Galway, was described in the Journal of the Royal Institute of Chemistry series on “Schools of Chemistry of Great Britain and Ireland.”5-9 The first was the Royal Dublin Society,lo9l1 founded in 1751.From 1815 until 1922 its headquarters was Leinster House, now the seat of the Irish Parliament. For a long time the Society maintained laboratories and was active in research but of late it has been more concerned with agriculture.However, it has recently appointed a full-time Science Officer. The Society has the distinction of founding the first modern chair of chemistry, held by William Higgins from 1796 to 1825.12 Earlier chemistry chairs were associated with medicine or pharmacy. Their scientific work dates back to 1792 when, through the influence of Richard Kirwan, the Dublin Society purchased the Leskean collection of minerals.The Royal Irish Academy,13 founded in 1786, is the equivalent of the Royal Societies of London and Edinburgh. Irish could mean Irish by birth or by lineage. Two societies were particularly important in the development of Irish science. One of its early Presidents was Richard Kirwan.Richard Kirwan (1733-1813) Kirwan belongs to the period when the foundations of stoicheiometry were laid. Partington4 Kirwan has been classified ranks him with Proust and Klaproth, at least in space devoted.172 HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Div. Ckem. SOC. as a forgotten chemist,14 although several biographies have been ~rittenl5-~2; the most important is by Donovan.17 Kirwan is descended from one of the 14 tribes of Galway.The Kirwans spread over Europe and from the Bordeaux branch we get Chateau Kirwan, a non-chemical, chemical claret. He was born at Cloughballymore, the seat of his maternal grandfather, but was brought up at Creggs Castle. Being a second son he was by tradition destined for a profession, in his case that of a clergyman of the Church of Rome.His early education was completed at Poitiers where he specialised in languages but continued his early interest in chemistry. His elder brother was killed in a coffee-house duel and Richard returned to Ireland and an inheritance of 43 000 a year. He was feted by all and sundry, including the tribes of Galway.The Dowager Lady Blake at whose house he was a frequent visitor gave a birthday party for her daughter, Anne. A well timed whisper before supper, “She has 44 000 of her own you know,” plus the best of wine had its effect. He knew about the wine from the state of his head next morning. Later that day Lady Blake and her brother called and congratu- lated him on his engagement, also telling him that they did not believe in long engagements. The marriage duly took place and a day later Kirwan was in prison for his wife’s debts.The litigation to recover his wife’s fortune continued after Kirwan’s death. In spite of the trick, it is said, Richard lived happily with his wife at Menlow, his mother-in-law’s residence, where he worked steadily at chemistry. Lady Blake disapproved of the smells and time spent on research and indicated that he should take up a more suitable pursuit for a gentleman, such as law. He studied law in London from 1761 and was called to the Irish Bar in 1766. During his law studies his wife died at Menlow, leaving a distressed Richard and two daughters.He returned to science in 1769, spending that year and the period 1777-79 in London.The latter were fertile years in his research. In 1780 he was elected to the Royal Society and he was awarded the Copley medal in 1782. Kirwan regularly attended the Sunday evening Conversaziones held by Sir Joseph Banks, President of the Royal Society. Their correspondence is preserved in “The Banks Papers”2*. The Kirwan letters are not authentic, being described as Dawson Turner copies.The Royal Irish Academy has a small laboratory notebook considered to be in Kirwan’s hand, which deals with experiments on hepatic air.25 Upon return to Dublin he was very active in Irish science and technology and was in 1799 elected President of the Royal Irish Academy. Despite family wishes his funeral was immense18; 900 or so attended, including members of the Kirwanian Society founded in his honour, but which regrettably disappeared in 1818.12926 There is plenty of documentary evidence to show that Kirwan was well regarded by contem- porary chemists.He was a member of almost every learned society in Europe and he publish- ed over 60 papers and also numerous books, which were translated into many languages. His books were cited at the time and also since as standard works in their areas.Madsen has drawn attention to his innovation in the determination of iron with ferr~cyanide.~’ The result was absolute, the titrand being standardised against the substance to be titrated and reported as the element. His “Elements of Mineralogy”28 was the first systematic work on the subject in the English language and contains much of analytical interest.“An Essay on the Analysis of Mineral is an excellent account of qualitative and quantitative analysis of the period. Kirwan was a phlogistonist and his defence30 was translated into French by Mme Lavoisier.* Later he was converted by a fellow countryman, William Higgins, who in addition to disposing of the phlogiston theory made notable contributions to bonding and mechanistic theories which, in some ways, pre-dated Dalton.12 Kinvan’s contributions to meteorology, via weather-pattern recognition, are only now being fully appreciated.22 It was said that he was consulted by half the farmers in Ireland. His library was in transit from Galway to London when it was captured by an American privateer.The books were sold in Salem, where they are to this day.l2?l7 To give them due credit the purchasers, a philosophical group, offered to pay Kirwan but he declined payment and said that he was pleased that the books were put to good use.The Kirwan family was featured by Cam, the Aer Lingus in-flight magazine.23 Richard was the second son of Martin Kirwan. In 1754 he went to Paris to enter the Jesuit noviciate.Kirwan lived at 11, Newman Street, off Oxford Street. He died starving a cold. He had an involuntary association with American science. His second library was left to the Academy.July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 173 Late in life he was eccentric. Numerous anecdotes are recorded, and he published some dubious philosophical material, e.g., “An Essay on Human Happine~s.”~~ Charles Alexander Cameron (1830-1921) He was born in Dublin where he received his training in medicine and held numerous teaching posts in the Dublin Medical Schools.The first Food and Drugs Act in 1860 established the permissive post of Public Analyst. Dublin was one of the few authorities to use the Act and appointed Cameron in 1862 to a post he held for 59 years.It was only the third appoint- ment in Great Britain and Ireland. Subsequent to the 1870 Act, Cameron was chosen by 33 counties and boroughs and was humorously referred to as the Public Analyst for Ireland. In the early days of the Society of Public Analysts he contributed a number of papers to The Analyst on the analysis of milk, water and f0ods.3~ The last paper, in 1896, was on “ammunition bread.”35 He served on Council in 1878-81, was Vice-president in 1882-83 and 1889-90 and finally the tenth President in 1893-94.s6 He was also Vice-president of the Institute of Chemistry from 1884 to 18901 and was knighted in 1885 for his services to public health and housing reform.His obituary32 concludes “that not the least of his achievements was in the retention of his full mental faculties and physical working powers beyond his 90th year.” Charles Alexander C a m e r ~ n ~ ~ ~ ~ ~ was the son of Captain Ewen Cameron of Locharber.James Emerson Reynolds (1844-1920) Reynolds, born in Booterstown, was intended for the medical profession, qualified in Edinburgh in 1865 but only practised until his father’s He then devoted himself to chemistry, in which he had never attended a systematic course of instruction in either the theoretical or practical aspects.Even before graduation his inclination to chemistry was marked; his first publication appeared in 186138 when he was 17. Prior to qualification he was lecturer in practical chemistry in the Ledwich School of Medicine and Surgery, Dublin. He was inspired by the lectures of Roscoe and Huggins to the Royal Dublin Society and published his first paper on spectrum analysis in 1864.39 Reynolds was appointed Keeper of the Minerals40 in 1867, a post which gave him access to a fairly well equipped laboratory. In turn he became Analyst to the Society41 and in 1871 received the title Professor of Analytical Chemistry.42 Among his publications are those on detection of methyl analysis of super phosphate^^^ and analysis of fertiliser materials.40 He was also concerned with medicinal chemistry, hygiene and In 1875 he was elected to the Chair of Chemistry at Trinity College, Dublin.He thendevot- ed himself almost exclusively to the duties of the Chair and to organic research. He was the first in these Islands to introduce quantitative work into the early training of chemists.His most important organic contribution was his synthesis of thiourea at the Royal Dublin Society,46 which was followed up at Trinity by preparation of derivatives and congeners. He retired in 1903 to London, continuing his work in the laboratories of the Royal Institu- tion. His last paper was “On the Synthesis of a Silicalcyanide and of a Feld~par.”4~ His obituary elegantly puts it,37 “The Keeper of the Minerals of 1867 was, up to the last, faithful to the conceptions which had dominated nearly half a century’s intellectual activity.” Emerson Reynolds was also active professionally. He was elected to the Royal Society in 1880 and was Vice-president in 1901-02. He was a member of the Third Organisation Committee, a member of the first Council of the Institute of Chemistry and Vice-president in 1882-84 and 1892-95.l In the Chemical Society he was three times Vice-president and was President in 1901; it was said he travelled 16 000 miles to fulfil the duties of this office.37 Walter Noel Hartley (1846-1913) His father was a portrait painter and several of his pictures He was educated privately and in 1863 went to study medicine in He took first-year chemistry classes under Lyon Playfair, whose laboratory he Hartley was born in Lichfield.are in the York Museum.48 Edinburgh.174 HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Din. Chem. SOC. attended. Here he made the acquaintance of a Dr. Arthur Gamgee who advised him to devote himself entirely to chemistry.In later life he often expressed gratitude for Gamgee’s advice and interest in his early studies. In 1864 Hartley went to Heidelberg with the intention of working in Bunsen’s laboratory; every place was occupied and Bunsen sent him to Kolbe at Marburg. After returning to England he filled several posts, including one with Dr. Thudicum. In 1871 he became Senior Demonstrator at King’s College, London, where he started his spectroscopic studies using apparatus left from earlier work by Miller.Hartley was the first to use dry plate photographs for spectra. In 1879 he took up the Chair of Chemistry at the Royal College of Science, Dublin. Hartley acknowledged previous work in an exemplary manner in his major papers of 188449 but was the first to make a systematic study of spectra for quantitative purposes and achieved quantitative results for the determination of beryllium in cerium compounds and of magnesium and calcium in limestone.He observed that the strongest lines were not necessarily the most persistent as the concentration of an element was reduced. Lines were arranged in the order of their disappearance, which was correlated with line length, concentration and exposure time.Hartley worked almost entirely with solutions and a condensed spark. The electrodes were graphite, wedge shaped in line with the slit and kept moist by capillary action. The spark gap was adjusted by using a plate of glass. The work on a white sou5O in 1896, given to him by Professor O’Reilly, Foreign Secretary of the Royal Irish Academy, was an early example of forensic spectroscopy.Matching standards were also used to eliminate matrix effects. Similar work was carried on by Hartley was also well known for his contributions to molecular spectroscopy. and Leonard52s54,55 up to 1920. Semi- quantitative work was possible by determining the concentrations required to give a minimal image. The work was difficult and tedious but the relation of structure and spectra was studied.Kayser wrote that “Hartley had contributed more than all the other workers to the study . ’ ’ 56,57 From the Royal Institute of Chemistry Centenary viewpoint he is important as he was Secretary to the organising committees in 1875-77. He was Vice-president twice and Dublin examiner for over 10 years1 Albert Edmund Letts (1852-1918) Letts58,59 was contemporary with Emerson Reynolds.Whereas Reynolds moved from analytical to organic chemistry Letts made the reverse transition. He is one of the more underestimated of the chemists who practised in Ireland. Letts obtained his first degree at King’s College and afterwards studied in Vienna and Berlin. In 1872 he became chief assistant to Crum Brown in Edinburgh. Four years later he was appointed the first Pro- fessor of Chemistry at University College, Bristol.In 1879 he was elected to succeed Thomas Andrews in Queen’s College, Belfast, a post he held till 1917. On Andrews’ advice he was chosen from a short list containing William Ramsey and W. A. Tilden. A retrospective views suggests that Ramsey might have been the better choice and would have allowed a continuance of Andrews’ work on gases.This is unfair. Letts arrived with an excellent pedigree as indicated in the citation for the Royal Society of Edinburgh, Keith Prize, 1887-89,60 for his research into organic compounds of phosphorus and sulphur.61-64 It was stated “the work was difficult, well carried out and of great interest.” It notes that he overcame the difficult analytical problem of determining the phosphorus contents.Letts gave up organic chemistry and studied the determination of atmospheric carbon dioxide in considerable depth up to 1902,65-6s the first paperC5 being 163 pages and 3 plates in length. This was followed by pollution studies,69-g3 the determination of nitrate, e t ~ . ~ ~ - Letts’ analytical interest was so strong that students ran the risk of being starved of practical work, as Letts was inclined to take over and complete the job himself.His text on qualita- tive analysis,s7 in two editions, was in use up to the 1930s. The series of papers on sewage pollution show a tenacity of purpose that we are told was characteristic. Letts was concerned with the enhanced growth of the seaweed Ulva Zatis~irna,6~-~~ which caused problems after it was washed ashore.Banks of weed, feet thick,July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 175 extended for several miles in Belfast Lough and also in Dublin Bay. The Ulva decomposed in warm weather and the stench was overpowering. Over a period of years various para- meters were studied and appropriate analytical methods devi~ed.75-~~ Several items were deemed of sufficient interest to be reported in full in Chemical News.The Ulva started to colonise the filter beds and may well have got to the City Hall but for Letts’ work and advice in the design of a new sewage system.81,82 Letts was recognised as an authority on the pollution of rivers, estuaries and tidal waters and with Adney made an extensive study of the Ulva problem.74 With Richardson he made a similar detailed study of muds and sludges.83 His last four papers were with Florence Rea on nitrate determination~~~-~6 and the chemistry of foul mud deposits.88 His was a good record of scientific endeavour and he made an excellent contribution in applied science and its application to environmental improvement.Letts was also con- cerned with College and University matters,sg including the raising of funds for the new departmental building, for which he had built up the need. The building was started in 1891, built and occupied in stages, and completed in 1907. This building has since been demolished. Stewart58 records that he was one of that rare species, “a fine old English gentleman.” He died just after retirement following a bicycle crash on the Isle of Wight.Cecil Leeburn Wilson (1912-74) Cecil Wil~on~O-~~ graduated from Queen’s in 1932 and obtained his MSc in 1933. He was Clerk and later President of the Chemical Society of Ulster, as was D. W. Wilson, the Divisional President, a few years later. A Musgrave scholarship took him to Glasgow where he acquired what was a lifelong interest, a love of microchemical methods. Upon return to Queen’s he gave the first course in the UK in general inorganic micro~hemistry.~~ His first book was “An Introduction to Microchemical Methods.”s4 Later, with R.Belcher, he wrote “Qualitative Inorganic Microanalysis,” which appeared in two editions.s5 Several other books appeared; with his brother D.W. Wilson he started the ongoing major series “Comprehensive Analytical Chemistry.’’ During the war he was seconded from Sir John Cass College to armament research. He used to recall how much he valued his microchemical skills while analysing detonators. His later forensic interests were in the less hazardous area of documents. They were founder members, with others, of the oldest specialist group of the Society for Analytical Chemistry, the Micro- chemical Methods Gro~p.~6 Queen’s University is almost unique in the UK for its current acceptance and regard for analytical chemistry.Cecil Wilson’s was the first personal chair of the subject, in 1958, and it was established in 1963 as the Inorganic and Analytical Chemistry Chair. This Chair was split in 1968 into two established chairs; he retained the Analytical Chemistry Chair until his untimely death.He was the first Editor of Talanta in 1958-64. 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J., Studies, 1954, 43, 441. Madsen, E. R., “The Development of Titrimetric Analysis till 1806,’’ G.E.C. Gad Publishers, Kinvan, R., “Elements of Mineralogy,” P. Elmsly, London, 1784.Kinvan, R., “An Essay on the Analysis of Mineral Waters,” D. Bremner, London, 1799. Kirwan, R., “An Essay on Phlogiston and the Constitution of Acids,” P. Elmsly, London, 1787. Kirwan, R., “An Essay on Human Happiness,” printed by Graisberry and Campbell, Dublin, 1810. Dyer, B., Analyst, 1921, 46, 175. h o n , J. Proc. Inst. Chem. Gt BY., 1921, 160. Cameron, C.A,, Analyst, 1876-7, 1, 95, 99; 1878, 3, 337, 338; 1879, 4, 11, 49; 1880, 5, 144; 1881) Cameron, C. A., Analyst, 1896, 21, 255. Chirnside, R. C., and Hamence, J. H., “The Practising Chemists,” Society for Analytical Chemistry, Thorpe, T. E., J . Chem. SOC., 1920, 117, 1633. Reynolds, J. E., Chem. News, Lond., 1861, 3, 141. Reynolds, J. E., J l R. Dubl. SOC., 1864, 4, 218. Reynolds, J.E., J l R. Dubl. SOC., 1870, 5, 180. Reynolds, J. E., J l R. Dubl. SOC., 1875, 6, 84. Reynolds, J. E., J l R. Dubl. Soc., 1875, 6, 359. Reynolds, J. E., J l R. Dubl. SOC., 1863, 4, 126. Reynolds, J. E., J l R. Dubl. SOG., 1875, 6, 359. Reynolds, J. E., J l R. Dubl. SOC., 1878, 7, 23. Reynolds, J. E., J . Chem. SOC., 1869, 7, 1. Reynolds, J. E., Proc. R. SOC., 1913, 87, 13. J.Y.B., J.Chem. SOC., 1913, 1207. Hartley, W. N., Phil. Trans. R. SOC., 1884, 175, 49, 325. Hartley, W. N., J . Chem. SOC., 1896, 69, 842. Pollok, J. H., Scient. Proc. R. Dubl. Soc., 1907, 11, 184. Pollok, J. H.. and Leonard, A. G. G., Scient. Proc. R. Dubl. SOC., 1907, 11, 217, 229, 257. Pollock, J. H., Scient. Proc. R. Dubl. Soc., 1909, 11, 331, 338. Leonard, A. G. G., Scient. Proc.R. Dubl. SOC., 1908, 11, 270. Leonard, A. G. G., and Whelan, P., Scient. Proc. R. Dubl. SOG., 1918, 15, 274. Kayser, H., “Handbuch der Spectroscopie,” Volume 3, Herzel, Leipzig, 1905. Lothian, G. F., “Absorption Spectrophotometry,” Hilger and Watts, London, 1949. Stewart, A. W., J . Chem. SOC., 1918, 113, 314. Letts, E. A., Proc. R. SOC. Edinb., 1912-1919, 39, 14. Brown, A. C., Proc.R. SOC. Edinb., 1889-1890, 17, 418. Brown, A. C., and Letts, E. A., Trans. R. SOC. Edinb., 1879, 28, 571. Letts, E. A., Trans. R. SOC. Edinb., 1879, 28, 583, 591, 601, 607, 612, 618. Letts, E. A., and Collie, N., Trans. R. SOC. Edinb., 1881, 30, 181. Letts, E. A., Trans. R. SOC. Edinb., 1881, 30, 285. Letts, E. A., and Blake, R. F., Scient. Proc. R. Dubl. SOC., 1900, 9, 107.Letts, E. A,, and Blake, R. F., Chem. News, 1900, 82, 149. Letts, E. A., and Blake, R. F., Brit. Ass. Advn. Sci. Rep., 1900, 693. Letts, E. A., and Blake, R. F., Scient. Proc. R. Dubl. Soc., 1901, 9, 436. Letts, E. A., and Hawthorne, J., Brit. Ass. Advn. Sci. Rep., 1900, 935. Letts, E. A., and Hawthorne, J., Chem. News, 1900, 82, 164. Letts, E. A., and Hawthorne, J., Proc. R. SOC.Edinb., 1900-1901, 23, 268. Letts, E. A., and Hawthorne, J., Brit. Ass. Advn. Sci. Rep., 1901, 831. Letts, E. A., and Totton, J. S., Brit. Ass. Advn. Sci. Rep., 1903, 851. Letts, E. A., and Adney, W. E., “5th Report of the Royal Commission on Sewage Disposal,” HM Letts, E. A., and Blake, R. F., Brit. Ass. Advn. Sci. Rep., 1900, 708. Letts, E. A., and Blake, R. F., Chem. News, 1900, 82, 163.Letts, E. A., and Blake, R. F., Scient. Proc. R. Dubl. SOG., 1901, 9, 454. Letts, E. A., and Blake, R. F., Brit. Ass. Advn. Sci. Rep., 1901, 601. Letts, E. A., and Blake, R. F., Brit. Ass. Advn. Sci. Rep., 1903, 606. Letts, E. A., Blake, R. F., Caldwell, W., and Hawthorne, J., Scient. Proc. R. Dubl. SOG., 1909, 9, Letts, E. A., “Final Report on the Scheme for Sewage Purification for Belfast and its Probable Copenhagen, 1958.6, 75; 1885, 10, 175; 1887, 12, 32; 1896, 20, 111. London, 1974. Stationery Office, London, 1908, Appendix VI. 333. Effect on the Lough,” Baird, Belfast, 1908.July, 1977 HISTORY O F AKALYTICAL CHEMISTRY 177 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. Letts, E. A., “Remarks on Recommendations of the Health Commission Regarding the Treatment of Belfast Sewage,” Baird, Belfast, 1908.Letts, E. A., and Richards, E. H., “7th Report of the Royal Commission on Sewage Disposal,” HM Stationery Office, London, 191 1, Appendix 111. Letts, E. A., and Rea, F. W., Analyst, 1914, 39, 350. Letts, E. A., and Rea, F. W., J . Chern. Soc., 1914, 105, 1157. Letts, E. A., and Rea, F. W., Proc. R.SOC. Edinb., 1915, 35, 168. Letts, E. A., “Quantitative Analysis Tables and Reactions of Certain Organic Substances,” Mayne and Boyd, Belfast, First Edition, 1892; Second Edition, 1905. Letts, E. A., and Rea, F. W., Scient. Proc. R. Dubl. SOC., 1917, 15, 171. Moody, T. W., and Reckett, J. C., “Queen’s Belfast, 1845-1949,” Faber and Faber. London, 1959. Svehla, G., Talanta, 1972, 19(5), 111.Belcher, R., Talanta, 1974, 21(5), I . Leonard, M. A., Proc. SOC. Analyt. Chern., 1974, 11, 185. Mackle, H., Chemy Brit., 1974, 10, 305. Wilson, C. L., “An Introduction to Microchemical Methods,” Methuen, London, 1938. Belcher, R., and Wilson, C. L., “Qualitative Inorganic Microanalysis,” Longmans, Green and CO., PYOC. SOC. Analyt. Chem., 1972, 9, 1. London, 1946, Second Edition.1958. Some Early British Contributions to Atomic Spectroscopy (1 672-1 835) T. S. West The 1Wacaulay Institute for Soil Research, Craigiebuckler, A berdeen, A B9 2Q J Sir Isaac Newton, experimenting with the production of colours by passing sunlight through a prism in a darkened room, noted in 1672 that a rectangular image of the hole in the room’s shutter was produced on the opposite wall of the room instead of the circular image he had expected.Within the elongated image, the colours of the rainbow were disposed from red to violet. This set Newton to thinking of the nature of light and laid the foundations upon which all spectroscopy has subsequently been built. Newton also resynthesised the original white light spot by viewing the dispersed colours in the rectangular image through another prism and showed that the colours could not be dispersed further by passage through a further prism.Unfortunately, Newton was a firm believer in the corpuscular theory of light and his followers rigidly adopted his beliefs so that the progress that could have been made by adopting Grimaldi’s wave theory was long delayed. Thomas Melvill (1726-53) of Glasgow discussed his experiments on light before a Society meeting in Edinburgh on January 3rd and February 7th, 1752.After discussing problems associated with the passage of light in straight lines through a sea of light beams without mutual interference, on the basis of the Newton - Democritus theory, he calculated the probable diameter of the corpuscles, discussed the heating effect of light beams and studied the colours of bodies in different coloured lights produced by burning mixtures of spirits and salts.He reported an exciting experiment in which he re-performed Newton’s experiment, but with the light from a salted flame. He wrote of how the bright yellow light was unique in producing a sharp image and he concluded that it was of one single degree of refrangibility, i.e., monochromatic.Unfortunately, like Newton, he also used a circular hole to mask the prism. There is every reason to suppose that his intuition could have led to a series of significant experi- ments. Melvill’s papers were published posthumously in “Essays and Observations- Physical and Literary,” in 1756. William Herschel (1738-1822) was born in Hanover, a possession of George 11, and came to England in his teens.He was a gifted teacher of music, tutoring up to 35 pupils a week in the city of Bath. Music led him to mathematics and mathematics led him to Newton’s works on optics. He and his sister Caroline ground the finest lenses in Europe and built telescopes. In spectroscopy (1800) Herschel discovered the infrared region of the spectrum by experimenting with a blackened thermometer bulb in the various parts of the prism-dispersed spectrum.In 1801, Ritter in Germany similarly discovered the ultraviolet region by experimenting with silver salts. Thomas Young (1773-1829), an infant prodigy who could read fluently a t the age of two He died the following year so that no further experiments were done.He discovered the first new planet recorded in historical times-Uranus.178 HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Div. Chem. soc. and who had read the Bible twice through by age four, graduated at Edinburgh and specialised in medicine. He discovered (1801) how the eye could focus on objects at different distances and was a protagonist of Grimaldi’s wave theory (ca.1663). On November 12th, 1801, he demonstrated the diffraction of light with a 500 line in-l grating before The Royal Society and, producing a spectrum, he calculated the wavelengths of Newton’s primary colours. His calculations look surprisingly good even today. Young’s influence on others was profound. William Hyde Wollaston (1766-1828) graduated as a medical doctor, perfected a tech- nique of shaping platinum ware, discovered and named palladium and rhodium in 1804, invented the concept of the “chemical equivalent weight” and introduced Michael Faraday to electromagnetism.He repeated Newton’s experiments using a slit instead of a circular hole and at a meeting of The Royal Society on June 24th, 1802, he showed that the spectrum was not a continuous gradation of colours, but consisted of sharp bands of definite colours which he described as red, yellowish green, blue and violet.He also recorded the appearance of black lines in the solar spectrum as seen through a slit and a prism. He did not of course realise the significance of the dark lines, but neither did Fraunhofer when he discovered many more in 1817. He also repeated Melvill’s experiment on candle flames and observed the yellow line but could not account for it.Wollaston seems not to have recognised the true significance of the use of a slit and the appearance of lines instead of continuous colour bands. He had one or two blind spots, such as the suppression of Hatchett’s discovery of niobium in 1809. He also exerted a decisive influence as a Royal Commissioner in 1839 against Britain adopting a decimal system of weights and measures.This influence may even now only be dispersed with difficulty. Nevertheless, Wollaston was a first-class experimenter and observer, even if his interpretation and deductions were somewhat less satisfactory on occasions. J. F. Herschel (1792-1871) was an astronomer like his father and made many contributions to his science.In spectroscopy he was the first to photograph the solar spectrum using Talbot’s new technique of photography. He coined the words “hypo,” “photographic negative” and “positive.” He used salted flames to produce monochromatic light, but the significance of slits, although he used them, and the sodium D lines, which he saw, escaped him.His contributions to spectrography, made between 1820 and 1840 were, however, very significant. William Henry Fox-Talbot (1800-77) ranks with Daguerre as the father of photography and his well known contributions to photography need not be reported here. In spectro- scopy he studied salted flames using cotton wicks dipped in spirits. He was able to produce flames free from yellow lines in their spectra, but noted that a wick that had been passed through the fingers showed the yellow lines for about 1 min.He noted that some red lines had a “definite refrangibility that appeared to be as characteristic of salts of potash as the yellow lines were of sodium.” “I suggest” he said in 1834 “that whenever the prism shows a homogeneous ray of any colour, this may indicate the formation or presence of a definite chemical compound.” In another paper he wrote about the same phenomena: “If this opinion should be correct and applicable to other definite rays, a glance at the prismatic spectrum of a flame may show it to contain substances which it would otherwise necessitate a laborious chemical analysis to detect.” In 1834, Talbot obtained a specimen of pure lithia from Michael Faraday and compared its spectrum with that of pure strontia.By naked eye the emissions in the flame were scarcely distinguishable, but by prismatic analysis lithia showed a single red ray whereas strontia showed a great number of red rays plus an orange and a bright blue ray. He observed “Hence I hesitate not to say that optical analysis can distinguish the minutest portion of these two substances from each other with as much certainty if not more than any other known experiment.” In 1835, Talbot distinguished between line and continuous spectra from “lime light .” Unquestionably, Talbot’s genius was most pronounced in spectroscopy and it is a matter of regret that history, particularly in the shape of Bunsen and Kirchhoff, has paid so little attention to his pioneering observations and conclusions.David Brewster (1781-1868), born in Jedburgh and educated to become a minister of the church, invented among other things the kaleidoscope (1816) and founded the BritishJuly, 79 7 7 HISTORY OF ANALYTICAL CHEMISTRY 179 Association for the Advancement of Science (1831). Speaking before the first meeting of the BA in 1831 he described the causation of the dark lines in the solar spectrum observed by Fraunhofer, and seen earlier by Wollaston, as being due to a process of atomic absorption.Brewster was in fact studying the spectrum of the sun with the objective of finding a principle of analysis on which species could be determined by their characteristic absorption of definite parts of the spectrum.Using an incandescent lamp source and nitrous oxide gas as absorber he observed the spectrum to be covered by hundreds of dark lines far more distinct than those in the solar spectrum. Absorption spectroscopy was born then, and Brewster correctly predicted that the new phenomenon would engage the interests of “philosophers” for many years to come. Charles Wheatstone (1802-1875) is the last British contributor to atomic spectroscopy that I have space to mention.He invented the telegraph in 1837 and thus anticipated Morse (1844), who is usually credited with its discovery; but both men “evolved” the idea after a visit to Joseph Henry’s laboratory in the USA. His name is better known in an electrical context, but his contribution to spectroscopy is, in my opinion, even greater.He observed and showed a drawing exhibiting seven definite rays cleanly separated on a dark background, the first public demonstration of a spark spectrum. Subsequently, he demonstrated and described spark spectra for molten zinc, cadmium, tin, bismuth and lead. He accounted for the number, position and colour of the lines and observed publicly that they were so different from each other that the metals could easily be distinguished in this way.\!heatstone in 1835 was then many years ahead of Bunsen and Kirchhoff in the 1860s. Although the summary of his lecture is extant he did not, unfortunately, publish the paper until 1861. This summary of early British contributions to analytical atomic spectroscopy brings us just to the threshold of quantitative spectroscopy, when other British scientists such as Draper, Stokes, Crookes, Hartley, Lockyer, Judd Lewis, Pollock and Leonard made funda- mental discoveries and advances that made atomic spectroscopy the invaluable tool it has now become.In 1835 he described before the BA the electromagnetic spark of mercury. William Crookes, Chemica/ News and Analysis D.Betteridge Cheiizistry Departmegat, University College of Swansea, Singleton Park, Swansea, SA 2 8PP Sir William Crookes, OM, FRS, the pre-eminent Victorian scientist who made notable contributions to the advancement of physics and chemistry, made a large part of his living through analysis. The main features of his life and scientific contributions are sunimarised in Table I, but in this paper I shall concentrate on his contributions to analysis, particularly through the medium of Chemical News.Crookes, having graduated from the Royal College of Chemistry, where he had studied under Hoffman, was unable to obtain a satisfactory and permanent position in the public service or as an academic. From 1857 onwards he supported himself entirely by work in analysis and jour- nalism, speculation and as a consultant.His income from analysis from his first 6 years was about El00 and he only made something like k50 p.a. from Chemical News. In 1864 he seriously considered making a move from London to Manchester, where analysts were far better paid. However, during the cattle plague of 1865-1867, Crookes contributed significantly to its containment by introducing carbolic acid and various disinfectants.From then on he was in constant demand as a consultant and was called upon to undertake a great variety of analyses. For example, from 1886 until 1913 he performed with Tidy and Odling, and with Dewar after Tidy’s death, a daily analysis of London waters. This brought him in an income of about L400 p.a., which was greater than that from Chemical News. Initially he experienced severe financial difficulties.Chemical News In 1859 Crookes founded Chemical News, which he continued to edit until a few months The constancy of verve and style suggests that Crookes maintained a before his death in 1919.180 HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Div. Chem. soc. dominant influence on the selection of articles, the editorials and the presentation of the journal, although from an early stage he did have at least one editorial assistant.Weekly, it covered the developments in chemistry and technology in a most catholic and entertaining manner. There were a remarkable number of scoops. Marie Curie’s thesis was published in toto, as was Faraday’s “Chemical History of the Candle,” the lectures upon which it is based having been recorded verbatim by Crookes.All of Crookes’ work on radiant matter and radiometry and spectra of the rare earths was included. During the developments in radiochemistry, which were very closely followed, one finds a full report of an after-dinner speech of Ramsay, in which he gave advance notice of the paper that he and Soddy had sent off to the Royal Society on the conversion of cc-particles to helium.Technical developments were fully described and in all of this there were numerous articles of analytical interest. Before the foundation of The Analyst, the papers of the Society of Public Analysts were published in Chemical News. Throughout the years there were many significant articles on food analy~is.~ Numerous papers on atomic spectroscopy were published at the time of Bunsen and Kirchhoff’s great discovery.There were innumerable articles on the molybdo- phosphate method for the determination of phosphorus and very many on titrimetric pro- cedures for the analysis of steel and other new materials. All of the major analytical develop- ments were mentioned and most were fully discussed in the journal.The length of treatment depended to some extent on copyright arrangements; many papers were re-published in full, while others were only abstracted. Papers published by the Royal Society in their various journals were often reproduced, as were many American papers, often from obscure journals. There was also a good coverage of Russian papers; however, papers from the French and Danish journals were largely abstracted.This policy, for TABLE I WILLIAM CROOKES, 1832-1919 Information from references 1 and 2 and British Museum Catalogue. However, information on these points is incomplete. Periods over which work is spread are indicated where known. 20 .Age, years Date Personal Scientific and technical Journals and books 1832 1848-54 Royal College of 1851 Hoffman’s assistant 1851 1st paper on selenoc yanide 1852 Photography Superintendent of the 1854 Spectrum of sodium Meteorological (unpublished) Department, Oxford College of Science, Born June 17, son of a tailor Chemistry 1854 1855-56 Teacher of chemistry, Photograph-moon 30 1856 1857 1860 1861 1863 1864 Chestkr Marriage Moves to 20 1857 Commercial analyses 1857- J .Photographic SOC. Mornington Rd., 58 Lond. (Editor) house plus 1859- Chemical News (Founder laboratory, lit by electricity Fails to get Chair, Royal Veterinary College 1919 and Editor 1861 Discovers thallium and prepares characteristic compounds FRS Severe financial hardship. Analysis in London only brought in LlO0 in 6 years. 1863 Quart. J . Sci.(Editor)July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 181 40 50 60 70 80 1865 1867 Considers moving to Manchester. Takes in lodger - apprentice 1865-69 (a) Cattle plague, carbolic acid and disinfectants ; (b) sodium amalgam for extraction of gold Younger brother dies from yellow fever 187 1-74 Spiritualism 1875 1878 1880 1886 Royal Medal of Royal Society (radiometer) FRIC Gold Medal of French Academy President of Chemical Section of British Association 1887-89 President of Chemical Society 1888 Davy Medal of Royal Society (high vac.) 1890 President of Institute 1870 Member of “Eclipse” expedition 1871-80 Director Native Guano Ltd.1872 Exact A , of thallium 1873 Fish fertiliser 1875 Radiometer 1875-90 Radiant matter (cathode rays) 1878-1905 Electric Light & Power Co.1883-1919 Spectra of rare earths 1886 Metal elements 1886-1913 Daily analysis of London water 1886 Protyle-origin of the elements 1888-96 Extraction of gold (Dolgelly) of Electrical Engineers 1897 Knighthood 1897-1905 South African 1898 President of British 1898 World supply of wheat, 1898- Explosives spinthariscope diamonds Association radioactivity, uranium X, 1907 Committee 1900-1 3 Honorary Secretary of Royal Institution 1904 Copley Medal of Royal Society (radiant force) 1907-18 Ordnance Board 1908 Ir and Rh for crucibles 1910 OM 1913 President of Royal Society 1914 Crookes glass 19 18 Scandium spectra 1919 Died April 4 1868 1870 1871 1872 1873 1874 1881 1886 1888 1894 1899 1906 Mitchell’s “Assay,” 3rd Edition (first edited by Crookes) “Beetroot Sugar” “Select Methods of Chemical Analysis,” 1st Edition (Editor) Wagners “Chemical Technology,” 1st English Edition (Editor) Mitchell’s “Assay,” 4th Edition (Editor) “Handbook of Dyeing and Printing” Il.litchell’s “Assay,” 5th Edition (Editor) “Select Methods,” 2nd Edition (Editor) Mitchell’s “Assay, ” 6th Edition (Editor) “Select Illethods,” 3rd Edition (Editor) “The Wheat Problem,” “ Select Methods,” 4th Edition (Editor)182 HISTORY OF ANALYTICAL CHEMISTRY Proc.Analyt. Div. Chem. SOC. example, means that the papers by Jones on the Jones reductor and other developments were fully reported, as were the works of Kern, the Russian, but Kjeldhal’s famous paper was only abstracted. Similarly, Tyndall’s work on optoacoustic spectroscopy was fully reported, but Bell’s work was noted only briefly.Nevertheless, the person reading Chemical News could scarcely fail to be informed of major developments taking place in theoretical, practical and industrial chemistry and the related sciences. The reader then, as now, must have been excited by the subject matter, gripped by the style and fascinated by the gossipy items and brief announcements, that were included in every issue.The range and style of these last are indicated below. 1859 In the very first issue we find a description of a simple gas-combustion furnace for organic analysis. A report of adulteration of food indicates the great concern felt at the time. “The Bath-bun Poisoning Case. A case of wholesale poisoning which has occurred within the last day or two at Clifton demands from us more than a passing record.A baker in that place, wishing to save his eggs and exaggerate his reputation, desired some yellow colouring matter to give a fictitious appearance of richness to his Bath-buns. Low eatinghouse keepers and cheap pastry-cooks in London have long been in the habit of using turmeric to give this appearance to their delicacies, but the Clifton baker was not sufficiently well up to the tricks of his trade as to be aware of the uses of this harmless drug.Casting about, therefore, for some substance which would answer his purpose, he by some means fixed his mind on chrome yellow- chromate of lead. A druggist who was not a colourman as well would not be likely to have chrome yellow in his shop, and this would appear to be the case with the Clifton tradesman.Accordingly, he sold the baker what he thought would answer the purpose of a yellow colouring matter just as well, and that sub- stance was orpiment! This the baker carried home, mixed in his buns, and sold them to his unsuspicious customers. The consequences were soon apparent. The first victims were some school boys, one of whom, with a good appetite and much pocket money, devoured three of the poisonous viands.They were all made exceedingly ill, and some narrowly escaped with their lives. Such is a simple narrative of this shameful case, in which it is hard to say which was most to blame, the baker who designed to put chrome yellow into his pastry; or the druggist who sold him orpiment instead of the less active poison.” (2,48).For this he applied to a druggist in his neighbourhood. 1877 From the issues in 1877, the year of foundation of the Royal Institute, we note that in the public sector the Public Analyst had become established. An advertisement for an analyst in Poplar reports that the salary is to be El00 p.a., and a minimum of one hundred analyses are to be performed (35, 86).In the West Riding of Yorkshire, Mr. A. H. Allen, FCS, was appointed at a salary of fT250 pa., plus 6s per analysis (35, 146). Apparently it paid to live in the North. However, J. A. Wanklyn, a regular and controversial contributor, had a dire warning about working for a Northern authority: “Chemists may be warned that unless they exact their fees beforehand, they will run great risk of being defrauded by the local government board.’’ (35, 105).There is a report from Casamour of the USA on volumetric analysis (35, 97, 130, 160, 170) including a description of a tapless burette, which operated on the piston principle (35, 130). A graduated piston was pushed down a central cylinder with a simple spigot at the top. A known amount of titrant was dispensed, there was no problem with taps or meniscus and the barrel, which was bench high, could be mounted permanently on the floor.J. Parry, of the Ebbw Vale Iron Works, communicated his procedures for the photographic recording of spark spectra of steels (36, 140). It required a 15-min exposure. There are regular reports on the analysis of metropolitan water by Crookes, Tidy and Odling.In a full page of small advertisements, those for tar distillation products are much in evidence (35,222). Some of the advertisements are rich in inadvertent humour, such as the one from the chemical engineering company, which promises “competent workers sent to all parts of the Kingdom for repairs.” Another offers a post-free catalogue sent on receipt of three stamps.There is a brief note that the Emperor of Brazil visited Sir William Crookes and wasJuly, 1977 HISTORY OF ANALYTICAL CHEMISTRY 183 shown his radiometer and various experiments to demonstrate radiant forces. This precedes an advertisement for a lecture to the Institute of Sanitary Engineers (35, 276). Crookes, as one who had virtually no formal education, was totally opposed to the idea of cramming for examina- tions and strongly deprecated texts arising from the introduction of examinations of the Science and Art Department, and the payment of teachers on the results of their pupils.In one of the reviews, the “anonymous” reviewer writes that “the people of England are rapidly becoming divided into three classes-examiners, examinees, and those preparing their country- men to undergo the fashionable operation.” (35, 230). Book reviews in Chemical News were always lively and controversial.Books One based on procedures published in Cheinical News and tested by Crookes himself appeared as “Select Methods of Chemical Analysis.” This work went through several editions and is quite different in style from Mitchell’s “Manual of Assaying,” which he also edited.“Select Methods. . .” is somewhat disappointing in view of Crookes’ forward thinking in other directions. There are relatively few instrumental methods, although electroanalysis gets a fair treatment. Nevertheless, the great success of the works suggests that, in practical terms, many analysts found it and Chemical News to be of great value.Never- theless, he was described by Lodge as an unassuming person who failed to make an impact on meeting.l Despite his considerable achievements in many fields he is considered by some to be a dilettante. This scarcely accords with his enthusiasm for spectroscopy which lasted for 64 years, his 60-year long editorial work on Chemical News, his 27 years of work on the analysis of London waters, etc., and the award of three medals by the Royal Society.His life story by D’Albel is well balanced and most interesting,, but one feels that there is a need for a re-evaluation of Crookes. In the meanwhile, readers of the first 120 volumes of Chemical News have a living memorial to a remarkable analytical chemist. Crookes also edited a number of books. Crookes in his time was a controversial man and his writings are witty and acerbic.References 1. D’Albe, E. E. F., “The Life of Sir William Crookes,” T. Fisher Unwin, London, 1923. 2. Findlay, A., in Findlay, A., and Mills, W. H., Editors, “British Chemists,” The Chemical Society, 3. Egan, H., in “Food Quality and Safety: A Century of Progress,” HM Stationery Office, London, 1975, London, 1947.p. 105. A History of Organic Reagents in Analytical Chemistry W. I. Stephen Department of Chemistry, University of Birmingham, P.O. Box 363, Birmingham, B15 2TT The undoubted importance of organic reagents in modern analytical chemistry is admirably illustrated by the work of the late Fritz Feig1.l His appreciation of the concept of analytico- functionality in organic compounds did much to further research into the development of new and improved reagents.Before Feigl’s time, however, the situation was very different and most developments were completely empirical ones. While the constitution and properties of more and more organic compounds were being ‘established in the middle and later years of the 19th century, the realisation that many reactions of the new compounds with inorganic substances could be used for analytical purposes gradually emerged.Before this time, organic compounds were used in their natural forms, either from plant or animal material. The classical example is Pliny’s use of an extract of the oak gall nut to detect the adulteration of copper sulphate with iron sulphate-the first recorded selective spot-test using an organic reagent, in this instance tannin or gallotannic acid.2184 HISTORY OF ANALYTICAL CHEMISTRY Proc.AnaZyt. Div. Chem. Soc. References to the uses of natural substances occur frequently in the writings of the alchemists and philosophers of the 16th and 17th centuries, and Szabadvgry3 gives many examples of analytical interest. Robert Boyle4 was instrumental in employing colour reactions as diagnostic tests for various chemical substances, using for reagents various plant extracts, such as syrup of violets, cornflower and litmus.His use of an extract of Lignum nephriticum as a test for acids could be construed as being the first fluorescence reaction used analytically. As chemical technology progressed and manufacturers were in need of procedures for controlling the quality of their products, new techniques of analysis gradually emerged and of these, the development of titrimetry is significant.Acids and alkalis were such important articles of commerce that methods for their analysis were obviously needed. Ranke-Madsen5 has admirably recorded the early history of this subject, but here it should be noted that the Englishman William Lewis6 was the first to describe an exact titrimetric process and to use an indicator paper, litmus, to show when neutralisation of acid or alkali had been achieved.Some 100 years later, in 1863, when Francis Sutton7 wrote the first book in English on volu- metric analysis, only litmus, cochineal and turmeric paper were used in acid - base titrations.The first synthetic organic compound to be used as an acid - base indicator appears to be phenolphthalein, proposed by Luck8 in 1877. This indicator was closely followed by methyl orangeg910 in 1878. Such was the impetus which synthetic organic chemistry had given to the development of new compounds with suitable acid - base properties that by 1901 a book de- voted solely to the subject had been published.ll The discovery of chlorine by Scheele in 1774 and the utilisation by the Frenchman, Berthollet, of its aqueous or alkaline solutions for the bleaching of textiles led to a new industrial process.Almost immediately, a new volumetric process was developed by Descroizilles12 to control the strength and quality of the new liquor. The method involved the oxidation of an acid indigo solution by the chlorine water, the blue indigo colour disappear- ing when an excess of chlorine was present.This is a remarkable process in that the natural organic dye, indigotin, is used quantitatively, its colour denoting the end-point of a volu- metric process. Indigo thus became the first redox indicator in titrimetry and Gay-Lussacl3 used it entirely in this sense when he introduced arsenic(II1) solutions for the titration of hypochlorite in 1835.Many of these natural substances continued to occupy premier roles in analytical processes well into the 20th century. However, from about 1850 onwards, the impetus given to the chemical industry by the new organic chemistry led to a demand for better analytical control of raw materials and basic chemicals.The synthetic organic compounds of known purity and constitution began to find use as analytical reagents. The phenols are good examples. Sprengell4 in 1863 recommended not only phenol itself, but also its disulphonic acid as reagents t o detect nitrate; the latter compound is still a valued reagent for this purpose. Diphenyl- amine was noted by Hofmann in 1864 to react with a solution of nitric acid and Kopp15 applied this well known reaction analytically in 1872.The use of pyrogallol in gas analysis was pioneered by none other than Liebigls in 1851. The industrious Griess, then chemist in a Burton brewery, was elaborating his famous diazo reaction during the years from about 1865 onwards. His recognition that this could be the basis of an analytical test for nitrous acid led to the publication in 1871 of a procedure involving 1,2-diaminobenzene as reagent.17 This reagent never seemed very popular, few if any references to its use appearing in the current literature.However, Griess was persistent and his synthesis of 1,3-diaminobenzene (metaphenylenediamine) in 1875 enabled him to recommend this compound as a superior reagent in 1878.18 Its highly sensitive reaction with nitrous acid leads to the formation of the dark coloured complex dyestuff, Bismark brown.He had told two German colleagues of his discovery and the paper next to Griess’ in Berichte der Deutschen. chemischen Gesellschaft described the quantitative application of Griess’ qualita- tive test.19 However, such was the progress in azo-dye chemistry that even this was short- lived. In the following year, Griess recommended the sulphanilic acid - a-naphthylamine - nitrous acid reaction,20 which remains in only slightly modified form as the reagent system used today.The sensitivity of the test is remarkable; under favourable conditions it can detect 1 part of nitrous acid in lo8 parts of water.One of the first to use the new Griess reaction was Robert Warington,21 son of Robert Warington, Snr., who became the first Secretary of The Chemical Society. His account of its use to detect and determine nitrous Griess was prepared this time.July, 1977 HISTORY OF ANALYTICAL CHEMISTRY 185 acid in the atmosphere makes most interesting reading. The Griess reaction is often called the Griess - Ilosvay reaction.Ilosvay’s contribution was to replace the mineral acid used by Griess with acetic acid.22 He also showed how to use the test for the nitrate ion following reduction with zinc. George Lunge23 recommended the final form of the reagent as a mixture of its two components, thus establishing Warington’s belief that it was unnecessary to wait between the addition of the sulphanilic acid and the oc-naphthylamine.Zambelli’~~~ contri- bution was to replace the naphthylamine with phenol or a-naphthol and to allow the coupling to occur in an alkaline medium. This procedure has certain advantages while retaining the sensitivity of the Griess - Warington reaction. The plant alkaloids had always attracted attention not only because of their physiological and pharmacological importance, but because many of their reactions with inorganic substances were analytically useful.Crystalline salts with, for example, chloroplatinic acid, were useful for their characterisation. The well known brucine test for nitric acid was described by K e r ~ t i n g ~ ~ in 1863. The cinchona alkaloids, quinine26 and ~inchonine,~~ proved useful precipitants for tungstic acid and of course bismuth as the complex iodide.2s The elusive alkaloid cinchoflamine (from Remijia purdieana) was shown, in 1884, to form an unusually sparingly soluble salt with nitric acid,29 some 30 years before Busch’s discovery of a similar property of certain complex triazoles.Unfortunately, modern studies of this interesting compound are lacking as a result of its inaccessibility.The alkali metal salts of xanthic acid were used to detect copper,30 nickeP1 and molybdenum32 by colour reactions in early times. Interestingly, the copper - dithiooxamide reaction seemed to be known to Wohler in 1825,33 although the modern use of the reagent is due to Ray.34 The corresponding acid, dithiooxalic acid, was recommended by Jones and T a ~ k e r ~ ~ in 1909 as a sensitive reagent for nickel and cobalt, and the ammonium salt of thioacetic acid was used as a convenient source of hydrogen sulphide in qualitative analysis long before the vogue for thioacetamide was prevalent .36 Among the dithiocarbamates, the ethyl derivative appeared to D e l a ~ i n e ~ ~ in 1908 to be well suited to the determination of copper.It is still a popular reagent for this purpose. Andreasch3* was the first to note the intense red colour given by thioglycolic acid and iron salts in 1879. This reagent pre-dates the introduction of acetylacetone by about 9 years. Combes,3O who first synthesised acetyl- acetone, noted its intense red colour with iron(II1) salts and recommended its use for the detection of iron.Pulsifer40 confirmed the use of this reagent for quantitative purposes in 1904, claiming it to be superior to thiocyanate. Vogel41 was responsible for recommending salicylic acid as a reagent for iron in 1876 and Smith’s in 1880 showed that it was then an established reagent. Less sensitive than thiocyanate, it was preferred when copper was present. Gregory’s of the reagent was published in 1907.Blau’s classic studies on bipyridines and phenanthrolines were first published in 1888.44 Although he described the nature and colours of the iron(I1) and iron(II1) complexes, no analytical use was suggested. In fact, Hill, in England, was responsible for the first analytical method using 2,2’-bi~yridine.~~ It was applied to the determination of iron in biological material .The alertness of some organic chemists to the analytical usefulness of certain of their new compounds is best exemplified by the work of Ilinski and von Knorre,46 who in 1885 showed that nitrosonaphthols could be usefully employed to separate nickel and cobalt, by selective precipitation of the cobalt complex. cc-Nitroso-P-naphthol is often accredited with being the first synthetic organic chelating agent used in chemical analysis, but salicylic acid and thioglycolic acid were both introduced earlier. During extensive studies of the metal complexes of various vicinal dioximes, the Russian chemist Chugaev4’ noted the characteristic reaction of nickel(I1) ions with dimethylglyoxime.His very short note entitled “A New Delicate Reagent for Nickel,’’ published in 1905, was a landmark of great significance in the history of organic analytical reagents.Brunck4* was the first to use the reagent quantita- tively in 1907. Shortly after this, Oskar Baudischg9 introduced cupferron (the ammonium salt of N-nitrosophenylhydroxylamine) into analytical practice and these two reagents dominated the field for 20 years, at least until Helmut Fischer50 showed the potentialities of dithizone in the late 1920s and early 1930s.There are many other fascinating aspects of this subject which cannot be included in this summarised version. Sulphur-containing compounds have proved a fruitful source of analytical reagents. It is hoped that a fuller account will appear elsewhere.186 1. 2. 3. 4. 5. 6. 7.8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. HISTORY OF ANALYTICAL CHEMISTRY Proc. Analyt. Div. Chem. SOC. References Feigl, F., “Chemistry of Specific, Selective and Sensitive Reactions,” Academic Press, New York, Plinius, C. S., “Naturalis Historiae Libri.’’ Volume 33, p. 45. SzabadvAry, F., “History of Analytical Chemistry,” Pergamon Press, Oxford, 1966. Shaw, P. (abridged,py), “The Philosophical Works of the Hon. R. Bovle,” Volume TIT, “The W. &. J . Tnnys, London, and J. Osborne and T. Longman, London, 1725, Madsen, E. R., “The Development of Titrimetric Analysis till 1806,” G.E.C. Gad Publishers, Lewis, W., “Experiments and Observations on American Potashes,” Society for Encouragement of Sutton, F., “Volumetric Analysis,” Churchill, London, 1863. Luck, E., 2. Analyt. Chem., 1877, 16, 332. Lunge, G., Bey. Dt. Chem. Ges., 1878, 11, 1944. Williams, G., Chem. News, 1878, 39, 98. Glaser, F., “Indicatoren der Acidimetric und Alkalimetric,” C. W. Kreidel’s Verlag, Wiesbaden, 1901. Berthollet, C. I>., Mkm. Acad. R. Sci., Paris, 1788, 376. Gay-Lussac, J. L., Annls Chim. Phys., 1835, 60, 225. Sprengel, H., Poggendorffs Annln, 1863, 121, 188. Kopp, E., Ber. Dt. Chem. Ges., 1872, 5, 252. von Liebig, J . , Jzcstus Liebigs Annln Chenz., 1851, 77, 107. Griess, P., Z . Analyt. Chem., 1871, 10, 92. Griess, P., Bev. Dt. Chenz. Ges., 1878, 11, 624. Preusse, C., and Tiemann, F., Ber. Dt. Chem. Ges., 1878, 11, 627. Griess, P., Bey. Dt. Chem. Ges., 1879, 12, 427. Warington, R., J . Chem. SOC., 1881, 39, 229. Ilosvay, L., Z . Analyt. Chem., 1894, 33, 223. Lunge, G., Analyst, 1890, 15, 17. Zambelli, L., J. Chem. SOC., 1887, 52, 533. Kersting, R., Justus Liebigs A n n l n Chem., 1863, 125, 254. Lefort, G., C.R. Hebd. Se‘anc. Acad. Sci., Paris, 1881, 92, 1461. Cremer, F., Engnq M i n . J., 1895, 59, 345. Leger, E., Bull. SOC. Chim. Paris, 1888, 50, 91. Arnaud, A., and Pade, L., C.R. Hebd. Se’anc. Acad. Sbi., Paris, 1884, 98, 1488. Schwartz, H., Dinglers Polytech. J . , 1868, 190, 220. Phipson, T. L., C.R. Hebd. Se’anc. Acad. Sci., Paris, 1877, 84, 1459. Sievert, M., Z. Ges. Naturw., 1864, 25, 5. Wohler, F., Poggendorffs Annln, 1825, 3, 178. Ray, P., and Ray, R. M., Q. J l Indian Chem. Soc., 1926, 3, 118. Jones, H. O., and Tasker, H. S., J . Chem. Soc., 1909, 95. 1904. Schiff, R., and Tarugi, N., Ber. Dt. Chem. Ges., 1894, 27, 3437. Delapine, M., C.R. Hebd. Se‘anc. Acad. Sci., Paris, 1908, 146, 981. Andreasch, R., Bey. Dt. Chem. Ges., 1879, 12, 1391. Combes, A., C.R. Hebd. Se‘anc. Acad. Sci., Paris, 1888, 105, 868. Pulsifer, H. P., J . Am. Chem. Soc., 1904, 26, 967. Vogel, A., Chem. ZentBl., 1876, 7, 375. Smith, E. F., Proc. Am. Phil. SOC., 1880, 18, 214. Gregory, A. W., Proc. Chem. Soc., 1907, 23, 263. Blau, F., Bcr. Dt. Chem. Ges., 1888, 21, 1077. Hill, R., Proc. R. Soc., 1930, B107, 205. Ilinski, M., and von Knorre, G., Ber. Dt. Chem. Ges., 1885, 18, 699. Chugaev, L. A., Ber. Dt. Chem. Ges., 1905, 38, 2520. Brunck, O., 2. Angew. Chem., 1907, 20, 834. Baudisch, O., Chemikerzeitung, 1909, 33, 1298. Fischer, H., Wiss. Ver68. Siemens-Werken, 1925, 4, 158. 1949. Sceptical Chemist, p. 301. Copenhagen, 1958. Arts, Manufactures and Commerce, London, 1767.

ISSN:0306-1396    

DOI:10.1039/AD9771400171

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

July, 1977 MODERN METHODS OF SPECIATION 187 Modern Methods of Speciation-Characterisation of Chemical Species The following are summaries of two of the papers presented at the Annual Chemical Congress on March 31st, 1977. Characterisation of Surface Species Using Electron Spectroscopy (ESCA) David M. Hercules Dr@rtntcnt of Chenzistry, University of Pittsbuvgh, Pittsburgh, Pa. 15260, USA Many analytical problems pose four questions to the investigator: what elements are present? ; how much of each element? ; what form or forms of the element? ; and what are the relative percentages of the different forms or species? For bulk analysis, detection of elements at the parts per billion (lo9) level and quantitative measurement at the same level are routine.An important aspect at the forefront of analytical chemistry is to determine the exact species present and to quantitate the distribution of species for an element, which is the theme of the present Symposium.In the field of surface analysis, only recently has one been able to detect the presence of elements on a surface, and quantitating surface elements is still a matter of research and debate.Even more recently (within the last few years) workers have endeavoured to identify the chemical nature of surface species and to quantitate them. This paper deals with some aspects of characterising the species present on a surface, as well as obtaining quantitative estimates of them. Usually, in a bulk analysis, one is not concerned with the distribution of materials through a sample, but rather one assumes the sample to be homogeneous.However, for surface analysis, the distribution of species from the surface inwards towards the bulk can be important for the result of an analysis. For less than a monolayer adsorbed on the surface, the distribution of species from the surface inwards has no relevance. Under these circumstances, one can readily express the results of analysis in meaningful quantitative units, such as a fractional monolayer or micrograms per square centimetre.Consider now a two-component system with one component high in concentration at the surface, and the other component at high concentration in the bulk. In this circumstance one might have a wafered situation where the concentration of the surface material drops abruptly to zero and the concentration of the bulk material arises similarly, as shown in Fig.1, profile 2. This is the situation of a sharp interface. Here, too, one can use meaningful surface units, such as micrograms per square centimetre. Another possibility is that one material dominates at the surface but its concentration inwards resembles a decreasing exponential function, while the bulk material represents an increasing exponential function, as shown in Fig.1, profile 3. There is no clear dividing line between the outer surface layer and the inner bulk. I t is therefore difficult to express the results of an analysis in meaningful units and the results of an analysis will depend on the distribution of the materials as well as the depth to which the measuring technique samples.The situation becomes even more complex for a system that has three or more components, as shown at the bottom of Fig. 1. Hence we can conclude that surface analysis has an added dimension, namely, the distribution of materials from the surface layer inwards toward the bulk. This distribution can take any form; variations can even be caused by the measuring technique used.,4n example of how the measured ratio may vary can be determined by considering a two- component mixture (A and B) in which A represents 100% of the surface but decreases towards the bulk in an exponential fashion, with l / e = 20 A . If one performs quantitative measurements on such a system using ESCA, the intensity ratios of A and B will vary, depend- ing on the escape depth of the photoelectron used.I t is clear that the measured intensity ratio can vary significantly if electrons of different escape This effect is illustrated in Table I.188 MODERN METHODS OF SPECIATION Proc. AnaZyt. Div. Chem. SOC. Adsorbed layer Thin layer 0 x- 0 0 X---., Multi - layered systems ? A ////, B'////// C 0 X+ Fig. 1. Situations important for quantitative surface analysis.(1) Profile for an adsorbed layer. (2) Profile for a two-component system having a sharp interface. (3) Profile for a two-component system having no interface ; exponential decrease in concentration. (4) Profile for a three-component system having sharp interfaces. (5) Profile for a three-component system with one component (B) concentrated at the interface of the other two.depths are used and it is therefore important to know the depth-distribution of analyses in a sample, or to be able to measure this distribution. Various ~ o r k e r s l - ~ have dealt with the enhancement of ESCA signals as a function of take- off angle. Usually this is considered for a thick layer, although some workers have dealt with sub-monolayer coverage.Generally, such studies have stressed the fact that for low take-off angles relative to the plane of the sample, the surface signal is enhanced. In fact, the surface signal is not enhanced, but the signal from the substrate is decreased, enhancing the surface to substrate ratio. This is a valuable technique for measuring adsorbed layers and for deter- mining species on the topmost layer of the sample.However, as the coverage of a sample decreases, the ability to discriminate in favour of surface species is lost. For example, at 0.1 monolayer coverage, the surface to bulk ratio will be essentially independent of angle; at monolayer coverage, however, the use of small angles definitely enhances the ratio. Another important aspect of the angular distribution of photoelectron intensities is how the intensity will vary as a function of thickness for a uniform film, several atomic layers thick.Qualitatively, one can consider that if the film is infinitely thin, one will see no enhancement of the surface layer relative to the bulk because the surface concentration will be zero. Similarly, if the layer is very thick, the surface layer will become the bulk and enhancement will be nil.At intermediate thicknesses, however, enhancement goes through a maximum at a thickness TABLE I EFFECT OF PHOTOELECTRON ESCAPE DEPTH ON ESCA SIGNALS FOR A TWO-COMPONENT SYSTEM CB = 100[1 - exp( - k x ) ] . CA = 100 - CU. k = 0.5 nm-l. Escape depth/nm Compound A Compound B 0.4 0.4 1.0 1.0 2.0 2.0 2.6 0.4 0.4 2.6 f A I Intensity ratio (A/B) 5.0 2.0 1.0 16.9 0.25July, 1977 MODERN METHODS OF SPECIATION 189 approximately 0.5 of the photoelectron escape depth.This means that although surface enhancement is limited, it is extremely valuable for films a few atomic layers thick. ESCA can be used for the determination of trace metals by extraction on to a solid probe.5 This is often accomplished by using the following sequence of reactions : [SOM] [SO-] [M+j SO-+M++SOM K f = - where S is a solid support and M is a metal ion in sloution.1 :1 metal - site coniplex: Using the appropriate equilibrium expressions, one can obtain the following equation for a where 8 is the fraction of surface sites covered by the metal, V the volume of solution interact- ing with the surface, C" the total metal concentration in solution, So the number of sites available and N Avogadro's number.The intensity of all ESCA signals will be proportional When plotting data from equation (l), one observes an interesting effect. For a plot of 8 veYsus lo&", one observes an S-shaped curve, resembling a titration curve. At verylow concentrations, the curve is essentially linear, but at moderate concentrations the curve is log-linear. Thus, although the trace-element technique using ESCA and a solid probe is fairly sensitive, a large portion of the concentration range will be non-linear. This has the disadvant- age that the technique is not sensitive to small differences in concentration, but on the other hand it allows the use of the ESCA probe technique for a wide range of concentrations.The particular 8 - concentration profile is dependent on such factors as solution pH, KA and Kf. Hydrodesulphurisation catalysts are important commercial catalysts for the removal of sulphur from liquid fuels. We have carried out a study of species on both cobalt molybdate and nickel tungstate catalysts.6-8 For the cobalt molybdate catalyst, it was possible to study the distribution of molybdenum oxidation states as a function of reduction time in hydrogen at 500 "C.The initial reaction corresponded to reduction of Mo(V1) to Mo(V), concentrations varying linearly over the first 60 min. After about 50 min, the Mo(V) concentration went through an inversion and began to decrease, with Mo( IV) increasing simultaneously. After about 160 min all Mo species reached a steady-state value of Mo(V1) = 27%, Mo(V) = 33% and Mo(1V) = 39%.No reduction of cobalt was observed. In contrast, with a nickel tungstate catalyst the tungsten was not reduced but nickel was reduced. The nickel concentration decreased in an approximately exponential fashion until after about 6 h it levelled off, with approximately 75% reduced.The reduction was to Ni(0). It was of interest to determine the nature of the nickel species present on the catalyst surface, for which a combination of ESCA and chemical reactions was used. The results are summarised in Table 11. It is clear that NiO is not a species present on the catalyst surface, and also that no single species can account for the observed behaviour.Note that the binding energies for both Ni,O, and NiA120, match closely those measured for the catalyst, while the value for NiWO, deviates significantly. Further, Ni,O, is completely reduced by hydrogen, to e. Similar behaviour was observed at lower temperatures. TABLE I1 ESCA BINDING ENERGIES AND CHEMICAL BEHAVIOUR OF KICKEL SPECIES ON Y-ALUMISA ESCA binding energy Species (Ni 2P3/2 energy) Behaviour NiO .. .. .. . . 854.9, 856.8, 862.1 Completely reduced in 2 h by H, a t 500 "C Ni,O, .. . . . . . . 857.1, 863.0 Completely reduced in 2 h by H, a t 500 "C NiWO, .. .. . . . . 857.5, 863.7 Completely reduced in 2 h by H, a t 500 O C Ni A1 ,O, . . . . .. 857.2, 863.3 Only slightly reduced in 2 h by H, a t 500 "C Nickel tungstate catalyst . . -50% reduced in 2 h by H, a t 500 "C; max.857.1, 863.0 reduction 75% a t 500 "C190 MODERN METHODS OF SPECIATION Proc. AnaZyyt. Div. Chem. SOC. whereas NiAl,O, is only slightly reduced. These results provide good evidence for two nickel species, Ni203 and NiAl,O,, on the catalyst surface. Recent additional studies using the nickel LMM Auger spectra have confirmed these conclusions. To summarise, it is apparent that ESCA can make a significant contribution to studies of surface speciation.ESCA information derived from such studies must be used judiciously, particularly when quantitative results are sought. I t is my prediction that ESCA, combined with other surface-sensitive techniques, will have a great impact in the future on areas such a s heterogeneous catalysis because of their unique ability to quantify surface species.1. 2. 3. 4. 8. 6. 7. 8. References Fadley, C. S., Faraday Discuss. Chem. SOC., 1975, 60, 18. Fadley, C. S., J . Electron Spectrosc., 1974, 5, 725. Baird, R. J., Fadley, C. S., Kawamoto, S. K., Mehta, M., Alvarez, R., and Silva, J. A., Analyt. Chem., Brunner, J., and Zogg, H., J . Electron Spectrosc., 1974, 5, 911. Hercules, D.M., Cox, L. E., Onisick, S., Nichols, G. D., and Carver, J . C., Analyt. Chem., 1973, 45, Patterson, T. A., Carver, J. C., Leyden, D. E., and Hercules, D. M., SpectrosL. Lett., 1976, 9, 65. Patterson, T. A., Carver, J. C., Leyden, D. E., and Hercules, D. M., J . Phys. Chem., 1976, 80, 1700. Ng, K. T., and Hercules, D. M., J . Phys. Chem., 1976, 80, 2094. 1976, 48, 843.1973. Fourier Transf orrn Nuclear Mag net ic Resonance Spectroscopy Through the Periodic Table Ian K. O'Neill Laboratory of the Government Chemist, Cornwall House, Stamford Street, London, SE1 9NQ Although nuclear magnetic resonance (NMR) spectroscopy has been used routinely since 1960 for the observation of protium, fluorine-19 and phosphorus-31 nuclei,l it has only been the introduction of pulse-Fourier transform nuclear magnetic resonance (FTNMR) spectroscopic techniques that have allowed most elements in the Periodic Table to be so observed.2 Publi- cation of the fast Fourier transform algorithm,3 the demonstration of the practicality of FTNRlR spectroscopy by Ernst4 and the rapidly diminishing cost of computing hardware have led to the introduction of FTNMR into most large chemical laboratories.Considerable impetus was given to the rapid commercial development of FTNMR by the realisation that carbon-13 observation (1 .lo/o natural abundance) would give structural detail from the skeleton of organic systems that would complement the substantial peripheral detail already given by protium observation. 13C-FTNMR spectroscopy5~6 is now widely used industrially and most of the following discussion will refer to carbon-13 information although these types of information (Table I) are available for any isotope that can be observed.Resolution Early carbon-13 observation' of natural rubber showed that highly detailed spectra could be obtained from viscous or rubbery material that would give unacceptably broad lH-NMR spectra.Broad-line lH-NMR equipment as used in the food industry does not resolve chemical species ; the same samples usually give excellent 13C- and 31P-FTNMR spectra.8 Highly detailed spectra have been obtained of phosphate metabolism within living and dying m u s ~ l e ~ ~ ~ ~ and of natural oils in intact viable oil seeds.ll Compared with lH-NMR observa- tion, there is far greater resolution (and speciation) arising from two factors: the line width is much smaller and the spectral width much greater with most other nuclei.Within a piece of retail chicken flesh, we observed at least 15 separate 13C-FTNMR signals for the fat molecules, and identified injected organic additives such as citrate. By defatting and hydrolysing the remaining protein, a mixture of all of the naturally occurring amino acids was obtained.13C-FTNMR spectroscopy then allowed separate observation of nearly every carbon of every amino acid, thus showing more than seventy spectral lines simultaneously. We have adapted this method to give a new assay technique1, for L-hydroxyproline (as indicator of connective tissue in meat products) that is superior to colorimetric or chromatographic methods.July, 1977 MODERN METHODS OF SPECIATION 19 1 Specificity and Lack of Sampling Effort In common with other techniques that give multiple indicators for each molecule (c.g., infra- red and mass spectroscopy and X-ray diffraction) FTNMR spectroscopy is intrinsically far more specific than single-indicator techniques such as chromatography.In the aforemen- tioned assay of L-hydroxyproline, 13C-FTNMR spectroscopy proved to tse so highly specific that separation from other amino acids was unnecessary.By removing the need for separations, chemical species can be seen in their “natural” state, so that additional information is avail- able. Staff time is not consumed by separative procedures that are otherwise needed t o provide specificity.FTNMR spectroscopy involves detection at radiofrequencies so that sample colour or inhomogeneity do not interfere. Another example is the 13P-FTNMR observa- tion of polyphosphates in meat products. The only sampling required is to cut the meat sample out and push it into the 10-mm 0.d. glass sample tube. Orthophosphate, pyrophos- phate, tripolyphosphate and cyclic phosphates are all detected simultaneously and the action of phosphatase enzymes within the meat can be studied.13 Multinuclear Observation At constant magnetic field, observation of more than one isotope requires a change of observ- ing frequency and the spectrometer modules that generate, amplify and detect it.The change of spectrometer modules is inconvenient and expensive and arises, in part, from the use of highly tuned radiofrequency circuits.Several recent methods employed to facilitate multi- nuclear observation include the use of more widely tunable circuits14 and the use of frequency synthesisers.15 A goal for spectrometer manufacturers is the complete automation of this change, whereby the operator can command the spectrometer computer to make the necessary frequency and tuning adjustments. All organic samples yield 1H- and 13C-FTNMR spectra that are interrelated by common chemical-shift trends and mutual protium - carbon-13 spin - spin coupling (Table I).If the sample contains phosphorus, fluorine, silicon or nitrogen2 additional highly specific informa- tion is also available. Multinuclear FTNMR observation, together with the use of relaxation times and shift reagents, leaves practically nothing to be discovered about the primary, secondary or tertiary structures of complex molecules, or mixtures of them.The technically limiting factor in the observation of many elements is sensitivity and/or the spectrometer time that must be given for each sample. Developments of superconducting FTNMR magnets, wide-bore sample tubes16 and new radiofrequency detection systemsl’ have increased sensi- tivity greatly.The information content of FTNMR spectroscopy is so high (Table I) that mere detection of each nuclear species is sufficient to characterise it, TABLE I TYPES OF INFORMATION AVAILABLE WITH FTNMR SPECTROSCOPY Experimental technique Choose nucleus to be observed by selecting frequency Measure chemical shift compared to reference Homo- and hetero-coupling and decoupling Alter chemical shift and coupling by change of solvent or temperature or addition of shift reagent Measure spin - lattice relaxation times, observe line widths Quantify chemical species Benefit Completely isotope specific Can observe light elements inaccessible to atomic absorption, X-ray fluorescence spectroscopy and electron spectroscopy for chemical analysis Can observe several nuclei per sample Distinguishes many species of same nucleus in one Gives structural detail of geometry, relative numbers Can check structural hypotheses by selective decoupling Manipulation of spectra to check structure and sample and separation of functional groups intermolecular association Checks intermolecular association, distinguishes same chemical species within differing micro-environments in sample Quantitative and structural analysis192 EQUIPMENT NEWS Proc.Analyt. Div. Chew. SOC. Comparison with Other Speciation Techniques FTNMR spectroscopy has become a family of correlated nuclear spectroscopies, each iso- tope providing information concerning molecular structure, mobility and the other magnetic isotopes present in the same molecule.For natural or synthetic organic macro-components in samples, FTNMR spectroscopy has greater characterisation ability for both known and unknown substances than any other technique currently available to the analyst. As with all other techniques, it has limitations and in this laboratory we use FTNMR spectroscopy together with infrared and mass spectroscopy to tackle the most difficult molecular structure problems in the UK public sector.We are currently examining FTNMR application to the quantitative analysis of mixtures of very similar organic substances, because conventional methods require substantial preliminary sample preparation. As often the only FTNMR sampling constraint is that the sample fit within the sample tube, FTNMR spectroscopy is uniquely capable of giving information about substances within the bulk of samples, including living creat~res.~7lO Perhaps there is no better example of the non-destructive nature of FTNMR than zeugmatographic FTNMR imaging of water mobility inside live mamrnal~,~*J~ with the ultimate aim being early cancer detection in humans.FTNMR has not only an unsurpassed ability to differentiate molecular species, but also marginally different environ- ments of the same molecular species. With further development of FTNMR instrumentation, the analyst can look forward to obtaining unprecedented detail of the combined states of most elements in the Periodic Table. 1. 2.3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. References Emsley, J. W., Feeney, J., and Sutcliffe, L. H., “High Resolution Nuclear Magnetic Resonance Harris, R. K., Chem. SOC. Rev., 1976, 5, 1. Cooley, J. W., and Turkey, J. W., Maths Comput., 1965, 19, 296. Ernst, R. R., and hnderson, W. A., Rev. Scient. Instr., 1966, 37, 93. Levy, G. C., and Nelson, G. L., “Carbon-13 Nuclear Magnetic Resonance for Organic Chemists,” Breitmaier, E., and Voelter, W., “13C NMR Spectroscopy,” Verlag Chemie, Weinheim/Bergstrasse, Duch, M.W., and Grant, D. M., Macromolecules, 1970, 3, 165. O’Neill, I. K., Prosser, H. J., Richards, C. P., and Sargent, M., unpublished results. Hoult, D. I., Busby, S. J . W., Gadian, D. G., Radda, G. K., Richards, R. E., and Seeley, P. J., Burt, C . T., Glonek, T., and Barany, M., Science, N.Y., 1977, 195, 145. Schaefer, J., and Stejskal, E. O., J . Am. Oil Chem. Soc., 1975, 52, 366. Jozefowicz, M. L., O’Neill, I. K., and Prosser, H. J., Analyt. Chem., 1977, 49, in the press. O’Neill, I. K., and Richards, C . P., paper presented a t the Third International Meeting on NBIR Traficante, D. D., Simms, J. A,, and Mulcay, M., J . Magn. Reson., 1974, 15, 484. Peters, C. S., Codrington, R., Walsh, H. C., and Ellis, P. D., J . M a p . Reson., 1973, 11, 431. Allerhand, A., Childers, R. F., and Oldfield, E., J . Magn. Reson., 1973, 11, 272. Hoult, D. I., and Richards, R. E., J . Magn. Reson., 1976, 24, 71. Lauterbur, P. C., Pure Appl. Chem., 1974, 40, 149. Damadian, R., Minkoff, L., Goldsmith, M., Stanford, M., and Koutcher, J., Science, N.Y., 1976, 194, Spectroscopy,” Pergamon Press, Oxford, 1965. Wiley-Interscience, New York, 1972. 1974. Nature, Lond., 1974, 252, 285. Spectroscopy, University of St. Andrews, Scotland, July, 1975. 1430.

ISSN:0306-1396    

DOI:10.1039/AD9771400187

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

192 Equipment News EQUIPMENT NEWS Wide-field Microscope The Diavar 2 includes UnivaR type objectives with a range of plan apochromatics from x10 upwards with a field of view of 22.5. The focusing system has a sensitivity of better than 0.1 pm and the 5x nosepiece is parcentral to within 2 pm. The diecast base carries all the optical com- ponents of the illumination system and a lamp Proc. Analyt.Div. Chew. SOC. housing capable of accepting sources with rat- ings up to 100 W. The 100-W halogen lamp also makes possible the use of a projection screen. The illumination system incorporates an asph- eric collector with a high numerical aperture, a field iris to adjust the actual size of the objective field and a filter turret built into the instrument base.July, 19 7 7 EQUIPMEKT NEWS 193 The binocular body provides a constant tube length with a tube factor of 1 x and with pro- vision for one focusable tube.An alternative body incorporates a photo tube for the operation of either a camera or a projection screen. The over-all eyepiece magnification is 10 x . Reichert-Jung UK Ltd., 820 Yeovil Road, Slough, Bucks. Apparatus Washing Machine The Helpex washing machine combines an automatic washer and dryer in a single cabinet.The machine is designed to wash and dry large amounts of glassware without pre- treatment, even if the glassware is contaminated with agar, silicon, albumen, blood, labels or wax pencil. Fine-bore micropipettes can be washed without soaking in chromosulphuric acid. With every wash cycle the machine can thoroughly wash and dry eight glassware boxes measuring 220 x 16.5 x 145mm or four boxes measuring 330 x 290 x 115 mm.Special-purpose boxes are available as well as ones for surgical instru- ments, gloves, syringes, needles, catheters, etc. Siemens Ltd., Great West House, Great West Road, Brentford, Middx., TW8 9DG. High-pressure Reactor The Greiner high-pressure reactor has an ultra- high-speed heating and cooling system and is intended for three-phase reactions such as catalytic, hydrogenation and oxidation reac- tions.The system keeps the reaction tempera- ture constant to within & 1% of the reaction temperature and overshooting of the set temperature is less than 5%. To heat the system to 150 "C takes between 3 and 5 min and cooling can be achieved in about the same time. The reactor chamber features a dip-tube facility to allow samples to be taken during operation.Siemens Ltd., Great West House, Great West Road, I3rentford, Middx., TW8 9DG. Scanning Electron Microscope - X-ray Spectrometer System The PSEM 500 scanning electron microscope has been interfaced with a fully focusing wave- length-dispersive X-ray spectrometer, to create the PSEM 500X.The system can be used for the analysis of X-rays from atomic number 5 (boron) to 92 (uranium) and vertical spectrometer orientation is used to give high mechanical reproducibility without the need for an optical microscope. Specimen-height accuracy and reproducibility are achieved by means of a fully eucentric goniometer coupled with a 4.6 mm fine 2- adjustment (in 0.2-mm steps) and the large Rowland circle (210 mm radius) of the spectro- meter.Torr) improves practical light-element detection as absorption of soft X-rays by specimen contamination is seldom encountered, and also allows operation of sources of higher brightness. A clean high-vacuum system (down to Philips, Eindhoven, The Netherlands. Scanning Electron Microscope The IS1 60 scanning electron microscope is announced. It has a guaranteed resolution of 60 A with attainable resolution of 50 and below.Magnification is from 10 to ZOOOOOx, con- tinuous and in steps with electronic digital read-out of the magnification. Two separate viewing CRTs provide a dual magnification facility with moveable viewfinder and zoom. The high-resolution CRTs with an automatic micron marker ensure sharp micrographs throughout the magnification range.Accelerat- ing voltages are from 2 to 30 kV, stepped and compensated. Dynamic focusing ensures edge-to-edge micro- graph sharpness and four-level gamma control enhances the detail in dark areas. Five scan modes, auto-brightness/contrast, derivative signal processing, specimen and induced current system, and cathodoluminescence are built-in features.Full specimen coverage of 4 in diameter x 1 in thick specimens is provided, X - Y movement tilt is from -10 to +70", rotation from 0 to 360" is continuous and 2 (vertical) movement is externally adjustable from 8 to 38 mm. Systems capability includes X-ray micro- analysis, wavelength spectrometry, scanning transmission detection, electron beam blanking and a pseudo-Kikuchi pattern system. The assembly ensures vibration and environmental isolation.International Scientific Instruments, Inc. (UK), Waterwitch House, Exeter Road, Xew- market, Suffolk. Equipment Ventilation Specialised ventilation systems that can be fitted to all types of atomic-absorption spectro- photometers are offered. Each unit is designed to give the correct flow-rate to draw off toxic and noxious waste without affecting the sensitivity of the flame.The systems can be adapted to handle fumes and heat from flame photometers, gas chromatographs and furnaces. Garrick Equipment Co. Ltd., 13 Garrick Street, London, WC2E 9AR.194 EQUIPMENT XEWS PYOC. Afzalyt. Div. Chem. SOC. Laboratory Personnel Protection Four new laboratory systems for the safety and protection of personnel in laboratories are introduced.1. Lzminar Flow : A self-contained recycling system needing no external extraction, ducting or fans. It is most suitable for handling pathogenic micro-organisms and low-radiation radioactive products (reference, Type “EOLE”) . 2. Laminar Flow: A vertical laminar-flow system with the option of one or two work positions facing each other.(reference, Type “FASAFAS”). 3. Filtering Absorption Canopy : A portable filtering canopy for bench work where the use of conventional fume cupboards is inconvenient. S o external fittings are required (reference, Type HF2). 4. Ventilation Cabinets : Atomic-absorption type ventilated cabinets for the storage of flam- mable and toxic chemicals. Continuous ventila- tion is by means of an activated carbon filter (reference, Type AVA1).Garrick Equipment Co. Ltd., 13 Garrick Street, London, WC2E 9AR. Viscometer The Haake Rotovisco RVll Viscometer has a drive system that is electronically controlled over the same 20 speeds (0.3-486 rev min-l) as the RV1, which it replaces. The torque measur- ing system uses a non-contact technique with a deflection of only 0.5” for the maximum torque of 500 cm g, giving rapid response even a t low speeds.The instrument is available with a wide range of interchangeable stainless-steel measuring attachments. MSE Scientific Instruments, Manor Royal, Crawley, Sussex. Mica and Quartz Retardation Plates A range of more than 30 retardation plates is announced.The plates provide precise phase shifts of lambda/4 or lambda/2 to an input polarised beam. Intermediate phase shifts are also available. They will rotate the polarisa- tion plane of lasers, convert linear to circular polarisation, prevent optical feedback in sys- tems, provide amplitude control of an electro- optical modulator and (in combination with a polarising beam-splitter) make possible a mono- chromatic variable-ratio beam-splitter.The diameters range from 10 to 50mm. Retarda- tion tolerances to lambda/300 (at a specific wavelength) are available in quartz, and to lambda/100 in wide-band mica. All the plates are of precision optical quality. 567, Arnhem, Holland. Melles Griot B.V., Nieuwekade 10, Postbus Radiation Detector A new pocket-sized electronic radiation detector with an audible alarm is available.The new dosimeter, which is designed for use with a base station for recharging and monitoring, measures 19 x 50 x 120mm, has no external controls and incorporates rechargeable silver - zinc batteries that are charged through an inductive loop. In addition to the radiation alarm, a second alarm signal indicates when the battery is low.Brandenburg Ltd., High Voltage Engineering Division, 939 London Road, Thornton Heath, Surrey, CR4 6 JE. Carbon Dioxide Incubator The T304GF is an incubator for the accurate control of temperature, carbon dioxide level and relative humidity. Temperature is controlled within the range 25-75 “C to a tolerance of 1 0 . 3 “C throughout the cabinet. The carbon dioxide level, ranging from zero to 2596, is continuously analysed and controlled through the use of a thermal conductivity sensor, which responds rapidly to changes in the carbon dioxide level as small as 0.1%.Humidity is produced by the controlled recirculation of the cabinet carbon dioxide - air mixture through a water-bath. A polymer foil hygrostat, accurate to 52.004 rh, senses the relative humidity and operates the circulating pump accordingly. Both temperature and carbon dioxide control centres are solid-state plug-in units, which can be easily replaced in the event of a failure.Controls are provided to set the required levels and these are displayed on digital meters. Visual or audible high/low alarms can be specified for the temperature and carbon dioxide functions.Assab Ltd., 110 East Street, Epsom, Surrey. Penless Chart Recorders The Servoscribe 700 is a chart recorder that uses a new thermal writing process and, by using tri- colour thermal paper, is capable of producing traces over 250mm for up to three channels. An integrator module can be incorporated for operation with any single channel, in which event 50 mm of the chart area is utilised for retention time and area print-out.Touch controls are provided for input range modules, motor drive speed selection, Calab - Variab switching, zero checking and integrator interlocking.July, 19 77 EQUIPMENT NEWS 195 Four types of recorder are available : 16 range linear, 16 range lin/log, single range linear and single range lin/log. All models have built-in signal retransmission and can be fitted with a remote chart drive facility which can be used for pulse control from TTL or CMOS signals.Smiths Industries Ltd., Industrial Instru- ment Division, Waterloo Road, Cricklewood, London. SIV2 TUII. Recorder/Controllers The Clearspan PlOlL and P102L general- purpose recorder/controllers have one and two pens, respectively, and give continuous traces on a chart having a 100-mm writing width.Both instruments have a basic recording sensitivity of 5 mV for full-scale deflection, enabling them to respond directly to the output from a thermocouple or resistance thermometer without intermediate amplifiers. Interchange- able plug-in range cards allow the instruments to record up to 300 V or 1 A d.c., 600 V or 5 A a.c., and temperatures up to 1600 "C.Other variables can be recorded by the use of suitable transducers. The linear motor is driven by the output from a differential amplifier, the two inputs of which are derived respectively from the slide-wire contact and, via an interchangeable range printed circuit board, from the variable being measured. Two control/alarm channels per pen allow the instrument to activate visual or audible warn- ings, or to control directly, via contactors if necessary, heating elements, fuel valves, air dampers, etc.Each scale has also one or two manually adjustable control set pointers. The recorders are available with two-step, three-step and high/low control or alarm on each pen. The design enables the two-channel (P102L) recorder/controller to record simultaneously two separate ranges and perform two different types of control.Foster Cambridge Ltd., Howard Road, Eaton Socon, Huntingdon, Cambs., PE19 3EU. Automated Nutrient Analyzer The Automated n'utrient Analyzer comprises a basic AutoAnalyzer I1 system linked to a block digester, giving a system suitable for general analysis in food and agricultural laboratories.A wide range of parameters can be determined in many different matrices, and the system is capable of handling up to 320 samples per day. Technicon Instruments Co. Ltd., Evans House, Hamilton Close, Houndmills, Basing- stoke, Hants., RG21 1BZ. Linear Mass Flowmeter The Flo-Tron 15 Linear Mass Flowmeter measures true mass liquid flow with no density, temperature or viscosity compensation equip- ment or factors needed.Linear flow range is from 30 lb h-l full scale up to 2 000 lb h-l full scale, with an accuracy of &*yo of the reading. Repeatability is good as calibration will not shift with time or with pressure and flow surges. AEP-International Ltd., Victor House, Norris Road, Staines, Middx. Compression Cells Sensotec introduce the 60 Series load cells for use when high-capacity, low-profile compres- sion cells are required.These cells utilise bonded foil strain gauges in a Wheatstone bridge design, which permits cells to accept large off-axis loads. They are designed with complete hermetic sealing and can be provided with a mechanical overload stop to provide up to 40% overload. The Series is intended for applications requiring low-profile cells from 2 000 to 50 000 lb.The dimensions are approxi- mately 7.6 cm diameter x 3.8 cm high. The Series 60-S load cells are designed for applications requiring transducers from 100 000 to 400 000 lb. The dimensions are 11.4 cm diameter x 3.8 cm high. Both transducers have 3 mV V-l output with linearity and hysteresis specifications of 0.07 yo full scale.In addition, several designs are available with higher output capacities of up to 6 mV V-1 with a maximum of 15 V input. Wessex Electronics Ltd., Stover Trading Estate, Uate, Bristol, BS17 5QP. Software Package for Gas Chromatograph - Mass Spectrometer Systems Batch-processor software, added to the data system of the Hewlett-Packard 5980A Series gas chromatograph - mass spectrometer (GC - MS), enables the system to operate unattended for up to 24 h under computer control.The software will be incorporated in all future HP 5934A data systems and can also be added to earlier HP 5933A systems. The unattended data system controls all programmed conditions and automatically examines each sample, finds the apex of each GC peak, strips out the un- wanted background and stores the resulting mass spectrum, The system also automatically performs library searches and completes tabula- tions, plots and graphs.The HP 5934A dual-disc data system is designed to control scan operations of HP Series 5980 mass spectrometers, store spectral data on196 CORRESPONDENCE PYOC. Analyt. Div. Chem. SOC. disc and then display and tabulate these data at operator command.The system is expandable to 255 interchangeable catalogued discs to pro- vide more than 5 billion bits of data storage. Its processor is a semiconductor-memory HP 21MX minicomputer. The HP 5980 Series GC - MS systems use the HP 5840A gas chroma- tograph and offer models with a single electron- ionisation source and a dual chemical - electron- ionisation source.Both have a 3-1 000 a.m.u. mass range covered in a single scan. Sensitivity is to picogram levels. Hewlett-Packard Ltd., King Street Lane, Winnersh, Wokingham, Berks., RGll 5AR. Automatic Sampler for Liquid Chromato- graphs A new automatic sampling system from Hewlett- Packard enables batches of up to 60 samples to be analysed automatically in sequence, and in replication if desired, by HP1084A and HP1082A processor-controlled liquid chromatographs.A detachable unit containing 60 glass vials is located on top of the liquid chromatograph and a variable-volume sample injector samples each vial in numerical sequence. The injection volume can be pre-set manually at any point between 10 and 200 pl. A microprocessor con- trols the analysis in either isocratic or gradient elution mode, monitoring and adjusting all operating parameters, measuring and integrat- ing peak areas, and performing all necessary calculations in a pre-programmed sequence. Hewlett-Packard Ltd., King Street Lane, Winnersh, Wokingham, Berks., RGll 5AR. X - Y Recorders An extension of the modular 26000 series of X - Y recorders is announced. It is claimed that the new recorders, designated the 26700 series, can cut by half the time needed to plot characteristics such as alpha-numerics and computer system data. Pen velocity is 150 cm s-1 on the Y axis and 90 cm s-I on the X axis, and pen acceleration is up to 9 000 cm s - ~ on the Y axis and 5 250 cm s - ~ on the X axis, the overshoot remaining at less than 1% of full scale. The recorders are sup- plied as single-pen models in main frames that offer a choice of A3 or A4 plotting. Accuracy is to the standard of the 26000 series and linearity and repeatability are better than 0.1% of full scale. A11 the modular options and accessories of the 26000 series will be accepted by the new series. Bryans Southern Instruments Ltd., 1 Willow Lane, Mitcham, Surrey, CR4 4UL.

ISSN:0306-1396    

DOI:10.1039/AD9771400192

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

196 CORRESPONDENCE Proc. Analyt. Div. Chem. SOC. Correspondence Correspondence is accepted on all matters of interest to analytical chemists. Letters should be addressed to the Editor, Proceedings of the Analytical Division, The Chemical Society, Burlington House, London, W1 V OBN. Code of Practice for the Use of Gas Cylinders in Analytical Laboratories Sir, I welcome the publication of the “Code of Practice for the Use of Gas Cylinders in Analyti- cal Laboratories.”l The Code complements that recently published by the Department of Health and Social Security in Health Equipment Information (Note 21/75).I would amplify only one section in the light of my own experience of gas cylinders. Para- graph 2.3, “Liquefied Gas,” could usefully have mentioned that carbon dioxide cylinders are fitted with over-pressure bursting discs situated directly opposite the outlet connection.The bursting of these discs occasionally occurred through the extreme heat of last summer, and this could have most alarming consequences if it occurs within a laboratory. I think it is helpful to spell this out, as carbon dioxide cylinders are widely used in clinical analytical laboratories. Reference 1.Proc. Analyt. Div. Chem. SOC., 1977, 14, 57. Yours faithfully, S. S . Brown Clinical Research Centre, Division of Clinical Chemistry, Watford Road, Hawow, Middlesex, H A 1 3 UJJ d y , 19 7 7 ANALYTICAL DIVISION DISTINGUISHED SERVICE AWARD Nomenclature, Symbols, Units and Their Usage in X-ray Emission Spectroscopy Sir, As Chairman of the Analytical Sub-commit- tee, I have been asked by the British National Committee for Chemistry to draw the attention of your readers to a Provisional Nomenclature Report recently issued by the Analytical Division of the International Union of Pure and Applied Chemistry on Xomenclature, Symbols, Units and Their Usage in X-ray Emission Spectroscopy.This report deserves very ser- ious consideration by all X-ray spectroscopists, particularly those engaged on analytical X-ray fluorescence. It will set the scene for approved nomenclature for years to come and all concern- ed are now offered the opportunity to influence and shape these recommendations by reading the report and sending in their comments.At present the report is open to criticism and review and will continue to be so until August of this year. It comprises 25 pages and copies can be obtained from: IUPAC Secre- tariat, Bank Court Chambers, 2/3 Pound Way, Cowley Centre, Oxford, OX4 3YF. Please ask for PNA 54. Yours faithfully, T. S . West The Macaulay Institute for Soil Research, Craigiebuckler, A berdeen, A B9 2Q.r 197

ISSN:0306-1396    

DOI:10.1039/AD9771400196

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

J d y , 19 7 7 ANALYTICAL DIVISION DISTINGUISHED SERVICE AWARD 197 SAC Silver Medal Nominations are invited for the award of the SAC Silver Medal, which is for the encourage- ment of young scientists working in any field covering the practice and teaching of analytical chemistry. The award is accompanied by a cash prize and is normally made annually t o the candidate who, in the opinion of the AD Council, has made the greatest contribution and whose work has made the most significant impact in any branch of analytical chemistry.In addi- tion, the future promise of the candidate is taken into consideration. It is hoped to provide an opportunity for the successful candidate to deliver a lecture to the Division on a suitable occasion subsequent to the presentation of the Medal.1. The award of the Silver Medal will normally be considered annually by the Honours Committee, acting on behalf of the Council of the Division, but an award may not be made if it is considered that the work of no candidate reaches the required standard. 2. Candidates must be British subjects of 38 years of age or under in the year in which the award is considered. Evidence of age will be required.3. The merits of the candidate’s work may be brought to the notice of the Council by any person (being a member of the Analytical Division of the Chemical Society) who desires to recommend the candidate by letter addressed to The President, Analy- tical Division, The Chemical Society, Burlington House, London, W1V OBN. The letter should be accompanied by a short statement on the candidate’s career (date of birth, education and experience, degrees and other qualifications, special awards, etc., with dates, and any other relevant information) and a list of titles of, and references to, papers or other works published by the candidate, independently The rules are as follows-198 CS AUTUMN MEETING PYOC.Analyt. Div. Chem.SOC. or jointly. One reprint of each paper (or other work) for which reprints are available should be submitted. 4. The award will be made on an over-all assessment of the candidate’s contribution, the impact of his/her work and his/her future promise in any field covered by the principles, teaching and practice of the analytical sciences. No restriction is placed as to where the work is conducted. 5. The Committee assessing the applications shall be at liberty to call any candidate for interview. 6. The successful candidate will receive the sum of 2t[ 100 in addition to the Medal. 7. The decision of the Council shall be final. 8. Any alteration to these Rules shall be sub- Recommendations for the next award should be made to The President, Analytical Division, The Chemical Society, Burlington House, London, W1V OBN, by August 31st, 1977. ject to the approval of the Council.

ISSN:0306-1396    

DOI:10.1039/AD977140197b

出版商:RSC    

年代:1977

数据来源: RSC

摘要:

198 CS AUTUMN MEETING PYOC. Analyt. Div. Chew. SOC. Course Solid - Liquid Separation September 6-9, 1977, Byadford Following the success of the 1974 and 1975 courses the Institution of Chemical Engineers is sponsoring a further and extended course on solid - liquid separation, to be held at the XJni- versity of Bradford. The course is intended for chemical engineers and graduates in related disciplines such as chemistry and mineral processing who are seek- ing a concise coverage of the essential principles and recent developments of importance in the subject. The lectures will be given by a group of international specialists and practical demon- strations of some equipment will be included. Further information can be obtained from Dr. L. Svarovsky, School of Powder Technology, University of Bradford, Bradford, West York- shire, BD7 1DP.

ISSN:0306-1396    

DOI:10.1039/AD977140198d

出版商:RSC    

年代:1977

数据来源: RSC