notes on nomenclature M.
GUY MELLON
Purdue University Lafayette, Indiana 47907
This column is happy to have as guest contributor Dr. M. G. Mellon, Professor Emeritus, Purdue University. Professor Mellon has made significant contributions to analytical chemistry, to the techniques for the maximum utilization of the chemical literature, and to the design of chemical laboratory buildings. He has long been a n advocate of more precise nomenclature in the area of analytical chemistry. He presents the need for such nomenclature improvements and points out some ways to obtain this improvement.
What Mean These Words? The use of words is perhaps our most important means of communication. In technical writing, a t least, their meanings should he clear enough that the product can not he misunderstood. In chemistry names are indispensible to designate various entities, such as elements, compounds, ions, radicals, instruments, processes, properties, operations, and others. The concern here is analytical chemistry. Current analytical writing is less than clear. Attestation, azotometry, bomb washing, catalimetric, colaminometric, copper mold, coulopotentiography, derivatographic, dosimetric, ellipsometry, exhalographic, float, frequentometric, head space, impedimetry, oncometer, oscimhometer, permittivity, polaristrohometric, riptographic, Rontgenometric, Schoninger flask, stalagmometric, thermoponderometric, and frustrated internal reflection. What mean these words? I may he frustrated by such usage, hut can a beam of radiant energy he so affected? They, along with others of uncertain meaning, have been appearing in the analytical sections of Chemical Abstracts Recently Professor Douglas Bush ( I ) began his discussion of "Polluting Our Language" with the following paragraph Along with our overriding anxieties about the state of the world and our own country we are resentfully aware of shoddiness in cars, foods, services, in almost everything except the language we use. While an aroused public applauds the exposure of civic corruption and environmental pollution, neither the public at large nor officialdom has any concern with the corruption and pollution of language except to contribute to it. And this kind of corruption is quite as disastrous as any other, if not more so, partly because common violation of traditional usage is an ugly debasement of our great heritage, partly because sloppy English is a symptom and agent of sloppy thinking and feeling and sloppy communication and confusion. To the famous question, "How do I know what I think till I hear what I say?" the answer might be, "Do you and I know then?" In the early 1940's criticism of inconsistent and questionable usage of terms and names in the Analytical Edition of Industrial and Engineering Chemistn led Dr. H. E. Howe, then the editor, to request the appointment of a committee to consider the prohl'em. Specifically, he hoped to obtain recommended guide lines to follow in improving current usage. 690
/
Journal ot Chemical Education
Dr. H o w arranged for the appoinrmmr nf a Committee on Yamlng Analytwal Methoda in the Division of Analhrical and hlicru Chem~stn.ut the American Chemical Society. In a Progress ~ e p o r in t 1947 ( 2 ) attention was directed to the introduction of questionable new terms, and to the inconsistent use of long known terms. Reference is made later to two attempts to deal with some of these terms and their definitions. Of more importance were the variations found in the usage of these and other terms in designating the kinds of procedures employed in analytical methods. Unrestrained free enterprise had resulted in naming methods in a t least the following ways 1) The originator(s)of the method a) The individuaKs);e.g., the Kjeldahl method h) The institution or laboratory; e.g., the Ural Polytechnic
Institute method 2) The organization approving the method a) Name only; e.g., the USP (U. S. Pharmacopoeia) meth-
ad h) Name and status of adoption; e.g., the ASTM (American Society for Testing and Materials) official or tentative method c ) Name and applicability; the AOAC (American Assoeiation of Analytical Chemists) general or specific method d) Name and number; the APHA (American Public Health Association) method I 3) The kind of material analyzed; e.g., the steel analysis method 4) The physical state of the sample material; e.g., the gas analysis method 5) The scale of operation used; e.g., the macro, micro, or ultramicro method 6) The kind of method of measurement used; e x . , the electrical method I ) The effect or action of the desired constituent: e.g., the emanation method 8) The instrument or special equipment used a ) In the preliminary treatment; e.g., the Parr bomb method h) In the separation of the desired constituent; e.g., the mercury cathode method c) In the measurement of the desired constituent; e.g., the refractometer method 9) A special method; e g., any method not gravimetric or titrimetric (by volume) 10) The combined process of separation (if necessary) and the operation of measurement; e.g., the extraction gravimetric method Subsequent to the publication of the first report, a new Committee on Nomenclature of the ACS Division of Analytical Chemistry, with L. T. Hallett as chairman, issued a Progress Report (3). Some 32 terms were defined. They ranged from accuracy to volumetric. Several, such as gasometric, spectroanalysis, and thermometric, were not recommended. Immediately following this report was one by a joint committee representing the Society for Applied Spectroscopy and the American Society for Testing and Materials with H. K. Hughes as chairman. Its Suggested Nomenclature in Applied Spectroscopy covered many terms used in absorption and emission spectroscopy (4). There is some duplication with the Hallett report. These two reports were a commendable start toward
recommending consistent terms and definitions. After two decades some entries need reconsideration and no doubt new ones should be added. Neither report considered the problem of naming a method of analysis, particularly a quantitative one, so that the entry in a subject index, such as those of Chemical Abstracts, would indicate the process of separation (if any) and the operation of measurement. Committees of various organizations, such as the American Society for Testing and Materials and the International Union of Pure and Applied Chemistrv. have recommended symbols, terms, and-definitions for-several specific areas. Examples are ion-exchange, flame emission spectroscopy, and gas chromatography: If, and when, a system of naming methods is attempted, these reports must he considered. The Present Problem
The overall general situation in terms, definitions, and nomenclature remains much the same as in 1947. There has been some improvement and some retrogression. The recommendations in the Hallett and Hughes reports have often been disregarded. Inconsistent terms have been coined for new techniques, and there is confusion in the use of old terms. Some examples will illustrate these statements. Analysis and determination should be clearly differentiated. Thus, one determines calcium in water, and analyzes the metal calcium for its minor components. The distinction becomes important in using computer output when the input is based on titles, as in Chemical Titles. If one wants only references on the analysis of calcium, the large majority of those obtained are likely to deal with the determination of calcium in something else. In this connection, many of the advertisements in periodicals for "analvzers" reallv refer to determinators. One firm uses determinator for-its equipment. Monitor appears occasionallv. Meter is common for DHinstruments. The term volumetric has long been applied to titrations by volume; but if the titrant is weighed, the operation is not volumetric. Yet author, reviewer, and editor seem to have erred in an article entitled, "A Weight Buret for Volumetric Analvsis." In anv case. the term volumetric is needed for determinations in which the desired constituent (or somethina chemically equivalent to it) is measured by volume. his-includes gases, liquids, and (not often) solids. Terms in the broad area of spectroscopy are often inconsistent. Methods involving arc or spark emission are specified widely as being spectrochemical, although ahsorption methods may be meant. About the only related chemical terms are electrochemical and thermochemical, neither of which is widely used. One never sees, e.g., gravichemical, densicbemical, or voluminochemical. In general, naming a method of measurement by the property measured seems appropriate. Many properties are so used: mass, volume, pressure (of gases), density, and a variety of electrical, optical, and other properties. Comhining the property name with the endings -metry, metric, and -meter provides for the area, the kind of determination, and the instrument. Wet, classical, chemical, conventional, and instrumental. Again, what mean these words? If one believes that technical writing should be clear and precise, do such terms have any place in analytical publications? Yet they appear in every batch of galley proof for Sections 79 and 80 of Chemical Abstracts. In using such terms authors generally aim to compare their method in some way with one or more older or different methods. Why do they not designate specifically the other methods, if gravimetric, titrimetric, manometric, or others are meant? If the author does not so desig-
nate the comparison methods, the abstractor is helpless. The use of wet is interesting, especially when applied to a case such as burning the carbon out of an alloyed steel a t 1200°C and absorbing the carbon dioxide in dry Ascarite for weighing. It stretches one's concept of wetness to apply the term to a system at 1200°C. Anyway, what property is measured in a wet method? Classical and conventional probably mean gravimetric or titrimetric. If so, why not so state? There are other old methods. To compare a new method with a method of chemical analysis seems rather absurd. Following Robert Boyle's definition, all methods providing information about the chemical composition of materials are methods of chemical analysis. As with chemical, the term instrumental is intended to differentiate certain methods from certain others. It can not be a differentiating term if one concedes that all measurement is instrumental in the sense that the operation involves determining the number of times the unit of measurement goes into the unknown, i.e., assigning a number to a physical property. No differentiating definition is known to me. An example of confusion is the use of iodimetry and iodometry. The latter term has not been recommended, but nearly every issue of Chemical Abstracts contains it. Fairly generally, in titrimetry the various subdivisions of the subject are named in terms of the nature of the reaction of the titrant. Thus, acidimetry is the use of acids (Arrhenius, Bronsted, Lewis, Pearson?), precipitimetry the use of precipitants, and iodimetry the use of a specific oxidant, the triiodide ion. Iodometry, in contrast, implies or desianates the use of sodium thiosulfate as reducine titrant. The Hallett report recommended thiosulfatimetr; I have used terms mentioned in item 10 (5. 6).This nomenclature was based on the assumption that the process of separation and the operation of measurement are the most important items to consider in selecting a functional name for indexing purposes. Of course, unless necessary, there is no separation in any procedure. This general idea of nomenclature for methods is being adopted in the new and revised methods of analysis of metals published as Volume 32 of the "Annual ASTM Standards'' of the American Society for Testing and Materials (7). Representative titles follow: Ion-exchange atomic absorption method (Pb); Chromatographic gravimetric method (S); Electrodeposition gravimetric method (Cu); Dimethylglyoxime extraction photometric method (Ni); Molybdenum blue extraction photometric method (Si); Sulfide iodatimetric titration method (Sn); and Combustion thermal conductivity method (C). Three of these names indicate the reagent used. Such titles, when indexed, give one a good idea of how the analysis is done. In contrast, Kjeldahl's method (for N) does not. Recent issues of Chemical Abstracts have reported a number of procedures in titles and/or abstract, as being extraction photometric methods. Maybe progress is possible. However, there bas been no general approval, let alone adoption, of such functional nomenclature. To apply it generally one needs a list of process terms for kinds of separations. Well known tvpes are absomtion. adsorption, condensation, diffusion, d&olution, electrode: position, extraction, partition, and volatilization (including combustion, disiillation, evaporation, and suhlimation). All of these words have the -tion process ending. Chromatography (in all its types) is inconsistent. What is the process in this case? Then the final need is a comprehensive list of operational terms for kinds of measurement. Many of these are already accepted. Some need reconsideration, and some additions are necessary. Volume 50. Number 10, October 1973
/
691
Indication of Kind ot Analytical Methods Used in 260 Papers Dealing with the Determination of Nickel
Index Heading Method Indicated in Entry Number Indexes Titles Abstracts Ni, detn. in steel iron and steel Total
160 90 10 260
0 0 0 0
95 66 9 170
144 80 10 234
In general, suhject indexes have been deficient for searching for particular kinds of methods. As already noted, we have had no consistent nomenclature to follow. And even what we have authors do not use very well. To illustrate the problem, a t one time I was concerned with photometric methods for nickel. The suhject indexes of Chemical Abstracts were searched for a 10-yr period. Under the heading, "Nickel, detn." there were 160 entries; and under the subheadings, "in steel" and "in iron and steel" there were, respectfully, 90 and 10 entries.
692 I Journal of Chemical Education
The table shows the nature of the information found in the indexes, the titles, and the ahstracts. Thus, the suhject indexes for these 260 entries show nothing of the kind of method used. The titles are adequate for 170, and the abstracts for 234 papers. This means that one had to examine the 26 papers for which no information was given. If they were in obscure languages and had to he translated, the searcher would not he very happy. Is it not feasible to select terms and names which are acceptable and consistent for analytical writers? Otherwise, there will remain the question, "What Mean These Words?" Literature Cited
.
... .-. . ... 17) ASTM-Committee E 3, "Annual ASTM Stsndsrds," American Saiety for Testing and Materials, P,hiladrlphia, Pa.
