Mav. 1923
INDUSTRIAL A N D ENGINEERING CHEMISTRY
529
The Development and Use of Standards for Reagent Ch emi cals1 By W. D. Collins U.
s. GEOLOGICAL SURVEY.
DEPARTMENT O s THE INT&RIOR, WASHINGTON, D. C .
P
UBLICATIONS on the subject of standards for reagent chemicals have necessarily followed in a general way the work of Krauch, published in 1888, and revised in 1891 a n d in 1896. The publication issued by E. Merck, of Darmstadt, in 1905, and revised in 1912, was a continuation of the series, as is Murray’s “Standards and Tests for Reagent Chemicals,” published in 1920. This last book is not a mere revision of the earlier ones, hut is the product of the author’s years of experience in charge of the control laboratories of Merck & Company, at Rahway, N. J. The close connection of these later publications with the firms of E. Merck, a t Darmstadt, and Merck & Company, of New York, has limited their usefulness as avowed reference standards for other manufacturers of chemicals. The Merck reagents have been sold as conforming t o the standards given in these texts. Raker & Adamson, now the Baker & Adamson Works of the General Chemical Company, of Easton, Pa., started over twenty years ago to put out a line of analyzed chemicals. Each bottle bore on the label an analysis showing the limits of strength and purity of the contents. A little later the J. T. Baker Company, at Phillipsburg, N. J., began the manufacture of a similar line of analyzed reagents. The tests used for the Baker and Adamson reagents have not been published. Those used by the J. T. Raker Company for a considerable number of their analyzed reagents have been described in different numbers of the Chemist-Analyst, published by the company. More recently, Powers-Weightman-Rosengarten and the Mallinckrodt Chemical Works have developed lines of reagent chemicals with analyses and standards of purity given on the labels. The tests used by Powers-Weightman-Rosengarten have not been published. The tests employed for some of the Mallinckrodt reagents are given in the Mallinckrodt Red Book, published in 1922. For a number of years Eimer & Amend has sold reagent chemicals which it guarantees. More recently, the Central Scientific Company has adopted the same practice. These two firms do not manufacture the reagents, but guarantee the quality .on the basis of analyses made in their own laboratories. This is, in fact, the practice of manufacturers with reference to some of their guaranteed reagents. The differences between the standards of the different manufacturers are not great. The difficulties that have been experienced in the use of these analyzed chemicals have rarely been from any laxity in the standards, but in practically all instances have been due to deficiencies in purity or strength that were so great as to suggest that testing of the particular lot in question had been .omitted entirely. A number of instances of this sort are given in a paper by H. E. Buc, on the quality of chemicals received by the Bureau of Chemistry during the war.2 Although this paper was confined to the experience of the author over a period of about four years, the record of laboratories where such tests have been made indicates that similar difficulties had been experienced before the war. The U. S. Pharmacopeia has always given certain standards for the reagents used in testing the different substances listed. 1 Presented with the report of the Committee on Guaranteed Reagents and Standard Apparatus at the fi5th Meeting of the American Chemical .Society, New Haven, Conn., April 2 to 7, 1923. 2 THISJOURNAL, 11 (1919), 1140.
These standards have in the past generally been somewhat less severe than the standards of purity claimed for some of the analyzed reagents. It has been noted, however, that the analyzed reagents, for which much greater purity was claimed, were frequently less pure than material sold under the designation “U. S. P,” This has resulted from the fact that if a chemical is purified sufficientlyto pass a moderate requirement for purity, such as the older U. S. P. standards, it is considerably purer than these standards require. A committee representing the Institute of Chemistry of Great Britain and Ireland, the Society of Public Analysts, and other analytical chemists published in 1915 a list of analytical reagents and tests. This list covered a large number of ordinary laboratory reagents. The standards and tests must have been taken in large measure from published works, and probably represented comparatively little original work done specifically for the report. The tests are not notably different from those of Krauch. A similar report was published by a committee representing Group 1 of the “Congress de la Chimie I n d ~ s t r i e l l e . ” ~This publication is not very different from that of the English committee. The Committee on Guaranteed Reagents and Standard Apparatus of the AMERICAN CHEMICAL SOCIETY published4 in 1921 tentative specifications for four reagents. These specifications also call for about the same standards of strength and purity, and prescribe tests that are not greatly different from those in other specifications. Most of the tests for ordinary impurities have been for many years so well standardized as to leave little opportunity for originality in the devising of new tests. In a few respects, however, improvements have been made in the application and interpretation of standard tests, like the use of silver nitrate for chloride and barium chloride for sulfate. Many specifications for reagents leave considerable doubt as t o the actual purity defined by the tests that are prescribed. The requirement may be that no precipitate be formed or that only a slight turbidity shall result on addition of a reagent. The difficulties arising from this usage are discussed in an article by Amy5 in which it is suggested that: Such tests could direct, for instance, that a 5 per cent solution of the salt mixed with definite amounts of the appropriate reagents and diluted to a definite volume, say 10 cc., should show no more turbidity than a 5 per cent solution of the C. P. chemical, to which has been added a definite volume of a standard solution of the impurity plus definite amounts of the appropriate reagents and diluted to the definite 10 cc. volume, the two fluids to be compared in test tubes.
It is understood that this suggestion is being followed by the committee now revising the U. S. Pharmacopeia. The same principle was usede by the Committee on Guaranteed Reagents and Standard Apparatus of the AMERICAN CHEMICAL SOCIETY, except that the quantity of impurity is stated as a definite weight rather than as a volume of a standard solution. A person or organization undertaking to draw up ne“w specifications for reagent chemicals faces a n extremely difficult task. a
Chimie
4
THISJOURNAL, 13 (1921), 735 J. A m . Pharm. Assoc., 9 (1920), 972. THISJOURNAL, 13 (1921), 948.
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induslrie, 9 (1923), 15.
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INDUXTBIAL APT! ENGINEERING CHEMISTRY.
Vol. 15, No: 5
It must be recognized a t the outset that the standards for rea- articles after they have been tested. Published specifications, gents for carehil, general analytical work cannot be set suffi- definitions, and tests are only minor aids to the chemist in obciently high to cover all uses of reagents without making the cost taining satisfactory reagents. Constant testing in his own labprohibitive. Careful examination of the published standards oratory is necessary unless his experience or that of others has and tests will reveal discrepancies between the actual limits of shown that the manufacturer whose reagents he uses does not sensitiveness of some tests and the limits given in the texts. permit untested reagents to be sold under his guarantee. It may also be found that either,the tests or limits for some imFor a number of years the Committee on Guaranteed Reagents purities are more severe than cad be b e t “by ahy reagents that paratus has tried to learn from members of the are obtainable commercially. On the other hand, manufa&&r-er.s AMERICANCHEMICAL SOCIETY their experiences with unsatisregularly produce some reagents of considerably higher purity factory reagents, but the instances reported to the committee than is required to pass tests that have long been recognized as have been so few that if it were not for their own experiences standard. members of the, committee wsuld think, that no reagents of In view of all that has been published on the subject and ip .poor quality were, manufactu or sold iu the United States. consideration of all the work now in progress, i t may be doubted This is due in part to the fact that comparatively little testing of whether further specifications prepared by a committee of the ,reagents is done in thg laboratories where they are used. ,Making SOCIETY are needed. If such specifica- new specifications will not improve the situation in this respect. AMERICAN CHEMICAL tions are merely copies of thpse already published, they will The best way to insure freedom from analytical errors due to add little, tq the welfare of analytical chemists. To investigate .poor reagents is by careful testing of the reagents. The next all the requirements for a single reagent,*to9 best way is to buy reagents guaranteed by a dealer or manufacof all manufacturers, and to work over eack.test to find its re- turer wbo has not failed to maintain close agreement between the liability and sensitiveness is no small task, When it is done the claimed and actual standards of purity of his reagents. The analyst may not be much better off. A specification accomplishes second is the only practicable way for many small laboratories little except as it is used by a buyer to govern his acceptance of and is the cheaper way for almost any laboratory.
Personals H. H. DOW,president ol the Dow Chemical Co., Midland, Mich., returned recently from a trip to Hawaii, Japan, and other points of interest in the Orient. Leroy W. Davis, formerly Cleveland representative of the Universal Packing Corp., Pittsburgh, Pa. is now employed as .a chemical engineer directly connected dith the sales department of the New Era Metal Products Co., Kalamazoo, Mich. Chester H. Penning has accepted an appointment as special expert with the chemical staff of the Tariff Commission. E. L. Rimbault, formerly reclamation manager of the National Aniline & Chemical Co., Inc., a t the Buffalo plant, has been appointed manager of the Intermediates and Certified Food Color Divisions, 40 Rector St., New York City. Milo R. Daughters, manager of research for The Dominion Canners, Ltd., Brighton, Ontario, has resigned to engage in business with the Polk Co., Haines Citj, Fla. Merrill A. Youtz, formerly of the Research Laboratory of Applied Chemistry, Massachusetts Institute of Technology, Cambridge, Mass., has accepted a position in the research laboratory of the Standard Oil Co., Whiting, Ind. R. P. Rose, chemical engineer for the U. S. Rubber Co., returned to this country the first of February after having spent two years in Sumatra, D. E. I., where he installed plants for the utilization of the Hopkinson process for producing rubber and equipment for the shipment of latex to this country in ship’s tanks. C, Everett Smith, until recently a graduate student at the University of Wisconsin, has accepted a position as chief chemist for the Minnesota Mining & Manufacturing Co., St. Paul, Minn., makers of sandpaper and coated abrasives. W. F. Lantz has been appointed chief chemist at the plant of the Bethlehem Steel Co.,Bethlehem, Pa. E. C. Moffett, formerly with the Ideal Disinfectant Corp., Woodbridge, N. J., is now in charge of the research laboratory of the American Cyanamid Co., Warners, N. J. The‘ division of chemistry and chemical technology of the National Research Council, Washington, D. C., has named James R. Withrow as chairman of the National Research Council Committee on the Use of Sodium Compounds as a Substitute for Potassium Compounds, both in Scientific and Industrial Work. Professor Withrow declined the position as chairman of this committee four years ago because of the pressure of university work. G. F. Moulton has resigned his position a t the Bureau of Standards to accept a place as chemist in the research department of F. C. Huyck & Sons, Albany, N. Y.
I. Joseph Farley, formerly an assistant examiner in the U. S. Patent Office, and a member of the District of Columbia Supreme Court and Court of Appeals Bar, has joined the staff of Richards & Geier, patent and trade-mark attorneys, 277 Broadway, New York City. F. W. Willard has been appointed superintendent in charge of chemical engineering, development, and research for the general Manufacturing Department of the Western Electric Company’s Hawthorne Works, Chicago, 111. L. E. Wemple, general manager of the American Zinc Oxide Company and the American Zinc Sales Co., subsidiaries a t Columbus, Ohio, of the American Zinc, Lead & Smelting co., has resigned his position to accept the position of vice president and production manager of the Evans Lead Co., Charleston, W. Va. E. N. Klemgard, formerly chemist and lubrication engineer for Fiske Brothers Refining Co., is a t present employed as chemist in the research laboratories of the Standard Oil Co., Richmond, Calif. H. A. Noyes, formerly chemist in the Department of Agriculture, East Lansing, Mich., is now associated with R. F. Bacon a t the New Rochelle Research Laboratories, 24 Grove Ave., New Rochelle, N. Y. Arthur H. Huisken, formerly employed as chemist in the Chemical Warfare Service located a t Edgewood Arsenal, Edgewood, Md., has accepted a position as chemical engineer in the Chemical Division of the Western Electric Co., Chicago, Ill. Wilson H. Low,for twenty years head chemist of the Cudahy Packing Co., Omaha, Neb., is now employed by the Western Chemicals, Inc., a t Alum, near Blair Junction, Nev. Charles Moureu has been elected president of the Chemical Society of France. George de Wyss has resigned his position as chemist with the Cudahy Packing Co., Omaha, Neb., to accept a position in the Research Laboratory of the Viscose Co., Marcus Hook, Pa. W. Nelson Smith, consulting electrical engineer of the Winnipeg Electric Railway Co., and John W. Shipley, professor of chemistry at the University of Manitoba, have recently been awarded the Plummer Medal for 1921-22 by the Engineering Institute of Canada, for their two research papers entitled, “The Self-Corrosion of Cast Iron and Other Metals in Alkaline Soils,” and “The Self-Corrosion of Buried Lead Pipes.” These papers were published in the Journal of the Elzgineering Institute of Canada,in October, 1921, and June and July, 1922; and-were also reproduced in full in the Sibley, Journal of Engmeering, published a t Cornell University in March and November, J922.
