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MOLARITY VERSUS PER CENT

MOLARITY VERSUS PER CENT Abstract To the Editor: In patch testing, the concentration of the active agent in the inert vehicle is often of critical importance. Per cent is the usual way of specifying concentration. In the case of metal salts, the use of per cent has led to a curious error. Surprisingly enough, the "5%" nickel sulfate solution used by many dermatologists contains only 3% nickel sulfate ! This error results from technicians simply weighing out 5 gm of the commercially available nickel sulfate hexahydrate to make 100 ml of solution. As nickel sulfate hexahydrate contains 40% water, the resulting solution is actually only 3% with respect to nickel sulfate.Specific inquiries to dermatologists both here and abroad revealed this type of error to be widespread. In most cases the dermatologist was unaware that the technician making the solution was simply weighing out the percentage in terms of the hydrate. Molarity is an unequivocal way References 1. Chrome Sensitivity, Editorial , Arch Derm 90:2, 1964.Crossref 2. Fregert, S., and Rorsman, H.: Allergy to Trivalent Chromium , Arch Derm 90:4, 1964.Crossref 3. Samitz, M. H., and Gross, S.: Effects of Hexavalent and Trivalent Chromium Compounds on Skin , Arch Derm 84:404, 1961.Crossref 4. Samitz, M. H.: Personal communication to the author. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Dermatology American Medical Association

MOLARITY VERSUS PER CENT

Archives of Dermatology , Volume 91 (1) – Jan 1, 1965

MOLARITY VERSUS PER CENT

Abstract

Abstract To the Editor: In patch testing, the concentration of the active agent in the inert vehicle is often of critical importance. Per cent is the usual way of specifying concentration. In the case of metal salts, the use of per cent has led to a curious error. Surprisingly enough, the "5%" nickel sulfate solution used by many dermatologists contains only 3% nickel sulfate ! This error results from technicians simply weighing out 5 gm of the commercially available nickel sulfate...
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References (3)

Publisher
American Medical Association
Copyright
Copyright © 1965 American Medical Association. All Rights Reserved.
ISSN
0003-987X
eISSN
1538-3652
DOI
10.1001/archderm.1965.01600070100028
Publisher site
See Article on Publisher Site

Abstract

Abstract To the Editor: In patch testing, the concentration of the active agent in the inert vehicle is often of critical importance. Per cent is the usual way of specifying concentration. In the case of metal salts, the use of per cent has led to a curious error. Surprisingly enough, the "5%" nickel sulfate solution used by many dermatologists contains only 3% nickel sulfate ! This error results from technicians simply weighing out 5 gm of the commercially available nickel sulfate hexahydrate to make 100 ml of solution. As nickel sulfate hexahydrate contains 40% water, the resulting solution is actually only 3% with respect to nickel sulfate.Specific inquiries to dermatologists both here and abroad revealed this type of error to be widespread. In most cases the dermatologist was unaware that the technician making the solution was simply weighing out the percentage in terms of the hydrate. Molarity is an unequivocal way References 1. Chrome Sensitivity, Editorial , Arch Derm 90:2, 1964.Crossref 2. Fregert, S., and Rorsman, H.: Allergy to Trivalent Chromium , Arch Derm 90:4, 1964.Crossref 3. Samitz, M. H., and Gross, S.: Effects of Hexavalent and Trivalent Chromium Compounds on Skin , Arch Derm 84:404, 1961.Crossref 4. Samitz, M. H.: Personal communication to the author.

Journal

Archives of DermatologyAmerican Medical Association

Published: Jan 1, 1965

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