THE QUANTITATIVE DETERMINATION OF ARSENIC 

 BY THE GUTZEIT METHOD. 



By Charles Robeet Sanger and Otis Fxshek Black. 



Several attempts have been made to apply the so-called Gutzeit 

 reactions to the quantitative determination of arsenic, especially in 

 England since the epidemic in 1900 of arsenical poisoning from beer. 



Kelj-nack and Kirkby^ suggested that an approximate valuation 

 of the amount of arsenic in a sample of beer may be made by compar- 

 ing the stain produced on mercuric chloride paper by the arsenical 

 hydrogen from a given portion of the sample with that produced by a 

 definite quantity of a standard solution of arsenic. 



Bird 2 made a careful study of the conditions under which the arseni- 

 cal stain on mercuric chloride paper may be best obtained and identi- 

 fied, -vsith especial reference to the interference of the hydrides of 

 sulphur, phosphorus, and antimony. Although his work is extremely 

 suggestive of a quantitative application, he himself considers that the 

 test is only approximately quantitative, in that the stain obtained from 

 a given amount of substance, say beer, may be shown to be greater or 

 less than the stain representing a fixed limit of arsenic for that amount. 

 He also regards it as a true negative test. 



Treadwell and Comment ^ compared the stain obtained from the 

 action of arsine on argentic nitrate paper with a series of stains fi'om 

 definite quantities of a standard solution of arsenic. The method, 

 applied by these authors to the detection of arsenic in mineral waters, 

 is said to have given good results. 



Dowzard, * after describing a modification of the Gutzeit test which 

 allows the detection of minute traces of arsenic in a small volume of 

 solution, suggested the preparation of a standard set of stains, which 

 should be kept in a tightly stoppered bottle in a dark place. 



^ Arsenical Poisoning in Beer Drinkers, p. 88. London, Balliere, Tindall, and 

 Cox, 1901. 



2 Analyst, 26, 181 (1901). 



3 'Treadwell, Kiirzes Lehrbuch der Analytischen Chemie, 2, s. 138 (1902). 

 * Chem. News, 86, 3 (1902). 



