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The Determination of Silver in Photographic Emulsionsby Discontinuous Flow Analysis
Author(s) -
Dole A. J.,
Cardwell T. J.,
Cattrall R. W.,
Di Giacomo R.,
Rodrigue C. G.,
Scollary G. R.
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199801)10:1<21::aid-elan21>3.0.co;2-9
Subject(s) - titration , chemistry , silver halide , thiosulfate , inorganic chemistry , repeatability , halide , potentiometric titration , sulfide , silver bromide , cyanide , sodium thiosulfate , flow injection analysis , sodium sulfide , silver sulfide , cyclic voltammetry , analytical chemistry (journal) , layer (electronics) , ion , electrochemistry , detection limit , chromatography , sulfur , electrode , organic chemistry
An investigation of the use of the flow‐based procedure of discontinuous flow analysis (DFA) for the determination of silver in photographic emulsions is described. It is shown that a procedure used by the photographic industry which involves the complexation of a silver halide with the thiosulfate ion followed by titration with thioacetamide produces poor repeatability when applied in DFA. Evidence is presented to demonstrate that this is due to a slowing of the response of the silver sensor used to detect the end‐point in the titration which is caused by the formation of a loosely bound layer of silver sulfide on the sensor surface. This surface layer has been identified using scanning electron microscopy and cyclic voltammetry. An alternative procedure is proposed for the determination using DFA which involves complexing the silver halide (bromide) with the cyanide ion followed by titration with sodium sulfide. The results from this method are within 2% compared with those obtained by AAS.