Application of pelletized sodium borohydride in the spectrophotometric determination of arsenic

The spectrophotometric determination of arsenic using sodium borohydride in pellet form, with excipients as the reducing agent and arseine former, has been studied. The use of pelletized sodium borohydride allows the formation of arsenic diethyldithiocarbamate and enables an accurate application of the method without the use of other reagents. The gradual reducing action of the pelletized sodium borohydride, together with the release of hydrogen thus forming arsine with As(III), is the main advantage of this procedure. The arsine thus formed bubbles through the chloroform solution of silver diethyldithiocarbamate to form the complex that allows the determination of the arsenic by visible spectrophotometry.