Solid-Phase Extraction of As(III) from Aqueous Samples Using On-Column Formation of As(III)-Trispyrrolidinedithiocarbamate

摘要

Two methods are presented for the selective preconcentration of As(III) by using complexation-type stationary phases. These phases are prepared: (1) by loading a C18-bonded silica with the cetyltrimethylammonium-pyrrolidinedithiocarbamate (CTA+-PDC#x2212;) ion-pair, or (2) by converting a strong anion-exchange (SAX) resin from the quaternary ammonium form into the pyrrolidinedithiocarbamate (PDC#x2212;) form. When As(III)-containing solutions are passed through such stationary phases, the immobilized PDC#x2212;yields the non-polar As(III)-trispyrrolidinedithiocarbamate (As(PDC)3) which is retained on the non-loaded second part of the C18 cartridge (method 1), or on an unloaded C18 cartridge coupled in series with the SAX cartridge (method 2).