Affiliation:
1. Department of Chemistry and Biochemistry, George Mason University , Fairfax, Virginia 22030-4444, USA
Abstract
This work describes a novel technique for the measurement of inorganic arsenic in water by generating arsine gas and detecting the conductivity of moving protons, H+ (aqueous or aq), produced by the reaction: Ag+ (aq) + AsH3 (gas, g) → AgAsH2 (solid, s) + H+ (aq). The detection is based on an electrochemical gradient of protons in a confined porous substrate (filter paper) and measures the change in the conductance due to the higher mobility of H+ compared to other ions. The conductance was measured with a pair of silver electrodes attached to opposite sides of the substrate with a bipolar pulse conductance technique. The method is established in theory and in practice. The theoretical equation for conductance change shows that a constant increase in conductance is directly proportional to the As(total) concentration. The method is validated with a standard reference material and applied to the measurement of the groundwater sample.
Subject
General Physics and Astronomy