Study of the determination of inorganic arsenic species by CE with capacitively coupled contactless conductivity detection

The determination of arsenic(III) and arsenic(V), as inorganic arsenite and arsenate, was investigated by CE with capacitively coupled contactless conductivity detection (CE‐C 4 D). It was found necessary to determine the two inorganic arsenic species separately employing two different electrolyte systems. Electrolyte solutions consisting of 50 mM CAPS/2 mM L ‐arginine (Arg) (pH 9.0) and of 45 mM acetic acid (pH 3.2) were used for arsenic(III) and arsenic(V) determinations, respectively. Detection limits of 0.29 and 0.15 μM were achieved for As(III) and As(V), respectively by using large‐volume injection to maximize the sensitivity. The analysis of contaminated well water samples from Vietnam is demonstrated.