Detection tube method for trace level arsenic. Issue 1 (March 2015) - Kiso, Yoshiaki
Graphical abstract: The color band length was correlated almost linearly with the arsenic concentration in the range of 0.01–0.1 mg L −1 . Highlights: The detection tube method enabled visual determination of As(V), at 0.01 mg As L −1 . The color development was conducted by a modified molybdenum blue method. As(III) was also detected at 0.01 mg As L −1 by this method after oxidation to As(V). Abstract: Arsenic pollution of surface and ground waters has been reported in many developing countries, and it is therefore an important task to detect arsenic rapidly using a simple and inexpensive tool. This work focused on the detection of arsenic at 0.01 mg As L −1 by visual determination. A small column packed with the poly(vinylchloride) particles coated with a quaternary ammonium salt was used as a detection tube. Molybdoarsenic heteropoly acid (molybdenum blue) was derived from arsenate under modified reaction conditions. The molybdenum blue solution (20 mL) was introduced into the detection tube by suction with a syringe to form color band. As(III) was measured after oxidation with sodium dichloroisocyanuric acid. The color band length in the detection tube was correlated linearly with the arsenic (As(III) + As(V)) concentration in the range of 0.01–0.1 mg As L −1, and the relative standard deviations in the concentration range were around 1%. Arsenic was successfully detected at 0.01 mg As L −1 using this detection tube.