极谱催化波快速测定水质中的痕量三价砷和总砷

Rapid Determination of Trace Amounts of Arsenic(Ⅲ)and Total Arsenic in Water by Catalytic Polarography

砷(Ⅲ)在H_2SO_4-有机酸-KI-Na_2SO_4-Mn(Ⅱ)-Co(Ⅱ)体系中有一灵敏的极谱催化波,峰电位在-0.75V左右(vs·SCE)。在此体系中测定水质中的三价砷或总砷,比目前一些极谱倦化波方法的灵敏度提高10～1000倍,在选定条件下,不经预处理,无需除氧,可检出5×10^(-10)mol/L As,线性范围为1×10^(-9)～3×10^(-6)mol/L。本方法具有选择性好、灵敏度高、快速、稳定、准确等优点。

In a solution of H_2SO_4-Na_2SO_4-KI-Mn(Ⅱ)-Co(Ⅱ) and an organic acid, the arsenic(Ⅲ) produces a sensitive catalytic polarogra hic wave at-0.75V(vs.SCE). Compared with common catalytic wave, the peak current is increased by 10～1000 times. Without prior treatment or removing oxygen, As(Ⅲ) and total arsenic in water can be determined by this method. It can be used to determine trace amounts of arsenic over the range of 1×10^(-9)～3×10^(-6)mol/L. The detection limit is 5×10^(-10)mol/L. This method is rapid, simple, sensitive and accurate.