利用协同催化效应萃取催化光度法测定痕量铬

Extraction Catalytic Spectrophotometric Determination of Trace Chromium by Synergetic Catalytic Effect

研究了在 pH 5 5的HAc NaAc介质中 ,利用Fe(Ⅲ ) ,Cr(Ⅵ )对H2 O2 氧化邻氨基酚的协同催化作用 ,用萃取平衡控制反应时间和水相中邻氨基酚的浓度及协同催化反应进行的程度 ,通过测量 4 2 4nm下有机相的吸光度 ,建立了协同萃取催化光度法测定铬的新方法。方法的线性范围为 :0 0 0 10～ 0 90mg·L-1,检出限为 5 0× 10 -6g·L-1。用于自来水和废水中铬的测定 ,结果满意。

In this paper, a new synergetic extraction catalytic spectrophotometric method for the determination of trace chromium was studied. The method is based on the iron (III) and chromium (VI) synergetic catalyzed oxidation of o-aminophenol by hydrogen peroxide in weak acidic medium at pH 5.5. The reaction time, concentration of o-aminophenol in aqueous phase, and degree of reaction were controlled by extraction equilibrium. The absorbance of organic phase was measured at 424 nm. The linear range of the method is 0.001 0-0.90 mg.L-1. The detection limit for chromium( VI) is 5.0 x 10(-6) g.L-1. The relative standard deviation (n = 11) for 0.20 mug . mL(-1) level of Cr( VI) is 2.0%. The method has been applied to the determination of chromium in tap water and waste water with satisfactory results.