催化过氧化氢氧化镍-铬蓝黑R络合物光度法测定水体中痕量汞

采用催化过氧化氢氧化Ni(Ⅱ)-铬蓝黑R络合物光度法测定汞,通过优化对比实验,确定最佳反应条件为在pH 4.12的HAc-NaAc缓冲溶液中,以2.00 mL4g/L聚乙烯醇(PVA)作表面活性剂,5.00 mL H_2O_2(1+9)溶液可氧化1.00 mL0.001 mol/L Ni~(2+)溶液与1.00 mL 0.400g/L铬蓝黑R溶液反应生成的Ni(Ⅱ)-铬蓝黑R络合物,75℃水浴加热,汞对该反应具有明显催化作用.在波长571 nm处催化体系和非催化体系的吸光度差值最大.Hg(Ⅱ)在0.1～2.0g/L范围内符合朗格一比尔定律,检出限为3.2×10~(-9)g/L.经实际水体样本论证,本法可用于自然水体中痕量汞的直接测定.

Spectrophotometric determination of trace mercury in water based on hydrogen peroxide catalyzing the oxidation reaction of nickel-palatine chrome black complex

A new catalytic kinetic spectrophotometric determination of trace mercury(Ⅱ) based on its catalytic oxidiz-ing discoloration reaction of nickel(Ⅱ)-palatine chrome black complex by 5.00 mL of 3.0% hydrogen peroxide with 2.00 mL of 0.4% polyvinyl alcohol (PVA) as an activating agent in the presence of acetic acid-sodium acetate buffersolution of pH 4.12. The maximum absorbance difference of catalytic system and non-catalytic system appears at 571 nm. The beer's law is well obeyed in the range of 0.1～2 μg/L for mercury, and the detection limit is 3.2 × 10~(-9) g/L. The method is free from interference of common ions after extraction separation, and it has been ap-plied to the determination of trace amounts of mercury in water.