酶催化分光光度法测定环境水中痕量钒

钒对牛血红蛋白模拟酶催化过氧化氢氧化罗丹明B体系有强烈的抑制作用, 据此建立了酶催化分光光度法测定痕量钒的新方法。试验从pH值、罗丹明B浓度、过氧化氢浓度、牛血红蛋白浓度和反应时间等方面探讨了体系的实验条件。在pH 9.8的NH₃·H₂O-NH₄Cl缓冲溶液中, 当罗丹明B、H₂O₂和血红蛋白的浓度分别为1.5×10^-5 mol/L、1.5×10^-4 mol/L和 2.0×10^-6 mol/L时, 测定钒的线性范围为3.1×10^-4 ~6.2×10^-3 g/L, 方法的检出限为2.1×10^-6 g/L。1 000倍Na⁺、K⁺、Cl^- 、NO₃^-、NH₄⁺ 、F^-、BrO₃^-, 500倍Ca²⁺、Fe³⁺ 、Al³⁺、 Mn²⁺、Ba²⁺、CO₃^2-, 100倍C₂O₄^2-, 5倍Cu²⁺对钒的测定没有干扰。对环境水样中痕量钒进行测定, 结果的相对标准偏差(n=7)为3.7%, 与萃取分光光度法的结果基本一致, t检验结果表明两种方法没有显著性差异。

Determination of trace vanadium in environmental water by enzymatic catalytic spectrophotometry

Vanadium(V) had strong quenching effect on the catalytic spetrophotimetric system of hemoglobin analog enzyme. Based on this, a novel enzymatic spectrophotometry for determining vanadium(V) was established.The influence of acidity, rhodamine B concentration, H₂O₂ concentration, hemoglobin concentration and reaction time on the system was studied.In NH₃·H₂O-NH₄Cl buffer solution of pH 9.8, when the concentration of rhodamine B, H₂O₂ and hemoglobin were 1.5×10^-5 mol/L, 1.5×10^-4 mol/L and 2.0×10^-6mol/L respectively, the linear range for the determination of vanadium(V) was 3.1×10^-4 - 6.2×10^-3g/L with the detection limit of 2.1×10^-6g/L.1 000 times of Na⁺, K⁺, Cl^-, NO₃^－, NH₄⁺, F^－ and BrO₃^－, 500 times of Ca²⁺, Fe³⁺, Al³⁺, Mn²⁺, Ba²⁺ and CO₃^2－, 100 times of C₂O₄^2－, 5 times of Cu²⁺ did not interfere the determination of vanadium(V). The RSD was 3.7% for 7 parallel determinations of vanadium(V) in environmental water.The results obtained by the extraction spectrophotometry and the proposed method are statistically compared. The t-test showed that the two methods had no significant differences.