【摘要】 痕量组分镉的测定对于工业、环境、健康有着重要的意义。研究了在pH=5.2邻苯二甲酸氢钾-NaOH介质中,痕量镉催化H2O2氧化3-(4′-氟苯基)-5-(2′-羧基苯偶氮)若丹宁,而荧光猝灭存在明显的催化作用,由此建立了动力学荧光法测定痕量镉的新方法。该体系的激发和发射波长分别为λex/λem=307nm/408nm,通过实验测定反应表观活化能为59.06kJ/mol;反应速率常数为0.101s-1;线性范围为0~10.0μg/L;检出限为3.9×10-7g/L。采用巯基葡聚糖凝胶分离富集,消除了共存离子的干扰,显著提高了方法的选择性和灵敏度。本方法应用于食品和人发中镉的测定获得满意的结果。更多还原

【Abstract】 A catalytic kinetic fluorescent quenching method was developtal for the determination of trace cadmium.The method was based on the catalytic effect of cadmium on oxidation of 3-(4’-fluorophenyl)-5-(2’-carboxylphenylazo)rhodanine by hydrogen peroxide in potassium hydrogen p hthalate-sodium hydroxide buffer solution(pH=5.2).And λex/λ em=307 nm/408 nm,the apparent active energy is 59.06 kJ/mol,the reaction r ate constant is 0.101 s-1,the linear range is 0-10 μg/L,the detectio n limit is 9.5×10-7 g/L.The cadmium can be enriched and separated with coexistent metal ions by sulfhydryl dextrane gel(SDG).The method can be used to determine trace amount of cadmium in food and hair samples with satisfactory results.更多还原