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    硫桥杯4芳烃衍生物膜修饰玻碳电极差分脉冲溶出伏安法测定铅

    Differential Pulse Stripping Voltammetric Determination of Lead with p-tert-Butylthiacalix4arene Derivative Modified Glassy Carbon Electrode

    • 摘要: 将硫桥杯4芳烃衍生物25,27-二(2-噻二唑基硫代乙氧基)-26,28-二甲氧基-5,11,17,23-四叔丁基硫桥杯4芳烃(TTCA)溶于二氯甲烷中,滴涂在玻碳电极表面,制得硫桥杯4芳烃修饰的玻碳电极。循环伏安当研究结果表明:将此修饰电极浸泡在1.0×10-6mol·L-1铅(Ⅱ)溶液中一段时间后转移至0.1 mol·L-1硝酸溶液中,以扫速100 mV·s-1在电位-0.8~-0.2 V范围内扫描所得的CV图上出现一对氧化还原峰。当此修饰电极在上述浓度的铅(Ⅱ)溶液中于-1.1 V富集300 s后用差分脉冲溶出伏安法检测时,铅(Ⅱ)在-0.516 V处出现一良好的氧化峰。铅(Ⅱ)浓度在2.0×10-7~2.0×10-5mol·L-1范围内与峰电流呈线性关系。其检出限(3S/N)为8.0×10-9mol·L-1。此法应用于水样中痕量铅的测定,测得回收率在95.0%~104.0%之间。

       

      Abstract: The p-tert-butylthiacalix4 arene derivative, 5,11,17,23-tetra-tert-butyl-25,27-di(2-thiadiazole-thio ethoxy)-26,28-dihydroxythiacalix4 arene (TTCA) dissolved in dichloro methane was dropped on the surface of glassy carbon electrode (GCE) to prepare the modified electrode. When the modified GCE was soaked in 1.0×10-6mol·L-1 Pb(Ⅱ) solution for a definite time, then transferred into 0.1 mol·L-1 HNO3 solution and scanned cyclic-voltammetrically at the rate of 100 mV·s-1 in the potential range of -0.8 V to -0.2 V, a pair of redox peak was observed in the CV-gram. When accumulation of Pb(Ⅱ) for 300 s at -1.1 V was accomplished at the modified GCE in the same solution, and the electrode reaction was studied by DPSV, a fine oxidation peak was observed at ca. -0.516 V in the DPS voltammogram. Linear relationship between values of peak current and concentration of Pb(Ⅱ) was obtained in the range of 2.0×10-7-2.0×10-5mol·L-1, with detection limit (3S/N) of 8.0×10-9mol·L-1. Based on these facts, the proposed method was applied to the determination of lead in water samples, giving value of recovery in the range of 95.0%-104.0%.

       

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