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

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%.