1-(3-硝基苯基)-3-4-(苯基偶氮)苯基-三氮烯修饰碳糊电极测定痕量锡

摘要

制备了三氮烯修饰碳糊电极(m NPPAPT/CPE),并研究了Sn(Ⅱ)在该电极上的吸附伏安行为,建立了一种测定痕量锡(Ⅱ)的新方法.采用二阶导数线性扫描溶出伏安法进行分析.结果表明:在1 mL 0.5 mol/LHCl溶液中,于1200mV处搅拌富集一定时间,在-1200～-200mV范围内以150 mV/s的扫描速度线性扫描,Sn(Ⅱ)吸附在修饰电极表面,于约-476 mV(vs SCE)处产生一个灵敏的阳极溶出峰,峰电流比未修饰电极增大约11倍.其峰电流与Sn(Ⅱ)浓度在4.0×10-10～1.0×10-8mol/L和1 0×10-8～4.0×106mol/L范围内分两段呈良好线性关系,其线性回归方程分别为ip (μA)=1.646C(μmol/L)+ 2.9566和ip(μA)=52.804C(μmol/L)-0.6402,相关系数分别为0.9973和0.9967;检出限(S/N-3)为2 7×10-10mol/L(富集时间120 s).本方法操作简便、灵敏度高,应用于罐头食品中锡含量的测定,结果满意.%A new method for the determination of trace tin(II) was described. In this study, a l-(3-Nitrophenyl)-3-(4-phenylazophenyl) triazen (m-NPPAPT) modified carbon paste electrode was pre pared and the adsorptivc stripping voltammetric behavior of tin(J) at the modified electrode was investigated. It was found that in 0. 5 mol/L HCI solution, a coordination compound formed by m-NP-PAPT with tin(II). The compound was accumulated and reduced on the surface of the modified elec trode at -1200 mV. When scanning linearly was from -1200 raV to -200 mV at a scan rate of 150 mV/s,the sensitive anodic stripping peak appeared at -476 mV ( vs. SCE). The sensitivity of the modified electrode in the determination of tin 1 increased about eleven-fold. The linear range was found to be 4. 0 ×10-10 - 1. 0×10-8 mol/L and 1. 0 ×10-8 - 4. 0×10-6 mol/L. The detection limit was 2. 7×10-10 mol/L (S/N = 3) for 120 s accumulation. The proposed method was satisfactorily applied to the determination of trace tin(II) in cans food.