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

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1mL 0.5mol/L HCl溶液中,于-1200mV处搅拌富集一定时间,在-1200～-200mV范围内以150mV/s的扫描速度线性扫描,Sn(Ⅱ)吸附在修饰电极表面,于约-476mV(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4.0×10-10～1.0×10-8 mol/L和1.0×10-8～4.0×10-6 mol/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2.7×10-10 mol/L(富集时间120s)。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。

Determination of Trace Tin by Anodic Stripping Voltammetry at A 1- ( 3-Nitrophenyl ) -3- ( 4-phenylazophenyl ) triazen Modified Carbon Paste Electrode

A new method for the determination of trace tin(Ⅱ) was described.In this study,a 1-(3-Nitrophenyl)-3(4-phenylazophenyl) triazen(m-NPPAPT) modified carbon paste electrode was prepared and the adsorptive stripping voltammetric behavior of tin(Ⅱ) at the modified electrode was investigated.It was found that in 0.5mol / 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 mV to -200 mV at a scan rate of 150mV / s,the sensitive anodic stripping peak appeared at -476mV(vs.SCE).The sensitivity of the modified electrode in the determination of tinⅡincreased 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 120saccumulation.The proposed method was satisfactorily applied to the determination of trace tin(Ⅱ) in cans food.