极谱络合吸附催化波法测定食品中痕量铁

[目的]应用极谱络合吸附催化法测定食品中痕量铁。[方法]应用单扫描示波极谱法研究Fe3+、5-Br-2-(5-溴-2-吡啶偶氮)-5-二乙胺基酚(5-Br-PADAP)、TEA、NaNO2及其络合物的单扫描示波极谱波。选择不同pH值,不同浓度TEA、5-Br-PADAP、NaNO2,分析它们对峰电流的影响。最后,测定了自来水、河水、啤酒、赤豆中痕量铁。[结果]在0.4 mol/L NH3.H2O-NH4Cl底液中(pH=9.26)加入三乙醇胺(TEA)(1+3)和2.0 mol/L NaNO2体系中得到1个非常灵敏的Fe3+-TEA-5-Br-PADAP-NaNO2配合物吸附催化波,其峰电位为-0.72 V(vs.SCE)。Fe3+浓度在0.01~300.00 ng/ml浓度范围内与二阶导数波高呈线性关系。[结论]单扫描示波极谱法灵敏度高,选择性好,操作简单,可成功地运用于各类水样、食品中微量或痕量铁的测定。

Determination of Trace Iron in Food by Polarographic Adsorptive Catalytic Wave Method

[Objective] The research aimed to determine the trace iron in food by polarographic adsorptive catalytic wave method.[Method] The single sweep oseillopclarvgraphic wave of Fe3+,5-Br-PADAP,TEA,NaNO2 and their complex Fe3+-TEA-5-Br-PADAP-NaNO2 were studied by single sweep oseillopclarvgraphic wave method.And the effects of different pH value,different concentration TEA,5-Br-PADAP, NaNO2 on peak current were analyzed.Finally,the trace iron of tap water,river, beer and adzuki bean was determined.[Result] The results showed that Fe3+-TEA5-Br-PADAP-NaNO2 complex exhibited a sensitive single sweep oseillopclarvgraphic wave at-0.72 V(vs.SCE).A linearrelationship between peak currents and concentrations of Fe3+ held in the range 0.01～300.00 ng/ml.[Conclusion] The single sweep oseillopclarvgraphic wave method was characterized by high sensitivity,good selectivity and simple operation,and could be used in determination of trace iron in all kinds of water sample and food.