2-(2-氰基-4-硝基-6-溴苯偶氮)对苯二酚分光光度法测定食品中铅

Spectrophotometric determination of lead in food with 2-(2-Bromo-6-Cyano-4-Nitrobenzeneazo) Hydr-oquinone as the chromogenic reagent

目的:探索测定食品中痕量铅的新方法。方法:以新试剂2-(2-氰基-4-硝基-6-溴苯偶氮)对苯二酚作为显色剂,研究分光光度法测定铅的优化条件。结果:在HAc-NaAc缓冲溶液中,铅(Ⅱ)与显色剂形成桔红色络合物,最大吸收波长为457nm,表观摩尔吸光系数ε=5.13×104 L.mol-1.cm-1,铅的质量在0～15μg/25mL范围内符合比耳定律。相对标准偏差为2.3%～2.8%。结论:该方法准确度、精密度良好,是一种简便、可靠的测定食品中铅的方法。

Objective： The aim was to explore the method for the determination of trace lead. Method： With 2-（2-Bromo-6-Cyano-4-Nitrobenzeneazo）Hydroquinone as the chromogenic reagent , the optimum of spectrophotometric determination of lead was studied. Result：In the buffer solution of HAc- NaAc ,lead could form orange complex with 2-（2-Bromo-6-Cyano-4-Nitrobenzeneazo）Hydroquinone. The maximum absorption of the complex occurred at 457 nm. The apparent molar absorptivity was 5.13× 104 L · mol^-1· cm^-1, and Beers lawwas obeyed in the range of 0- 15 μg/25 mL. , RSD was 2.3%-2.8%. Conclusion：The method has good accuracy and precision. It s a convenient and reliable method for analyzing tea.