邻羟基苯基荧光酮分光光度法测定铅

Spectrophotometric Determination of Lead with Salicylfluorone as Chromogenic Agent

在pH=9.5的NH3.H2O-NH4Cl缓冲介质中,阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)存在下,Pb2+与邻羟基苯基荧光酮(o-HPF)可形成Pb-o-HPF-CT-MAB三元配合物,其最大吸收峰在560nm波长处,表观摩尔吸光系数ε=7.7×104 L.mol-1.cm-1。配合物中Pb∶o-HPF=1∶1,Pb2+的含量在0～1.8μg.mL-1范围内符合比耳定律。拟定方法用于不同产地魔芋中铅含量的测定,结果满意。

In NH3·H2O-NH4Cl buffer solution（pH=9.5） and the presence of cetyltnimethyl ammonium bromide（CTMAB）,Pb2＋ reacts with salicylfluorone（o-HPF） and forms the three-complex with maximum absorption at 560 nm,and the apparent molar absorptivity is ε=7.7×104 L·mol-1·cm-1.The molar ratio of Pb and o-HPF is 1：1.Beer＇s law is obeyed in the concentration range of 0～1.8 μg·mL-1.The proposed method has been applied to the determination of Pb in konjac samples from different areas with satisfactory results.