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目前食品及其包装袋中痕量铅的测定仍然用双硫腙法(ε=7×10~4),还要用有机溶剂苯萃取,不但操作繁琐,还有一定毒性。近来用大环卟啉类化合物测定某些痕量元素,已引起人们的重视,对测定铅已有报道。本文合成了新型结构meso-四-(4-甲基-3-磷基苯)卟啉(简称TTPS_4);研究了它和Pb(Ⅱ)的显色条件,其摩尔吸光系数ε_(484)=2.82×10~5,是同类试剂中灵敏度最高的。在掩蔽剂三乙醇胺及氟化铵存在下,不经分离直接测
At present, the determination of trace amount of lead in food and its packaging is still using the dithizone method (ε = 7 × 10 ~ 4), but also with organic solvent benzene extraction, not only tedious operation, but also some toxicity. Recently, the determination of some trace elements by macrocyclic porphyrin compounds has drawn people’s attention, and the determination of lead has been reported. In this paper, a novel meso-tetrakis- (4-methyl-3-phosphinophenyl) porphyrin (referred to as TTPS_4) has been synthesized. The conditions for its color development were discussed. The molar absorptivity ε_ (484) 2.82 × 10 ~ 5, is the highest sensitivity of similar reagents. In the presence of masking agent triethanolamine and ammonium fluoride, without direct measurement