6,6″-二甲基-4′-苯基-2,2′∶6′,2″-三联吡啶与铅显色反应的分光光度研究

Spectrophotometric Study on a Color Reaction of Lead with 6, 6″-Dimethyl-4′ -phenyl-2, 2′∶ 6′, 2″-terpyridine

用作者合成的新显色剂 6,6″-二甲基 - 4′-苯基 - 2 ,2′∶6′ ,2″ -三联吡啶 (TPY)分光光度法测定痕量铅 ,在 pH5 0～ 6 0的HAc -NaAc介质中 ,该试剂与铅形成稳定络合物 ,其最大吸收波长在 375nm处 ,Pb2 +∶TPY =3∶4,表观摩尔吸光系数ε=5 71× 1 0 4 ,铅量在 0～ 2 5μg/2 5mL范围内服从比尔定律 ,用于纯铜试样的分析 ,结果满意。

A new color reaction of lead with 6, 6″ -dimethyl-4′-phenyl-2, 2′∶ 6′, 2″-terpyridine (TPY) has been studied by spectrophotometry. In the range of pH 5.0-6.0, lead reacts with TPY to form a stable complex with composition ratio of 3∶4. The molar absorptivity is 5.71×10 4L·(mol·cm) -1 at 375nm. Beer's law is obeyed in the range of 0-25μg/25mL for lead. Precision and accuracy experiments showed that the method was accurate. The method has been applied directly to determine micro lead in pure copper with satisfactory results.