【摘要】 研究了在乙醇存在下,甲基百里香酚蓝(MTB)与铅的显色反应。在pH5·9的六次甲基四胺-盐酸缓冲介质中,铅与MTB发生灵敏的显色反应生成蓝色络合物,最大吸收峰位于605nm,表观摩尔吸光系数为1·72×104;在25mL溶液中,铅量在0~50μg范围内符合比尔定律;MTB与铅的反应迅速,络合物的吸光度至少可以稳定24h。该法有良好的选择性,可用于植物叶片中微量铅的直接测定。更多还原

【Abstract】 The color reaction of PbⅡ with methylthymol blue（MTB） in the presence of ethanol has been studied in detail.In （CH2）6N4-HCl buffer medium at pH 5.9,lead reacts with MTB sensitively and selectively to form a blue complex,which has a maximum absorptive peak at 605 nm with an apparent molar absorptivity being 1.7210⁴Lmol^-1cm^-1.Beer’s law is obeyed in the range of 0-50 g/25 mL for PbⅡ.The reaction of lead Ⅱ with MTB is rapid and the absorbance of complex can be stable for at least 24h.The proposed method has very good selectivity,which has been applied to determine lead directly in botanic leaf.更多还原