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光度试金中有一类基于氧化还原显色反应的方法,其中以N,N’-四甲基-邻-联甲苯胺(Tetron)法较佳,是书籍推荐方法之一。本文用金属锌在乙酸介质中将蓝色(氧化型)二甲苯蓝FF(C.I.N0715)还原成隐色(还原)型,后者在一定条件下被Au(Ⅲ)氧化显色。其最大光吸收处在608nm;在0-10μg/10ml范围内服从Beer定律;表观摩尔吸光系数为1.3×10~5·1·mol~(-1)·cm(-1),与最灵敏的萃取光度试剂硫代米氏酮(ε=1.6×10~5)相近,而较酚藏花红萃取显色(ε=5.2×10~4)和Tetron法(灵敏度为0.004μg/cm~2)灵敏。虽本法对氧化性离子如Fe~(3+)、Cu~(2+)
There is a class of photometric gold assay based on redox chromogenic reaction, among which N, N’-tetramethyl-o-toluidine (Tetron) method is preferred, which is one of the recommended methods for books. In this paper, blue (oxidized) xylene blue FF (C.I.N0715) was reduced to leuco (reduced) form with zinc metal in acetic acid medium, which was oxidized by Au (Ⅲ) under certain conditions. The maximum light absorption is at 608 nm. Beer’s law is obeyed in the range of 0-10 μg / 10 ml. The apparent molar absorptivity is 1.3 × 10 -5.1 · mol -1 (cm -1) (Ε = 1.6 × 10 ~ 5), but higher than that of phenolic extract (ε = 5.2 × 10 ~ 4) and Tetron method (sensitivity of 0.004μg / cm ~ 2) Sensitive. Although the law of the oxidizing ions such as Fe ~ (3 +), Cu ~ (2+)