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催化动力分析法测定汞的指示反应多为氧化还原反应,也有人[1-7]采用亚铁氰化钾与邻菲啰啉的配位体取代反应。我们[8]在研究Au~(3+)对铁氰化钾与EDTA的配位体取代反应的催化作用时,发现Hg~(2+)也有一定的催化作用,因此有可能利用这一指示反应来测定微量Hg~(2+)。实验证明,在邻苯二甲酸缓冲溶液(pH3.50—3.80)中,采用固定时间法和离子选择电报监测反应产物CN~-,可测定微量汞,线性范围为5.0×10~(-8)—5.0×10~(-6)MHg~(2+),检测限为2.0×10~(-8)M。本法与同类配位体取代反应的催化动力分析法相比,具有灵敏度高和线性范围宽的优点。
Catalytic kinetic analysis of mercury indicator reaction mostly redox reactions, some people use [1-7] potassium ferrocyanide and phenanthroline ligand instead of the reaction. When we studied the catalytic effect of Au ~ (3+) on the ligand replacement reaction of potassium ferricyanide and EDTA, we found that Hg ~ (2+) also has a certain catalytic effect, so it is possible to use this indicator Reaction to determine trace Hg ~ (2+). Experiments show that in the buffer solution of PHB (pH3.50-3.80), fixed time method and ion-selective telemetry are used to monitor the reaction product CN ~ -, and the trace mercury can be measured with a linear range of 5.0 × 10 ~ (-8) -5.0 × 10 -6 MHg 2+, and the detection limit was 2.0 × 10 -8 M. This method has the advantages of high sensitivity and wide linear range as compared with catalytic kinetic analysis in which the same type of ligand replaces the reaction.