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催化动力学分析法,是以催化反应为基础来测定物质含量的方法。其特点是灵敏度很高且简单易行,目前已广泛地用于痕量元素的测定,我们曾用银-过二硫酸铵-硫酸锰体系测定过高纯碳酸锂中的痕量银;周内外对催化动力学法有若干报道。Raman曾将六氰铁(Ⅱ)酸钾-α,α′r-联吡啶-汞(Ⅱ)体系测汞(Ⅱ),我们发现该体系对测定痕量银效果很好。我们借硫脲助催化,并改善了其它条件,使其能测定ng量的银,表观摩尔吸光率ε高达1.2×10~6L·mol~(-1)·cm~(-1);恒温加热时间仅需5min。不经分离,直接测定自来水中痕量银,并进行了标准加入试验,回收率在95～105%,还用此法测定了3批高纯碳酸锂中的痕量银,结果与萃取-原子吸收法相符。另外用此法测定了氯化银的溶度积,与文献值一致。变动系数为5.18%。
Catalytic kinetic analysis is based on the catalytic reaction to determine the content of substances. It is characterized by its high sensitivity and simplicity. It has been widely used in the determination of trace elements. We have used silver-ammonium peroxodisulfate-manganese sulfate system to determine trace silver in over-pure lithium carbonate. There are several reports on catalytic kinetics. Raman has detected the mercury (II) by the potassium hexacyanoferrate (II) -alpha, α’r-bipyridine-mercury (Ⅱ) system, and we found that this system works well for the determination of trace silver. With thiourea as a catalyst, we improved other conditions to determine the silver content in ng, and the apparent molar absorptivity ε was as high as 1.2 × 10 -6 L · mol -1 · cm -1. Heating time only 5min. Without separation, direct determination of trace silver in tap water, and the standard addition test, the recovery rate of 95 ~ 105%, also used this method was measured in three batches of high purity lithium carbonate trace silver, the results with the extraction - atomic Absorption method match. In addition, this method was used to determine the solubility product of silver chloride, consistent with the literature. The coefficient of variation is 5.18%.