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Singh 曾将菲醌单缩氨硫脲(PTS)用作络合滴定汞的指示剂,但灵敏度不高。我们进一步试验了该试剂与汞的反应,表明汞在室温下与试剂形成不溶于水的红色络合物,但对微量汞沉淀难于达到定量完全,沉淀可溶于酮、醇、酯,用惰性有机溶剂苯萃取时则富集于第三相。因此,利用惰性载体菲醌有可能进行共沉淀富集。我们研究了载体富集微量汞的条件。结果表明,在0.01—1M硝酸或硫酸介质中,对ppb级汞的收率可达98—105％,且选择性好,适用于普通水或污水中痕量汞的测定。 (一)仪器与试剂 PTS:自行合成。红色片状结晶,配成饱和酒精(95％溶液。PTS纯度为
Singh used phenanthrenequinone thiosemicarbazide (PTS) as an indicator of complexometric titration with mercury, but the sensitivity is not high. We further tested the reaction of this reagent with mercury, indicating that mercury forms a red, water-insoluble complex with the reagent at room temperature but is difficult to quantify for trace amounts of mercury and that the precipitate is soluble in ketones, alcohols, and esters with inert When organic solvent benzene is extracted, it is enriched in the third phase. Therefore, it is possible to perform coprecipitation enrichment with phenanthrenequinone, an inert carrier. We studied the conditions for the enrichment of trace amounts of mercury in the carrier. The results show that the yield of ppb mercury can reach 98-105% in 0.01-1M nitric acid or sulfuric acid medium with good selectivity and is suitable for the determination of trace mercury in ordinary water or sewage. (A) instruments and reagents PTS: self-synthesis. Red flaky crystals, dubbed saturated alcohol (95% solution. PTS purity