氨硫脲的容量测定法

碘量法测定氨硫脲(对乙酰氨基苯甲醛缩氨硫脲)有操作简便省时的优点,为硷量法和银盐重量法所不及.硷量法手续繁复,终点不够明显,银盐重量法虽准确,但费时较多.关于碘量法测定氨硫脲的结果文献记载有不一致处.本文仅就碘量法反应所需的条件进行试验,以求得适用于氨硫脲的含量测定法。

VOLUMETRIC DETERMINATION OF TIBIONE

A Modified iodometric method for determination of Tibione,was found to be better than alkalimetric method or argentimetric method in its rapidity,simplicity and reproducibility. The method suggested is as follows: Weigh accurately about 0.1 g of tibione into a 50 ml volumitric flask,add 20 ml 1 N sodium hydroxide,mix well,and dilute to the mark with water.Transfer 10 ml of the solution (equivalent to 0.02 g of Tibione)into a glass-stopped flask,add 10 ml 1 N sodium hydroxide and 25 ml 0.1N iodine solution rapidly,and allow to stand in the dark for 10 minutes at 2—4c. Then acidify with 10 ml 1N hydrochloric acid and titrate the liberated iodine with sodium thiosulfate solution,using starch solution as indicator.One 0.1N iodine solution is equivalent to 0.002954 g Tibione.