用二苯胺磺酸钠作指示剂的二氯化锡—氯化汞—重铬酸钾测定铁,是一个公认的准确、快速的分析方法,已在国内外广泛应用多年,目前由于汞害问题,渐为无汞测铁方法所替代,故很少有人进一步研究它了,只是作为一种标准分析方法而被保留应用。我们在作无汞测铁时,需要用有汞测铁准确的进行对照,同时也在标样、外验等工作中发现,尚有一些因素影响此法的准确度,本文就这些影响因素作了探讨和试验,其结果是值得在使用此法时予以注意的。 Determination of iron with tin dichloride-mercuric chloride-potassium dichromate using sodium diphenylamine sulfonate as an indicator is an accepted, accurate and rapid analytical method that has been widely used both at home and abroad for many years. Currently, , Gradually replaced by mercury-free measuring method, so few people study it further, but as a standard analytical method was reserved for application. When we are doing mercury-free iron measurement, we need to use mercury to measure the iron accurately, and at the same time, we find out that there are some factors that affect the accuracy of this method. In this paper, The discussion and experiment, the result is worth to pay attention to when using this method.