室温下四价锡离子在pH5～6时不与EDTA络合,而在pH2左右时,却可与EDTA络合,我们利用Sn~(4+)的这一性质进行锡的测定。一试剂硫脲-抗坏血酸溶液:每100毫升饱合硫脲中含5克抗坏血酸。六次甲基四胺:30% 二甲酚橙-孔雀绿混合指示剂:1%,加少许孔雀绿二分析方法称取试样0.5克于250毫升三角瓶中,加盐酸 At room temperature, tetravalent tin ions do not complex with EDTA at pH5 ~ 6, but can be complexed with EDTA at about pH2. We use this property of Sn ~ (4 +) to determine tin. A reagent thiourea-ascorbic acid solution: containing 5 g of ascorbic acid per 100 ml of saturated thiourea. Hexamethylenetetramine: 30% xylenol orange - malachite green mixed indicator: 1%, add a little malachite green two analytical methods Weigh 0.5 grams of sample in 250 ml Erlenmeyer flask, add hydrochloric acid