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本文报道一个光度法测定纳克量锡的新方法。在聚乙烯醇（ＰＶＡ）存在下锡（Ⅳ）与钨酸盐和耐尔蓝（ＮＢ）反应形成离子缔合物，离子缔合物的最大吸收位于５８０ｎｍ，表观摩尔吸光系数ε值２．９５×１０７Ｌ·ｍｏ１－１·ｃｍ－１，服从比耳定律范围０～２．０μｇ／Ｌ，检出限（３σ）０．０８３μｇ／Ｌ（ｎ＝１０），对２．０μｇ／Ｌ锡测定的ＲＳＤ为１．４２％（ｎ＝１１），离子缔合物至少稳定７２ｈ。考察了４０多种共存离子的影响，大多数常见元素不干扰。测定锡的适宜条件［Ｈ２ＳＯ４］＝１．２０ｍｏ１／Ｌ，［ＷＯ２－４］＝６．０５×１０－５ｍｏ１／Ｌ，［ＮＢ］＝５．５×１０－５ｍｏ１／Ｌ和ＰＶＡ０．０８％。本法已用于某些合金钢和锌合金中纳克量锡的测定，结果与推荐值吻合，回收率满意。
This paper reports a new method for the determination of tin content by spectrophotometry. In the presence of polyvinyl alcohol (PVA), tin (Ⅳ) reacts with tungstate and nile blue (NB) to form an ion association product with a maximum absorption at 580 nm and an apparent molar absorptivity ε of 2. The detection limit (3σ) was 0.083μg / L (n = 10). The detection limit was 2.0μg / L The RSD was 1.42% (n = 11) and the ion association was stable for at least 72h. Examined the impact of more than 40 kinds of coexisting ions, the most common elements do not interfere. The optimum conditions for the determination of tin [H2SO4] = 1.20 mol / L, [WO2-4] = 6.05 × 10 -5 mol / L, [NB] = 5.5 × 10 -5 mol / L and PVA 0.08%. This method has been used to determine the amount of nanocrystalline tin in some alloy steels and zinc alloys. The results are consistent with the recommended values and the recovery rate is satisfactory.