论文部分内容阅读
聚乙烯醇（ＰＶＡ）存在下，锡与钨酸盐形成锡钨杂多络阴离子，继而与丁基罗丹明Ｂ（ＢＲＢ）形成离子缔合物。离子缔合物的最大吸收位于５６５ｎｍ，表观摩尔吸光系数ε为２．５４×１０７Ｌ·ｍｏｌ－１·ｃｍ－１，服从比耳定律范围０～６０ｎｇ／２５ｍＬ，测定限（３σ）０．０７３ｎｇ／ｍＬ（ｎ＝１２），对４０ｎｇ／２５ｍＬ锡测定的相对标准１．４５％（ｎ＝１１），离子缔合物至少稳定２４０ｈ。考察了４０多种共存离子的影响，大多数常见元素不干扰。研究了离子缔合物的红外光谱，锡钨杂多络阴离子具有Ｋｅｇｇｉｎ结构。测定锡的适宜条件为［Ｈ２ＳＯ４］＝１．３２ｍｏｌ／Ｌ，［ＷＯ２－４］＝６．０５×１０－５ｍｏｌ／Ｌ，［ＢＲＢ］＝３．０×１０－５ｍｏｌ／Ｌ和ＰＶＡ０．８ｇ／Ｌ。本法已用于某些合金钢和锌合金中锡的测定，结果满意。
In the presence of polyvinyl alcohol (PVA), tin and tungstate form tin-tungsten heteropolyanions, which in turn form ionic complexes with butyl rhodamine B (BRB). The maximum absorption of ion association at 565nm, the apparent molar absorptivity ε was 2.54 × 107L · mol-1 · cm-1, obeying the Beer’s law range 0 ~ 60ng / 25mL, the determination limit (3σ) 0.073ng / ML (n = 12), a relative standard of 1.45% (n = 11) for 40 ng / 25 mL of tin and an ionic association of at least 240 h. Examined the impact of more than 40 kinds of coexisting ions, the most common elements do not interfere. The infrared spectra of ion-association compounds were studied. The tin-tungsten heteropolyanions have Keggin structure. The suitable conditions for the determination of tin were [H2SO4] = 1.32 mol / L, [WO2-4] = 6.05 × 10-5 mol / L, [BRB] = 3.0 × 10-5 mol / L and PVA0.8g / L. This method has been used for the determination of tin in some alloy steels and zinc alloys with satisfactory results.