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在聚乙烯醇(PVA)存在下,锗与钨酸钠形成的杂多酸在酸性介质中与罗丹明B发生离子缔合显色反应;该缔合物的λmax为585nm;表现摩尔吸光系数为2.417×106L·mol-1·cm-1,锗量在0-0.5μg/25mL范围内服从比耳定律,缔合物可稳定60h以上.缔合物中Ge、W和RB的摩尔比为Ge:W:RB=1:12:4.考察了30多种共存离子的影响,大多数常见元素不干扰锗的测定,本法用于人参样品中锗的测定,获得满意的结果.
In the presence of polyvinyl alcohol (PVA), the heteropolyacid formed by germanium and sodium tungstate undergoes ion association color reaction with rhodamine B in an acidic medium; the λmax of the association product is 585 nm; the molar extinction coefficient 2.417 × 106L · mol-1 · cm-1, germanium content in the range of 0-0.5μg / 25mL obey Beer’s law, association can be stable more than 60h. The molar ratio of Ge, W and RB in the complex is Ge: W: RB = 1: 12: 4. The effects of more than 30 kinds of coexisting ions were investigated. Most of the common elements did not interfere with the determination of germanium. This method was applied to the determination of germanium in ginseng samples and satisfactory results were obtained.