沉淀浮选预分离/富集与FAAS联用测定粮食中痕量Cu和Mn的研究

提出了以8-羟基喹啉为沉淀剂，十二烷基苯磺酸钠为浮选剂，沉淀浮选预分离富集与火焰原子吸收光谱法联用测定痕量Cu和Mn的新方法。研究了浮选分离富集Cu和Mn的最佳条件。讨论了多种浮选条件对单一离子测定的影响及pH 9时混合离子浮选的相互影响，并考察了多种离子对Cu和Mn测定的影响。研究表明，pH为9时Cu的浮选率最大，在此条件下改变混合金属离子的浓度比，当Mn/Cu≥8时，Cu的回收率小于90%。方法简便，快速，灵敏度高，精密度理想，又可避免使用有毒的有机溶剂。铜的校准曲线线性范围为0.5～5.0 μg·mL-1,相关线性系数为0.999 6，方法检出限为1.59×10-3 μg·mL-1。锰的校准曲线线性范围为0.5～5.0μg·mL-1,相关线性系数为0.9987，方法检出限为3.52×10-3 μg·mL-1。该法应用于粮食中铜锰含量的测定，加标回收率达到87.6%～100.7%，结果令人满意。

Study on the Determination of Trace Cu and Mn in Foodstuff Preconcentration by Precipitate Flotation and FAAS

In the present paper, the use of 8-hydroxyquinoline(oxine, HQ) complexs in precipitate flotation to separate and preconcentrate Cu and Mn, using SDBS as collector, followed by AAS spectrophotometric determination is proposed. The optimum conditions of precipitate flotation were studied. The effects of several parameters of flotation processes condition on single metal ions precipitation-flotation and multi-metal ions coprecipitation-flotation of Cu and Mn at pH 9 were investigated. The experimental results show that the flotation rate of Cu is supreme with pH 9. Under the condition of pH 9 and changing the ratio of concentration, when Mn/Cu> or =8, the recovery rate of Cu is less than 90%. This method is simple, rapid, accurate, sensitive and precise and avoids using the virulent organic solvent. The linear range of Cu is 0.5-5.0 microg x mL(-1) with the correlative coefficient of 0.9996, detection limit of this method was found to be 1.59 x 10(-3) microg x mL(-1), the linear range of Mn is 0.5-5.0 microg x mL(-1) with the correlative coefficient of 0.9987, and the detection limit of this method was found to be 3.52 x 10(-3) microg x mL(-1). The method was applied to the determination of Cu and Mn in foodstuff, and the recovery is 87.6%-100.7%. The result was satisfactory.