摘要
研究在邻菲啰啉活化条件下,Cu2+催化溴酸钾氧化甲基紫的褪色反应,建立催化褪色光度法测定痕量Cu2+的新方法。讨论酸度、试剂用量、反应温度、反应时间、表面活性剂和共存离子等的影响,确定了最佳实验条件。结果表明:在25ml溶液中,72℃恒温反应15min,根据加Cu2+溶液和不加Cu2+溶液的吸光度差值与Cu2+质量浓度绘制工作曲线,并由试样的吸光度差值确定痕量Cu2+的含量。该法的测定波长为578nm;线性范围为2.40×10-3～5.12×10-2μg/ml;检出限为2.4×10-6g/L,该法用于绿茶、面粉、大米、奶粉、干海带中痕量Cu2+的测定,最大相对标准偏差为4.22%,回收率为96.0%～104.0%。
With the activation of p-phenanthroline, potassium bromate oxidized methyl violet fading reaction catalyzed by copper （Ⅱ） was investigated, and a new catalytic discoloring spectrophotometry for determining trace copper was proposed. The effects of acidity, reagent dosage, reaction temperature, reaction time, surfactant and coexisting ions on the reaction were discussed and the optimal conditions were investigated. After reaction at 72 ℃ for 15 min in a 25 ml volumetric flask, the calibration curve was drawn for the relationship of absorbance difference between copper （II） containing solution and non-copper （II） containing solution with copper （II） mass concentration, and then the content of trace copper （II） was determined by the absorbance difference. The detection wavelength of this method was 578 nm, the linear range was between 2.4 × 10^-3 and 5.12 × 10^-2 μg/ml, and the detection limit was 2.4×10^-6g/L. When this method was applied to the determination of copper in green tea, wheat flour, rice, milk powder, and dried kelp, the maximum relative standard deviation was 4.22%, and the spike recoveries were 96.0% to 104.0%.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2009年第10期169-172,共4页
Food Science
基金
辽宁省自然科学基金项目(20032133)
关键词
催化光度法
邻菲哕啉
溴酸钾
甲基紫
铜
catalytic spectrophotometry
p-phenanthroline
potassium bromate
methyl violet
copper
