微波消解-双指示剂双波长催化分光光度法测定食品中的铬.PDF

234 2011, Vol. 32, No. 22 食品科学 ※分析检测 1 2 1 1 侯法菊 ，苗延虹 ，陈玉静 ，徐 慧 (1.鲁东大学化学与材料科学学院，山东 烟台 264025 ；2. 山东农业大学化学与材料科学学院，山东 泰安 271000) 利用稀 H2 SO4 介质中，痕量铬(Ⅵ)对氯酸钾氧化甲基绿和结晶紫褪色的反应有较强催化作用的原理，通过 测量 550nm 和 620nm 波长处非催化体系和催化体系吸光度的变化，计算ΔA 值，建立双指示剂双波长动力学光度分 析法测定食品中铬的方法。结果表明：方法检出限为 0.003 μg/mL ，回收率在98.3%～102.0% 之间，相对标准偏 差小于 2.7% ，线性范围为0.045～0.200 μg/mL ，方法简便快速。 双波长分光光度法；铬；食品 Microwave Digestion Coupled with Dual-Wavelength Dual-Indicator Catalytic Kinetic Spectrophotometry for Determination of Chromium in Food 1 2 1 1 HOU Fa-ju ，MIAO Yan-hong ，CHEN Yu-jing ，XU Hui (1. College of Chemistry and Material Science, Ludong University, Yantai 264025, China； ， 2. College of Chemistry and Material Science, Shandong Agricultural University, Tai an 271000, China) Abstract ：Trace chromium (VI) catalyzes the oxidation of crystallized violet and methyl green by potassium chlorate in dilute H2 SO4 solution, which will cause the discoloring of the solution. A dual-wavelength and dual-indicator catalytic kinetic spectrophotometric method to quantify the concentration of chromium (Ⅵ) was proposed by determining the difference of absorbance ( ΔA) of the reaction solution with and without trace chromium (Ⅵ) as catalyst. The results showed that limit of detection of the proposed method was 0.003 mg/L and that the recovery for chromium (Ⅵ) was between 98.3% and 102.0% with a relative standard deviation of less than 2.7%. The linear range was 0.045 －0.200 μg/mL. Our results