催化动力学光度法快速测定卤肉制品中的痕量铬

Rapid determination of trace chromium in stewed meat products by catalytic kinetic spectrophotometry

目的建立催化动力学光度法快速测定卤肉制品中痕量铬。方法以卤肉制品为样品,通过单因素试验考察Cr(Ⅵ)-H2O2-溴甲酚绿催化反应体系中的pH、过氧化氢用量、溴甲酚绿用量、反应温度和反应时间对体系吸光度的影响,在最优反应条件下测定卤肉制品中的痕量铬。结果催化动力学光度法测定卤肉制品中痕量铬的最佳波长是630nm,反应体系pH4.4,过氧化氢的用量为0.2mL,溴甲酚绿用量为0.4 mL,在60℃水浴中加热5 min。该方法检出限为0.256μg/mL,平均加标回收率为88.5%~106.0%,相对标准偏差为1.1%~3.0%(n=5)。结论与GB 5009.123—2014《食品安全国家标准食品中铬的测定》中的电感耦合等离子体质谱法(inductively coupled plasma-mass spectrometry, ICP-MS)相比,本研究所建立的方法操作简单,所用仪器价廉易得、成本低、易于推广。

Objective To establish a method for the rapid determination of trace chromium in stewed meat products by catalytic kinetic spectrophotometry. Methods Taking stewed meat products as samples, the effects of pH, hydrogen peroxide dosage, bromocresol green dosage, reaction temperature and reaction time on the absorbance of Cr(VI)-H2O2 bromocresol green catalytic reaction system were investigated by single factor experiment. The chromium content in the stewed meat products was determined under the optimal reaction conditions. Results The optimum conditions were as follows: Wavelength 630 nm, pH 4.4, 0.2 mL hydrogen peroxide, 0.4 mL bromocresol green, 60 ℃ water bath heating for 5 min. The limit of detection was 0.256 μg/mL, and the average recoveries were 88.5%-106.0% with the relative standard deviations in the range of 1.1%-3.0%(n=5). Conclusion Compared with the inductively coupled plasma-mass spectrometry(ICP-MS) in the GB 5009.123—2014 National standard for food safety-Determination of chromium in food, the method established in this study is simple to operate, the instrument used is cheap and easy to obtain, low cost and easy to promote.