基于可见分光光度法的食用油过氧化值检测

为了构建食用油过氧化值快速检测分析方法,以食用油为试验材料,利用可见分光光度计测定碘与淀粉的显色变化,建立食用油过氧化值的检测模型,探讨测定波长、饱和碘化钾添加量、反应时间、淀粉指示剂添加量、溶剂混合比例和油脂种类等因素对测定结果的影响。通过模型建立和验证、盲样验证及精密度分析,结果表明:检测条件对测定结果影响均不显著;当取样质量为(0.100±0.010)g,入射光波长为535nm时,食用油过氧化值模型为:y=28.856x+0.1331(y为过氧化值,mmol/kg,x为溶液吸光度),R2=0.9985。模型预测值与国标法测定值高度线性相关,盲样验证相对误差均10%,检出限为0.79mmol/kg,符合国家标准的相关要求,基于可见分光光度法的食用油过氧化值检测方法是可行的。

Determination of Peroxide Value of Edible Oils by Vis Spectrophotometry

In order to develop rapid determination method of peroxide value in edible oils, using edible oils as raw materials, calibrations which based on chromomeric reaction of I2-KI solution were developed and validated for determination of peroxide value, and effects on determination of the varying condition, such as detective wavelength, amount of saturated potassium iodide, reaction temperature, amount of starch indicator, types of oil samples and ratio of organic solvent were explored. Method was validated by Chinese national standard methods. Results showed that experi- mental conditions had no significant effect on determination. When edible oil sample was （0.100±0.010） g, calibration was y=28.856x＋0.1331 （where x is the value of the absorbance, y is peroxide value）, R^2=0.9985. Linear correlativity of determination of peroxide value between two methods was very well, relative deviation of blind samples experiment＇s data were less than 10%, according with national standard requirement, the lowest detectable limitation was 0.79mmol/kg. Proposed method was workable.