姜黄素分光光度法测定广州市售食品中硼含量

Determination of boron in foods from Guangzhou by curcumin spectrophotometry

目的用姜黄素分光光度法检测广州市售食品中硼含量。方法食品样品用1%Na2CO3调至碱性后灰化,然后在酸性条件下硼转化为硼酸,硼酸与姜黄素生成红色化合物,比色定量。结果硼含量在0～1μg/ml范围内有良好的线性关系,相关系数r=0.999 6,检出限为0.017μg/ml。相对标准偏差在0.09%～6.11%,加标回收率为88.9%～103.6%。用该法测定广州市售68种食品中硼,豆类硼含量范围2.99～34.73 mg/kg,水果类硼含量范围0.10～4.50 mg/kg,蔬菜类硼含量范围0.09～2.91 mg/kg,其他食品大部分硼含量相对较低,有3个样品硼含量远高于同类食品。结论姜黄素分光光度法设备易普及,重现性、灵敏度及准确性能满足分析要求,适用于多类食品中硼含量的测定。豆类、水果、蔬菜等硼含量较高,动物性食品以及多数谷类硼含量较低,部分加工食品可能存在违法添加硼砂或硼酸的情况。

Objective To determine boron in foods from Guangzhou by curcumin spectrophotometry.Methods Samples were pretreated by dry ashing after alkalified with 1% Na2CO3 and then turned into boric acid under acidic condition.A red compound was formed by the reaction of boric acid with curcumin,which was quantified by spectrophotometry.Results A good linearity was obtained in the range of 0-1 μg/ml,r=0.999 6,and the detective limit was 0.017 μg/ml.The relative standard deviation was 0.09%-6.11%,and the mean recovery was 88.9 %-103.6%.Boron contents in 68 kinds of food from Guangzhou were 2.99-34.73 mg/kg,in fruits were 0.10-4.50 mg/kg and in vegetables were 0.09-2.91 mg/kg.Boron contents in most other samples were low except in 3 samples.Conclusion The method needs only general equipment,and its repeatability,sensitivity and accuracy could meet the requirements of boron analysis in different kinds of food.The concentration of boron in dried fruits,beans and vegetables was higher,and that in fish,meat,egg and grain was lower.Some foods may be added with borax or boric acid unlawfully.