分光光度法测定食品中的铝含量

Study on determination of aluminium in food by spectrophotometry

依据国家标准方法[1]对样品的前处理和样品的测定进行研究。样品前处理采用干灰化法。在pH6.0的乙酸-乙酸钠缓冲介质中,铝在聚乙二醇辛基苯醚(OP)和溴化十六烷基三甲胺的存在下与铬天青S形成稳定的四元混合胶束体系,其吸光度与铝含量在一定浓度范围内成正比。结果:摩尔吸光系数为7.1×104L/mol.cm。铝含量在0.00～5.00μg/25mL呈良好的线性关系,相关系数r=0.9995,回收率在95.8%～99.8%之间。该法操作简单,显色灵敏、稳定、精密度和准确度高,适用于各种食品中铝含量测定的要求。

The pretreatment and determination of sample was studied according to the state standard. The samples were pretreated by dry ashing. In the medium（pH = 6.0） of acetic acid - sodium acetate, aluminium combined with chrome azurol S （CAS） to form a stable quatemion - mixed micelles system with the existence of polyethlene glycol mono- （P）octyl phengl ether （OP） and hexadecy trimethylammonium bromide. The absorbency was direct proportion to the content of aluminium in a certain range of concentration. The result showed that molar absorption coefficients was 7.1 × 10^4 L/mol·cm. Calibration curves were linear when the content of aluminium was in the range of 0.00 - 5.00μg/25 mL with a correlation coefficient r = 0.9995 and the recovery rate 95.8 % - 99.8 %. The method is simple, sensitive, stable, precision and veracity. It can be used to determine the content of aluminium in food.