超声波提取—原子荧光光度法测定食品中无机砷及其不确定度的评估

Evaluation of uncertainty in measurement of inorganic arsenic in foods by ultrasonic-atomic fluorescence spectrometry

建立一种简便快捷、准确度高的食品中无机砷的测定方法，并对其测量结果的不确定度进行评估。食品中的无机砷经超声波提取后，采用原子荧光分光光度法测定其含量，然后用统计学方法计算测量结果的不确定度。结果显示，超声波提取30min后的测定结果与国标法提取18h的测定结果间无显著性差异；最低检出限为0．104ng／mL，回收率达到95．7％～100．5％，相对标准偏差为4．3％，线性范围为0～100ng／mL。本法简便快速、准确可靠，可用于食品中无机砷的检测，扩展不确定度为0．0074mg／kg，影响测量结果不确定度的主要来源有校准曲线、测量重复性和标准系列溶液的配制。

To establish a simple and accurate method for the determination of inorganic arsenic in foods, and evaluate the uncertainty in the measurement. The inorganic arsenic in foods was extracted by ultrasonic wave and measured using atomic fluorescence spectrometry, and the factors influenced upon the measurements were ana lyzed. The results shown, There is no significant difference between the results ultrasonic extracted 30 min by this method and that of the GB method, extracted 18 h. The detection limit was 0. 104 ng/mL and linear range was 0 - 100 ng/mL with recovery of 95. 7% 100. 5% and RSD of 4. 3%. This method showed to be rapid and accurate, and can be used for the measurement of inorganic arsenic in foodstuff. The expanded uncertainty was 0. 007 4 mg/kg with 95% confidence level. The calibration curve, determination repeatability and concentration of standard solution were the primary sources factors for the measurement uncertainty.