三乙胺增强-电感耦合等离子体质谱法测定食品中痕量砷

Determination of trace arsenic in food by inductively coupled plasma mass spectrometry using triethylamine as a signal enhancer

中文关键词:  电感耦合等离子体质谱法  砷  有机增敏  食品  三乙胺

英文关键词:inductively coupled plasma mass spectrometry  arsenic  organic enhancer  food  triethylamine

中文摘要:

      目的 建立三乙胺triethylamine (TEA)增强-电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry, ICP-MS)准确测定食品中的痕量砷。方法 采用微波消解法进行样品前处理, 以8%的三乙胺作为基体改进剂, 采用碰撞池技术规避质谱干扰, 锗作为内标校正非质谱干扰, 用ICP-MS检测样品中的痕量砷。结果 以8%的三乙胺作为基体改进剂, 可以使砷的信号增加14.1倍, 显著地改善方法的精密度和准确度, 方法检出限为0.42 μg/kg。将该方法用于3种生物标准物质(小麦GBW10011、湖南大米GBW10045、芹菜GBW10048)中砷的测定, 测定值均在认定值范围内, 结果的相对标准偏差(relative standard deviations, RSDs)为2.5%~5.9% (n=6)。结论 该方法检出限低、准确度和精密度高, 可用于食品中痕量砷的检测。

英文摘要:

      Objective To achieve accurate determination of trace arsenic in food samples by inductively coupled plasma mass spectrometry (ICP-MS) with triethylamine (TEA) as a matrix modifier. Methods The samples were digested by microwave digestion procedure, and the trace arsenic was determined by ICP-MS with 8% TEA as a matrix modifier, the mass spectral interference was corrected with collision cell technology, and the signal drift in the determination was compensated with germanium as internal standard. Results The signal intensity of arsenic was enhanced by adding 8% TEA and the enhancement factor was about 14.1. The precision and accuracy of the method were significantly enhanced and the limit of detection was 0.42 μg/kg. The validity of the method with modifier was examined by analyzing 3 kinds of biological reference materials (wheat GBW10011、hunan rice GBW10045, celery GBW10048), and the measured values were in good agreement with the certified values, and the relative standard deviations (RSDs) were 2.5%?5.9% (n=6). Conclusion This proposed method has low detection limit, high accuracy and precision, which is suitable for the precise determination of trace level arsenic in food samples.