电喷雾质谱法测定海藻中无机砷含量

建立了基于分子量测定海藻中无机砷含量的新方法——电喷雾质谱法。探讨了提取方法、溶液pH、还原剂、螯合剂、提取剂、质谱仪参数等实验条件对实验准确度、灵敏度的影响。在优化条件下,As(Ⅲ)的线性范围为0~151.4 ng/mL,As(Ⅴ)的线性范围为0~175.0 ng/mL,相关线性回归系数均在0.99以上,方法检出限(S/N3)0.024 mg/kg,方法定量限(S/N10)0.048 mg/kg。实验在不同浓度下加标回收率为81.0%~95.6%,相对标准偏差为2.52%~7.54%。该方法简单,灵敏度高,重现性好,避免了有机砷引起的假阳性现象,适用于海藻中无机砷的测定,可为海藻中无机砷监督检验提供有力技术支撑。

Detection of inorganic arsenic in algae by electrospray ionization mass spectrometry

A new method based on molecular mass for rapid determination of inorganic arsenic in algae by electrospray ionization mass spectrometry was developed. Several conditions affecting accuracy and sensitivity such as extraction method, pH of solvent, reductant, chelating agent, extractant and instrument parameters were studied. Under the optimum conditions, the calibration curve of As （ III ） was linear in the range of 0 - 151.4 ng/mL, the calibration curve of As （ V ） was linear in the range of 0 - 175.0 ng/mL, and the correlation coefficients were all above 0.99. The limit of detection（ S/N 〉 3 ）was 0. 024 mg/kg and the limit of quantitation （ S/N 〉 10） was 0. 048 mg/kg. The recoveries at different spiked concentration levels ranged from 81.0% to 95.6% with relative standard deviations（2.52% -7.54% ）. This method is simple, of high sensitivity and good reproducibility, without interference of organic arsenic. It can be applied to analyze inorganic arsenic in algae and can provide technological support for food safety management.