基于离子色谱-电感耦合等离子体质谱法测定花椒中三价铬和六价铬

Determination of Trivalent Chromium and Hexavalent Chromium in Zanthoxylum bungeanum by Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry

为分析花椒中三价铬和六价铬,采用离子色谱-电感耦合等离子体质谱法对其三价铬和六价铬进行测定,并进行方法学考察、含量测定和体外模拟胃酸条件下三价铬和六价铬的转化。结果表明,该方法能在3 min内将三价铬和六价铬分离开,峰形好;方法线性关系好(标准曲线质量浓度为0.5~20μg/mL,r>0.999),三价铬和六价铬的定量限分别为0.06 mg/kg和0.07 mg/kg。红花椒、青花椒和藤椒中三价铬和六价铬加标回收率(加标量分别为0.2,0.5,1.0 mg/kg)为80%~100%,RSD均小于10%,由此说明该方法的适用性、准确性和精密度好。红花椒、青花椒和藤椒中总铬含量差异很大;30批次花椒中均未检出六价铬;花椒中的三价铬占其总铬含量的1%~10%。在37℃、pH 2~3盐酸条件下(胃酸),随着时间的增加,胃酸组和花椒组中六价铬转化率均明显增加,在加入量相同、转化时间相同的条件下,花椒组中六价铬转化率明显高于胃酸组,说明花椒有利于六价铬向三价铬转化。文章为花椒中铬形态分析提供了理论基础和方法支撑。

In order to analyze the trivalent chromium and hexavalent chromium in Zanthoxylum bungeanum,ion chromatography-inductively coupled plasma mass spectrometry is used to determine their content.Methodological investigation,content determination and in vitro simulation of the conversion of trivalent chromium and hexavalent chromium under gastric acid conditions are conducted.The results show that the method can separate trivalent chromium and hexavalent chromium within 3 min,and the peak shape is good.The method has a good linear relationship(the mass concentration of standard curve is 0.5~20μg/mL,r>0.999).The quantification limits of trivalent chromium and hexavalent chromium are 0.06 mg/kg and 0.07 mg/kg respectively.The spiked recovery rates of trivalent chromium and hexavalent chromium in Zanthoxylum bungeanum,Zanthoxylum schinifolium and Zanthoxylum armatum(with spiked amount of 0.2,0.5,1.0 mg/kg respectively)are 80%~100%,and the RSDs are all less than 10%,which indicates that the applicability,accuracy and precision of the method are good.There is a great difference in total chromium content in Zanthoxylum bungeanum,Zanthoxylum schinifolium and Zanthoxylum armatum.Hexavalent chromium is not detected in 30 batches of Zanthoxylum bungeanum.Trivalent chromium in Zanthoxylum bungeanum accounts for 1%~10%of the total chromium content.Under the conditions of 37℃,pH 2~3 hydrochloric acid(gastric acid),the conversion rates of hexavalent chromium in the gastric acid group and Zanthoxylum bungeanum group both significantly increase with the increase of time.With the same addition amount and the same conversion time,the conversion rate of hexavalent chromium in Zanthoxylum bungeanum group is significantly higher than that in the gastric acid group,indicating that Zanthoxylum bungeanum is conducive to the conversion of hexavalent chromium to trivalent chromium.This paper has provided a theoretical basis and methodological support for the analysis of chromium forms in Zanthoxylum bungeanum.