基于Captiva EMR-Lipid净化的婴儿配方乳粉中氯酸盐和高氯酸盐的离子色谱-串联质谱测定

建立一种非抑制型离子色谱-串联质谱测定婴儿配方奶粉中氯酸盐和高氯酸盐的方法。样品使用纯水溶解，乙腈沉淀样品中蛋白质。蛋白沉淀离心后的上清液使用脂质去除产品Captiva EMR-Lipid进行除脂净化。方法使用0.7 mol/L甲胺溶液和乙腈作为流动相，IonPac AS16离子色谱柱作为分析柱，使用电喷雾离子源、负离子多反应监测模式进行检测，内标法定量。氯酸盐在质量浓度5～200 μg/L范围内线性良好，其相关系数大于0.999。高氯酸盐在质量浓度1.25～50 μg/L范围内呈现良好的线性，相关系数大于0.999。氯酸盐和高氯酸盐在阳性样品中3 个不同的加标水平下的加标回收率分别为98.8%～101%和97.2%～112%，相对标准偏差分别为1.1%～2.6%和1.3%～6.8%。氯酸盐和高氯酸盐的方法检出限分别为4.8 μg/kg和1.6 μg/kg，定量限分别为16 μg/kg和5.0 μg/kg。该方法操作简单、准确度高，适用于婴儿配方奶粉中氯酸盐和高氯酸盐的日常检测。

Determination of Chlorate and Perchlorate in Infant Formula Powder by Ion Chromatography Coupled with Tandem Mass Spectrometry Based on Captiva EMR-Lipid Clean-up

The aim of this study was to develop a method for the determination of chlorate and perchlorate in infant formula powder by using non-suppressed ion chromatography-tandem mass spectrometry. After being dissolved in pure water, proteins in the samples were precipitated with acetonitrile. After centrifugation, the supernatant was cleaned up by using Captiva EMR-Lipid, which could remove lipids from the matrix. The resulting filtrate was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). An aqueous solution containing 0.7 mol/L methylamine and acetonitrile were applied as the mobile phase. The separation was performed on an IonPac AS16 column. Data were collected by multi-reaction monitoring (MRM) in electrospray negative ionization mode. The quantitative analysis was carried out by the internal standard method. The calibration curves for chlorate and perchlorate showed a good linearity in the range of 5–200 and 1.25–50 μg/L with a correlation coefficient greater than 0.999, respectively. The recoveries of chlorate and perchlorate in positive samples at three different spiked levels were in a range of 98.8%–101% and 97.2%–112% with relative standard deviations (RSD) of 1.1%–2.6% and 1.3%–6.8%, respectively. The limits of detection (LOD) and limits of quantification (LOQ) of this method were 4.8 and 16 μg/kg for chlorate, and 1.6 and 5.0 μg/kg for perchlorate respectively. This method is suitable for the routine detection of chlorate and perchlorate in infant formula powder with the advantages of simple pretreatment and high accuracy.