Abstract: 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.

Key words: infant formula powder; chlorate; perchlorate; ion chromatography-tandem mass spectrometry; enhanced matrix removal lipid (Captiva EMR-Lipid) cartridge