Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) approaches for analysis of chlorinated paraffins in edible fats and oils

Abstract

Chlorinated paraffins (CPs) are high production volume chemicals composed of complex mixtures of thousands of compounds that have been applied widely as flame retardants and plasticizers. CPs have demonstrated toxic and bioaccumulative properties, while evidence suggests dietary intake to constitute a major pathway for human exposure. This study reports on the optimization and validation of an analytical method for the quantification of short- and medium-chained CPs (SCCPs and MCCPs, respectively) using gas chromatography-mass spectrometry (GC-MS) in fats and oils, and the development of liquid chromatography-high resolution mass spectrometry (LC-HRMS) methods for investigation of long chain CP (LCCP) occurrence. Extraction was performed by ultrasonication in n-hexane and dichloromethane followed by sulphuric acid and acidified silica cleanup and fractionation on neutral silica to remove potentially interfering organohalogen contaminants. Quantification of GC-MS results using a chlorine-content calibration procedure was assessed via repeated analysis (n=3) of olive oil fortified with SCCP and MCCP technical mixtures at two concentration levels and spiked lard samples from a recent European Union Reference Laboratory (EURL) interlaboratory study. The average accuracy ranged from 76 to 126% in the olive oil samples and from 57 to 150% in fortified lard, meeting the EURLs acceptability criteria for all tests, while the precision was < 15%. The applicability of the method was demonstrated by analysis of 26 fats and oil samples purchased in Belgium. SCCPs were detected in 31% of samples, ranging < LOQ to 19 ng/g, and MCCPs were present in 85%, ranging < LOQ to 190 ng/g. Each of four samples selected for homologue profiling by LC-HRMS were also found to contain LCCPs. This research demonstrates reliable methods for CP analysis in fats and oils and highlights the potential for contamination of these products by CPs. Fats and oils appear to be substantial contributors to overall human exposure to CPs.