A simplified screening method for short- and medium-chain chlorinated paraffins in food by gas chromatography-low resolution mass spectrometry

This study evaluates the performance of a simplified screening method for short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) based on gas chromatography-electron capture negative ionization/mass spectrometry (GC-ECNI/MS) analysis and chlorine content quantification. The response from different combinations of 'indicator' congener groups present in technical mixture standards were used within calibration calculations to test the hypothesis that Sigma SCCPs and Sigma MCCPs could be quantified with acceptable accuracy using only a subset of the commonly analysed C-10 to C-17 and C-15 to Cl-10 groups. Potential combinations were assessed with respect to calibration curve performance and accuracy of SCCP and MCCP analysis of spiked food samples (olive oil, salmon, pork sausage, breakfast cereal, cow's milk and lard). Based on these trials, a screening method which quantifies Sigma SCCPs and Sigma MCCPs using only congener groups with 6 and 8 chlorine atoms for each carbon chain length was proposed. Concentrations of SCCPs and MCCPs in triplicate analyses of spiked food samples calculated using the proposed screening method deviated by <= 25% for the vast majority of samples (maximum deviation 37%) from levels determined using all analysed congener groups. The mean trueness of the screening method as applied to each of the spiked food samples and lard samples from a previous European Union Reference Laboratory (EURL) interlaboratory study ranged from 65 to 110% for Sigma SCCPs and 102 to 175% for Sigma MCCPs. Relative standard deviations (RSDs) were <= 25% for all triplicate analyses and matrix specific LOQs ranged from 0.7 to 6 ng/g ww for Sigma SCCPs and from 1.3 to 12 ng/g ww for Sigma MCCPs. The proposed screening method has the potential to deliver substantial time savings in instrumental analysis and manual labour without greatly reducing the overall accuracy and sensitivity of SCCP and MCCP quantification. (C) 2020 Elsevier B.V. All rights reserved.