High-Throughput Determination and Characterization of Short-, Medium-, and Long-Chain Chlorinated Paraffins in Human Blood

The industrial chlorinated paraffins (CPs) are comprised of short-chain (SCCPs), medium chain (MCCPs), and long chain (LCCPs) CPs. Although SCCPs and MCCPs are environmentally ubiquitous, little is known about CPs in humans. This study established a method for simultaneous determination of 261 SCCP, MCCP, and LCCP congener groups in one injection by reversed ultrahigh-pressure liquid chromatography coupled with chlorine-enhanced electron spray ionization-quadrupole time-of-flight mass spectrometry. The method yielded good peak shapes, high sensitivities, and low coeluted interferences for all examined CPs. LCCPs with carbon numbers of 21 to 27 were detected in their standard technical mixtures, and MCCPs and LCCPs impurities were detected in the LCCP and MCCP standard technical mixtures, respectively, causing quantification deviations when these mixtures were used for calibration. After considering these impurities' contribution to the total concentrations, the quantification accuracies for ∑SCCPs, ∑MCCPs, and ∑LCCPs ranged from 95.1 ± 8.4% to 105.6 ± 9.2% in the eight CP technical mixtures. The method was successfully applied to determine CPs in about 6 g human blood samples from a general population, and estimated ∑SCCP, ∑MCCP, and ∑LCCP concentrations to be 370-35 000, 130-3200, and 22-530 ng/g lipid weight (n = 50), respectively. A comparison of blood and soil/air CP profiles from the same areas suggested a relatively higher potential for the accumulation of SCCPs, compared with MCCPs, in humans.