Accumulation of short-, medium-, and long- chain chlorinated paraffins in tissues of laying hens after dietary exposure.

Reliable human health risk assessment associated with chlorinated paraffins (CPs) exposure is limited by the lack of data on the fate of this complex family of contaminants. To gain knowledge on the accumulation and distribution of CPs in biota after ingestion, laying hens were dietary exposed to technical mixtures of short- (SCCPs), medium- (MCCPs), or long-chain (LCCPs) CPs of various chlorine contents during 91 days, at 200 ng/g of feed, each. Adipose tissue, liver, muscle and serum were collected at the steady-state, along with excreta. All C10-C36 CPs were detected in liver. However, differences were observed in CP distribution: LCCPs high %Cl were retained in the liver; LCCPs low %Cl circulated through the serum and were distributed in the different compartments, but were mostly excreted through the eggs; SCCPs and MCCPs were found in all tissues at similar levels. Finally, a mass balance indicated a potential for biotransformation.

Transfer of short-, medium-, and long-chain chlorinated paraffins to eggs of laying hens after dietary exposure.

Chlorinated paraffins (CPs) are a complex family of contaminants. Lack of exposure data and an understanding of the fate of these chemicals in the environment affect our ability to reliably assess the human health risk associated with CP exposure. The present study focused on the evaluation of CP transfer from feed to eggs of laying hens exposed over 91 days. Laying hens were provided feed spiked with five technical mixtures of short-, medium- or long-chain CPs and featuring low or high chlorine contents, at concentrations of 200 ng/g each. Eggs were collected daily. All mixtures except the LCCPs with high chlorine content transferred into the eggs, with accumulation ratios increasing with the chain length and chlorine content. Concentrations at the steady-state varied between 41 and 1397 ng/g lw depending on the mixture. Additionally, the homologue-dependant transfer resulted in a change of pattern compared to that from the spiked feed.

Addressing Main Challenges Regarding Short- and Medium-Chain Chlorinated Paraffin Analysis Using GC/ECNI-MS and LC/ESI-MS Methods.

The risk assessment of chlorinated paraffins (CPs), chemicals of widespread industrial use, is struggling without standardized analytical methods to obtain reliable occurrence data. Indeed, scientists face analytical challenges that hinder the comparability of analytical methods, among them uncontrolled ionization efficiency and lack of quantification standards. In this study, our goal was to investigate potential issues faced when comparing data from different mass spectrometry platforms and quantification methods. First, the injection of the same set of single-chain length standards in three different instrumental mass spectrometry set-ups (liquid chromatography-electrospray-Orbitrap (LC/ESI-HRMS), liquid chromatography-electrospray-time-of-flight (LC/ESI-MS), and gas chromatography-electron capture negative ion-Orbitrap (GC/ECNI-HRMS)) revealed a shift of homologue response patterns even in-between LC/ESI-based set-ups, which was more pronounced for CPs of low chlorination degree. This finding emphasizes the need for a comprehensive description of instrument parameters when publishing occurrence data. Second, the quantification of a data set of samples with four quantification methods showed that quantification at the sum SCCP and MCCP levels presented good comparability, while quantification at the homologue level remained unsatisfactory. In light of those results, we suggest that (i) response pattern comparison should only be performed between similar instrumental set-ups, (ii) experimental chlorination degrees should be used when quantifying according to the %Cl (instead of those provided by the suppliers), and (iii) concentration results should be expressed as the sum of SCCPs and MCCPs primarily, with an indication on the match between samples and quantification standards (for example their chlorine content).

Optimized characterization of short-, medium, and long-chain chlorinated paraffins in liquid chromatography-high resolution mass spectrometry.

Chlorinated paraffins (CPs), or polychlorinated n-alkanes, form a complex family of chemicals as they exist as mixtures of several thousands of isomers. To facilitate their classification, they are subdivided into short-chains (C10C13, SCCPs), medium-chains (C14C17, MCCPs), and long-chains (C≥18, LCCPs) and further subdivided according to their chlorination degree. Until recently, the most common strategy implemented for their analysis was GC-ECNI-LRMS, with the main disadvantage being the high dependence of the response to the chlorination degree and the incapability of analysing LCCPs. In this work, we developed a method based on liquid chromatography coupled with electrospray ionisation-Orbitrap mass spectrometry (LC-ESI-HRMS) to expand the analysis capabilities of CPs. Although the different physico-chemical properties of CPs have led to compromises on the choice of analytical parameters, the addition of a mixture of DCM/ACN post-column with appropriate LC-ESI(-)-HRMS parameters enabled optimal and simultaneous detection of SCCPs, MCCPs and LCCPs from 10 to 36 carbons in one single injection. The combination of both the optimised LC-ESI parameters and the high resolution of the mass spectrometer (R = 140,000 @200 m/z) allowed separation of CPs signals of interest from unwanted halogenated ones, leading to minimum interferences in the detection. The optimised method was then successfully applied to the characterization of three types of vegetable oil, which were mostly contaminated with MCCPs. Additionally, the implementation of the LCHRMS strategy enabled the identification of highly chlorinated LCCPs in edible oil for the first time at dozens of ng g-1 lw, which demonstrates the need of such comprehensive methods to expand the knowledge about CPs occurrence in food and environmental matrices.