Developments and interlaboratory study of the analysis of short-chain chlorinated paraffins

To survey the conformity and quality of the results between laboratories for short-chain chlorinated paraffins (SCCPs) determination, we reviewed current and novel analytical methods and organized four worldwide laboratory exercises between 2011 and 2017. Participants were requested to analyse test solutions and extracts of various matrices with their method of choice. Thirty-three laboratories participated (9–22 per round), of which 55–81% were able to submit data. Large differences in results between laboratories were found (CVs 23–137%) but results improved over time, while the levels in the test materials decreased. In the last round acceptable CV values (<25%) were obtained for the test solution. In the last round, results obtained by the GC–ECNI-LRMS technique varied most, which is disconcerting as this technique is most commonly applied. We strongly suggest to continue monitoring comparability of laboratories to assess consensus in SCCP analysis, with a focus on quantification procedures applied.