Short-chain chlorinated paraffins (SCCPs) are listed in the Stockholm Convention. Therefore, selecting suitable methods for their accurate quantification is essential. Nowadays, the quality of commercial reagents employed as quantification standards is not guaranteed. As a solution, we adopted an SCCP formulation reference material with known homolog composition ratios as the quantification standard to evaluate the appropriateness of the methods. By mixing the SCCP formulation and interferences, an analytical sample was independently prepared and used as the simulation environmental sample. The homolog compositional profiles of the SCCPs resembled those of the quantification standard and the analytical sample. The mass fractions and the homolog profiles, including the carbon chain length and chlorine homolog profiles, of the SCCPs were reported by 14 different laboratories. For the mass fraction, the results reported by participants were consistent, except for the participants that employed low-resolution gas chromatography (GC). The results generated from liquid chromatography (LC) and GC were slightly different, despite of the similar homolog composition ratios between the quantification standard and the analytical sample. Although there were discreet discrepancies in the overall chlorine homolog profiles, the carbon chain length profiles acquired from GC and LC were similar. The differences depended on the method employed. Additionally, compared with the low-resolution data, the high-resolution data displayed less fluctuation since the effect of the interferences on the analytical sample was reduced because of the mass accuracy of high-resolution instruments. Accordingly, the interlaboratory trial employing the similar homolog compositional profiles of the quantification standard and the analytical sample proved valuable in elucidating the differences among methods, considering equipment, resolution specification, and ionization.

Chlorinated paraffins (CPs) are industrial chemicals that have been primarily used in applications involving metalworking fluids. Among CPs, short-chain chlorinated paraffins (SCCPs) are a well-known environmental pollutant and are listed under Annex A of the Stockholm Convention on Persistent Organic Pollutants. CPs are alkanes substituted with chlorine atoms, and SCCPs are comprised of 10-13 carbon atoms. Reliable quantification of SCCPs is a critical issue because of the large number of SCCP isomers that are in use across multiple industries. Some interlaboratory comparisons of SCCP analyses have been conducted, and the reliability of these results was overwhelmingly determined as inferior to that of comparable PCB and dioxin analyses because of variations in the quality of commercial reagents that were employed as quantification standards. In order to address such inconsistencies, this study endeavored to prepare and evaluate a novel SCCP formulation as a candidate reference material for use as a reliable quantification standard. A subject trial study was hence performed to evaluate methods such as gas- and liquid-chromatography mass spectrometry (GC/MS and LC/MS) on sample matrices (without a clean-up process), and to subsequently elucidate the interpreted specifications for their candidacy as a reliable quantification standard. Results ultimately showed that the SCCP concentrations obtained from GC and LC were comparable. When the homologs reported by a subset of 14 separate laboratories were unified (excluding all results for Cl4 homologs), the carbon chain length profiles obtained from GC and LC were found to be similar; however, the overall chlorine homolog profiles did exhibit slight differences. Moreover, the results from high-resolution MS showed less variation than those from low-resolution MS. Thus, it was overarchingly determined that the deployment of this candidate reference material would serve as an effective mechanism for estimating the comparability of SCCP quantifications/evaluations of standard materials.