A reference material (NMIJ RM 4076-a) for the determination of short-chain chlorinated paraffins

Chlorinated paraffins are primary industrial chemical products used for metalworking fluids and flame retardants. However, short-chain chlorinated paraffins (SCCPs) are registered in Annex A of the Stockholm Convention on Persistent Organic Pollutants. Therefore, since an accurate quantitative determination of SCCPs is crucial to monitor the level of pollution, analysis quality assurance with reference materials is needed. In this study, a reference material (RM), NMIJ RM 4076-a, was developed by the National Metrology Institute of Japan at the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) for the quantification of SCCPs. We determined the mass fraction of SCCPs by subtracting the impurities quantified using the mass-balance method, a combination of gas chromatography-flame ionization detection, Karl Fischer titrations, headspace-gas chromatography-mass spectrometry, and thermal gravimetric analysis. The mass fraction value of NMIJ RM 4076-a was concluded to be 0.9996 kg/kg. The standard uncertainty of this mass fraction was evaluated on the basis of the mass-balance method, the sample homogeneity, and stability obtained using the above analytical techniques. Accordingly, the expanded uncertainty estimated using a coverage factor of k = 2 was found to be 0.0013 kg/kg. The mass fraction of chlorine and the homologue compositional ratios are also given for this RM as supplementary technical information. This RM is expected to be applicable for use in the calibration of instruments, or for checking the validity of analytical methods or instruments for estimating the comparability of SCCP analyses.