Chlorinated paraffins (Bafu project)

Chlorinated paraffins (CPs) are high production volume chemicals (1 Mio t y-1), widely used as additives in metal working fluids, as flame retardants or plasticisers. Nowadays, CPs are ubiquitous environmental contaminants. They are persistent, have high bioaccumulation potentials and chronic toxic effects have been observed for short-chain CPs in fish and aquatic invertebrates. In other words, CPs are candidates for the Stockholm Convention on persistent organic pollutants (POPs) and information about their environmental fate is highly needed.

This project aims investigating environmental levels and temporal trends of CPs in Switzerland and their transformation potential. The chemical analysis of CPs is very challenging. CPs are applied as complex mixtures of thousands of isomers with complex isotopic patterns. Respective mass spectra are heavily interfered. The Fig. shows mixtures of CPs exhibit complex isotopic patterns, such as  (a) Simulated CP spectrum ([M+Cl]¯-ions, mass resolution ca. 4000) of penta- to decachlorinated C10-C13 homologues;  and in (b) mass interferences of different homologues; differing concentrations in a CP material (c) further complicates the analysis.

Currently, only a small number of laboratories world-wide, including Empa, have the expertise to analyse short-, medium- and long-chain CPs. As of recently, we apply a new and promising LC/MS-based method that allows simultaneous analysis of CPs of all chain lengths. Advanced data processing based on mathematical deconvolution allows the quantification of CPs and potential transformation products in technical and environmental samples. Therefore, Empa provides expertise and advanced analytical techniques to investigate the environmental fate of CPs.

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