Determination of chlorinated paraffins in cutting fluids and lubricants

An analytical routine procedure to classify chlorinated paraffins in technical products such as cutting fluids and lubricants is presented. Classification is based on chain length and chlorination degree (short chain, highly chlorinated congeners being subject to legal restrictions). After sample clean up with solid phase extraction over silica, screening is performed with gas chromatography and electron capture detection (ECD). Positive identification and quantitation is then performed with gas chromatography/mass spectrometry using negative chemical ionisation (NCI). Both methods show good reproducibility and repeatability and the average recovery of the chlorinated paraffins with the NCI method is 98%. The detection limits for restricted paraffins in samples range between 0.02-0.08% (w/w) for the ECD method and between 0.2-2.6% (w/w) for the NCI method. The procedure has been applied successfully to the analysis of 37 cutting fluids or lubricants. Short chain, highly chlorinated paraffins were detected in 8 (21%) samples in concentrations from 1 to 70% (w/w). The described procedure can be recommended as an analytical routine method for supervising future legal restrictions on the use of chlorinated paraffins in cutting fluids and lubricants.