Determination of short polychlorinated alkanes in leather using gas chromatography-electron capture negative chemical ionisation mass spectrometry

International audience ; Polychlorinated alkanes (PCA) are organic compounds of general formula CxH(2x+2-y)Cly. PCA are extremely complex industrial mixtures of randomly chlorinated petroleum distillate. They are made of several thousands structural isomers. The short chain isomers (sPCA) have a carbon number between 10 and 13. All PCAs have a high environmental persistence and accumulate in the biosphere. They were included in all regulatory programs implying reliable methods for their determination in various samples. The content of sPCA is regulated in leather. The objective of this study was to develop a reliable and sensitive analytical method to determine and to quantify sPCA in real-world leather samples. The protocol started by an ultrasound-assisted hexane extraction of the ground leather sample. The extract was purified by filtration on a Florisil (R) (magnesium silicate) column with hexane/dichloromethane 9/1 v/v eluant. The concentrated extract was redissolved in 5 mL isooctane for analysis with a gas chromatograph coupled with a mass spectrometer in the electron capture negative ionization mode. The method was validated and used with real-world samples giving a reliable limit of quantification of 2 mg/kg +/- 0.2 mg/kg for the sPCA family.