ABSTRACT
A method based on thioacidolysis and advanced gas chromatography/mass spectrometry (GC/HRMS) analysis of degradation products has been developed in order to assess whether trace amounts of chlorinated nonphenolic alkyl-aryl ether structures of the β-O-4 type occur in high molecular weight lignin-derived or lignin-containing materials of industrial or natural origin. The identification and determination of chlorinated thioacidolysis degradation products was focused on GC/HRMS analysis in the selected ion monitoring (SIM) mode of silyl esters of degradation products originating from etherified lignin structures of the β-O-4 type. The identification of the chlorinated degradation products was based on the comparison of GC retention times and accurate mass numbers for the base peaks in the mass spectra with corresponding data for reference compounds. A mixture of monochlorinated reference compounds (thioacidolysis degradation products originating from guaiacyl and syringyl structures) was obtained by chlorination of a hardwood steam explosion lignin followed by thioacidolysis and silylation of the degradation products. The method has been found to be useful for detection of trace amounts (>1 μg/g) of chlorinated etherified lignin structures of the β-O-4 type in lignin-containing samples.
