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SummaryMany organic materials release polar compounds containing -OH groups when subjected to pyrolysis. To improve GC detection of such polar compounds derivatisation with the silylating reagent hexamethyldisilazane (HMDS) can be achieved in situ while pyrolysing the sample (pyrolysis -silylation).In this study pyrolysis -silylation in combination with GC-MS was applied for the analysis of natural resins, utilised in artistic fields namely sandarac (Cupressaceae), Manila copal (Araucariaceae), colophon~ Venice turpentine, Strasbourg turpentine (Pinaceae), dammar, mastic, and shellac.Pyrolysis-silylation of natural resins resulted in the formation of several silylated compounds characteristic of the different kinds of resins.The trimethylsilyl (TMS) ester of sandaracopimaric acid was a prominent compound released from sandarac. Pinaceae resins produced TMS esters of pimaric, isopimaric, methyl dehydroabietic and abietic acids. TMS esters of linear aliphatic and aromatic acids were generated from shellac. Distinctive though as yet unidentified silylated compounds were released from Manila copal and triterpenic resins.

The mass spectra of trimethylsilyl (TMS) derivatives of possible hydroxylated pyrolysis products of glucose and cellulose were recorded by gas chromatography/mass spectrometry (GC/MS) analyses of TMS derivatives of 2-hydroxymethylfuran, 2-hydroxy-1-methyl-1-cyclopenten-3-one, 5-(hydroxymethyl)-2-furaldehyde, 5-methyl-2-furoic acid, 4-hydroxy-6-methyl-(2H)-pyran-2-one, 2-methyl-3-hydroxy-(4H)-pyran-4-one (maltol) and 1,6-anhydro-beta-D-glucopyranose (levoglucosan, LG). Also, 2-O-TMS-1,6-anhydro-beta-D-glucopyranose, 4-O-TMS-1,6-anhydro-beta-D-glucopyranose and 2,4-bis-O-TMS-1,6-anhydro-beta-D-glucopyranose were identified from the interpretation of electron impact and chemical ionisation mass spectra of products obtained from partially silylated levoglucosan solutions, together with information from the known relative reactivities of OH groups of anhydrosugars. A peak at m/z 116 was found to be characteristic of the mass spectra of partially silylated anhydrosugars, and is absent from the mass spectra of the persilylated species. Pyrolysis/GC/MS of cellulose in the presence of hexamethyldisilazane afforded principally the 2- and 4-TMS ethers and the 2,4-bis-TMS ether of LG, whereas the 5-TMS-oxymethyl-2-furaldehyde was a prominent pyrolysis/silylation product of glucose. The mass spectra of other relevant pyrolysis/silylation products are presented.