Multivariate analysis of pyrolysis-GC/MS data for identification of polysaccharide binding media

The method of Thermally assisted Hydrolysis and Methylation (THM) was applied to the analysis of plant gums that can be found in artistic and archaeological objects. The main products obtained by THM of gums arabic, cherry, tragacanth, ghatti and karaya are permethylated and partially methylated 3-deoxyaldonic acids, characteristic products obtained from alkaline hydrolysis of monosaccharides. These markers allowed only a preliminary distinction between the different gums because they are not representative of the entire monosaccharides profile. As classification on the basis of sugars quantification is impossible, multivariate data analysis was employed, using the peak areas of THM products as variables. Calculations were performed on several different sets of data, enhancing the capability of the method to differentiate gums, also when submitted to accelerated ageing treatments. A case study on samples coming from ancient Egyptian cartonnage funerary masks is presented.