Quantitative determination of wine polysaccharides by gas chromatography–mass spectrometry (GC–MS) and size exclusion chromatography (SEC)

Wine polysaccharides play an important role on a number of technological and quality properties of wines and thus several methods have been proposed for their quantification. The present study evaluates the suitability of gas chromatography with mass spectrometry detector (GC–MS) for determining the content of wine monosaccharides and thus polysaccharide families. Factors affecting the yield of polysaccharide precipitation were firstly evaluated and the GC–MS method was characterised and compared with the previously reported GC–FID method. Repeatability and reproducibility values were similar in both methods, with values ranging from 1% to 14%. LODs obtained by MS were below 1.0 μg for all monosaccharides and LOQs were below 1.8 μg. Moreover, a recovery study of the whole method was carried out and it provided absolute recoveries between 81% and 116% for different wine samples, very good values taking into account the multi-step procedure. Both GC–MS and GC–FID were applied to determine the content of wine polysaccharide families in three wine samples and no significant differences were observed. Finally, high-resolution size exclusion chromatography with refractive index detector (HRSEC-RID) was applied to obtain the molecular weight distributions of the wine polysaccharides and to estimate their global content. The correlation observed between the polysaccharide values obtained with the GC method and the HRSEC-RID method (r = 0.746, p < 0.05) indicated that the latter could serve as a rapid and simple method to give an estimation of total wine polysaccharides although it can not be used to quantify in a precise way.