Investigation of the sorbitol content of wines and an assessment of its authenticity using stable isotope ratio mass spectrometry

A survey of sorbitol concentrations in wines sold in the UK has been carried out using high-performance liquid chromatography (HPLC) with refractive index detection. Most wines were found to contain less than 0.2 g l–1 of sorbitol. However, some wines from one country contained sorbitol at concentrations up to 6.0 g l–1. These concentrations were confirmed by gas chromatography (GC) and the identification of sorbitol was confirmed by mass spectrometry. The sorbitol was isolated from three wines by semi-preparative HPLC. The δ13CPDB ratios of these isolates were measured by stable isotope ratio mass spectrometry (SIRMS) and were found to be inconsistent with that expected from grape products. The isotope ratios of further samples were examined by GC-SIRMS. This proved to be a rapid and convenient technique and was particularly valuable when limited amounts of analyte were present in the sample.