1H NMR spectrometry for methanol quantification in apple wines and ciders as optimised by comparison to SIDA-HS-GC-MS

Methanol, a hepato-and neurotoxic compound, is present in apple-based beverages as a by-product of the enzymatic degradation of pectin. Stable isotope dilution assay (SIDA) employing gas chromatography-mass spectrometry (GC-MS) is the state-of-the-art method for methanol determination in beverages. Despite higher initial investment costs, quantitative 1H NMR spectroscopy (qNMR) is a simpler and faster analytical technique to quantify numerous analytes in liquid foods. Beyond targeted analyses, qNMR spectral fingerprints in the product might be used for non-targeted analytical goals, such as adulteration and contamination detections. Here, an existing 1H-qNMR method used for wine profiling was optimised for methanol quantification in apple-based products, including cross-validation against a SIDA-HS-GC-MS method and reference values from interlaboratory trials. The optimisation involved a pivotally important estimation of a correction factor by an external calibration approach, making qNMR results comparable to SIDA-HS-GC-MS. The optimised qNMR method is suggested to be an alternative for methanol quantification in beverages.

Automated summary

This study optimized a method originally used for wine analysis for quantification of methanol in apple-based beverages. By comparing it with other methods, the optimized method was found to provide reliable results. The optimized qNMR method can be considered as an alternative approach for methanol quantification.