1 H-NMR profile of mezcal and its distillation fractions using two sample preparation methods: direct analysis and solid-phase extraction

Distillation fractions (head, body, and tail) and mezcal samples were analyzed by proton nuclear magnetic resonance spectroscopy ( 1 H-NMR). Samples were obtained from five rural producers in Oaxaca State, Mexico, where the distilled beverage was produced using as raw material Agave angustifolia , commonly known as “Espadín”. The distillation cuts were done by the producers according to their experience and samples were taken from each distillation fraction. 1 H-NMR spectra were acquired by two sample preparation methods: direct analysis (DA) and solid-phase extraction (SPE) using styrene–divinylbenzene sorbent to concentrate aromatic compounds. When DA-NMR was used, fifteen compounds were identified and quantitated at mg/L level, including higher alcohols, aldehydes, esters, and organic acids. On the other hand, nine compounds were identified by SPE-NMR, including fatty acids, aromatic alcohols, aldehydes, and polycyclic aromatic hydrocarbons. The study showed that 1 H-NMR can be done by DA and with SPE as a complementary method for analysis of mezcal and its distillation fractions. These methodologies are useful for both research and industrial purposes. Graphic abstract