Quantitative Detection of Pyrazines in Edible Oils Using SABRE Hyperpolarized NMR Spectroscopy.

Abstract

Pyrazines are key flavor compounds in various foods, and their detection is essential for assessing quality, authenticity, and potential adulteration. However, because food matrices are complex mixtures, detecting pyrazines typically requires complex pretreatment steps to eliminate interference from structurally similar molecules. In this study, we present a highly selective detection method for pyrazines in food using sensitive and quantitative hyperpolarized NMR. Trace pyrazine compounds in edible oils were detected on a benchtop NMR system (60 MHz, 1.4 T) utilizing signal amplification by reversible exchange (SABRE) hyperpolarization through cosubstrate strategy. Thanks to the high selectivity of SABRE toward pyrazines, our method requires only a simple extraction procedure to achieve accurate quantification of pyrazine with the concentration of 59.3 μmol/L in sesame oil, and the limit of quantification is as low as 21.0 μmol/L. Compared to conventional high-field NMR (500 MHz, 11.7 T), our approach demonstrates high sensitivity and accuracy on a low-field NMR spectrometer. Our works validate SABRE as a powerful tool for highly selective trace analysis, with potential applications in food quality assessment, flavor profiling, and bioactivity analysis.