Quantitation of Thioprolines in Grape Wine by Isotope Dilution–Liquid Chromatography–Tandem Mass Spectrometry

• DOI: 10.1021/acs.jafc.5b05604
• Publication Date: 2016-01-23T16:17:36Z
• Authors: Jingjing Liu; Xiangpeng Meng; Wan Chan
• Keywords: 0303 health sciences; HPLC-MS/MS; grape wine; Indicator Dilution Techniques; thioprolines; Wine; 2-methylthiazolidine-4-carboxylic acid; 03 medical and health sciences; Tandem Mass Spectrometry; Thiazolidines; Vitis; thiazolidine-4-carboxylic acid; Chromatography, High Pressure Liquid

Cysteine reacts with reactive carbonyls to form thioprolines, which have been demonstrated to possess various pharmaceutical properties. Therefore, thioproline formation is considered as a major detoxification pathway for carcinogenic reactive carbonyls. In this study, we report the initial identification of thiazolidine-4-carboxylic acid (1) and 2-methylthiazolidine-4-carboxylic acid (2), two very common thioprolines, formed by reacting formaldehyde and acetaldehyde with cysteine in grape wine samples. We have developed an isotope dilution-liquid chromatography-tandem mass spectrometry method featuring high sensitivity (limit of detection of ≤1.5 ng/mL) and selectivity to quantitate compounds 1 and 2. The method after validated to be highly accurate (recovery of ≥92%) and precise [intraday relative standard deviation (RSD) of ≤4.1% and interday RSD of ≤9.7%] was applied to determine the varying compound 1 and 2 contents in grape wine samples. Results revealed the grape type and storage duration-dependent formation of thioprolines in grape wines. Overall, the results are expected to facilitate compound-dependent investigations of the health benefits of grape wine, and our findings could be adopted to predict the age of grape wine.