Quantification of Vanillin, Ethyl Vanillin and Methyl Vanillin Among Thai Rice Cultivars by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was developed and validated for vanillin, ethyl vanillin, and methyl vanillin determination in Thai rice cultivars by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) under the selected reaction monitoring mode. In rice samples, the limit of detection was 13.3, 11.2 and 5.0 mg/kg for vanillin, ethyl vanillin, and methyl vanillin. A high correlation coefficient was obtained (R2 = 0.9999, 0.9999 and 0.9998) within the linear range (0 - 300 mg/L) in the MS method. The recoveries ranging from 90.63 % ± 6.25 to 108.7 % ± 2.35 were obtained in different spiking concentrations. The average RSD% of intra-day for vanillin, ethyl vanillin, and methyl vanillin was 6.90, 5.13 and 2.16 %, and the inter-day were 6.72, 5.30 and 5.64 %, respectively. The developed method was applied to 24 commercial rice samples. Vanillin, were found in 24 samples ranging from 95.2 to 773.2 mg/kg. However, ethyl vanillin and methyl vanillin were not detected under LOD. The developed UPLC-MS/MS method for vanillin, ethyl vanillin and methyl vanillin determination include the merits of simple preparation steps and high sensitivity. HIGHLIGHTS Method development for analyzing vanillin, ethyl vanillin, and methyl vanillin in rice grain by UPLC-MS/MS. High accuracy and precision method for determining vanillin and its derivatives. Quantitative analysis of vanillin, ethyl vanillin, and methyl vanillin in Thai rice cultivars. GRAPHICAL ABSTRACT