Simultaneous Analysis of Vanillin and Coumarin in Mangrove Plants and Commercial Food Products Using UPLC-ESI-MS/MS

Background: Vanillin is a key constituent of natural vanilla. Usage of natural vanilla is affected due to its high price and limited supply, which leads to the use of artificial vanilla flavoring substances. Coumarin is a commonly encountered adulterant in beverage, food, and cosmetics as a flavoring and fragrance enhancer. However, coumarin has been banned for use as a food additive due to its toxic effects. To comply with the quality of vanillin in food and food products needs to be ensured. Methods: A rapid, simple and selective analytical method has been developed and validated using ultra-high performance liquid chromatography-tandem mass spectrometry for quantitative analysis of vanillin and coumarin. We also optimized fragmentation pattern of these metabolites while increasing collision energy to elucidate its structural information. The suitability and robustness of the method was checked by Zorbax Eclipse XDB C8 column (4.6 × 150 mm, 5 μm) using mobile phase comprising of methanol (A) and water with 0.1% formic acid (B) (90:10) with a flow rate 200 μL/min. The separation was achieved within 4.2 min with total run time of 5.0 min. The analysis was done by multiple reaction monitoring using 153/93 and 147/91 pair transition in positive electrospray ionization for vanillin and coumarin respectively. Results: The lower limit of quantification of vanillin and coumarin was 0.39 ng/mL and 3.9 ng/mL respectively. The intra and inter-day precisions for vanillin and coumarin were lower than 8.87 and 8.62 whereas, accuracy was within ± 2.13 and ± 1.53 respectively. The vanillin and coumarin was found to be stable under the examined conditions. This method was successfully applied for quantification of vanillin and coumarin in mangrove species and commercial food products. Conclusion: The described method and fragmentation pattern could be useful to direct confirmation and quality monitoring of a commercial food products assimilated with vanillin.