A fast, accurate and comprehensive LC-MS/MS method validation for the sensitive quantification of water-soluble vitamins in walnut, almond, hazelnut and pistachio fruits

Abstract

Evaluating nutritional values of food products such as nuts has been of great importance nowadays. In the current study, development and validation of a robust and fast LC-MS/MS method was carried out for simultaneous determination of pantothenic acid (B5), riboflavin (B2), biotin (B7), thiamine (B1), cyanocobalamine (B12), nicotinamide (B3), nicotinic acid (B3), pyridoxine (B6) and folic acid (B9) in walnut, almond, hazelnut and pistachio samples from Turkey. Isotope labeled vitamin standards were used to compensate the sensitivity losses and increase the degree of precision. The validation parameters of the developed analytical method were accuracy (recovery), linearity, limit of quantification (LOQ), intra-day and inter-day precision (repeatability), relative standard uncertainty (U% at 95% confidence level (k = 2)), and limit of detection (LOD). Chromatographic parameters were optimized to have optimum separation of nine water soluble vitamins (WSVs) and MS detection was performed using a tandem mass spectrometer. Linearity of the established LC–MS/MS method was in the range of 25–1000 ng/mL for the studied vitamins. The coefficients of determination for the vitamins were between 0.9973 and 0.9999. LOD/LOQ values of the analytes were 10.48/12.54, 13.08/19.59, 5.77/7.70, 12.48/17.71, 12.38/14.90, 6.55/10.08, 8.08/9.81, 13.03/16.38, 13.08/19.59 for B1, B2, nicotinamide (B3), nicotinic acid (B3), B5, B6, B7, B9 and B12, respectively.