RESUMO
Methods for Vitamin B5 determination in food products remain limited by their low sensitivity and poor selectivity. Here, we have developed a liquid chromatography-mass spectrometry (LC-MS) method for Vitamin B5 determination in wide range of fortified food products. Vitamin B5 was extracted from food samples by heat treatment and analysed by LC-MS in the positive mode using electrospray ionisation (ESI). Vitamin B5 was quantified using hopantenic acid (HOPA) as internal standard after their separation on a C18 narrow-bore column with a gradient of mobile phase made of water/acetonitrile and trifluoroacetic acid (TFA) 0.025%. MS with single ion monitoring mode at mass m/z 220 was used for Vitamin B5 quantification. Calibration curve between 0.5 and 10 microg/ml of Vitamin B5 was linear (r2=0.9993) and the detection limit was determined to be 800 pg. The overall quantitative efficiency of the method was evaluated using Nestle reference sample (infant formula). The intra-assay RSD was 4.8% (n=8), the inter-assay RSD 6.4% (n=4) and the recoveries of the spiked samples were above 95%. Application of the LC-MS method to Vitamin B5 determination in wide range of fortified food products including three US National Institute of Standards and Technology (NIST) reference samples (RM 8435, RM 8415 and SRM 1546) shows consistent results with those obtained by microbiology and recoveries of Vitamin B5 between 93 and 104% for the spiked samples.
