Determination of 5-hydroxymethylfurfural in vinegar samples by HPLC

The aim of this study was to establish an overview of the HMF (5-hydroxymethylfurfural) content of different vinegar samples. A reverse-phase HPLC method with diode-array detection without extensive sample cleanup was used. The recoveries of HMF in spiked vinegar were found to be in the range of 95-101%. The detection limit was in the range of 80 mu g/L. The sample preparation consisted simply of dilution and filtration of the vinegar samples. The HMF content was analyzed in various kinds of vinegar (n = 120) and balsamic vinegar (n = 35). Depending on their HMF content the vinegars could be divided into four groups: samples with no, low, medium, and high HMF concentrations. Few vinegar samples investigated contained no HMF. Most of the other samples contained HMF in a low range up to 10 mg/L, whereas sherry vinegar and some apple vinegars had concentrations up to 35 mg/L. Only the balsamic vinegars showed a very high concentration of 300 mg/L to 3.3 g/L of HMF. The highest concentrations were found in traditionally produced balsamic vinegar samples. Depending on their age, up to 5.5 g/kg could be determined.