Determination of organic acids in fruits and vegetables by liquid chromatography with tandem-mass spectrometry

A method using liquid chromatography coupled to tandem-mass spectrometry (LC–MS/MS) with triple quadrupole in selective reaction monitoring mode was developed to determine organic acids (glutamic, tartaric, quinic, malonic, malic, shikimic, α-ketoglutaric, pyruvic, citric, succinic and fumaric acids) in fruits (melon, grape, peach, orange, lemon) and vegetables (green and red pepper, tomato, lettuce and lamb’s lettuce). The negative ion mode of ESI was used. All the validation parameters were found to be within the range of acceptance for all the compounds. Different matrix effects were observed in the studied vegetables and samples were quantified by the standard additions approach. The main advantages of this method are its selectivity, which is one of the main weaknesses of most methods when analysing organic acid in complex matrices, and its simplicity since little sample preparation is needed.