Development of a New High-Performance Liquid Chromatography–Electrospray Ionization Time-of-Flight Mass Spectrometry Method for the Determination of Low Molecular Mass Organic Acids in Plant Tissue Extracts

7 Pag., 5 Tabl., 2 Fig.A liquid chromatography–electrospray ionization time-of-flight mass spectrometry method has been developed for the direct and simultaneous determination of 10 low molecular mass organic acids in different plant tissue extracts. The method does not include a derivatization step. Quantification was accomplished using 13C-labeled malic and succinic acids as internal standards. Good limits of detection (0.05–1.27 pmol) were obtained for malic, 2-oxoglutaric, succinic, quinic, shikimic, cis-aconitic, and citric acids, whereas for oxalic, ascorbic, and fumaric acids limits of detection were 255, 25, and 11 pmol, respectively. Repeatability values for the retention time and peak area were <5%, with the exception of ascorbic acid. Analyte recovery was between 92% and 110% in most cases, with the exception of oxalic (39–108%), 2-oxoglutaric (44–69%), and ascorbic (22–86%) acids, which may require specific extraction procedures and use of the corresponding 13C-labeled organic acid as internal standards to improve accuracy. The method was applied to three types of plant materials: sugar beet leaf extracts, tomato xylem sap, and commercial orange juice.This study was supported by the Spanish Ministry of Science and Innovation (MICINN; Projects AGL2007-61948 and AGL2009-09018, cofinanced with FEDER), the European Commission (Thematic Priority 5—Food Quality and Safety, sixth Framework RTD Programme, Contract FP6-FOOD-CT-2006-016279), the trilateral Project Hot Iron (ERA-NET Plant Genome Research KKBE; MICINN Project EUI2008-03618), and the Aragn Government (group A03). R.R.-A. and S.L.-G. were supported by an FPI-MCINN fellowship and a CSIC Grant (I3P-2005) from the I3P programme, cofinanced by the European Social Fund, respectively. Acquisition of the HPLC–TOFMS apparatus was cofinanced with FEDER.Peer reviewe