Sample Preparation Optimization for the Analysis of Gliadins in Food by Matrixassisted Laser DesorptionIonization Timeofflight Mass Spectrometry

Abstract

Analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF-MS) of wheat gliadin extracts from distinct types of wheat varieties displays a similar characteristic gliadin mass pattern within the 30–40 kDa range. Direct observation of this pattern in food samples was used to identify gluten gliadins in food rapidly and easily. A modified sample preparation for gliadin analysis by MALDI/TOF-MS has improved sensitivity of gliadin detection by a factor of more than 50. This procedure allows the direct detection of complex mixtures of gluten gliadins in food sample extracts down to a concentration of 0.01 mg ml-1, i.e. down to levels which are toxic for coeliac patients. This highly sensitive improved method has been also exemplified by the facile detection of individual proteins at low concentrations (100–400 pmol ml-1). © 1997 by John Wiley & Sons, Ltd.