Direct profiling of saccharides, organic acids and anthocyanins in fruits using electrospray droplet impact/secondary ion mass spectrometry.

Electrospray droplet impact (EDI)/secondary ion mass spectrometry (SIMS) is a new desorption/ionization technique for mass spectrometry in which highly charged water clusters produced from atmospheric-pressure electrospray are accelerated in vacuum by several kV and impact on the sample deposited on the metal substrate. In this study, we applied EDI/SIMS directly to fruits, such as bananas, strawberries, grapes and apples. The major components in the fruits--fructose, glucose, sucrose and organic acids--could be observed with strong signal intensities. EDI/SIMS was also applied to the analysis of different regions of strawberries and apples. Compared with matrix-assisted laser desorption/ionization (MALDI), ion signals with lower background signals could be obtained, particularly for the low molecular weight analytes.