Analysis of trans-resveratrol by laser desorption coupled with resonant ionization spectrometry. Application to trans-resveratrol content in vine leaves and grape skin.

A method has been developed for nonvolatile compound analysis in fruits, namely, trans-resveratrol in grapes and vine leaves. This has been accomplished by the combination of laser desorption with resonance-enhanced multiphoton ionization coupled to time-of-flight mass spectrometry detection. After the optimization of the experimental conditions and the finding of the resonant wave-length of the substance, the full validation of the technique (i.e., linearity, repeatability, reproducibility, accuracy, detection limit, and quantification limit) was carried out with satisfactory results. Essential features of the method are as follows: (1) an enhanced desorption yield due to the mixing of the analyte with metal powder and (2) a high resolution and sensitivity and a low detection limit due to laser resonant ionization and mass spectrometric detection. Application to the analysis of trans-resveratrol in vine leaves and grape skin demonstrated the capabilities of the analytical method reaching detection limits of only few ppb.