The assay of pterostilbene in spiked matrices by liquid chromatography tandem mass spectrometry and isotope dilution method

Pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene) is an active component found in several plant species, exhibitingimportant pharmacological properties. A new and reliable method of assaying this phyto compound in various matrices ispresented; the assay is based on (1) the selectivity of liquid chromatography (LC) hyphenatedwith electrospray ionisation (ESI),(2) the specificity of a two-step mass spectrometric analysis (MS/MS) and (3) the accuracy of the isotope dilution method. Thelabelled analogue may be conveniently synthesised in a few steps. The sensitivity of the method is confirmed by the very lowlimit of detection (LOD) and limit of quantitation (LOQ) values achieved in the assay of pterostilbene in two distinct fortifiedmatrices, and is further supported by the observed accuracy values.