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Development and validation of a specific method to quantify intact glucosinolates in honey by LC–MS/MS

Ares, Ana M., Valverde, Silvia, Nozal, María J., Bernal, José L., Bernal, José
Subtropical plant science 2016 v.46 pp. 114-122
acetonitrile, anion exchange, biomarkers, detection limit, formic acid, freshness, glucosinolates, honey, liquid chromatography, metabolites, solid phase extraction, tandem mass spectrometry
Glucosinolates (GLSs), which are secondary plant metabolites, have been scarcely investigated in honey. Recently, research has been conducted into the potential of GLSs as botanical biomarkers or as a parameter to establish honey freshness, but the employed methodologies were not specifically developed for intact GLSs quantification in honey. The aim of this study was to develop a new method to quantify twelve intact GLSs in honey, by using liquid chromatography with tandem mass spectrometry. An efficient extraction procedure was proposed; this involved dissolution of the honey with heated water, followed by solid-phase extraction with a weak anion exchange sorbent. Chromatography was performed on a C18 analytical column with a mobile phase of formic acid in water (0.5%, v/v) and formic acid in acetonitrile (0.5%, v/v). The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, carry-over effect, reinjection reproducibility, precision and accuracy. The LOD and LOQ values were below 4μgkg−1 and 10μgkg−1, respectively. The proposed method was applied to analyze intact-GLSs in honey from different botanical origins. Four of the intact GLSs studied were identified at low concentration levels (<25μgkg−1) in several of the samples analyzed.