Analysis of Intact Glucosinolates in Beeswax by Liquid Chromatography Tandem Mass Spectrometry

Abstract

A new method was developed to determine 12 intact glucosinolates (glucoiberin, glucoraphanin, glucoerucin, gluconapin, glucotropaeolin, glucobrassicin, gluconasturtiin, glucoalyssin, 4-hydroxyglucobrassicin, 4-methoxyglucobrassicin, neoglucobrassicin, sinigrin) in beeswax, which is an authorized food additive in the European Union, by means of liquid chromatography tandem mass spectrometry with electrospray ionization. An efficient extraction procedure was proposed (average analyte recoveries were between 88 and 101 %); this involved the dissolution of melted beeswax with hexane, a solvent extraction using a mixture of ethanol and water (80:20, v/v), and a concentration step in a rotary evaporator. Chromatography was performed on a C 18 analytical column with a mobile phase of formic acid in water (0.5 %, v/v) and formic acid in acetonitrile (0.5 %, v/v), at a flow rate of 1 mL/min. The method was fully validated in terms of selectivity, limits of detection and quantification, linearity, precision, and accuracy. The limits of detection and quantification values were below 7 and 23 μg/kg, respectively. The proposed method was applied to analyze beeswax samples collected from organic apiaries.

Determination of 18 Intact Glucosinolates in Brassicaceae Vegetables by UHPLC-MS/MS: Comparing Tissue Disruption Methods for Sample Preparation

“…Importantly, solvent standard curves could be used to directly quantify the GSL content in different Brassicaceae vegetables. This is because the coelution of matrix components did not enhance or suppress the signal responses of the target GSLs (the matrix effects were in the range of 80–120%, Figure S4 ) [ 34 ]. The LOQs of the 13 GSLs in the freeze-dried sample powder and frozen-fresh sample powder ranged from 5.72–17.40 nmol/g dry weight and 0.80–1.43 nmol/g fresh weight ( Table 2 ), respectively.…”