Simultaneous determination of betaines and other quaternary ammonium related compounds in bee pollen by hydrophilic interaction liquid chromatography-mass spectrometry

Abstract

The objective of this work was to develop a new method to determine nine betaines and other quaternary ammonium related compounds in bee pollen from different botanical origins; hydrophilic interaction liquid chromatography coupled to mass spectrometry (HILIC-MS) was the technique employed. A quick and efficient sample treatment (average analyte recoveries were between 82% and 95% and no significant matrix effect on ionization was found), involving an extraction with an acetonitrile and water mixture (1:1, v/v), centrifugation, freezing with dry ice followed by dilution, was presented. Chromatographic analysis (15 min) was by means of a core–shell HILIC column and a mobile phase applied in gradient elution mode. The analytical characteristics of the method were evaluated and the data demonstrated that not only was it selective, but it also displayed a wide linearity range and good precision. Several bee pollen samples from different botanical origins were analyzed with the proposed methodology, and three betaines (betaine, choline and trigonelline) were detected in all of them in a wide range of concentrations (57–62236 mg/kg).