Determination of Bongkrekic Acid in Food by Dispersive Solid Phase Extraction-High Performance Liquid Chromatography-Tandem Mass Spectrometry Using Nitro Modified Zirconium Metal Organic Framework

Dispersive solid phase extraction (DSPE) using nitro modified zirconium-based metal organic framework (NO2-MOF) as adsorbent for determination of bongkrekic acid in food was developed. The synthesized NO2-MOF were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), infrared spectroscopy (IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption experiment, etc, indicating that a structural stable MOF material with large BET surface area was obtained. There existed electrostatic interaction, pi-pi stacking, hydrogen bond and other weak intermolecular interactions between MOF and bongkrekic acid molecules to achieve selective adsorption of target molecules. Main experimental factors affecting DSPE were optimized, including pH value, amount of the adsorbent, extraction time, and type of desorption solvent. The established method was applied to detection of bongkrekic acid in auricularia auricula and rice flour, with limit of quantification of 1.6 mu g/kg, and limit of detection of 0.5 mu g/kg. In conclusion, the established method for determination of bongkrekic acid in food by DSPE had the advantages such as short pretreatment time, high sensitivity and precision with satisfactory recoveries of 75%-96%, and was environmentally friendly. This work provided a more reliable technique for determination of extremely trace amount of bongkrekic acid in related food such as auricularia auricula, tremella and rice flour.