Molecularly imprinted polymer (MIP) and magnetic molecularly imprinted polymer (mag-MIP) for solid extraction and pre-concentration of quercetin have been successfully prepared by thermal polymerization method using quercetin (Q) as a template, acrylamide (AA) as a functional monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent. The MIP and mag-MIP were successfully applied in analysis of quercetin by mass spectrometry (MS) methods. To perform ambient plasma ionization experiments, a setup consisting of the heated crucible, a flowing atmospheric-pressure afterglow (FAPA) plasma ion source, and amaZon SL ion trap (Bruker, Bremen, Germany) was used. The heated crucible with programmable temperature allowed desorption of the analytes from MIPs structure which resulted in their direct introduction into the ion stream. The results of Q-MIP/Q-mag-MIP and FAPA-MS measurements were compared with those of the analysis of quercetin by the ESI-MS method without extractions and pre-concentration of analytes on polymers. Limits of detection (LOD) for quercetin solutions in both positive and negative ESI-MS were established at 10-8 M and 10-7 M, respectively. The linearity (R2 = 0.9999) of the proposed analytical procedure for quercetin determination in positive ions was provided in the range between 10-4 M and 10-7 M. Moreover, the same parameters were established for FAPA-MS in positive ions, reaching LOD at 0.005 mg/gMIP and the linearity of the method in the range of 0.015-0.075 mg/gMIP with the correlation coefficient value R2 = 0.9850.
Keywords: ESI-MS; FAPA-MS; magnetic molecularly imprinted polymer (mag-MIP); mass spectrometry (MS); molecularly imprinted polymer (MIP); quercetin.