Amantadine‐functionalized magnetic microspheres and stable isotope labeled internal standards for reducing matrix effect in determination of five opium alkaloids by liquid chromatography‐quadrupole linear ion trap mass spectrometry

Amantadine‐functionalized magnetic microspheres (Fe₃O₄@SiO₂@ADME) were prepared and applied as magnetic solid‐phase extraction (MSPE) adsorbents for the enrichment and analysis of five opium alkaloids in hotpot seasoning samples with liquid chromatography coupled to quadrupole linear ion trap mass spectrometry (LC‐QqQ_LIT‐MS/MS). The adsorbents could strongly adsorb the opium alkaloids via hydrogen‐bonding, hydrophobic, and π–π conjugation effects. The established MSPE, combined with stable isotope‐labeled internal standards could reduce the matrix effect significantly. In the LC‐QqQ_LIT‐MS/MS analysis, the precursor and product ions of the analytes were monitored quantitatively and qualitatively by the multiple reaction monitoring and enhanced product ion mode, improving the reliability of detection for real samples. Under the optimum conditions, the limits of detection and limits of quantification were found to be in the range of 0.05–0.8 μg/kg and 0.25–2.5 μg/kg, respectively, and the recoveries of all targets were in the range 80.1–115.3%, with the intra‐day and inter‐day relative standard deviations being less than 9.4 and 10.7%, respectively. Finally, the proposed method was successfully applied to the determination of illegal additives of opium alkaloids in hotpot seasoning samples.