In-syringe polypropylene fiber-supported liquid-phase microextraction followed by LC-MS/MS for rapid and sensitive determination of tyrosine kinase inhibitors in plasma

A rapid, sensitive, and green sample preparation method based on polypropylene fiber-supported liquid-phase microextraction followed by liquid chromatography–tandem mass spectrometry was developed for the determination of tyrosine kinase inhibitors in plasma. Commercial oil absorbent pads composed of polypropylene fibers were used to support n-octanol as the extraction phase. The high chemical purity of the polypropylene fiber minimized background interference, enabling reliable trace-level analysis. The in-syringe format allowed simple push–pull operation, and extraction conditions were optimized for maximum efficiency. The method demonstrated excellent linearity (R 2  > 0.995), low limits of quantification (0.067–3.0 ng/mL), and high precision, with intra- and inter-day recoveries ranging from 79.5 % to 113.6 % and relative standard deviations below 14.2 %. A blinded spiked sample analysis confirmed the method’s reliability for clinical application. The greenness of the method, as evaluated by five green assessment tools, demonstrated excellent environmental compatibility. Overall, the proposed in-syringe polypropylene fiber-supported liquid-phase microextraction method offers a simple, cost-effective, and environmentally sustainable solution for the analysis of tyrosine kinase inhibitors in complex biological matrices.