Synthesis of hydroxyl-rich covalent organic framework-coated stainless steel fiber for efficient solid-phase microextraction of psychiatric drugs from water and milk samples.

The increasing misuse of psychiatric drugs has led to their emergence as environmental contaminants in water and food matrices, raising public health concerns. In this study, a hydroxyl-rich covalent organic framework (Py-DHBD-COF) was solvothermally synthesized and coated onto a stainless steel fiber for use in direct-immersion solid-phase microextraction (DI-SPME). The fabricated fiber was employed to extract psychiatric drugs from environmental water and pretreated milk extracts, followed by analysis using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The hydroxyl-rich structure of the Py-DHBD-COF coating can provide hydrogen-bonding, hydrophobic interactions, and π-π interactions with the target analytes, resulting in high extraction efficiency. Key parameters affecting extraction performance, including extraction time, volume, pH, and desorption conditions, were systematically optimized. Under optimal conditions, the method exhibited good linearity (R2 = 0.9992-0.9996) for quetiapine, olanzapine, and clozapine over a concentration range of 1-500 ng/mL, with low limits of detection (0.010-0.024 ng/mL). The reproducibility was satisfactory, showing relative standard deviations below 5.38%, and recoveries ranged from 85.1 to 114.6% in both sample matrices. These results demonstrate that the proposed SPME-HPLC-MS/MS method is a sensitive, reliable, and environmentally friendly approach for monitoring trace levels of psychiatric drugs in complex water and milk samples.