Covalent Organic Framework-Based Solid Phase Microextraction Coating for Rapid Screening and Quantification of Drugs of Abuse and Artificial Sweeteners in Surface Waters

Solid-phase microextraction (SPME) has emerged as a powerful tool used for extracting analytes from complex matrices, offering high sensitivity, automation potential, and high-throughput efficiency. Despite its advantages, its performance is often limited by the selectivity and physicochemical properties of conventional coatings. This study addresses the limitations of conventional SPME coatings for monitoring environmental contaminants by introducing a nitrogen-rich covalent organic framework (COF) as an SPME extraction phase/coating. The COF-based SPME coating was implemented in a coated-blade spray (CBS) device format and was used to develop a robust analytical workflow that combined ambient mass spectrometry ionization via CBS for rapid screening, followed by LC-MS/MS for confirmation and quantification. Statistical validation using a t test showed that only 3 of 43 analytes exhibited statistically significant differences in loss during the microdesorption step of the CBS-MS/MS screening. The results demonstrate that the COF-based SPME coating facilitates simultaneous extraction of analytes with varying polarities from river samples without altering the sample matrix. The final protocol achieved limits of quantification ranging from 0.025 to 5 ng mL–1. The method was successfully applied to river samples, quantifying the target analytes and demonstrating that LC separation remains essential for confirmation. This work highlighted the effectiveness of a COF-based SPME coating as a next-generation extraction phase that simplifies rapid ambient MS screening, followed by traditional LC-MS/MS for confirmation and quantification, all within a single coated SPME device.