p-AAB/MXene as a novel adsorbent and SALDI matrix for highly efficient enrichment and rapid MS detection of emerging environmental organic pollutants in beverages and PM_2.5

Due to the complicated sample matrix and low concentration, analysis of small-molecule emerging environmental pollutants generally required complex sample preparation and long instrumental detection. It guarantees the sensitivity but is not conducive to rapid screening. In this work, a p-aminoazobenzene (p-AAB) with excellent energy absorption capability was used to modify multilayer Ti₃C₂T_X (MXene) to prepare novel material p-AAB/MXene. The modification significantly improved the laser absorption of original material, and made p-AAB/MXene could be employed as matrix for surface-assisted laser desorption/ionization-time of flight-mass spectrometry (SALDI-TOF MS) analysis of small-molecule emerging pollutants. More importantly, p-AAB/MXene could be used as adsorbent to enrich target compounds, then directly sent to SALDI-TOF MS detection without any other sample pre-treatment. Dual characteristics of enrichment material and matrix made p-AAB/MXene-based SALDI-TOF MS method successfully be applied to rapid and accurate detection of emerging environmental pollutants, p-phenylenediamine-quinones (PPDQs) and diamide insecticides (DAIs), in food (beverage) and environmental (PM_2.5) samples. High sensitivity (LOD at ng mL^-1 level) and satisfactory precision (RSD < 11%) indicated the qualified analytical performance of developed approach. The determined concentrations also elucidated the broad occurrence of PPDQs and DAIs in beverages and PM_2.5. The results further confirmed the SALDI-TOF MS using p-AAB/MXene as both adsorbent and matrix had considerable potential for efficient and time-saving analysis of trace and ultra-trace small-molecule emerging environmental organic pollutants in complicated samples.