Novel magnetic single-layer nano-MXene as a highly effective adsorbent and new SALDI-TOF-MS matrix for enrichment and rapid determination of p-Phenylenediamine antioxidants in water

A novel magnetic single-layer nano-MXene (SNM@Fe₃O₄) was prepared for the first time with small size, high surface area, abundant active sites and excellent energy absorption/transfer capability. The combined experimental and theoretical investigation revealed SNM@Fe₃O₄ could be served as a highly effective adsorbent for enrichment and a new surface-assisted laser desorption/ionization-time of flight-mass spectrometry (SALDI-TOF-MS) matrix for rapid analysis of p-Phenylenediamine (PPD) antioxidants, a kind of emerging environmental contaminants, in actual water samples from North and South China. The SNM@Fe₃O₄-based SALDI-TOF-MS approach featured free matrix interference, acceptable linearity (R² ≥ 0.97), high sensitivity (LOD at ng mL⁻¹ level) and qualified precision (RSD ≤ 8.46 %) for the four PPDs’ detection. The corresponding determined pollution levels also revealed the widespread occurrence of PPDs in Chinese water system. Compared to previous works, SNM@Fe₃O₄-based method achieved reproducible and more rapid analysis of PPDs in water, demonstrating a considerable potential of our self-synthesized nanomaterial for sensitive analysis of low-concentration organic small-molecule compounds in complicated sample matrix.