A cheap 3D-printed boron, nitrogen, sulfur-MXene quantum dots-based target plate for multi-dimensional MALDI MS imaging of small-molecule environmental pollutants

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-TOF MSI) generally possess difficulties for analysis of small-molecule environmental pollutants. In the present study, an unreported straightforwardly synthesized ternary-doped boron, nitrogen, sulfur-MXene quantum dots (BNS-MQDs) was incorporated into photopolymer clear resin, and the mixture was applied to manufacture of a novel 3D-printed MALDI target plate (3D-MTP). Due to BNS-MQDs’ nano-size, uniform shape and excellent capabilities of energy absorption/transfer, their doping helped the self-made 3D-MTP successfully achieve multi-dimensional MALDI-TOF MSI of small-molecule environmental contaminants. 3D printing technology also made construction of 3D-MTP cheap ($ 0.1) and time-saving (20 min), considerably reducing experimental cost. Furthermore, MALDI-TOF MSI using BNS-MQDs-based 3D-MTP did not need manual and instrumental matrix spray, which is conducive to obtaining accurate and reproducible imaging results. Besides excellent performance of 2D MSI of environmental contaminants, 3D-MTP was also successfully employed to 3D MALDI-TOF MSI of an emerging polluted antioxidant, N, N’ -di-2-naphthyl-p-phenylenediamine (DNPD), in female zebrafish after exposure. The enrichment of DNPD in female zebrafish was found in eye, gill, liver, intestine and ovary for the first time. Overall, the developed BNS-MQDs-based 3D-MTP showed compelling application prospects in multi-dimensional MALDI-TOF MSI research of small-molecule environmental xenobiotics.