Abstract: Functionalized nanoparticles assisted desorption electrospray ionization for analysis of ultraviolet absorbers in urine was developed. The electrospray was performed with high voltage on a laboratory-made screen-printed plate with silver or graphite. In this study, the ultraviolet absorbers including 3-(4-methylbenzylidene)-camphor (4-MBC), 2-ethyl-4-(dimethylamino)-benzoate(O-PABA) and 2-hydro- xy-4-(octyloxy)-benzophenone (BP-12) were extracted with iron oxide-coated silicon dioxide nanoparticles (SiO2@Fe3O4 NPs) as the affinity adsorbent. After extraction, the analytes were isolated from magnetic NPs with solvent. The extract or the magnetic NPs without desorption was dipped on the screen-printed to evaluate the effect on the ionization efficiency. From the results, the nanoparticles can enhance the intensity of the signal detected and short the analytical time. This technique demonstrates that the nanoparticles assisted desorption electrospray ionization offers a high specific and high throughput screening for trace analysis.