One-step preparation of carbonaceous spheres rich in phosphate groups via hydrothermal carbonization for effective...

A green strategy was developed to prepare carbonaceous spheres rich in phosphoric acid groups on the surface with D-Glucose 6-phosphate sodium salt (called G6PNa₂) as a sole carbon source through one-step hydrothermal carbonization method. The method is simple and facile and meets the standards of green chemistry as water is the sole solvent employed. Following the hydrothermal carbonization synthesis, the carbonaceous spheres were further functionalized with Ti⁴⁺. The main factors including reaction temperature, reaction time, and concentration of G6PNa₂ were systematically studied in order to obtain the desirable morphology and the optimum phosphopeptides enrichment, for the resulting Ti⁴⁺ functionalized carbonaceous spheres (CS-Ti⁴⁺). The performance evaluation of the CS-Ti⁴⁺ prepared under the optimum conditions demonstrated excellent selectivity (1:1000), low detection limit (1 fmol) and high recovery rate (85%) towards phosphopeptides. Furthermore, 24 low-abundance phosphopeptides were captured from human saliva using CS-Ti⁴⁺, indicating its great potential in mass spectrometry-based phosphoproteome studies.