Dispersive micro-solid phase extraction (D-μSPE) of nickel on activated nanodiamonds@Bi₂WO₆ nanocomposite from water...

This study presents an original nano-sorbent using activated nanodiamonds@Bi₂WO₆ to separate and enrich nickel ions from water and food samples. FTIR, XRD, FE-SEM, FE-SEM-EDX, EDS-TEAM, TGA, and BET were used to characterize the nanocomposite. It has a large surface area, active functional groups, and better reactivity. Ni(II) ions were determined as Ni(II)-PADAP chelates using UV-VIS spectroscopy. The parameters were studied and optimized, including pH (6), eluent type and volume (1 mL), ligand quantity (10 μg), sorbent dosage (20 mg), and contact time (1 min). The method has a low limit of detection (LOD) of 1.6 μg L^-1, a limit of quantification (LOQ) of 5.3 μg L^-1, a relative standard deviation of 4.5%, and a preconcentration factor of 10. The method was validated by applying to certified reference materials (BCR estuarine water 505 and 1573a NIST). The method was successfully applied to tap waters, industrial waste waters, and vegetables.