DEVELOPMENT OF AMINOFUNCTIONALIZED SILICA MATRIX AS A POTENTIAL ADSORBENT FOR Pt⁴⁺ IONS IN PRECONCENTRATION SYSTEMS FOR FAAS ANALYSIS

The use of materials such as organofunctionalized silica for application in solid phase extraction (SPE) allows the preconcentration of several ions, including Pt, and subsequent detection. This work aims to synthesize and characterize an organofunctionalized silica (Sil-TMSDT) with the silylant N’(trimethoxysilyl)propylethylenetriamine and its application as a solid phase in the preconcentration Pt⁴⁺ ions in aqueous media, using detection by flame atomization atomic absorption spectroscopy (FAAS). The Fourier-transform infrared spectroscopy (FTIR) spectra and scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) confirmed the aminofunctionalization of the silica. For the adsorption process, a preconcentration mini-column with 200 mg of Sil-TMSDT, a solution of 0.485 mg L⁻¹ of K₂[PtCl₆] at pH 10 and HNO₃ 0.5 mol L⁻¹ as eluent were used, obtaining an enrichment factor of 15-fold with retention efficiency higher than 99%. The Pt⁴⁺ ion determined by FAAS showed a linear response between 0.02 and 0.40 mg L⁻¹; a linear coefficient where R = 0.9981; a 16-fold preconcentration factor; a limit of quantification (LOQ) and limit of detection (LOD) of 0.045 and 0.014 mg L⁻¹, respectively. The proposal system showed analytical applicability to determining Pt⁴⁺ ion in an aqueous medium and could be used to detect traces of this potentially toxic metal in biological fluids such as urine and blood.

Keywords:
silica; solid phase extraction; preconcentration; platinum; FAAS