ION PRECONCENTRATION Pt(4+) IN AQUEOUS MEDIUM USING MODIFIED SILICA ORGANOFUNCTIONALIZED
Silica, solid phase extraction (SPE), platinum, preconcentration, atomic absorption.
Studies have been carried out to determine and quantify traces of heavy metals in biological fluids, from the accumulation in tissues during the treatment of various diseases. Among these metals, platinum, widely used in oncologic treatments, stands out. Due to the low concentration in which these metals are found, it is necessary to use pre-concentration techniques and sophisticated equipment for their safe quantification. Using materials such as organofunctionalized silica for application in solid-phase extraction (SPE) enables the preconcentration of these ions and ensures safer quantification using flame atomic absorption spectroscopy (FAAS). The present work aims the synthesis of organofunctionalized silica by sol-gel method via basic catalysis, with the silylant N'-[(trimethoxysilyl)propylethylenetriamine (TMSTD), the characterization via FTIR, electronic absorption spectroscopy, thermogravimetric analysis, Scanning Electron Microscopy (SEM), surface area analysis (BET); and its application as a stationary phase in the preconcentration of Pt(4+) ions in aqueous media and detection using the FAAS analytical technique. The FTIR spectra showed the organofunctionalization of silica with the identification of bands at 2904 and 2829 cm-1 referring to NH groups and 1029 cm-1 referring to Si-O-Si groups. The anchoring of the silylant resulted in a decrease in surface area measurements from 466 to 109 m2 g-1, which is related to the silylation process and the presence of organic groups. In the optimization studies the best results were at pH 10, the eluent used was HNO3 0.5 mol L-1 with a volume of 2.5 mL and a working range of 0-20 mg L-1. The developed method presented a QOL and LOD of 0.005 and 0.001 mg L-1, respectively and an R2 value of 0.9981. Therefore, the proposed method presented robustness and efficiency for the preconcentration of Pt(4+) ions using FAAS detection.