Composite materials based on hybrid mesoporous solids for flow through determination of ultratrace levels of Cd(II)

STRIPEIKIS, JORGE; MINABERRY, YANINA; TUDINO, MABEL BEATRIZ

Analytical Methods

Royal Society of Chemistry

Lugar: Cambridge; Año: 2018 vol. 10 p. 3113 - 3294

1759-9660

In this work we present a solid phase extraction (SPE) flow through system coupled to graphite furnace atomic absorptionspectrometry (GFAAS) for the determination of Cd(II) at ultratrace levels. The flow system holds a minicolumn which wasfilled, one in turn, with three different lab made materials: a) mesoporous silica functionalized with 3-aminopropyl groupsfrom 3-aminopropyl triethoxysilane (HMS); b) HMS with a resin, Amberlite IR120; c) HMS-Amberlite IR120 and polyvinylalcohol (PVA). All the solids were characterized by FTIR and SEM. Batch experiments were performed in order to study theoptimum adsorption pH, the adsorption kinetics and the maximum adsorption capacity.The materials were compared interms of their aptitude for the pre-concentration of the analyte under dynamic conditions. Microvolumes of HCl wereemployed for the release of cadmium and its introduction into the electrothermal atomizer.The operational variables of the flow system were also tested and optimized. The comparison of the figures of meritrevealed HMS-A-PVA as the best option from an analytical point of view: limit of detection= 4.7 ng L-1, limit ofquantification= 16 ng L-1, RSD %= 4 (n =6, 100 ng L-1), linear range: from LOQ up to 200 ng L-1 and a lifetime over 600cycles with no obstructions to the free movement of fluids, material bleeding or changes on the analytical sensitivity. Theproposed method was shown to be tolerable to several ions typically present in natural waters and was successfullyapplied to determination of trace of Cd(II) in real samples. A full discussion of the main findings with emphasis on theinteraction metal ion/fillings will be provided.