Hybrid ionic liquid-3D graphene-Ni foam for on-line preconcentration and separation of Hg species in water with atomic fluorescence spectrometry detection

FRANCISCO J. IBAÑEZ; MERCEDES, MESSINA; ANNALY, CRUZ SOTOLONGO; WUILLOUD, RODOLFO G; FRANCISCO J. IBAÑEZ; MERCEDES, MESSINA; ANNALY, CRUZ SOTOLONGO; WUILLOUD, RODOLFO G

TALANTA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 210

0039-9140

A preconcentration method based on a novel hybrid sorption nanomaterial consisting in a 3D graphene-Ni foam functionalized with an ionic liquid (IL) was developed for Hg species determination. The capability of different phosphonium-ionic liquids (PILs) to functionalizethe hybrid material and form ion-pairs with Hg(II) chlorocomplex was evaluated. A comparative study with PILs containing the trihexyl(tetradecyl)phosphonium cation but different anions (dicyanamide and decanoate) and trihexyl(tetradecyl)phosphonium chloride was performed. Inorganic Hg (InHg) species was selectively retained forming a chlorocomplex (HgCl42−) followed by its retention in a column filled with the IL-3D graphene-Ni foam material implemented in an on-line micro solid from the column wasperformed with SnCl2, which was also used as reducing agent for subsequent detection by cold vapor generation atomic fluorescence spectrometry (CV-AFS). Organic mercury species (OrgHg) were not retained on both the sorption material and in the column. The effect of several parameters determining the efficiency of the preconcentration and detection system (sample loading and elution flow rate, sample volume, instrumental conditions, etc.) was investigated. A sensitivity enhancement factor (EF) of 180 was achieved for InHg. The detection limit obtained after the preconcentration of 100 mL of sample was 3.6 ng L−1 ofInHg. The relative standard deviation (RSD) was 4.1% (at 1 µg L−1 InHg and n = 10) calculated from the peak height of the absorbance signals (Gaussian form and reproducible peaks). This work reports the first application of the IL-3D graphene-Ni foam in an on preconcentration system for the speciation analysis of Hg in mineral, tap, and river water samples