Determination of silver nanoparticles by atomic absorption spectrometry after dispersive suspended microextraction followed by oxidative dissolution back-extraction

Tatiana G Choleva; George Z Tsogas; Dimosthenis L Giokas

doi:10.1016/j.talanta.2018.12.053

Determination of silver nanoparticles by atomic absorption spectrometry after dispersive suspended microextraction followed by oxidative dissolution back-extraction

Talanta. 2019 May 1:196:255-261. doi: 10.1016/j.talanta.2018.12.053. Epub 2018 Dec 19.

Authors

Tatiana G Choleva¹, George Z Tsogas¹, Dimosthenis L Giokas²

Affiliations

¹ Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece.
² Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece. Electronic address: dgiokas@cc.uoi.gr.

PMID: 30683361
DOI: 10.1016/j.talanta.2018.12.053

Abstract

This study presents a liquid phase microextraction method for the quantification of silver nanoparticles (AgNPs) in environmental samples by means of directly suspended microextraction and atomic absorption spectrometry. The method is based on the dispersion of octanol into fine droplets where AgNPs are partitioned and extracted from the bulk aqueous phase. Then octanol is re-dispersed again in a strongly acidic and oxidizing aqueous medium in order to selectively decompose AgNPs to silver ions. The aqueous extract is then analyzed by atomic absorption spectrometry. Under the working conditions, the method offers high selectivity for AgNPs since most nanoparticle species cannot be extracted into the octanol phase, while the selective back-extraction procedure ensures that only AgNPs are dissolved to the final extract medium. The method works equally well for AgNPs of different size and coatings, thus enabling the determination of the total concentration AgNPs in real samples. Method application in different water samples was used to evaluate the utility of the method in the analysis of real samples of variable complexity with satisfactory results in terms of detection limit (less than 100 femto-mole of AgNPs), recoveries (90-104%) and reproducibility (lower than 7%).

Keywords: Atomic absorption spectrometry; Back-extraction; Directly suspended microextraction; Dissolution; Environmental samples; Silver nanoparticles.