Dispersive micro solid-phase extraction (DµSPE) with graphene oxide as adsorbent for sensitive elemental analysis of aqueous samples by laser induced breakdown spectroscopy (LIBS)

Abstract

In this work, the combination of dispersive micro solid-phase extraction (DµSPE) with laser-induced breakdown spectroscopy (LIBS) was evaluated for simultaneous preconcentration and detection of Zn, Cd, Mn, Ni, Cr and Pb in aqueous samples. Two adsorbent materials were tested in the microextraction step, namely graphene oxide and activated carbon. In both cases, the microextraction process consisted in the dispersion of a small quantity of adsorbent in the sample solution containing the analytes. However, while the use of activated carbon required a previous chelation of the metals, this step was avoided with the use of graphene oxide. After extraction, the analytes retained in the adsorbents were analysed by LIBS. Several experimental factors affecting the extraction of the metals (adsorbent amount, pH and extraction time) were optimized by means of the traditional univariate approach. Under optimum microextraction conditions, the analytical features of the proposed DµSPE-LIBS methods were assessed, leading to limits of detection below 100 µg kg and 50 µg kg with the use of activated carbon and graphene oxide, respectively, as adsorbents in the DµSPE process. Trueness evaluation of the most sensitive procedure was carried out by spike and recovery experiments in a real sample of tap water, leading to recovery values in the range 98-110%.

Electrospray deposition followed by laser-induced breakdown spectroscopy (ESD-LIBS): a new method for trace elemental analysis of aqueous samples

“…[10][11][12][13] With the aim to overcome the limitation of LIBS analysis of liquids, different strategies involving the use of sample preparation procedures have been investigated by many authors. Among them, it can be cited the absorption or drying of the sample on a solid matrix, [14][15][16][17][18] the application of solid phase extraction (SPE) procedures, 19,20 or the use of modern microextraction procedures in both Liquid-Liquid Microextraction (LLME) [21][22][23][24] and Solid Phase Microextraction (SPME) 25,26 modalities, among others. In general, the use of these sample preparation procedures prior LIBS detection leads to a substantial improvement in the analytical performance of the method, by decreasing the limits of detection at the low µg L -1 level.…”

Laser Induced-Breakdown Spectroscopy (Libs): Histórico, Fundamentos, Aplicações E Potencialidades

“…A estratégia foi aplicada em amostras de água de abastecimento público e os LOD obtidos estavam abaixo do estabelecido pelo Conselho Nacional do Meio Ambiente (CONAMA), que são de 1 mg L -1 para Cr (III) e 0,1 mg L -1 para Cr (VI). Nessa mesma abordagem, Ruiz et al 232 usaram a extração em fase sólida para a pré-concentração simultânea de Cd, Cr, Mn, Ni, Pb e Zn em amostras de água. Os autores usaram o grafeno como material adsorvente e o método proposto foi aplicado com sucesso.…”

Magnetic dispersive solid-phase extraction using a zeolite-based composite for direct electrochemical determination of lead(II) in urine using screen-printed electrodes

“…Besides the advances in miniaturized extraction techniques, small-scale separation/detection systems are also fundamental to further development of fast, simple, environmentally friendly and portable analytical methods. Thus, several publications have proposed the combination of liquid-phase and solid-phase microextraction techniques with miniaturized detection systems, such as cuvetteless micro-spectrophotometry [5], µvolume-fluorospectrometry [6], ion mobility spectrometry [7], person-portable gas chromatography-mass spectrometry [8], laser-induced breakdown spectroscopy [9], and screen-printed electrodes (SPEs) [10][11][12][13][14][15] .…”