Sono-induced cold vapour generation interfaced with capacitively coupled plasma microtorch optical emission spectrometry: analytical characterization and comparison with atomic fluorescence spectrometry

Abstract

Sono-induced cold vapour generation in 0.2 mol L À1 formic acid has been interfaced for the first time with a low power (10 W) and low argon consumption (100 mL min À1 ) capacitively coupled plasma microtorch for mercury determination by optical emission using a low resolution microspectrometer. The method meets the requirements of green analytical chemistry in terms of the derivatisation method, cost-effective conditions for plasma generation and miniaturized instrumentation. The method is based on sample ultrasonication in a batch reactor, purging of mercury vapour, moisture removal from vapour in a Nafion tubing, Hg preconcentration on a gold filament microcollector, thermal desorption and introduction of mercury vapour into plasma via an Ar stream. Emission episode spectra of Hg were recorded at 253.652 nm. Under the optimized conditions, a detection limit of 5.0 AE 0.3 ng L À1 was found, which was better than the 12 ng L À1 obtained by atomic fluorescence spectrometry after chemical cold vapour generation with SnCl 2 . The analytical capability of the new method was demonstrated by analysing the certified reference materials and real samples of fish tissue, soil and sediment mineralized in an acidic mixture.The method is highly sensitive and the matrix effects associated with cold vapour generation were avoided by sample dilution. Mercury was determined using external calibration with recovery and precision in the range of 96.3-104.5% and 0.8-7%, respectively. No systematic error against atomic fluorescence with chemical cold vapour generation using SnCl 2 was observed.

Determination of mercury in mosses by novel cold vapor generation atmospheric pressure glow microdischarge optical emission spectrometry after multivariate optimization

“…[12][13][14] One of the most interesting devices is a low-power capacitively coupled microplasma (mCCP) combined with cold vapor generation (CVG) that has been intensively explored for OES by Frentiu and co-workers. [15][16][17][18][19][20] The detection limit (DL) for Hg obtained with a mCCP is of the order of tens of ng per L (ref. 15 and 16) and can be improved by using an additional pre-concentration system.…”

“…15 and 16) and can be improved by using an additional pre-concentration system. 17,18 Other alternative low-power miniaturized plasma-or discharge-based radiation sources, including pulsed direct current microplasma (Pdc), 21 dielectric barrier discharge (DBD), [22][23][24][25][26] microwave microstrip plasma (MSP), 27,28 electrolyte cathode glow discharge (ELCAD) [29][30][31] or atmospheric pressure glow microdischarge (APGD), 32 are also developed and used for the determination of traces of Hg that is commonly preconcentrated prior to spectrochemical measurements by using chemical vapor generation (CVG) systems, [15][16][17][18][19][21][22][23][25][26][27][28]32 a sonoinduced CVG system, 20 a Au-on-W coiled lament, 24 or a solid phase extraction (SPE) tube. 31 In our recent paper, 32 a miniaturized atmospheric pressure glow discharge (mAPGD) generated between a miniature He ow jet nozzle anode and a small-sized owing liquid cathode (FLC) was successfully combined with CVG for the OES quantication of traces of Hg.…”

“…In the overwhelming majority of papers related to new miniaturized plasma-or discharge-based radiation sources, the OFAT method was favored and applied to test the effect of different factors and select their optimal working conditions. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Although it is the most popular and generally accepted experimental approach, it requires more individual experiments to be run to achieve the desired precision of important effects of factors, cannot estimate interactions between factors and oen misses their optimal settings. 33 Because the discharge phase is loaded with products (Hg vapors) and by-products (excess of H 2 , H 2 O vapor) of the CVG reaction, which takes place in a reaction/separation unit, a large number of experimental factors affect the performance of CVG-mAPGD-OES and numerous interactions could be expected.…”

Analytical performances and validation of optical emission and atomic absorption spectrometry methods for multielemental determination in vegetables and fruits

“…Amounts of 500 mg dried CRMs or real samples (dried goji fruits commercially available) were subjected to microwave-assisted digestion in a mixture of 9 mL 65% HNO 3 and 3 mL 30% H 2 O 2 using the MWS3+ Berghof microwave digester (Berghof, Germany) according to the five stage temperature program previously used for the preparation of food samples. 55 Prior to digestion, samples were left in the HNO 3 -H 2 O 2 mixture at room temperature for 12 h for a preliminary oxidation. The digest was diluted to 25 mL with 2% (v/v) HNO 3 and passed through the 0.45 µm Whatman membrane filter nylon (Merck, Darmstadt, Germany).…”

Simultaneous Determination of As, Bi, Sb, Se, Te, Hg, Pb and Sn by Small-Sized Electrothermal Vaporization Capacitively Coupled Plasma Microtorch Optical Emission Spectrometry Using Direct Liquid Microsampling

“…Undoubtedly, the classical hydride generation (HG)/cold vapor (CV) generation using NaBH 4 and SnCl 2 [ 11 , 12 , 13 ] combined with spectrometric methods are the most common approaches. Such examples are HG-AFS and CV-AFS [ 14 , 15 , 16 , 17 , 18 , 19 ], HG coupled with high-resolution continuum source electrothermal atomic absorption spectrometry or quartz furnace atomic absorption spectrometry (HG-HR-CS-ETAAS, HG-HR-CS-QFAAS) [ 20 , 21 , 22 ] and graphite furnace atomic absorption spectrometry (HG-GFAAS) [ 23 ]. Other ways are HG-ICP OES [ 24 ], HG-ICP-MS [ 25 , 26 ], and hydride generation laser-induced breakdown spectrometry (HG-LIBS) [ 27 ].…”