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The study presents for the first time the figures of merit of a completely miniaturized instrumentation based on a capacitively coupled plasma microtorch as the core element interfaced with a small-sized electrothermal vaporization device and a low-resolution microspectrometer for the simultaneous determination of Cd, Pb, Cu and Zn by optical emission spectrometry in soil as total and labile fractions after diffusive gradients in thin-film (DGT) accumulation. The coupling of the low-power and low-argon consumption plasma (15 W; 150 mL min−1) with the DGT passive accumulation technique, although requiring a too-long time for sample preparation, allowed a considerable improvement of the detection limits and avoidance of the non-spectral matrix effects, otherwise a recognized process in low power microplasmas, when a complex matrix is analysed, like environmental samples. The detection limits for the total content in soil were (mg kg−1), 0.10(Cd), 0.40(Pb), 0.15(Cu), and 0.03(Zn), one order of magnitude better than in the procedure without DGT accumulation and 10–3300-times lower than the guide values in soil. In the DGT-based labile fraction exhibiting the highest bioavailability the detection limits were (μg kg−1) 0.01(Cd, Cu, and Zn) and 0.03(Pb), which allowed the determination of Cd, Pb, Cu and Zn in the concentration range (μg kg−1) of 0.3–2.0, 0.8–18.4, 2.4–56.3 and 9.4–60.6, respectively. Validation through the analysis of certified reference materials (CRMs) showed a recovery of 85–123% with a relative expanded uncertainty of 19–35% (k = 2) for the total content of analytes. The analysis of the certified reference materials highlighted that the DGT accumulation was not affected by the multielemental matrix, since the experimental diffusion coefficients of the analytes were similar in the four analyzed CRMs and to those provided by the manufacturer, respectively. Precision for the measurements of the total content and DGT-labile fraction in real samples evaluated from the combined uncertainty was 10–19% and 10–15%, respectively. The Bland–Altman plot applied to the results of real samples indicated the lack of statistical differences versus line-source graphite furnace atomic absorption spectrometry for both the total content and DGT-based labile fraction. [ABSTRACT FROM AUTHOR]

An eco-scale method based on UV–Vis photochemical vapor generation and detection in a capacitively coupled plasma microtorch by optical emission measurement with a low resolution microspectrometer was developed for Hg speciation as Hg 2+ and CH 3 Hg + in seafood. Our proposal provides a simpler, greener analytical method in terms of sample preparation and derivatization, and use of small-scale instrumentation. Coupling of UV–Vis photo-reactor with plasma microtorch is a very promising approach to develop eco-scale methods for Hg speciation in seafood with major advantages to classical methods. The most distinctive characteristic of the method is the use of a single reagent, formic acid, for the extraction of Hg species from solid sample and as medium for the photo-induced cold vapor generation. An amount of 0.2 g lyophilized sample was subjected to ultrasound assisted extraction in 10 ml HCOOH 98–100% at 50 °C for 3 h then on line UV–Vis photo-induced derivatization in 0.6 mol l −1 HCOOH was achieved. Total Hg and Hg 2+ species were quantified against Hg 2+ external standard solutions by measuring emission at 253.652 nm in a low power/low Ar consumption (15 W/100 ml min −1 ) plasma source with Maya2000 Pro (Ocean Optics) microspectrometer. Under UV exposure both Hg 2+ and CH 3 Hg + species were converted with same efficiency to cold vapor, while natural room light (Vis) achieved selectively derivatization of Hg 2+ . Concentration of CH 3 Hg + was obtained by subtracting Hg 2+ amount from total. The proposed method was compared with Thermal Decomposition Atomic Absorption Spectrometry eco-scale method developed for the determination of total Hg from solid sample and CH 3 Hg + according to the procedure recommended by the European Commission. The limits of detection/quantification provided by the proposed method were 9/27 μg kg −1 total Hg and 4.8/14.4 μg kg −1 Hg 2+ . Study of accuracy against certified reference materials gave recovery of 99 ± 6% total Hg, 99 ± 9% Hg 2+ and 99 ± 10% CH 3 Hg + , while precisions assessed from measurements on real sample were 2.6–10.2%, 2.0–13.4% and 5.3–14.5% respectively, similar to those in the reference method. [ABSTRACT FROM AUTHOR]

This study presents for the first time the coupling between in-situ Diffusive Gradient in Thin-film (DGT) passive sampling technique and ex-situ small-sized instrumentation based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry (SSETV-μCCP-OES) for the simultaneous determination of Cd, Pb, Cu, Zn and Hg in surface water. Unique features of the DGT-SSETV-μCCP-OES are low power and low Ar consumption for plasma generation (15 W, 150 mL min−1) and significant improvement of the detection limits following DGT passive sampling. The new method was validated in terms of river water analysis in comparison with graphite furnace atomic absorption spectrometry and thermal decomposition atomic absorption spectrometry. Combining the abilities of preconcentration by in-situ Chelex-DGT passive sampling with plasma microtorch equipped with a low resolution microspectrometer provided multielemental simultaneous determination with detection limits of (μg L−1) 0.01 (Cd, Zn and Hg), 0.02 (Cu) and 0.07 (Pb) in water, at least one order of magnitude better than using grab sampling without preconcentration. It was possible the quantification of labile fraction of priority hazardous metals (Cd, Pb) in river water below the instrumental limits of detection (μg L−1) of 0.12 and 0.80 obtained in SSETV-μCCP-OES without DGT sampling. The precision of the method was in the range 15.3–22.4% (combined uncertainty), while the accuracy was 95–103% and trueness of 27–33% (expanded uncertainty, k = 2). The DGT-SSETV-μCCP-OES coupling proved to be an ideal and powerful tool for surface water analysis in compliance with green and white analytical chemistry concepts. The application of the RGB-12 algorithm provided very good red/green (AGREEprep)/blue/white scores (%) of 100/80/98/93, determined primarily by in-situ DGT passive sampling, very good detection limits and cost-effective SSETV-μCCP-OES instrumentation. [Display omitted] • In-situ DGT sampling was coupled with a cost-effective ex-situ microplasma set-up. • The applicability was checked by determining Cd, Pb, Hg, Zn, Cu in river water. • DGT passive sampling allowed the removal of As–Cd spectral interference. • The LODs have been improved 10 times by the new DGT-SSETV-μCCP-OES coupling. • The new DGT-SSETV-μCCP-OES method exhibits 93/80% whiteness/greenness score. [ABSTRACT FROM AUTHOR]

The simultaneous determination of chemical vapor-generating elements involving derivatization is difficult even by inductively coupled plasma optical emission spectrometry or mass spectrometry. This study proposes a new direct liquid microsampling method for the simultaneous determination of As, Bi, Se, Te, Hg, Pb, and Sn, using a fully miniaturized set-up based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry. The method is cost-effective, free from non-spectral interference, and easy to run by avoiding derivatization. The method involves the vaporization of analytes from the 10 µL sample and recording of episodic spectra generated in low-power (15 W) and low-Ar consumption (150 mL min−1) plasma microtorch interfaced with low-resolution microspectrometers. Selective vaporization at 1300 °C ensured the avoidance of non-spectral effects and allowed the use of external calibration. Several spectral lines for each element even in the range 180–210 nm could be selected. Generally, this spectral range is examined with large-scale instrumentation. Even in the absence of derivatization, the obtained detection limits were low (0.02–0.75 mg kg−1) and allowed analysis of environmental samples, such as cave and river sediments. The recovery was in the range of 86–116%, and the accuracy was better than 10%. The method is of general interest and could be implemented on any miniaturized or classical laboratory spectrometric instrumentation. [ABSTRACT FROM AUTHOR]

An analytical method for the quantification of total Hg and CH 3 Hg+ in biological tissues (fish, mushroom) and water sediment was developed based on small-sized electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry using a low-resolution microspectrometer as detector. Sample preparation was carried out according to the procedure recommended by JRC Technical Report of European Commission for the determination of CH 3 Hg+ in seafood and adapted by us for lower consumption of reagents. Amounts of 0.1 – 0.5 g sample were subjected to extraction in 5 ml of 47% HBr then CH 3 Hg+ was extracted in 2 × 1 ml toluene and back-extracted in 2 ml aqueous solution of 1% l -cysteine. Total Hg/CH 3 Hg+ were quantified in 10 μl of acidic extract/ l -cysteine solution after electrothermal vaporization and measurement of 253.652 nm Hg signal in the episodic emission spectra. Under the optimal working conditions of system (70 °C sample drying, 1300 °C sample vaporization, 10 W plasma power and 150 ml min−1 Ar flow) the limits of detection were 7.0 μg kg−1 total Hg and 3.5 μg kg−1 CH 3 Hg+. Comparison of slopes in external calibration and standard addition procedure revealed the lack of non-spectral interferences of multimineral matrix, so that the calibration against Hg2+ standards was adopted. Pooled recovery of total mercury/methylmercury was 101 ± 7%/100 ± 7%, while precision assessed from measurements of real samples was in the range 1.6-9.6%/2.7-12.8%. The proposed method validated according to Eurachem Guide 2014 is selective and complies with demands in European legislation (Decisions 657/2002; 333/2007; 836/2011) and Association of Official Analytical Chemists Guide in terms of performances for food control. The method displays a high degree of greenness by circumventing cold vapor generation, use of small amounts of reagents and full-miniaturized instrumentation resulting in low analytical costs without reducing results quality. Besides, the method is simple and rapid, since it uses external calibration curves prepared from Hg2+standard solutions both for total Hg and CH 3 Hg+ determination. Image 1 • Total Hg and CH 3 Hg+ were directly quantified in biological samples and water sediments. • Quantification is based on external calibration using Hg2+ standards. • The method is free from non-spectral interferences and complies with GAC practice. • Method validation proved compliance with EU legislation relative to food control. [ABSTRACT FROM AUTHOR]

[Display omitted] • DGT sampling was used for Fe, Mn, Cu, Pb and Zn fractionation analysis in beer; • Total and DGT-labile fractions of metals were measured in beer; • DGT can reliably assess the labile fraction of metals in beer; • Average DGT fractions of Fe, Cu, Pb, Zn and Mn were: 7, 15, 12, 31, 29 %, respectively. Fractionation analysis of Fe, Mn, Cu, Zn and Pb in beer is of high interest since their labile forms affect its stability and have implications for toxicity. In this study, we used the Diffusive Gradient in Thin-film (DGT) technique for the first time as a tool for passive sampling of labile species of Fe, Mn, Cu, Zn and Pb from beer. The validity of methodologies for total, total-dissolved and DGT-labile concentrations of Fe, Cu, Mn, Zn and Pb in beer was checked and then were applied to measure metals concentrations in two beer sorts: filtered and unfiltered (craft) beer. Commercial beer spiked with target analytes was used to check the linear accumulation of metals by DGT for 72 h DGT deployment period. The obtained determination coefficients were in the range of 0.986–0.998. The total concentrations of metals in beers determined by GFAAS were in the range of 60.4–957 µg/L (Fe), 58.0–206 µg/L (Mn), 45.6–314 µg/L (Cu), 70.0–313 µg/L (Zn) and 0.75–4.22 µg/L (Pb). Of these, the DGT-labile fractions of Fe, Cu, Mn, Zn and Pb were 5.0 – 7.8 µg/L Fe, 4.5 – 15.0 µg/L Cu, 23.1 – 37.0 µg/L Mn, 17.7 – 41.5 µg/L Zn and 0.15 – 0.35 µg/L Pb. This study provides a simple and reliable methodology for the fractionation of metals in beer. [ABSTRACT FROM AUTHOR]

A highly sensitive method based on UV photochemical vapor generation capacitively coupled plasma microtorch optical emission using a low resolution microspectrometer was developed for total mercury determination in food and water. The method fulfils most of the eco-scale criteria in terms of derivatization and cost-effective miniaturized instrumentation, which are major benefits compared to cold vapor atomic fluorescence spectrometry and inductively coupled plasma optical emission spectrometry. Formic acid was the single reagent used for the extraction of Hg species from solid samples and as a reaction medium for the UV photo-induced cold vapor generation. A 200 mg lyophilized sample was subjected to ultrasonic assisted extraction in 10 mL of HCOOH 98–100% at 50 °C for 3 h, and then on-line derivatization to cold vapor was performed in 0.6 mol L−1 HCOOH. Water and food with low Hg content adjusted in HCOOH 0.6 mol L−1 underwent on-line preconcentration of Hg vapor on a gold filament microcollector. Total Hg was quantified against external standards containing Hg2+ by recording emission at 253.652 nm in a low power/Ar consumption (15 W/100 mL min−1) plasma source with a Maya2000 Pro (Ocean Optics) microspectrometer. The proposed method was compared with common laboratory approaches based on derivatization with SnCl2 and detection by inductively coupled plasma optical emission spectrometry/atomic fluorescence spectrometry, and thermal decomposition atomic absorption spectrometry. The limits of detection obtained without/with preconcentration were 3.5/0.1 ng L−1 in solution and 9/0.25 μg kg−1 in the solid, much better than those in the reference methods. The proposed method was found to be free from interference coming from multimineral matrices and organic matter, and suitable for sample analysis with various matrices as it provided a recovery of Hg without/with preconcentration of 101 ± 7%/101 ± 12% in food and 97 ± 12% in water. [ABSTRACT FROM AUTHOR]

The aim of the study was to develop the hydrogeochemical profiling of caves based on the elemental composition of water and silty soil samples and a multivariate statistical analysis. Major and trace elements, including rare earths, were determined in the water and soil samples. The general characteristics of water, anions content, inorganic and organic carbon fractions and nitrogen species (NO3− and NH4+) were also considered. The ANOVA—principal component analysis (PCA) and two-way joining analysis were applied on samples collected from Cloșani Cave, Romania. The ANOVA-PCA revealed that the hydrogeochemical characteristics of Ca2+-HCO3− water facies were described by five factors, the strongest being associated with water-carbonate rock interactions and the occurrence of Ca, Mg and HCO3− (43.4%). Although organic carbon fractions have a lower influence (20.1%) than inorganic ones on water characteristics, they are involved in the chemical processes of nitrogen and of the elements involved in redox processes (Fe, Mn, Cr and Sn). The seasonal variability of water characteristics, especially during the spring, was observed. The variability of silty soil samples was described by four principal components, the strongest influence being attributed to rare earth elements (52.2%). The ANOVA-PCA provided deeper information compared to Gibbs and Piper diagrams and the correlation analysis. [ABSTRACT FROM AUTHOR]