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

Abstract

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.

Application of Inductively Coupled Plasma Spectrometric Techniques and Multivariate Statistical Analysis in the Hydrogeochemical Profiling of Caves—Case Study Cloșani, Romania

“…The parameters showed either a positive or negative skewness. Some of them (Al, Cr, Sb, TOC, DOC, Cl − , SO 4 2− and NH 4 + ) showed leptokurtic distribution (kurtosis > 3) caused by some significantly different outliers, while Ba showed a leptokurtic and platykurtic (kurtosis < −3) distribution in the C2 and C3 sampling points, respectively. Consequently, the median values for these parameters were more relevant for the water characterization.…”

“…Iron and manganese oxides, as major components in the karst system, pH and redox conditions, influence the trace element chemistry and the equilibrium between their mobile and nonmobile species [2]. Soil bedrocks, cave deposits, detrital materials and sediments are natural sources of metals occurrences in water [3,4]. Elevated concentrations of Ca, Mg, Sr and K in a cave can be explained by mineral weathering of the local bedrock and soil atop the cave under the influence of water and their transfer to the cave through dripping [5].…”

“…The mineral compositions of the silty soil samples were investigated by X-ray diffraction (XRD). Along with the elementary profile of the water samples, the distribution on different inorganic and organic fractions of carbon (total carbon-TC, total organic carbon-TOC, total inorganic carbon-TIC, dissolved carbon-DC and dissolved inorganic carbon-DIC); the content of anions (HCO 3 − , F − , Cl − , NO 3 − , SO 4 2− and PO 4 3− ); NH 4 + ; pH; electrical conductivity (EC); total dissolved substance (TDS) and alkalinity were determined. The chemical conceptual model, which described the pattern of hydrogeochemical processes in the cave considered as the case study, was conducted by a combination of classical Gibbs and Piper diagrams, the Stuyfzand Hydrogeochemical Classification System (SHCS) and unsupervised chemometric tools, such as ANOVA-PCA and heat maps obtained after a two-way joining analysis as a clustering method.…”

Simultaneous determination of Cd, Pb, Cu and Zn as total and labile fractions in soil using a small-sized electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometer after diffusive gradients in thin-film passive accumulation

“…However, the non-spectral effects could be overcome by the selective vaporization of analytes at 1300 °C and was successfully applied to the speciation of Hg as Hg 2+ and CH 3 Hg + in food, and determination of As, Sb, Bi, Se, Te, Hg and Sn in environmental samples. 35,36 The diffusive gradients in thin-lm (DGT) technique proposed by Davison and Zhang 37,38 has been extensively used in the analysis of surface water, soil, water sediment, food, etc. as a passive sampling technique.…”

“…However, the non-spectral effects could be overcome by the selective vaporization of analytes at 1300 °C and was successfully applied to the speciation of Hg as Hg 2+ and CH 3 Hg + in food, and determination of As, Sb, Bi, Se, Te, Hg and Sn in environmental samples. 35,36…”