Multielement trace metal determination by electrodeposition, scanning electron microscopic x-ray fluorescence, and inductively coupled plasma-mass spectrometry

Abstract

Multielement analysis of multicomponent metallic electrodeposits Is described, based on scanning electron microscopy with energy dispersive X-ray fluorescence [EDXRF] detection, followed by dissolution and Inductively coupled plasma mass spectrometry [ICP-MS] detection. Application of the method Is described for determination of trace elements in seawater, including Zn, Mn, Co, Cu, Cr, Ni, Fe, Cd, Pb, and Hg. These elements are simultaneously electrodeposKed onto a niobium wire working electrode at -1.40 V vs an Ag/AgCI reference and subjected to EDXRF analysis. Internal standardization is practical for quantitative calibration at the 1 ppm analyte concentration level In an analyte:internal standard concentration ratio range of 0.02-50. Detection limits for EDXRF range from 1.9 ppb for Fe to 50 ppb for Cd. The deposit is dissolved for subsequent ICP-MS determination. Significant reduction in ICP-MS matrix interferences by Na, Ca, Mg, K, and Cl ions is achieved by deposition at potentials more positive than their very negative reduction potentials. Measurement of elemental isotope ratios is achieved with 0-8 % relative error. ICP-MS detection limits for all elements except Zn and Fe are superior to those of EDXRF. Mn, Ni, Cd, Pb, and Hg can easily be determined in the range of 13-86 parts per trillion with ICP-MS.

Determination of mercury in process and lagoon waters by inductively coupled plasma-mass spectrometric analysis after electrochemical preconcentration: comparison with anodic stripping at gold and polymer coated electrodes

“…These problems can be solved by performing the electrochemical deposition of mercury followed by stripping after transfer in a "clean" solution which is then sent to the ICP-MS instruments. The EC-ICP-MS approach has been used for a variety of analytes such as for instance Cr and V [21], As and Se [22], Cu and Cd [23], while for mercury only one example has been reported in the literature [24]. The method proposed in ref.…”

Methods for Speciation of Metals in Soils

“…Here the S K α (2.307 keV) and the Pb M α lines (2.393 keV) are within the energy resolution of the EDX detectors (approximately 0.15 keV), thus they are often difficult to separate or identify. This method has been used in petrology (Welton, 1984) and to study sediment and suspended trace metal contaminants in rivers, bays, and marine sites (Ramamoorthy and Massalski, 1978; Jedwab, 1979; Luther et al, 1980; Norrish et al, 1986), aquatic colloids (Leppard, 1992), sewage sludge and sludge‐amended soil, solid metal phases (Essington and Mattigod, 1985, 1991), airborne particulates and fly ash (Linton et al, 1976; Keyser et al, 1978; Farmer and Linton, 1984; Hansen et al, 1984), clay minerals (Beutelspacher and Van Der Marel, 1968; Jaynes and Bigham, 1986), Fe and Al sesquioxide coatings on mineral–soil particle surfaces (Hendershot and Lavkulich, 1983), humic matter (Tan, 1985), Pb (and other metals) in house and urban dusts (Linton et al, 1980; Hunt et al, 1992) and in soils (Smart and Tovey, 1982; Whalley, 1985; Bain et al, 1986; Mattigod et al, 1986; Rybicka et al, 1994; Yarlagadda et al, 1995; Adamo et al, 1996; Garcia‐Rizo et al, 1999; Welter et al, 1999), metals in solidified matrices (Neuwirth et al, 1989; McWhinney et al, 1990; Cocke et al, 1992; Roy et al, 1992; Cotter‐Howells and Caporn, 1996), ferric oxides (Landa and Gast, 1973), and as a tool to determine trace metals by electrodeposition (Chong et al, 1990). The technique is limited by low sensitivity with EDX, but can be improved by using wavelength dispersive X‐ray analysis (WDX).…”

Highly Selective Determination of Total Iron in Environmental Water Samples by HPLC

“…[6] The determination of iron in natural waters is meaningful to reveal the biogeochemistry function of the essential element. A number of analytical techniques, such as spectrophotometry, [7] chemiluminescence, [8,9] high performance liquid chromatography (HPLC), [10] capillary electrophoresis, [11] cathodic stripping voltammetry, [12,13] and inductively coupled plasma mass spectrometry [14,15] have been developed for the determination of trace levels of iron in environmental water samples. These methods have been always carried out with a preliminary concentration and separation, such as a column adsorption and a solvent extraction, because of the low iron concentration and the interference with many diverse ions in natural waters.…”