Inorganic solid-phase extractant

Simultaneous speciation of inorganic selenium and tellurium in water samples by ICP-MS was performed after selective solid phase extraction (SPE), as discussed by Yu et al 9 Under acidic conditions Se (IV) and (TV) complexes with ammonium pyrrolidine dithiocarbamate were formed. The detection limits for Se and species in water samples were found to be 7ngl 1 and 3 ng 1 1, respectively. 

Conventional radiochemical methods for the determination of long-lived radionuclides at low concentration levels require a careful chemical separation of the analyte, e.g., by liquid-liquid, solid phase extraction or ion chromatography. The chemical separation of the interferents from the long-lived radionuclide at the ultratrace level and its enrichment in order to achieve low detection limits is often very time consuming. Inorganic mass spectrometry is especially advantageous in comparison to radioanalytical techniques for the characterization of radionuclides with long half-lives (> 104 a) at the ultratrace level and very low radioactive environmental or waste samples. 

Solid-phase extractions (SPE), in which DOM is selectively concentrated on a solid-phase extractant such as XAD-2 resin or Ci8 adsorbent. In these methods, both inorganic solutes and water are removed concurrently, and a suitable solvent is used to desorb the concentrated, desalted DOM from the solid-phase extractant. In principle, all inorganic solutes may be removed by SPE. 

Spivakov, B.Y., G.I. Malofeeva, and O.M. Petrukhin. 2006. Solid-phase extraction on alkyl-bonded silica gels in inorganic analysis. Anal. Sci. 22 503-519. 

The solvent extracts can be cleaned up by traditional column chromatography or by solid-phase extraction cartridges. This is a common cleanup method that is widely used in biological, clinical, and environmental sample preparation. More details are presented in Chapter 2. Some examples include the cleanup of pesticide residues and chlorinated hydrocarbons, the separation of nitrogen compounds from hydrocarbons, the separation of aromatic compounds from an aliphatic-aromatic mixture, and similar applications for use with fats, oils, and waxes. This approach provides efficient cleanup of steroids, esters, ketones, glycerides, alkaloids, and carbohydrates as well. Cations, anions, metals, and inorganic compounds are also candidates for this method [7],... 

One of the drawbacks of ion exchange chromatography is the need for a secondary technique to remove inorganic salts from the purified product. Desalting can often be performed by ultrafiltration, solid phase extraction or by gel filtration. The latter mode of separation is described briefly in Section 3.5. 

The major disadvantage of solid phase extraction is that it provides a chemically biased view of the DOM reservoir, and seems to preferentially extract compounds with relatively low amounts of N. Other problems include sample contamination by various resins and incomplete elution of adsorbed DOM. SoHd phase extraction remains, however, the only technique capable of reproducibly isolating DOM compounds within the entire range of MWs. Furthermore, the radiocarbon content (A " C) of DOC isolated by XAD resins is depleted relative to the total dissolved inorganic carbon (DIG) reservoir values for XAD isolates are between —300... 

Bueno M. and Potin-Gautier M. (2002) Solid-phase extraction for the simultaneous preconcentration of organic (selenocys-tine) and inorganic Se(IV), Se(VI) selenium in natural waters. J. Chromatogr. A 963, 185-193. 

Yalcin S. and Le X C. (1998) Low pressure chromatographic separation of inorganic arsenic species using solid phase extraction cartridges. Talanta 47, 787-796. 

Munoz, J., Gallego, M., and Valcarcel, M. (2004). Solid-phase extraction-gas chromatography-mass spectrometry using a fuUerene sorbent for the determination of inorganic mercury(11), methylmercury(I) and ethylmercury(I) in surface waters at sub-ng/ml levels. J. Chromatogr. A, 1055, 185-90. 

UV—Vis = spectrophotometry CL = chemiluminescence FAAS = flame atomic absorption spectrometry MIP = molecularly imprinted polymer SPE = solid phase extraction DIC = dissolved inorganic carbon DOC = dissolved organic carbon. 

Solid-phase extraction on anion exchange resins is very rarely used. Recoveries for the organic acids may show great variabihty which may be caused by incomplete removal from the resin, especially at low concentrations, or it may be attributed to breakthrough of the carboxylate ions during the extraction process if the matrix contains significant amounts of inorganic anions. 

Speciation Overview Waters, Sediments, and Soils. Environmental Analysis. Extraction Solid-Phase Extraction. Food and Nutritional Analysis Overview. Geochemistry Soil, Minor Inorganic Components. Ion Exchange Overview. Isotope Dilution Analysis. Liquid Chromatography Overview. Polarography Overview. Sample Handling Sample Preservation. Voltammetry Overview. Water Analysis Industrial Effluents. X-Ray Absorption and Diffraction X-Ray Absorption. 

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