Capillary electrophoresis speciation analysis

G. Forte, M. D Amato and S. Caroli, Capillary electrophoresis speciation analysis of various arsenical compounds, Microchem. J., 79,15-19, 2005. 

There are few methods which can measure well-defined metal fractions with sufficient sensitivity for direct use with environmental samples (approach B in Fig. 8.2). Nevertheless, this approach is necessary in the experimental determination of the distribution of compounds that are labile with respect to the time scales of the analytical method. Recent literature indicates that high-performance liquid (HPLC) and gas chromatographic (GC) based techniques may have such capabilities (Batley and Low, 1989 Chau and Wong, 1989 van Loon and Barefoot, 1992 Kitazume et al, 1993 Rottmann and Heumann, 1994 Baxter and Freeh, 1995 Szpunar-Lobinska et al, 1995 Ellis and Roberts, 1997 Vogl and Heumann, 1998). The ability to vary both the stationary and mobile phases, in conjunction with suitable detector selection (e.g. ICP-MS), provides considerable discriminatory power. HPLC is the superior method GC has the disadvantage that species normally need to be derivatised to volatile forms prior to analysis. Capillary electrophoresis also shows promise as a metal speciation tool its main advantage is the absence of potential equilibria perturbation, interactions... 

Li, Y., X.-B. Yin, and X.-P. Yan. 2008. Recent advances in on-line coupling of capillary electrophoresis to atomic absorption and fluorescence spectrometry for speciation analysis and studies of metal-biomolecule interactions. Anal. Chim. Acta 615 105-114. 

S. S. Kannamkumarath, Katarzyna Wrobel, Kazimierz Wrobel, C. B Hymer, J. A. Caruso, Capillary electrophoresis D inductively coupled plasmaDmass spectrometry an attractive complementary technique for elemental speciation analysis, J. Chromatogr. A, 975 (2002), 245 D 266. 

In past years, on line chromatographic coupling techniques such as HPLC and CE coupled to ICP-MS with the isotope dilution technique have been used for element quantification in speciation analysis. An interesting application of the isotope dilution technique in medical research was proposed recently by Prange and co-workers, who added highly enriched " S, Cu, Zn and Cd spikes to the interface of the CE-ICP-MS system. The authors separated isoforms of metallothionein (e.g., of rabbit liver) by capillary electrophoresis and quantified S, Cd, Cu and Zn concentrations in isoforms by ICP-SFMS using the isotope dilution technique. A new selenized yeast reference material (SELM-1) for methionine, selenomethionine (SeMet) and total selenium content has also certified by an intercomparison exercise. ... 

Detection techniques of high sensitivity, selectivity, and ease of coupling with sample preparation procedures are of special interest for measuring PGM content in biological and environmental samples. ICP MS, electrothermal atomic absorption spectrometry (ET AAS), adsorptive voltammetry (AV), and neutron activation analysis (NAA) have fotmd the widest applications, both for direct determination of the total metal content in the examined samples and for coupling with instrumental separation techniques. Mass spectrometry coupled with techniques such as electrospray ionization (ESI) and capillary electrophoresis (CE) (e.g., ESI MS", LC ESI MS", LC ICP MS, CE MS", and CE ICP MS) offer powerful potential for speciation analysis of metals. MS is widely used for examination of the distribution of the metals in various materials (elemental analysis) and for elucidation of the... 

Harms J and Schwedt G (1994) Application of capillary electrophoresis in element speciation analysis of plant and food extracts. Fresenius J Anal Chem 350 93-100. 

D Schlegel, J Mattusch, R Wennrich. Speciation analysis of arsenic and selenium compounds by capillary electrophoresis. Fresenius J Anal Chem 354 535-539,1996. 

Kannamkumarath, S. S., WuiUoud, R. G, Jayasinghe, S., and Caruso, J. A., Fast speciation analysis of iodophenol compounds in river waters by capillary electrophoresis-inductively coupled plasma-mass spectrometry with off-line solid-phase microextraction. Electrophoresis, 25,1843, 2004. 

Liu YM and Cheng JK (2003) Elemental speciation analysis in capillary electrophoresis. Electrophoresis 24 1993-2012. 

The improvement in the mass spectrometer will of course lead to better detection limits and capabilities. Again, the low-flow pneumatic nebulizer will probably continue to lead the work performed in building CE-ICP-MS interfaces. Also, the current selection of commercial low-flow nebulizer will aid in the construction and use of interfaces. Finally, two books worthy of further reading are Akbar Montaser s Inductively Coupled Plasma Mass Spectrometry (Wiley-VCH, New York, 1998) and Joseph A. Caruso et al. s Elemental Speciation—New Approaches for Trace Elemental Analysis, Comprehensive Analytical Chemistry XXXIII (Elsevier Science, Amsterdam, The Netherlands, 2000). Specific chapters were cited in this entry, but both books comprise other chapters containing a wealth of information about capillary electrophoresis-inductively coupled plasma-mass spectrometry. 

D.D. Wang, F. Li, X.P. Yan, On-hne hyphenation of flow injection, miniaturized capillary electrophoresis and atomic fluorescence spectrometry for high-throughput speciation analysis, J. Chromatogr. A 1117 (2006) 246-249. 

C.A. Suarez, G.C.L. Araujo, M.F. Gine, M.H. Kakazu, J.E.S. Sarkis, Sequential injection analysis (SIA) for arsenic speciation by capillary electrophoresis hyphenated to inductively coupled plasma sector filed mass spectrometry (CE-ICP-SFMS), Spectrosc. Lett. 42 (2009) 376—382. 

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