Speciation liquid chromatography

Inoue Y, Kawabata K (1993) Speciation of organotin compounds by inductively coupled plasma mass spectrometry combined with liquid chromatography. Journal of the Mass Spectrometry Society of Japan, 41 (4) 245-251. 

Zhang X, Cornelis R, De Kimpe J, and Mees L (1996) Arsenic speciation in serum of uraemic patients based on liquid chromatography with hydride generation atomic absorption spectrometry and on-line UV photo-oxidation digestion. Anal Chim Acta 319 177-185. 

H. De Beer, Metal Speciation by High Performance Liquid Chromatography, PhD. Thesis, Rand Afrikaans University, South Africa (1993). 

Bloxam et al. [482] used liquid chromatography with an inductively coupled plasma mass spectrometric detector in speciation studies on ppt levels of mercury in seawater. 

On the basis of the preceding discussion, it should be obvious that ultratrace elemental analysis can be performed without any major problems by atomic spectroscopy. A major disadvantage with elemental analysis is that it does not provide information on element speciation. Speciation has major significance since it can define whether the element can become bioavailable. For example, complexed iron will be metabolized more readily than unbound iron and the measure of total iron in the sample will not discriminate between the available and nonavailable forms. There are many other similar examples and analytical procedures that must be developed which will enable elemental speciation to be performed. Liquid chromatographic procedures (either ion-exchange, ion-pair, liquid-solid, or liquid-liquid chromatography) are the best methods to speciate samples since they can separate solutes on the basis of a number of parameters. Chromatographic separation can be used as part of the sample preparation step and the column effluent can be monitored with atomic spectroscopy. This mode of operation combines the excellent separation characteristics with the element selectivity of atomic spectroscopy. AAS with a flame as the atom reservoir or AES with an inductively coupled plasma have been used successfully to speciate various ultratrace elements. 

Yang et al. [83] accomplished speciation of organotin compounds using reverse-phase liquid chromatography with inductively coupled plasma mass spectrometric detection. The separation was complete in 6min and detection limits were in the range 2.8-16pg of tin for various species. 

C.B. Hymer and J.A. Caruso, Arsenic and its speciation analysis using high-performance liquid chromatography and inductively coupled plasma mass spectrometry. J. Chromatogr.A 1045 (2004) 1-14. 

Liang, Z. Hsu, C.S. Molecular Speciation of Saturates by Online Liquid Chromatography-Field Ionization Mass Spectrometry. Energy Fuels 1998, 72, 637-643. 

B.6 Speciation of Arsenic Compounds by Ion-Exchange High-Performance Liquid Chromatography with Hydride Generation Atomic Fluorescence Detection. 

Among the fractionation techniques that have been used to study the speciation of trace element containing species include liquid chromatography, gas chromatography, ultrafiltration, dialysis, protein precipitation, electrophoresis and others. In the following sections the application of the above techniques will be discussed. 

The application of atomic spectroscopic instruments as element-specific detectors in chromatography has been reviewed by van Loon More recently, Krull has extensively reviewed their use in high pressure liquid chromatography (HPLC). Atomic spectrometry has found wide acceptance in the field of liquid chromatography because, in most cases, the fractions can be directly analysed after elution from the column. However, it is possible to use the technique for the analysis of solid samples without first dissolving the matrix. This is particularly useful after electrophoresis, where the fractions are fixed either in a gel or on paper. Kamel et al. have shown that it is possible to cut the appropriate sections and insert them into the carbon furnace for analysis. The disadvantage of this approach is that the precision is usually poorer (about 10%) and it is difficult to calibrate the instrument. Nevertheless, this approach is very useful if it is used for qualitative speciation. 

J. M. Costa-Fernandez, F. Lunzer, R. Pereiro, N. Bordel and A. Sanz-Medel, Direct coupling of high-performance liquid chromatography to microwave-induced plasma atomic emission spectrometry via volatile-species generation and its application to mercury and arsenic speciation, J. Anal. At. Spectrom., 10, 1995, 1019-1025. 

J. Gomez-Ariza, M.-A. Caro-de-la-Torre, I. Giraldez and E. Morales, Speciation analysis of selenium compounds in yeasts using pressurized liquid extraction and liquid chromatography-microwave-assisted digestion-hydride generation-atomic fluorescence spectrometry. Anal. Chim. Acta, 524(1-2), 2004, 305-314. 

C.F. Harrington, The speciation of mercury and organomercury compounds by using high-performance liquid chromatography, Trends Anal. Chem., 12 (2000) 167-178. 

Manning, B.A. and Martens, D.A. (1997) Speciation of arsenic(III) and arsenic(V) in sediment extracts by high- performance liquid chromatography-hydride generation atomic absorption spectrophotometry. Environmental Science and Technology, 31(1), 171-77. 

Thompson, J. J. and Houk, R. S., Inductively coupled plasma mass spectrometric detection for multielement flow injection analysis and elemental speciation by reversed phase liquid chromatography, Anal. Chem., 58, 2541-2548, 1986. 

Gas chromatography and high-performance liquid chromatography have both been combined with the introduction of hydride generation into inductively coupled plasma mass spectrometry for the speciation determination of arsenic in soils [36]. 

Wrobel K, Gonzalez EB, Wrobel K, et al. 1995. Aluminum and silicon speciation in human serum by ion-exchange high-performance liquid chromatography-electrothermal atomic absorption spectrometry and gel electrophoresis. Analyst 120 809-815. 

Separation processes in liquid chromatography (LC) are discussed in Chapter 2 and referred to in many other chapters. The great majority of hybrid LC applications to speciation problems have used HPLC coupled to different detectors as discussed below (Sections 4.4.2-4.4.4). 

Figure 4.5 Separation of two trialkyl lead and three organomercury species. Column 1.5mm i.d. x 5cm long flow rate lOOpimirT1 mobile phase 5mM ammonium pentanesulfonate in 20 80 v/v ACN-H20 (pH 3.4) injection volume 2jul, sample size, 40 pg (as Pb) for (Me)3Pb+, 80 pg (as Pb) for (Et)3Pb+ and 2 ng (as Hg) for each of the organomercury species. Taken from Speciation of mercury and lead compounds by microbore column liquid chromatography inductively coupled plasma chromatography mass spectrometry (Shum ef a/. 1992).

Corr, J.J. and Larsen, E.H. (1996) Arsenic speciation by liquid chromatography coupled with ion spray tandem mass spectrometry. J. Anal. At. Spectrom., 11, 1215-1224. 

Diemer, J. and Heumann, K.G. (1997) Bromide/bromate speciation by NTI-IDMS and ICP-MS coupled with ion exchange chromatography. Fresenius J. Anal. Chem., 357,74-79. Duan, YX., Wu, M., Jin, Q.H. and Hieftje, G.M. (1995) Vapour generation of nonmetals coupled to microwave plasma-torch mass-spectrometry. Spectrochim. Acta B, 50,355-368. Ebdon, L., Hill, S. and Jones, R (1987) Interface system for directly coupled high performance liquid chromatography-flame atomic absorption spectrometry for trace metal determination./. Anal. At. Spectrom., 2, 205-210. 

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