Applications speciation

ICP-MS is being used more frequently in combination with a front-end separation technique such as GC, as a specific and highly selective detector for a variety of speciation applications. GC-ICP-MS is a powerful... 

A gas chromatograph coupled to a MC-ICP-MS for the precise determination of isotope ratios as part of the speciation application has been described, for example, for the elements S, Pb, Hg and Sb.2 Transient signals of sulfur isotope ratios (32S/34S) have been measured in an isotopic gas standard (PIGS 2010, IRMM) to determine SF6 using GC-MC-ICP-MS (Isoprobe, Micromass, UK) with a hexapole collision cell.42 For data evaluation of chromatographic peaks, peak integration limits were defined by the determination of a uniform isotope ratio zone inside... 

SFC has received attention as an alternative separation technique to liquid and gas chromatography. The coupling of SFC to plasma detectors has been studied because plasma source spectrometry meets a number of requirements for suitable detection. There have been two main approaches in designing interfaces. The first is the use of a restrictor tube in a heated cross-flow nebuliser. This was designed for packed columns. For a capillary system, a restrictor was introduced into the central channel of the ICP torch. The restrictor was heated to overcome the eluent freezing upon decompression as it left the restrictor. The interface and transfer lines were also heated to maintain supercritical conditions. Several speciation applications have been reported in which SFC-ICP-MS was used. These include alkyl tin compounds (Oudsema and Poole, 1992), chromium (Carey et al., 1994), lead and mercury (Carey et al., 1992), and arsenic (Kumar et al., 1995). Detection limits for trimethylarsine, triphenylarsine and triphenyl arsenic oxide were in the range of 0.4-5 pg. 

These two elements have a variety of important chemical forms and provide a number of very interesting speciation applications, but to discuss these here would exceed the limitations of this article. The reader is referred to Table 3 and selected references. ... 

The basic principles of ESR spectroscopy were reviewed lucidly in the context of surface speciation applications by McBride (33, 56). A comprehensive introduction oriented toward the use of ESR methods in mineral geochemistry was published by Calas (57). Senesi (58) did the same for organic geochemistry. Fundamentally, ESR spectroscopy detects chemical species with unpaired electrons. With respect to adsorbed metals, investigation is limited to to paramagnetic transition elements in certain oxidation states [e.g., V(IV), Cr(III), Mn(II), Fe(III), and Cu(II)], either as principal surface species or as in situ molecular probes of surface environments. 

Jaudon P, Massiani C, Galea J, et al. 1989. Groundwater pollution by manganese. Manganese speciation Application to the selection and discussion of an in situ groundwater treatment. Sci Total Environ 84 169-183. 

Chapters on sample introduction and hyphenated sample treatment and ICP systems have also been further updated since the last edition. No doubt that chromatographic, electrophoresis, flow injection and field flow fraction separations have extended ICP-MS (and AES) measurements as the mainstay of elanental specia-tion measurements in biological and environmental fields. Without the combination of these separation techniques and ICP measurements, elemental speciation applications would be severely hampered... if not impossible (Chapter 18). The ability to measure P and S with high sensitivity has opened up new opportunities in proteomics, for example. Species-specific and unspecific isotopic dilution (ID-MS) has been critical in quantifying speciation analysis and revealing recovery errors (Chapter 13). Species-specific techniques have been applied to identify species transformations, resulting in the development of multi-species methods whereas, hyphenated species-unspecific ICP-ID-MS determinations of heteroatoms such as sulfur have become a common quantification technique in proteomics. 

Speciation applications require analytical technology that can measure the presence and concentration of forms of the analyte elements that are present in the original specimen at the time of sampling. Extensive sample preparation usually results in modification of the form of the species being determined, thereby precluding accurate speciation measurements. To avoid this problem, on-line chromatographic techniques are utilized to measure the species present in the sample with a minimum of sample pretreatment. 

The study of biochemical natural products has also been aided through the application of two-dimensional GC. In many studies, it has been observed that volatile organic compounds from plants (for example, in fruits) show species-specific distributions in chiral abundances. Observations have shown that related species produce similar compounds, but at differing ratios, and the study of such distributions yields information on speciation and plant genetics. In particular, the determination of hydroxyl fatty acid adducts produced from bacterial processes has been a successful application. In the reported applications, enantiomeric determination of polyhydroxyl alkanoic acids extracted from intracellular regions has been enabled (45). 

A development of the study of adsorption currents is referred to as Tensammetry, and a useful review50 refers to the application of this technique to the examination of natural waters as an aid to speciation , the procedure for deciding how a metal ion is distributed between the various species in which the metal may be present. 

The technique can be used to measure concentrations in the range 10 6-10 9M and as such is eminently suitable for the determination of trace metal impurities of recent years it has found application in the analysis of semiconductor materials, in the investigation of pollution problems, and in speciation studies. 

Anodic stripping voltametry Applicable to few metals and dependent on metal speciation 10 to 10 ° M... 

DNA analysis, performance of polymerase chain reactions, clinical assays for pH, enzymes, proteins, oxygen etc., trace pollution monitoring and other sorts of biological analyzes are at the focus of recent developments [5]. Another reference lists environmental monitoring (including speciation), clinical monitoring, and quality control in production processes as applications of pTAS equipment in chemical analysis [30]. 

Some selected applications (chemical class, mobile phase, stationary phase, column, detector) are as follows fatty acids, C02, PEG or CN-PS, OTC, FID organotin, C02, PhMe-PS, OTC, FPD [305], ThepSFC-ICP system is an effective tool for speciation of metal-containing compounds [362], even in the presence of modifiers to control the retention of components. 

HPLC-QFAAS is also problematical. Most development of atomic plasma emission in HPLC detection has been with the ICP and to some extent the DCP, in contrast with the dominance of the microwave-induced plasmas as element-selective GC detectors. An integrated GC-MIP system has been introduced commercially. Significant polymer/additive analysis applications are not abundant for GC and SFC hyphenations. Wider adoption of plasma spectral chromatographic detection for trace analysis and elemental speciation will depend on the introduction of standardised commercial instrumentation to permit interlaboratory comparison of data and the development of standard methods of analysis which can be widely used. 

Applications Since the introduction of commercial GC-MIP-AES systems, organometallic analysis can be performed routinely, e.g. for speciation of organotin compounds used as PVC stabilisers [356], The hyphenated GC-AED technique can be used to improve the efficiency of additive analysis. While on the one hand... 

The choice of method for a particular application should take into account this categorisation, as well as the precision and accuracy required. This chapter mainly deals with bulk analysis and speciation. 

Applications EXAFS spectroscopy is obviously well suited to speciate and quantify the state of heavy metals, e.g. in soils [310]. Similarly, it allows differentiation of ZnO and Zn stearate on the basis of the X-ray absorption structure of zinc. 

Applications Table 8.58 shows the main fields of application of inorganic mass spectrometry. Mass-spectrometric techniques find wide application in inorganic analysis, and are being used for the determination of elemental concentrations and of isotopic abundances for speciation and surface characterisation for imaging and depth profiling. Solid-state mass spectrometry is usable as a quantitative method only after calibration by standard samples. 

Applications ICP-MS has become the technique of choice for the determination of elements in a wide range of liquid samples at concentrations in the ng L 1 to [igL-1 range. Typical applications of ICP-MS are multi-element analysis of liquids (even with high solid contents) element speciation by hyphenation to chromatographic techniques continuous on-line gas analysis multi-element trace analysis of polymers and trace analysis in high-purity materials. ICP-MS is routinely used for quality control purposes. 

Application to solid polymer/additive formulations is restricted, for obvious reasons. SS-ETV-ICP-MS (cup-in-tube) has been used for the simultaneous determination of four elements (Co, Mn, P and Ti) with very different furnace characteristics in mg-size PET samples [413]. The results were compared to ICP-AES (after sample dissolution) and XRF. Table 8.66 shows the very good agreement between the various analytical approaches. The advantage of directly introducing the solid sample in an ETV device is also clearly shown by the fact that the detection limit is even better than that reported for ICP-HRMS. The technique also enables speciation of Sb in PET, and the determination of various sulfur species in aramide fibres. ETV offers some advantages over the well-established specific sulfur analysers very low sample consumption the possibility of using an aqueous standard for calibration and the flexibility to carry out the determination of other analytes. The method cannot be considered as very economic. 

Applications Electrochemical techniques, while lacking the wide elemental range and long linear response of some atomic and mass spectrometry technologies, offer a valuable alternative in a number of specific applications, and have particular advantages for direct speciation and anion determination. In ion chromatography, amperometric, potentiometric and conductometric detection is widely used [472], see also Section 4.4.2.5. 

With the exception of GC-MIP-AES there are no commercial instruments available for speciation analysis of organometallic species. Recently, a prototype automated speciation analyser (ASA) for practical applications was described [544,545], which consists of a P T system (or focused microwave-assisted extraction), multicapillary GC (MC-GC), MIP and plasma emission detection (PED). MCGC-MIP-PED provides short analysis times ([Pg.676]

Applications Speciation analysis is particularly important in plant and animal biochemistry and nutrition (food/food supplements), clinical biochemistry, industrial chemistry and environmental chemistry. In the... 

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