Analytical methods inductively coupled plasma-optical

Analytical techniques used for clinical trace metal analysis include photometry, atomic absorption spectrophotometry (AAS), inductively coupled plasma optical emission (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS). Other techniques, such as neutron activation analysis (NAA) and x-ray fluorescence (XRF), and electrochemical methods, such as anodic stripping voltammetry (ASV), are used less commonly For example. NAA requires a nuclear irradiation facility and is not readily available and ASV requires completely mineralized solutions for analysis, which is a time-consuming process. 

Introducing samples to the plasma via liquids reduces sensitivity because the concentration of the analyte is limited to the volume of solvent that the plasma can tolerate. An electro-thermal method seems an obvious choice to increase the detection limit as it will vaporise entirely most neat samples or using an increased concentration of sample in a suitable solvent. The sample is placed on a suitable open graphite rod in an enclosed compartment and heated rapidly (Figure 2.15). The electronics required for ICP-OES-ETV (inductively coupled plasma-optical emission spectroscopy-electro-thermal volatilisation) is similar to that for A AS and detection limits are better than ICP-AES. 

The analytical performance of ICP-MS is compared with other analytical techniques for the determination of trace metal oxide particulates after the simulated detonation of an RDD [10]. Table 20.9 shows a comparison of the instrumental parameters used in inductively coupled plasma optical emission spectroscopy (ICP-OES) and an ICP-MS instrument. These two techniques were used to analyze Sr, Ti, and Ce in ceramic oxides that may be used in RDDs. ICP-MS provided lower detection limits for the metals than ICP-OES. Overall method performance was comparable with ICP-OES and instrumental neutron activation analysis (INAA), another well-established nuclear and radiological analytical technique. 

For determination of the elements, mainly spectrometric techniques are used here. Depending on the kind of element and the expected concentration level, the following methods are applied flame atomic emission spectrometry (flame AES), flame atomic absorption spectrometry (flame AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), electrothermal atomisation (graphite furnace) atomic absorption spectrometry (ETA-AAS), inductively coupled plasma mass spectrometry (ICP-MS), spectrophotometry and segmented flow analysis (SFA). Besides, potentiometry (ion selective electrodes (ISE)) and coulometry will be encountered. In many cases, more than one method is described to determine a component. This provides a reference, as well as an alternative in case of instrumental or analytical problems. 

Robinson D. and Lenn P. D. (1967) Plasma diagnostics by spectroscopic methods, Appl. Opt. 6 983-1000. Kalnicki D. j., Kniseley R. N. and Fassel V. A. (1975) Inductively coupled plasma optical emission spectroscopy. Excitation temperatures experienced by analyte species, Spectrochim. Acta, Part B 30 511-525. Corliss C. H. and Bozman W. R. (1%2) Experimental transition probabilities for spectral lines of 70 elements derived from the NBS tables of spectral line intensities. The... 

Numerous methods have been pubUshed for the determination of trace amounts of tellurium (33—42). Instmmental analytical methods (qv) used to determine trace amounts of tellurium include atomic absorption spectrometry, flame, graphite furnace, and hydride generation inductively coupled argon plasma optical emission spectrometry inductively coupled plasma mass spectrometry neutron activation analysis and spectrophotometry (see Mass spectrometry Spectroscopy, optical). Other instmmental methods include polarography, potentiometry, emission spectroscopy, x-ray diffraction, and x-ray fluorescence. 

The most frequently applied analytical methods used for characterizing bulk and layered systems (wafers and layers for microelectronics see the example in the schematic on the right-hand side) are summarized in Figure 9.4. Besides mass spectrometric techniques there are a multitude of alternative powerful analytical techniques for characterizing such multi-layered systems. The analytical methods used for determining trace and ultratrace elements in, for example, high purity materials for microelectronic applications include AAS (atomic absorption spectrometry), XRF (X-ray fluorescence analysis), ICP-OES (optical emission spectroscopy with inductively coupled plasma), NAA (neutron activation analysis) and others. For the characterization of layered systems or for the determination of surface contamination, XPS (X-ray photon electron spectroscopy), SEM-EDX (secondary electron microscopy combined with energy disperse X-ray analysis) and... 

Since the mid-1960s, a variety of analytical chemistry techniques have been used to characterize obsidian sources and artifacts for provenance research (4, 32-36). The most common of these methods include optical emission spectroscopy (OES), atomic absorption spectroscopy (AAS), particle-induced X-ray emission spectroscopy (PIXE), inductively coupled plasma-mass spectrometry (ICP-MS), laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectroscopy (XRF), and neutron activation analysis (NAA). When selecting a method of analysis for obsidian, one must consider accuracy, precision, cost, promptness of results, existence of comparative data, and availability. Most of the above-mentioned techniques are capable of determining a number of elements, but some of the methods are more labor-intensive, more destructive, and less precise than others. The two methods with the longest and most successful histoty of success for obsidian provenance research are XRF and NAA. 

A major difficulty encountered with atomic absorption techniques is the presence of incompletely absorbed background emission from the source and scattered light from the optical system. As the background becomes more intense relative to the absorption of the analyte, the precision of the measurement decreases dramatically. For this reason, several background correction techniques have been implemented. A commonly used method is the method of proximity, which was discussed in relation to inductively coupled plasma spectroscopy. 

Different inductively coupled plasma (ICP) methods have been developed which can be used for sulfur analysis. Of these, ICP-AES or ICP-OES (optical emission spectroscopy) and ICP-MS (mass spectrometry) have been widely used. Both have a very broad analytical range. 

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