Elemental analysis inductively coupled plasma-optical

McLeod et al. (1984) described the simultaneous determination of Na, K, Ca, Mg, Li. Cu, Fe and Zn in blood serum by flow-injection analysis - inductively coupled plasma optical emission spectrometry (FIA-ICP-OES) using aqueous synthetic multi-element solutions for calibration. With an injected volume of 20 fiL the performane data for copper in an 1 + 1 diluted serum ranged for precision from 1.1% to 2.2% with a detection limit of 0.01 mg/L. 

In Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), a gaseous, solid (as fine particles), or liquid (as an aerosol) sample is directed into the center of a gaseous plasma. The sample is vaporized, atomized, and partially ionized in the plasma. Atoms and ions are excited and emit light at characteristic wavelengths in the ultraviolet or visible region of the spectrum. The emission line intensities are proportional to the concentration of each element in the sample. A grating spectrometer is used for either simultaneous or sequential multielement analysis. The concentration of each element is determined from measured intensities via calibration with standards. 

Inductively Coupled Plasma-Optical (ICP-optical) methods and ICPMS are extremely sensitive elemental survey techniques that also are described in this volume. ICP methods, however, require a solution for analysis, so that the direct... 

Multielement analysis will become more important in industrial hygiene analysis as the number of elements per sample and the numbers of samples increases. Additional requirements that will push development of atomic absorption techniques and may encourage the use of new techniques are lower detction and sample speciation. Sample speciation will probably require the use of a chromatographic technique coupled to the spectroscopic instrumentation as an elemental detector. This type of instrumental marriage will not be seen in routine analysis. The use of Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) (17), Zeeman-effect atomic absorption spectroscopy (ZAA) (18), and X-ray fluorescence (XRF) (19) will increase in industrial hygiene laboratories because they each offer advantages or detection that AAS does not. 

K. M. Hua, M. Kay, H. E. Indyk, Nutritional element analysis in infant formulas by direct dispersion and inductively coupled plasma-optical emission spectrometry, Food Chem., 68 (2000), 463-470. 

As in other more mature trace element techniques such as atomic absorption (AA) and inductively coupled plasma optical emission spectrometry (ICP-OES), quantitative analysis in ICP-MS is the fundamental tool used to determine analyte concentrations in unknown samples. In this mode of operation, the instrument is calibrated by measuring the intensity for all elements of interest in a number of known calibration standards that represent a range of concentrations likely to be encountered in your unknown samples. When the full range of calibration standards and blank have been run, the software creates a calibration curve of the measured intensity versus concentration for each element in the standard solutions. Once calibration data are acquired, the unknown samples are analyzed by plotting the intensity of the elements... 

Analytical performance can mean different things to different people. The major reason that the trace element community was attracted to ICP-MS almost 20 years ago was its extremely low mnltielement DLs. Other multielement techniques, such as inductively coupled plasma optical anission spectrometry (ICP-OES), offered very high throughput but just could not get down to ultratrace levels. Eveu though electrothermal atomization (ETA) offered much better detection capability than ICP-OES, it did not offer the sample thronghput capability that many applications demanded. In addition, ETA was predominantly a single-element technique and so was impractical for carrying out rapid multielement analysis. These limitations quickly led to the commercialization and acceptance of ICP-MS as a tool for rapid ultratrace element analysis. However, there are certain areas where ICP-MS is known to have weaknesses. For example, dissolved solids for most sample matrices must be kept below 0.2%, otherwise this can lead to serious drift problems and poor precision. 

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. 

Garbarino, John R. and Tedmund M. Struzeski, Methods Of Analysis by the US. Geological Survey National Water Quality Laboratory—Determination of Elements in Whole-Water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry, U.S. Department of the Interior U. S. Geological Survey, Denver, 1998. 

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... 

For these techniques, a dissolved sample is usually employed in the analysis to form a liquid spray which is delivered to an atomiser e.g. a flame or electrically generated plasma). Concerning optical spectrometry, techniques based on photon absorption, photon emission and fluorescence will be described (Section 1.2), while for mass spectrometry (MS) particular attention will be paid to the use of an inductively coupled plasma (TCP) as the atomisation/ionisation source (Section 1.3). The use of on-line coupled systems to the above liquid analysis techniques such as flow injection manifolds and chromatographic systems will be dealt with in Section 1.4 because they have become commonplace in most laboratories, opening up new opportunities for sample handling and pretreatment and also to obtain element-specific molecular information. 

Inorganic pigments and lakes (organic dyes bonded to an inorganic support) can be recognized by the ratio of elements in their composition, making elemental analysis an important tool in their identification. EDS may facilitate an initial qualitative analysis, but quantitative analysis and the detection of trace elements are needed to identify the inorganic colorant components. Due to sample size restrictions, the methods that can be employed are limited. The techniques of inductively-coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectroscopy (ICP-OES), and laser ablation ICP-MS are described in the literature (56). 

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. 

Inductively coupled plasma mass spectrometry is a relatively new technique for elemental analysis and has superior limits of detection over optical methods. Also, this technique has an order of magnitude better detection limit than that obtained by the conventional fluorometric method. Uranium has many stable and unstable isotopes but 238U has the largest percentage abundance (99.274%). 

---