Inductively coupled plasma advantage

Brenner et al. [ 169] applied inductively coupled plasma atomic emission spectrometry to the determination of calcium (and sulfate) in brines. The principal advantage of the technique was that it avoided tedious matrix matching of calibration standards when sulfate was determined indirectly by flame techniques. It also avoided time-consuming sample handling when the samples were processed by the gravimetric method. The detection limit was 70 ig/l and a linear dynamic range of 1 g/1 was obtained for sulfate. 

Winge et al. [730] have investigated the determination of twenty or more trace elements in saline waters by the inductively coupled plasma technique. They give details of experimental procedures, detection limits, and precision and accuracy data. The technique when applied directly to the sample is not sufficiently sensitive for the determination of many of the elements at the low concentrations at which they occur in seawater, and for these samples preconcentration techniques are required. However, it has the advantages of being amenable to automation and capable of analyzing several elements simultaneously. 

List the advantages and disadvantages of dc-arc spectrometry and inductively coupled plasma spectrometry, when used to determine trace metals in solid samples. Indicate the main reasons for preferring ICP spectrometry, in most cases. 

Since about 1990, however, inductively coupled plasma (ICP, see Section 2.1.5) has become increasingly popular at the expense of TI in this area of application [9]. Although TI can provide better results for some analyses, ICP is more versatile and requires less sample preparation effort. Moreover, the advantage of better precision for TI is often compromised by the sample, for example, sample inhomogeneity. Nevertheless, there are still many examples where TI is used, such as for isotope analysis [10-13] and geochronology [14]. 

Chapters 7 and 8 describe two major techniques for the monitoring of trace elements in environmental samples atomic absorption (AA) and inductively coupled plasma-atomic emission spectroscopy (ICP). AA is most ideally suited for analyses where a limited number of trace metal concentrations are needed with high accuracy and precision. ICP has the advantage of multielement analysis with high speed. 

For resonance lines, self-absorption broadening may be very important, because it is applied to the sum of all the factors described above. As the maximum absorption occurs at the centre of the line, proportionally more intensity is lost on self-absorption here than at the wings. Thus, as the concentration of atoms in the atom cell increases, not only the intensity of the line but also its profile changes (Fig. 4.2b) High levels of self-absorption can actually result in self-reversal, i.e. a minimum at the centre of the line. This can be very significant for emission lines in flames but is far less pronounced in sources such as the inductively coupled plasma, which is a major advantage of this source. 

A number of instrumental analytical techniques can be used to measure the total phosphorus content of organophosphorus compounds, regardless of the chemical bonding of phosphorus within the molecules, as opposed to the determination of phosphate in mineralized samples. If the substances are soluble, there is no need for their destruction and for the conversion of phosphorus into phosphate, a considerable advantage over chemical procedures. The most important methods are flame photometry and inductively coupled plasma atomic emission spectrometry the previously described atomic absorption spectrometry is sometimes useful. 

State the advantages and disadvantages of the inductively coupled plasma compared with conventional flames in atomic spectroscopy. 

The ultimate test of the utility of activation analysis as an analytical technique is whether there are competitive technologies that have the advantages of activation analysis with fewer drawbacks. One candidate for this designation is inductively coupled plasma-mass spectroscopy (ICP-MS). 

Metals can be conveniently determined by emission spectroscopy using inductively coupled plasma (ICP). A great advantage of ICP emission spectroscopy as applied to environmental analysis is that several metals can be determined simultaneously by this method. Thus, multielement analysis of unknown samples can be performed rapidly by this technique. Another advantage is that, unlike atomic absorption spectroscopy, the chemical interference in this method is very low. Chemical interferences are generally attributed to the formation of molecular compounds (from the atoms) as well as to ionization and thermochemical effects. The principle of the ICP method is described below. 

The availability of inductively coupled plasma mass spectrometry (ICPMS) has provided a method of detection of many impurities at very low concentrations directly in the organometallic compound itself. ICP mass spectrometry is a relatively recently developed chemical analysis technique that is useful in the detection of trace element concentrations in a liquid or solid matrix. ICPMS can measure the presence of almost all elements simultaneously, thus giving a detailed, semiquantitative picture of the impurity distribution in the sample. This technique has sensitivities for many elements in the parts-per-billion to parts-per-trillion range. It has the advantage that it is extremely sensitive and can analyze small samples (10 ml or less) of organometallics directly. The ICPMS technique employs a plasma to dissociate the material to be characterized into... 

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