Spectrometry optical emission

The history of optical emission spectrometry (OES) goes back to Bunsen and KirchhofF, who reported in 1860 on spectroscopic investigations of the alkali and alkaline earth elements with the aid of their spectroscope [1], The elements cesium and rubidium and later on thorium and indium were also discovered on the basis of their atomic emission spectra. From these early beginnings, qualitative and quantitative aspects of atomic spectrometry were considered. The occurrence of atomic spectral lines was understood as unequivocal proof of the presence of these elements in a mixture. Bunsen and KirchhofF in addition, however, also estimated the amounts of sodium that had to be brought into the flame to give a detectable line emission and thereby laid the foundation for quantitative analyses and trace determinations with atomic spectrometry. 

These can be successfully performed with OES. Indeed, the unambiguous detection and identification of a single non-interfered atomic spectral line of an element is sufficient to testify to its presence in the radiation source and in the sample. The most intense line under a given set of working conditions is known as the most sensitive line. These elemental lines are situated for the various elements in widely different spectral ranges and may differ from one radiation source to another, as a result of the excitation and ionization processes. Here, the temperatures of the radiation sources are relevant, as the atom and ion lines of which the norm temperatures (see Section 1.4) are closest to the plasma temperatures will be the predominant ones. However, not only the plasma temperatures but also the analyte dilutions will be important, so as to identify the most intense spectral lines for a radiation source. Freedom from spectral interferences is also important. 

In addition, spectral hne tables, in which the wavelengths of the spectral lines together with their excitation energy and a number indicating their relative intensity for a certain radiation source are tabulated, are very usefiil. They are available for different sources, such as arc and spark sources [379-381], but also in a much less complete form for newer radiation sources such as glow discharges [382] and inductively coupled plasmas [383]. 

Qualitative analysis by atomic spectrometric methods has now been given totally 

Photographically recorded emission spectra from atlas. (Reprinted with permission from Ref. [377].) 

---

Highly sensitive iastmmental techniques, such as x-ray fluorescence, atomic absorption spectrometry, and iaductively coupled plasma optical emission spectrometry, have wide appHcation for the analysis of silver ia a multitude of materials. In order to minimize the effects of various matrices ia which silver may exist, samples are treated with perchloric or nitric acid. Direct-aspiration atomic absorption (25) and iaductively coupled plasma (26) have silver detection limits of 10 and 7 l-lg/L, respectively. The use of a graphic furnace ia an atomic absorption spectrograph lowers the silver detection limit to 0.2 l-ig/L. 

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 Inductively Coupled Plasma (ICP) has become the most popular source for multielement analysis via optical spectroscopy since the introduction of the first commercial instruments in 1974. About 6000 ICP-Optical Emission Spectrometry (ICP-OES) instruments are in operation throughout the world. 

Instrumentation for inductively coupled plasma-optical emission spectrometry. 

R. Payling, D. Jones, A. Bengtson (eds.J Glow Discharge Optical Emission Spectrometry, John Wiley and Sons, Chichester 1997. 

Lomer, M.C.E. et ah. Determination of titanium dioxide in foods using inductively coupled plasma optical emission spectrometry. Analyst, 125, 2339, 2002. 

Solid Sampling Atomic Absorption Spectrometry ICP Optical Emission Spectrometry ICP Mass Spectrometry... 

After Bengtson et al. [161]. Reprinted from A. Bengtson etal., in Glow Discharge Optical Emission Spectrometry (R. Payling et al, eds), pp. 3-11. Copyright 1997 John Wiley Sons, Limited. Reproduced with permission. 

Mass spectrometry is the only universal multielement method which allows the determination of all elements and their isotopes in both solids and liquids. Detection limits for virtually all elements are low. Mass spectrometry can be more easily applied than other spectroscopic techniques as an absolute method, because the analyte atoms produce the analytical signal themselves, and their amount is not deduced from emitted or absorbed radiation the spectra are simple compared to the line-rich spectra often found in optical emission spectrometry. The resolving power of conventional mass spectrometers is sufficient to separate all isotope signals, although expensive instruments and skill are required to eliminate interferences from molecules and polyatomic cluster ions. 

OES Optical emission spectrometry PFT-NMR Pulse Fourier-transform NMR... 

OES Acronym for optical emission spectrometry. oil A liquid lipid. 

Inductively Coupled Plasma Mass Spectrometry Inductively Coupled Plasma Optical Emission Spectrometry Ion Cyclotron Resonance Ion Diffraction... 

Thiel G, Danzer K (1997) Direct analysis of mineral components in wine by inductively coupled plasma optical emission spectrometry (ICP-OES). Fresenius J Anal Chem 357 553... 

Berndt et al. [740] have shown that traces of bismuth, cadmium, copper, cobalt, indium, nickel, lead, thallium, and zinc could be separated from samples of seawater, mineral water, and drinking water by complexation with the ammonium salt of pyrrolidine- 1-dithiocarboxylic acid, followed by filtration through a filter covered with a layer of active carbon. Sample volumes could range from 100 ml to 10 litres. The elements were dissolved in nitric acid and then determined by atomic absorption or inductively coupled plasma optical emission spectrometry. 

The basic instrumentation used for spectrometric measurements has already been described in the previous chapter (p. 277). Methods of excitation, monochromators and detectors used in atomic emission and absorption techniques are included in Table 8.1. Sources of radiation physically separated from the sample are required for atomic absorption, atomic fluorescence and X-ray fluorescence spectrometry (cf. molecular absorption spectrometry), whereas in flame photometry, arc/spark and plasma emission techniques, the sample is excited directly by thermal means. Diffraction gratings or prism monochromators are used for dispersion in all the techniques including X-ray fluorescence where a single crystal of appropriate lattice dimensions acts as a grating. Atomic fluorescence spectra are sufficiently simple to allow the use of an interference filter in many instances. Photomultiplier detectors are used in every technique except X-ray fluorescence where proportional counting or scintillation devices are employed. Photographic recording of a complete spectrum facilitates qualitative analysis by optical emission spectrometry, but is now rarely used. 

Atomic techniques such as atomic absorption spectrometry (AA), inductively coupled plasma-optical emission spectrometry (ICP-OES), and inductively coupled plasma-mass spectrometry (ICP-MS), have been widely used in the pharmaceutical industry for metal analysis.190-192 A content uniformity analysis of a calcium salt API tablet formulation by ICP-AES exhibited significantly improved efficiency and fast analysis time (1 min per sample) compared to an HPLC method.193... 

The samples were air-dried at room temperature, sieved to < 63 pm and analysed by x-ray diffraction (XRD) and scanning electron microscopy combined with an energy dispersive system (SEM-EDS). For chemical analysis, samples were submitted to an extraction with Aqua Regia and analysed by inductively coupled plasma-optical emission spectrometry (ICP/OES). Firing experiments were performed following the procedure described by Brindley Brown (1980). 

Boss, C. B. and Fredeen, K. J. (1999). Concepts, Instrumentation and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry. Norwalk, CO, Perkin Elmer (2nd edn.). 

Tsolakidou, A. and Kilikoglou, V. (2002). Comparative analysis of ancient ceramics by neutron activation analysis, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry, and X-ray fluorescence. Analytical and... 

Inductively coupled plasma optical emission spectrometry has been applied to the determination of boron in soil extracts in amounts down to 0.5m L 1 [5]. 

Once the sample is in solution in the acid and the digest made up to a standard volume the determination of metals is completed by standard procedures such as atomic absorption spectrometry or inductively coupled plasma optical emission spectrometry. 

---