High emission spectrometry

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. 

Instmmental methods such as atomic absorption and emission spectrometry, and gamma activation ate employed in most beryUium determinations however, gravimetric and tritrimetric methods remain useful when high accuracy is required. 

Inductively coupled plasma atomic emission spectrometry Electrothermal atomic absorption spectrometry High pressure liquid chromatography... 

Method abbreviations D-AT-FAAS (derivative flame AAS with atom trapping), ETAAS (electrothermal AAS), GC (gas chromatography), HGAAS (hydride generation AAS), HR-ICP-MS (high resolution inductively coupled plasma mass spectrometry), ICP-AES (inductively coupled plasma atomic emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry), TXRF (total reflection X-ray fluorescence spectrometry), Q-ICP-MS (quadrapole inductively coupled plasma mass spectrometry)... 

Plasma sources were developed for emission spectrometric analysis in the late-1960s. Commercial inductively coupled and d.c. plasma spectrometers were introduced in the mid-1970s. By comparison with AAS, atomic plasma emission spectroscopy (APES) can achieve simultaneous multi-element measurement, while maintaining a wide dynamic measurement range and high sensitivities and selectivities over background elements. As a result of the wide variety of radiation sources, optical atomic emission spectrometry is very suitable for multi-element trace determinations. With several techniques, absolute detection limits are below the ng level. 

Spark sources are especially important for metal analysis. To date, medium-voltage sparks (0.5-1 kV) often at high frequencies (1 kHz and more), are used under an argon atmosphere. Spark analyses can be performed in less than 30 s. For accurate analyses, extensive sets of calibration samples must be used, and mathematical procedures may be helpful so as to perform corrections for matrix interferences. In arc and spark emission spectrometry, the spectral lines used are situated in the UV (180-380nm), VIS (380-550nm) and VUV (<180 nm) regions. Atomic emission spectrometry with spark excitation is a standard method for production and product control in the metal industry. 

Principles and Characteristics Particle-induced X-ray emission spectrometry (PIXE) is a high-energy ion beam analysis technique, which is often considered as a complement to XRF. PIXE analysis is typically carried out with a proton beam (proton-induced X-ray emission) and requires nuclear physics facilities such as a Van der Graaff accelerator, or otherwise a small electrostatic particle accelerator. As the highest sensitivity is obtained at rather low proton energies (2-4 MeV), recently, small and relatively inexpensive tandem accelerators have been developed for PIXE applications, which are commercially available. Compact cyclotrons are also often used. 

HP-OIT High-pressure oxidative induction emission spectrometry... 

HPSE liquid chromatography High-pressure solvent extraction ICR emission spectrometry Ion-cyclotron resonance... 

It has been reported that the differential determination of arsenic [36-41] and also antimony [42,43] is possible by hydride generation-atomic absorption spectrophotometry. The HGA-AS is a simple and sensitive method for the determination of elements which form gaseous hydrides [35,44-47] and mg/1 levels of these elements can be determined with high precision by this method. This technique has also been applied to analyses of various samples, utilising automated methods [48-50] and combining various kinds of detection methods, such as gas chromatography [51], atomic fluorescence spectrometry [52,53], and inductively coupled plasma emission spectrometry [47]. 

The number of excited atoms at typical flame temperatures (ca 2200-3200 K) is very low indeed compared with the number of ground-state atoms, even for easily excited lines. For difficult-to-excite lines (e.g. Zn 213.9 nm), it can be shown that only about one excited atom will exist at any given time in an air-propane flame when aspirating a 1 mg 1 zinc solution. This is one reason why flames are poor sources for atomic emission spectrometry, but are well suited to atomic absorption spectrometry, i.e. most of the atoms are in the ground state. As will be seen, the typical temperatures obtainable in plasma sources are of the order of 8000 K, at which there is a much high ratio of excited-to ground-state atoms, and hence a much greater intensity of atomic emission. 

A wide range of instrumentation may be employed for flame atomic emission spectrometry, from filter photometers to highly sophisticated... 

Today, as a direct solid-state analytical technique, dc GDMS is more frequently applied for multi-element determination of trace contaminants, mostly of high purity metallic bulk samples (or of alloys) especially for process control in industrial laboratories. The capability of GDMS in comparison to GD-OES (glow discharge optical emission spectrometry) is demonstrated in a round robin test for trace and ultratrace analysis on pure copper materials.17 All mass spectrometric laboratories in this round robin test used the GDMS VG 9000 as the instrument, but for several... 

J. M. Costa-Fernandez, F. Lunzer, R. Pereiro, N. Bordel and A. Sanz-Medel, Direct coupling of high-performance liquid chromatography to microwave-induced plasma atomic emission spectrometry via volatile-species generation and its application to mercury and arsenic speciation, J. Anal. At. Spectrom., 10, 1995, 1019-1025. 

Nakashima R, Sasaki S, Shibata S. 1975. Determination of silver in biological materials by high-frequency plasma-torch emission spectrometry. Analytica Chimica Acta 77 65-70. 

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