Flame emission background correction

Minimizing Spectral Interferences The most important spectral interference is a continuous source of background emission from the flame or plasma and emission bands from molecular species. This background emission is particularly severe for flames in which the temperature is insufficient to break down refractory compounds, such as oxides and hydroxides. Background corrections for flame emission are made by scanning over the emission line and drawing a baseline (Figure 10.51). Because the temperature of a plasma is... 

Method for background correction in flame atomic emission. 

Fick s law 592 Filter funnel 102 Filter papers 115 folding of, 116 incineration of, 120, 121 macerated, 450 quantitative, (T) 116 Filter pulp 450 Filtering crucibles 102 Filters, optical 661 Filtration 102, 106, 115 accelerated, 450 technique of, 116, 117 with filter papers, 116 with filtering crucibles, 117 Flame emission spectroscopy 779, 797 background correction, 795 elementary theory of, 780 D. of alkali metals by, 812... 

Beam chopping corrects for flame emission but not for scattering. Most spectrometers provide an additional means to correct for scattering and broad background absorption. Deuterium lamps and Zeeman correction systems are most common. 

Barium. Before the routine use of AAS, Ba was analyzed by emission spectrograph or a KMnO spot test (13). Alkali and alkaline earth metals are analyzed in nitrous oxide/acetylene flames with ionization suppressants such as 1000 ppm Cs. For barium analysis by P CAM 173, background correction must be used whenever greater than 1000 ppm calcium is in the analyte solution. There are strong Ca(0H)2 absorptions and emission at 553.6 nm, which is the barium analytical line. 

For the analytical determination of metals (Cd, Cu, Fe, Mn, Pb and Zn) in surface sediments, suspended particulate matter and biological matrices, digestion with a 3 1 HNO3-HCIO4 mixture under controlled temperature was used (36). Analysis of sediments and suspended particulate matter were made by Flame Atomic Absorption Spectrometry (FAAS) with air-acetylene flame and deuterium background correction. The analysis of metals in lichens and molluscs were performed by ICP-AES. The operating conditions for FAAS and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) analysis are shown in Tables 6.1 and 6.2, respectively. 

Flame atomic absorption is subject to many of the same chemical and physical interferences as flame atomic emission (see Section 28C-2). Spectral interferences by elements that absorb at the analyte wavelength are rare in AA. Molecular constituents and radiation scattering can cause interferences, however. These are often corrected by the background correction. schemes discussed in Seetion 28D-2. In some cases, if the source of interference is known, an excess of the interferent can be added to both the sample and the standards. The added substance is sometimes called a radiation buffer. 

For the homogeneity studies, the extractants (0.05 mol L EDTA, 0.43 mol L" acetic acid and 0.005 mol L DTPA) were prepared as laid out in the certification reports [15, 17], The trace element contents (Cd, Cr, Cu, Ni, Pb and Zn) in the extracts were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) for the CRMs 483/484, flame atomic absorption spectrometry (FAAS) or electrothermal atomic absorption spectrometry with Zeeman background correction (ZETAAS) for the CRM 600. In the case of the CRM 483, little analytical difficulty was experienced as illustrated by the good agreement obtained between the within-bottle and between-bottle CVs for the CRM 484, lower extractable contents, closer to the detection limits and consequent poorer analytical precision was observed in particular for Cr (EDTA extractable contents), Cd and Pb (acetic acid extractable contents). No particular difficulties were experienced for the CRM 600. On the basis of these results, the materials were considered to be homogeneous at a level of 5 g for EDTA- and acetic acid-extractable contents and 10 g for DTPA-extractable contents (as specified in the extraction protocols). 

Figure 13.13 Scheme of a AA spectrometer showing deuterium lamp background correction. This double beam assembly includes a deuterium lamp whose broad emission is superimposed, using a semi-transparent mirror, upon the spectral lines emitted by the HCL. Beam path a passes through the flame while beam path b is a reference path. The instrument measures the ratio of the intensities transmitted by the two beams and for the two sources. The domain of correction is limited to the spectral range of the deuterium lamp, being 200-350 nm (reproduced from the optical scheme of model Spectra AA-10/20, Varian). 

Applications considerations are included in many chapters in Vol 3 of Dean and Rains (1975) devoted to the determination of specific elements, and in various natural and manufactured materials. Methods for analytical atomic spectroscopy, 8th edition (ASTM 1987) contains a wealth of information based on evaluation and approval deliberations by the respected ASTM, including various computation practices, general laboratory practices, practices and methods for analysis of metallurgical and inorganic materials by spectrochemical techniques including flame atomic emission. Dawson et al. (1993) have published a tutorial review on background and background correction in analytical atomic emission spectrometry. 

In atomic emission spectroscopy flames, sparks, and MIPs will have their niche for dedicated apphcations, however the ICP stays the most versatile plasma for multi-element determination. The advances in instrumentation and the analytical methodology make quantitative analysis with ICP-AES rather straightforward once the matrix is understood and background correction and spectral overlap correction protocols are implemented. Modern spectrometer software automatically provides aids to overcome spectral and chemical interference as well as multivariate calibration methods. In this way, ICP-AES has matured in robustness and automation to the point where high throughput analysis can be performed on a routine basis. 

See also Atomic Emission Spectrometry interferences and Background Correction Flame Photometry inductively Coupled Plasma Microwave-induced Piasma. 

See also Atomic Absorption Spectrometry Principles and Instrumentation Interferences and Background Correction Flame. Atomic Emission Spectrometry Inductively Coupled Plasma. Quality Assurance Internal Standards. 

See also Atomic Absorption Spectrometry Interferences and Background Correction. Atomic Emission Spectrometry Principles and Instrumentation Interferences and Background Correction Flame Photometry Inductively Coupled Plasma Microwave-Induced Plasma. Atomic Mass Spectrometry Inductively Coupled Plasma Laser Microprobe. Countercurrent Chromatography Solvent Extraction with a Helical Column. Derivatization of Analytes. Elemental Speciation Overview Practicalities and Instrumentation. Extraction Solvent Extraction Principles Solvent Extraction Multistage Countercurrent Distribution Microwave-Assisted Solvent Extraction Pressurized Fluid Extraction Solid-Phase Extraction Solid-Phase Microextraction. Gas Chromatography Ovenriew. Isotope Dilution Analysis. Liquid Chromatography Ovenriew. 

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