Atomic emission spectrometry interference

ATOMIC EMISSION SPECTROMETRY/Interferences and Background Correction... 

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

See ATOMIC ABSORPTION SPECTROMETRY Interferences and Background Correction. ATOMIC EMISSION SPECTROMETRY Interferences and Background Correction... 

Note that the interfacing of LC techniques with MS puts significant constraints on the solvents that can be used i.e., they must be volatile, with a low salt concentration, for MS compatibility. Narrow-bore columns, which use much smaller amounts of salt and organic modifier, appear to have potential for facilitating IEC-MS applications.40 Despite the excellent sensitivity of MS detection for most elements, however, there are cases where matrix effects can interfere. In this situation, combination of IEC with atomic emission spectrometry (AES) or atomic absorption spectrometry (AAS) may be preferable, and can also provide better precision.21 32 4142 Other types of... 

Principles and Characteristics Flame emission instruments are similar to flame absorption instruments, except that the flame is the excitation source. Many modem instruments are adaptable for either emission or absorption measurements. Graphite furnaces are in use as excitation sources for AES, giving rise to a technique called electrothermal atomisation atomic emission spectrometry (ETA AES) or graphite furnace atomic emission spectrometry (GFAES). In flame emission spectrometry, the same kind of interferences are encountered as in atomic absorption methods. As flame emission spectra are simple, interferences between overlapping lines occur only occasionally. 

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. 

Boumans PWJM (1994) Detection limits and spectral interferences in atomic emission spectrometry. Anal Chem 66 459A... 

Instrumentation. Flame Characteristics. Flame Processes. Emission Spectra. Quantitative Measurements and Interferences. Applications of Flame Photometry and Flame Atomic Emission Spectrometry. 

Flame AAS (often abbreviated FAAS) was until recently the most widely used method for trace metal analysis. However, it has now largely been superseded by inductively coupled plasma atomic emission spectrometry (see Chapter 4). It is particularly applicable where the sample is in solution or readily solubilized. It is very simple to use and, as we shall see, remarkably free from interferences. Its growth in popularity has been so rapid that on two occasions, the mid-1960s and the early 1970s, the growth in sales of atomic absorption instruments has exceeded that necessary to ensure that the whole face of the globe would be covered by atomic absorption instruments before the end of the century. 

Line Coincidence Tables for Inductively Coupled Plasma Atomic Emission Spectrometry, Boumans, P.W.J.M, Pergamon Press, New York, 1984. The most comprehensive compilation available of sensitive lines for use in ICPAES, with listings of potential interferences. 

Z. Zhang and X. Ma, Methods for correction of spectral interferences in inductively coupled plasma atomic emission spectrometry, Ciirr. Top. Anal. Chem., 3, 2002, 105-123. 

Inductively coupled plasma atomic emission spectrometry has proved to be an excellent technique for the direct analysis of soil extracts because it is precise, accurate and not time-consuming, the level of matrix interference being very low. Of course, the graphite furnace technique yields better detection limits than the inductively coupled plasma procedure. 

Machat, J., Otruba, V., Kanicky, V. Spectral and non-spectral interferences in the determination of selenium by inductively coupled plasma atomic emission spectrometry. J. Anal. At. Spectrom. 17, 1096-1102 (2002)... 

Schiefer HP, Gramain P, Kraeminger E. 1980. Improvement of the uranium determination in flame atomic emission spectrometry by addition of cobalt nitrate an interference agent. Fresenius Z. Anal Chem 303 29. 

The low detection limits, relative lack of interference and broad linear domain of the measurements obtained with the ICP cleaiiy proved the superiority of this emission source over those previously used in analysis by atomic emission spectrometry. Since then, research on plasmas for use in analysis has continued to expand and the technique has continued to be developed. 

Multielement Analysis by Atomic Emission Spectrometry. Applications of a Simultaneous Multielement Wavelength Profiling Facility for Diagnosis of Stray Light and Spectral Line Interference Effects, Third Annual Meeting of the Federation of Analytical Chemistry and Spectroscopy Societies, Philadelphia, PA, November 15, 1976, paper no. 79. 

When a small-bore column, such as 0.5 mm i.d., was used, aU peaks appeared simultaneously if the volume of the retained stationary phase was over 15%. However, if the retention volume of the stationary phase was less than 10% in a small-bore column, peak separation was observed as shown in Fig. 5. " Each peak was detected by plasma atomic emission spectrometry. This peak profile shows enrichment profiles with separation of Mg, Cu, Mn, and Ca in tap water. The intensity of Ca is shown in the right axis, 3 orders higher than that of the other elements, while the intensity of Mn is amplified 10 times. The spectral interference of Ca to the signal of Cu is observed. This separation phenomenon is considered to be quite useful for exact determination of trace metals. 

Knowledge of the atomic spectra is also very important so as to be able to select interference-free analysis lines for a given element in a well-defined matrix at a certain concentration level. To do this, wavelength atlases or spectral cards for the different sources can be used, as they have been published for arcs and sparks, glow discharges and inductively coupled plasma atomic emission spectrometry (see earlier). In the case of ICP-OES, for example, an atlas with spectral scans around a large number of prominent analytical lines [329] is available, as well as tables with normalized intensities and critical concentrations for atomic emission spectrometers with different spectral bandwidths for a large number of these measured ICP line intensities, and also for intensities calculated from arc and spark tables [334]. The problem of the selection of interference-free lines in any case is much more complex than in AAS or AFS work. 

The oldest of the spectroscopic radiation sources, a flame, has a low temperature (see Section 4.3.1) but therefore good spatial and temporal stability. It easily takes up wet aerosols produced by pneumatic nebulization. Flame atomic emission spectrometry [265] is still a most sensitive technique for the determination of the alkali elements, as eg. is applied for serum analysis. With the aid of hot flames such as the nitrous oxide-acetylene flame, a number of elements can be determined, however, not down to low concentrations [349]. Moreover, interferences arising from the formation of stable compounds are high. Further spectral interferences can also occur. They are due to the emission of intense rotation-vibration band spectra, including the OH (310-330 nm), NH (around 340 nm), N2 bands (around 390 nm), C2 bands (Swan bands around 450 nm, etc.) [20], Also analyte bands may occur. The S2 bands and the CS bands around 390 nm [350] can even be used for the determination of these elements while performing element-specific detection in gas chromatography. However, SiO and other bands may hamper analyses considerably. 

Analytical Techniques. The primary method used to determine the metallic element concentration in the tailings was IX Plasma Atomic Emission Spectrometry (IXP). It was used for the determination of both major and minor components. In the former case, the analysis is straightforward, but in the case of minor constituents, it was necessary to use matrix matching, i.e., to use standard solutions having the same concentration of the major component as the unknown, to compensate for the background emission interference of the other solutes. This requires the initial determination of the major components to define the appropriate doping levels. The... 

Sulfate S is extracted from air-dry soil of <2 mm particle size with deionised water, using a soil to solution ratio of 1 5 and an extraction time of 17 hour at 25°C. This extracting solution will not displace adsorbed S, and will not necessarily dissolve all the gypsum that could be present. The extracted S is then determined in an aliquot of clear soil extract by inductively coupled plasma atomic emission spectrometry (ICPAES). In conjunction with vacuum optics, ICPAES is an efficient technique for the measurement of S in soil extracts. At the wavelength, 182.036 nm, there is virtually no interference from Ca2+. 

Instrumentation. Flame characteristics. Flame processes. Emission spectra. Quantitative measurements and interferences. Applicaiion.s of flame photometry and flame atomic emission spectrometry. 

Potassium analysis is usually carried out by flame spectrometry. Atomic emission spectrometry (AES) is slightly more sensitive, though atomic absorption spectrometry (AAS) is somewhat more immune to interference. Interferences occur in the presence of high concentrations of sodium and due to the formation of refractory potassium phosphates in the flame. A solution containing 0.4 mmol cesium chloride and 0.15 mmolL lanthanum nitrate dissolved in 0.1 M HCl will reduce both cation enhancement and anionic suppression (Wieland 1992, Birch and Padgham 1993). 

Regarding historical insight and descriptions of principles and fundamentals of flame atomic emission spectrometry, a chapter on flame photometry appeared in the first edition of Treatise on Analytical Chemistry (Vallee and Thiers 1965) covering the flame and burner, photometer/spec-trometer, fundamental discussion of excitation and processes within the flame, cation and anion interferences and handling of analytical samples. In an analogous, expanded, detailed and excellent treatment of EAES in the second edition of the Treatise on Analytical Chemistry, Syty (1981) discusses types of flames used for excitation, processes within flames, spectral, chemical and physical interferences and remedies. 

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