Atomic Emission Spectrometry.. . . 688 21.11. References

Inductively coupled argon plasma (icp) and direct current argon plasma (dcp) atomic emission spectrometry are solution techniques that have been appHed to copper-beryUium, nickel—beryUium, and aluminum—beryUium aUoys, beryUium compounds, and process solutions. The internal reference method, essential in spark source emission spectrometry, is also useful in minimizing drift in plasma emission spectrometry (17). Electrothermal (graphite... 

In the context of chemometrics, optimization refers to the use of estimated parameters to control and optimize the outcome of experiments. Given a model that relates input variables to the output of a system, it is possible to find the set of inputs that optimizes the output. The system to be optimized may pertain to any type of analytical process, such as increasing resolution in hplc separations, increasing sensitivity in atomic emission spectrometry by controlling fuel and oxidant flow rates (14), or even in industrial processes, to optimize yield of a reaction as a function of input variables, temperature, pressure, and reactant concentration. The outputs ate the dependent variables, usually quantities such as instmment response, yield of a reaction, and resolution, and the input, or independent, variables are typically quantities like instmment settings, reaction conditions, or experimental media. 

Moens L, Verreft P, Boonen S, Vanhaecke F and Dams R (1995) Solid sampling electrothermal vaporization for sample introduction in inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. Spectrochim Acta 508 463-475. Mooijman KA, In t Veld PH, Hoekstra JA, Heisterkamp SH, Havelaar AH, Notermans SHW, Roberts D, Griepink B, Maier E (1992) Development of Microbiological Reference Materials. European Commission Report EUR 14375 EN, Community Bureau of Reference, Brussels. 

With solid sampling-electrothermal vaporization-inductively coupled atomic emission spectrometry (SS-ETV-ICP-AES), Cu in two environmental CRMs was determined using a third CRM with similar matrix as calibrant. Comparison with a reference solution showed good agreement (Verrept et al. 1993). 

The ICP provides the most useful atom cell for atomic emission spectrometry. Critically discuss this statement with particular reference to the analysis of real samples. 

Coal contains several elements whose individual concentrations are generally less than 0.01%. These elements are commonly and collectively referred to as trace elements. These elements occur primarily as part of the mineral matter in coal. Hence, there is another standard test method for determination of major and minor elements in coal ash by ICP-atomic emission spectrometry, inductively coupled plasma mass spectrometry, and graphite furnace atomic absorption spectrometry (ASTM D-6357). The test methods pertain to the determination of antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, vanadium, and zinc (as well as other trace elements) in coal ash. 

This method was developed as a second, independent method to complement the usual colorimetric procedure in the determination of a certified concentration of dissolved silica in a planned seawater reference material. Ion exclusion affords a separation of the dissolved silica not only from the major seawater cations but also from potentially interfering anions. The detection limit, conservatively estimated at 2.3ng g 1 as Si (0.08pM), is superior to that achievable by direct analysis by inductively coupled plasma atomic emission spectrometry. 

The most important analytical techniques which are used in multielement trace analysis are ICP-MS, atomic absorption spectrometry (AAS) and ICP atomic emission spectrometry (AES). NAA is applied as reference method in order to establish certibed values. The regular atomic spectrometry update on clinical and biological materials, foods and beverages (ASU review) gives an overview of the recent developments in elemental analysis of food and beverages [81]. 

Inductively Coupled Plasma Atomic Emission Spectrometry ICP-AES is a technique half-way between FAAS and ET-AAS in terms of detection power. Among all ICP-AES features its robustness against matrix effects and its ability to carry out multielemental analysis predominate as the most advantageous [76-80], Multielemental analysis has also been successfully used to establish reference values [6, 76, 81-84] for many major and trace essential elements in different matrices of biological and nutritional interest, particularly in milk samples [81-83], Reference values for minor and trace element in human milk are collected in Table 13.8. 

S. Caroli, A. Alimonti, P. Delle Femmine, F. Petrucci, O. Senofonte, N. Violante, A. Menditto, G. Morisi, A. Menotti, P. Falconieri, Role of inductively coupled plasma atomic emission spectrometry in the assessment of reference values for trace elements in biological matrices, J. Anal. Atom. Spectrom., 7 (1992), 859-864. 

The most widely used spectrochemical methods are flame atomic absorption spectrometry (FAAS), electrothermal atomization atomic absorption spectrometry (ETA-AAS), and inductively coupled plasma atomic emission spectrometry (ICP-AES). Some work has been performed using inductively coupled plasma mass spectrometry (ICP-MS) and the unique properties of Hg have allowed the use of cold vapor (CV) A AS. It is beyond the scope of this chapter to describe these well-established and well-accepted spectrochemical techniques. The reader is referred to several excellent texts which describe in detail the basic principles, instrumentation, and method development of these analytical techniques [1-4]. The most toxic elements, such as As, Cd, Cr, Pb, and particularly Hg have been the most widely studied. Other metals, such as Ba, Cu, Fe, Mn, V, and Zn, have also been investigated. 

This multiauthored book aims at highlighting the role played by atomic and mass spectrometry (with particular reference to atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry) in supporting and promoting research and control of foodstuffs and food commodities as regards both essential and potentially toxic chemical elements. The progress made so far in this field is overviewed and emphasis is put on the open problems that require further investment and development in the public and private sectors. 

This article focuses primarily on traditional low-temperature flame photometry. High-temperature flame photometry has evolved into separate techniques, typically identified by their temperature sources (e.g., inductively coupled plasma-atomic emission spectrometry, ICP-AES ). Some references to other related analytical tools, including high-temperature flame photometry, are made here to establish perspective. 

Inductively coupled plasma-atomic emission spectrometry was investigated for simultaneous multielement determinations in human urine. Emission intensities of constant, added amounts of internal reference elements were used to compensate for variations in nebulization efficiency. Spectral background and stray-light contributions were measured, and their effects were eliminated with a minicomputer-con-trolled background correction scheme. Analyte concentrations were determined by the method of additions and by reference to analytical calibration curves. Internal reference and background correction techniques provided significant improvements in accuracy. However, with the simple sample preparation procedure that was used, lack of sufficient detecting power prevented quantitative determination of normal levels of many trace elements in urine. 

Sabbioni E, Nicoiaou GR, Peitea R, Beccaloni E, Coni E, Alimonti A and Caeoli S (1990) Inductively coupled atomic emission spectrometry and neutron activation analysis for the determination of element reference values in human lung tissue. Biol Trace Flem Res 26-27 757-768. 

Reed KC and Bygeave FL (1974b) The inhibition of mitochondrial calcium transport by lanthanides and ruthenium red. Biochem J 140 143-155. Sabbioni F, Nicoiaou GR, Peitea R, Beccaloni F, Coni F, Alimonti A and Caeoli S (1990) Inductively coupled atomic emission spectrometry and neutron activation analysis for the determination of clement reference values in human lung tissue. Biol Trace Flem Res 26-27 757-768. Sanborn WG and Langee GA (1970) Specific uncoupling of excitation and concentration in mammalian cardiac tissue by lanthanum. J Gen Physiol 56 191-217. 

Determinative methods included under generic heading ofinductively coupled plasma atomic emission spectrometry are ICPAES, DCPAES, furnace ICPAES, etc., and include all variants. (2-7) Refer to footnotes to Table 2.7. 

The tungsten content of a reference ore sample was measured both by X-ray fluorescence (XRF) spectrometry, the standard method, and by inductively coupled plasma-atomic emission spectrometry (ICP). The results as weight percent tungsten are given in the following table. Are the results of the two methods significantly different at the 95% confidence level Is there any bias in the ICP method (Hint The standard method can be considered to have a mean = /a.)... 

Flame atomic emission spectrometry Basic information on FAES is presented elsewhere in this encyclopedia. Sodium measurements are performed at 590 nm with the use of a propane flame (1925°C). Physiological samples for sodium determination are highly diluted before measurement. The diluent and the calibrator solution contain the same concentration of lithium ions so as to balance flame instability by a concomitant measurement of lithium in the reference beam (the so-called lithium guideHne). At the same time, lithium ions inhibit the ionization of sodium atoms. This procedure cannot be used in the case of therapy with lithium salts. That is why some authors prefer the concomitant measurement of caesium to that of lithium. Dilution adjusts the viscosity of the sample to that of the calibrator solution to produce identical aspiration rate and drop size on nebulization. As other electrolytes interfere with sodium measurement, their concentration in the caH-brator solution must be similar to their concentration in the sample. For the measurement of sodium in urine, calibrator solutions different from those for serum measurement are needed as the electrolyte concentrations in urine samples are quite different from those in serum and their relations are very variable. As the concentration of the electrolytes in serum is rather constant, calibrator solutions for serum measurements can fulfill their function better than those for urine in other words, urine determinations are usually less accurate. FAES proved to be sufficiently reliable to be used as the basic principle of the sodium reference measurement procedure. In routine use, however, FAES is less accurate. Its application is given up by most clinical laboratories in favor of potentiometric measurements... 

See also Atomic Absorption Spectrometry Principles and Instrumentation. Atomic Emission Spectrometry Principles and Instrumentation. Elemental Speciation Overview. Food and Nutritional Analysis Sample Preparation. Ion-Selective Electrodes Overview. Quality Assurance Reference Materials. Sample Dissolution for Elemental Analysis Dry Ashing Oxygen Flask Combustion Wet Digestion Microwave Digestion. Spectrophotometry Inorganic Compounds. Titrimetry ... 

See also Atomic Absorption Spectrometry Flame. Atomic Emission Spectrometry Inductively Coupled Plasma. Quality Assurance Reference Materials. Water Analysis Seawater - Dissolved Organic Carbon. 

Some of these approaches are also used in atomic emission spectrometry and in ICP-MS and are discussed in greata detail in Chapters 7,9, and 10, and in the references by Sneddon, Robinson, and Skelly Frame and Keliher listed in the bibliography. 

Spontaneous emission of photons. This process refers to a spontaneous transition of the electron from the excited state 2 to the lower energy state 1 with emission of a photon of frequency vi2 = E2 - Ef jh. This process constitutes the photophysical basis of atomic emission spectrometry, which will be termed here optical emission spectrometry in order to use the acronym OES instead of AES because the latter acronym can be confused with that for Auger electron spectroscopy. 

For determination of the elements, mainly spectrometric techniques are used here. Depending on the kind of element and the expected concentration level, the following methods are applied flame atomic emission spectrometry (flame AES), flame atomic absorption spectrometry (flame AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), electrothermal atomisation (graphite furnace) atomic absorption spectrometry (ETA-AAS), inductively coupled plasma mass spectrometry (ICP-MS), spectrophotometry and segmented flow analysis (SFA). Besides, potentiometry (ion selective electrodes (ISE)) and coulometry will be encountered. In many cases, more than one method is described to determine a component. This provides a reference, as well as an alternative in case of instrumental or analytical problems. 

Balaram,V., Anjaiah, K.V., and Reddy, M. R. P. (1995). Comparative study on the trace and rare earth element analysis of an Indian polymetallic nodule reference sample by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. A [Pg.192]

Fujimori, E., Sawatari, H., Chiba, K., and Haraguchi, H. (1996). Determination of minor and trace elements in urine reference sample by a combined system of inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. Anal. Sci. Int.J.Jpn. Soc.Anal. Chem. 12(3), 465. 

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