Electrothermal atomizers, atomic spectroscopy

The section on Spectroscopy has been retained but with some revisions and expansion. The section includes ultraviolet-visible spectroscopy, fluorescence, infrared and Raman spectroscopy, and X-ray spectrometry. Detection limits are listed for the elements when using flame emission, flame atomic absorption, electrothermal atomic absorption, argon induction coupled plasma, and flame atomic fluorescence. Nuclear magnetic resonance embraces tables for the nuclear properties of the elements, proton chemical shifts and coupling constants, and similar material for carbon-13, boron-11, nitrogen-15, fluorine-19, silicon-19, and phosphoms-31. 

Scale of Operation Atomic absorption spectroscopy is ideally suited for the analysis of trace and ultratrace analytes, particularly when using electrothermal atomization. By diluting samples, atomic absorption also can be applied to minor and major analytes. Most analyses use macro or meso samples. The small volume requirement for electrothermal atomization or flame microsampling, however, allows the use of micro, or even ultramicro samples. 

The development of methods using sorbents modified with analytical reagents that enable analytical signal measuring directly on the surface by solid-phase spectrometry, visually or by electrothermic atomic absorption spectroscopy (ETAAS) after elution is now a subject of growing interest. 

K. W. Jackson (ed.), Electrothermal Atomization for Analytical Atomic Spectroscopy, John Wiley Sons, Ltd, Chichester (1999). 

Other frequently used methods for determining fluoride include ion and gas chromatography [150,204,205] and aluminium monofluoride (AIF) molecular absorption spectrometry [206,207]. Less frequently employed methods include enzymatic [208], catalytic [209], polarographic [210] and voltammetric methods [211], helium microwave-induced [212] or inductively coupled plasma atomic emission spectrometry [213], electrothermal atomic absorption spectrometry [214], inductively coupled plasma-mass spectrometry [215], radioactivation [216], proton-induced gamma emission [217], near-infrared spectroscopy [218] and neutron activation analysis [219]. 

Analysis. Atomic absorption, emission, and mass spectrographic separation are the most sensitive methods for the analysis of Si. Electrothermal atomization-atomic absorption spectroscopy ETAAS has a sensitivity of 10 ppb, ICPAES 1 ppb, and ICPMS 10 ppb. Colorimetric agents permit spectrometric analysis down to about 10 ppb. 

J. C. Rodriguez-Garcia, J. Barciela-Garcia, C. Herrero-Latorre, S. Garcia-Martin and R. M. Pena-Crecente, Direct and combined methods for the determination of chromium, copper and nickel in honey by electrothermal atomic absorption spectroscopy, J. Agric. Food Chem., 53(17), 2005, 6616-6623. 

This book is rooted in an informal discussion with three researchers. Dr Alatzne Carlosena, Dr Monica Felipe and Dr Maria Jesus Cal, after they had some problems measuring antimony in soils and sediments by electrothermal atomic absorption spectrometry. While we reviewed the results and debated possible problems, much like in a brainstorming session, I realized that some of their difficulties were highly similar to those found in molecular spectrometry (mid-IR spectroscopy, where I had some experience), namely a lack of peak reproducibility, noise, uncontrollable amounts of concomitants, possible matrix interferences, etc. 

AMS = accelerated mass spectroscopy EDTA = ethylene diamine tetra acetic acid GFAAS = graphite furnace atomic absorption spectrometry ICP-AES = inductively coupled plasma - atomic emission spectroscopy NAA = neutron activation analysis ETAAS = electrothermal atomic absorption spectrometry SEC/ICP-MS = size-exclusion chromatography/ICP-AES/mass spectrometry HLPC/ICP-AES = high-performance liquid chromatography/ICP-AES LAMMA = laser ablation microprobe mass analysis NA = not applicable ppq = parts per quadrillion... 

Marshall, J., and Franks, J. (1990) Multielement analysis and reduction of spectral interferences using electrothermal vaporization inductively coupled plasma-mass spectrometry. Atomic Spectroscopy 11, 177-186. 

W. A. Maher, Determination of selenium in marine organisms using hydride generation and electrothermal atomic absorption spectroscopy, Anal. Lett, A16 (1983), 801-809. 

There are also many possibilities for the off-line combination of FFF with various detectors, and virtually any analysis technique can be applied to the fractions as long as the sample quantity is sufficient. One useful combination is electron microscopy on fractions collected from an FFF channel [155]. Electrothermal atomic adsorption spectroscopy (EAAS) [156] has also been described. 

Thirty-two sherds representing five different examples of Kayenta Anasazi Pueblo II pottery (Tusayan Corrugated [TC], Medicine Black-on-Red [MB], Tusayan Black-on-Red [TB], Dogoszhi Black-on-White [DB], and Sosi Black-on-White [SB]) have been analyzed for the elements As, Ba, Co, Cr, Cm, Fe, Mn, Ni, Pb, Se, V, and Zn by using the techniques of flame atomic absorption spectroscopy (.FAA) and electrothermal atomic absorption spectroscopy (ETAA). Analytical procedures for the chemical analysis of ceramics afford accuracy and sensitivity and require only a modest capital investment for instrumentation. The sherd samples were collected at two sites, one in southern Utah (Navajo Mountain [NM]) and the second in northern Arizona (Klethla Valley [KV]). These sites are approximately 60 km apart. Statistical treatment of the data shows that only three clay types were used in the 32 sherds analyzed, and that only three elements (Fe, Pb, and Ni) are necessary to account for 100% of the dispersion observed within this sample set. 

Appendix. Instrumentatal Conditions for Electrothermal Atomization Atomic Absorption Spectroscopy of Sherd Samples... 

Harrison I, Littlejohn D, FeU GS. Determination of selenium in human hair and nail by electrothermal atomic absorption spectrometry. J of Analytical Atomic Spectroscopy 1995 10 215-9. 

Atomic absorption spectrometry with flame (AA-F) or electrothermal atomization furnace (AA-ETA), inductively coupled plasma-emission spectroscopy (ICP-ES), inductively coupled plasma-mass spectrometry (ICP-MS), and high-performance liquid chromatography-mass spectrometry (LC-MS) are state-of-the-art analytical techniques used to measure metals in biological fluids. They are specific and sensitive and provide the cfinical laboratory with the capability to measure a broad array of metals at clinically significant concentrations. For example, ICP-MS is used to measure several metals simultaneously. Photometric assays are also available but require large volumes of sample and have limited analytical performance. Spot tests are also... 

Bavazzano P, Perico A, Rosendahl K, Apostoli P. Determination of urinary arsenic by solvent extraction and electrothermal atomic absorption spectroscopy. I Anal At Spectrom 1996 11 521-4. 

Electrothermal atomizers, which first appeared on the market in about 1970, generally provide enhanced sensitivity because the entire sample is atomized in a short period and the average residence time of the atoms in the optical path is a second ormore. Also, samples are introduced into a confined-volume furnace, which means that they are not diluted nearly as much as they would be in a plasma or flame. Electrothermal atomizers are used for atomic absoiption and atomic fluorescence measurements but have not been applied generally to emission work. They are, however, used to vaporize samples in inductively coupled plasma emission spectroscopy. 

For detailed discussions of electrothermal atomizers, see B. E. Erickson. Anal. Chem., 2000, 72, 543A Electrothermal Atomization for Anahtical Atomic Spectrometry. K. W. Jackson, Ed. New York Wiley, 1999 D. J. Buther and J. Sneddon. A Practical Guide to Graphite Furnace Atomic Absorption Spectrometry. New York Wiley. 1998 C. W. Fuller, Electrothermal Atomization for Atomic Absorption Spectroscopy. London The Chemical Society. 1978. 

---