Zeeman effect background correction atomic

Instrumentation for diode laser based AAS is now commercially available and the method certainly will expand as diode lasers penetrating further into the UV range become available, especially because of their analytical figures of merit that have been discussed and also because of their price. In diode laser AAS the use of monochromators for spectral isolation of the analyte lines becomes completely superfluous and correction for non-element specific absorption no longer requires techniques such as Zeeman-effect background correction atomic absorption or the use of broad band sources such as deuterium lamps. 

Fernandez FJ, Giddings R. 1982. Elimination of spectral interference using Zeeman effect background correction. Atomic Spectroscopy 3 61-65. 

Lum and Callaghan [ 140 ] did not use matrix modification in the electother-mal atomic absorption spectrophotometric determination of cadmium in seawater. The undiluted seawater was analysed directly with the aid of Zeeman effect background correction. The limit of detection was 2 ng/1. 

In the method described by Willie et al. [167] atomic absorption measurements were made with a Perkin-Elmer 5000 spectrometer fitted with a Model HGA 500 graphite furnace and Zeeman effect background correction system. Peak absorbance signals were recorded with a Perkin-Elmer PRS-10 printer-sequencer. A selenium electrodeless lamp (Perkin-Elmer Corp.) operated at 6W was used as the source. Absorption was measured at the 196.0nm line. The spectral band-pass was 0.7nm. Standard Perkin-Elmer pyrolytic graphite-coated tubes were used in all studies. 

Other types of background correction have also been developed. The Zeeman effect background correction system started gaining popularity in the early 1980s. An atomic spectral line when generated in the presence of a strong magnetic field can be split into a number of components... 

Dube P. 1988. Determination of chromium in human urine by graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. Analyst 113 917-921. 

Zeeman Effect Background Correction Background correction with electrothermal atomizers can be done by means of the Zeeman effect. Here a magnetic field splits normally degenerate spectral lines into components with different polarization characteristics. Analyte and background absorption can be separated because of their different magnetic and polarization behaviors. 

In order to determine Bi by GF AAS under stabilized temperature platform furnace (STPF) conditions using the Pd-Mg modifier, a pyrolysis temperature of 1200 °C must be applied (Hiltenkamp and Werth 1988). The optimum atomization temperature under these conditions is 1900 °C the characteristic mass with Zeeman effect background correction (BC) is 28 pg, while in a non-Zeeman instrument it is about 20 pg. 

Chakraborti D, Burguera M and Burguera JL (1993) Analysis of standard reference materials after microwave-oven digestion in open vessels using graphite furnace atomic absorption spectrophotometry and Zeeman-effect background correction. Fresenius J Anal Chem 347 233-237. 

Nixon. D.E., Moyer, T.P., Squillace, D.P. and McCarthy, J.T. (1989). Determination of serum nickel by graphite furnace atomic absorption spectrometry with Zeeman-effect background correction Values in a normal population and a population undergoing dialysis. Analyst 114,1671-1674. 

Radziuk B, Rodel G, Stenz H, Becker-Ross H, Florek S (1995) Spectrometer system for simultaneous multielement electrothermal atomic absorption spectrometry using line sources and Zeeman-effect background correction. J Anal At Spectrom 10 127—136 Rao CRM, Reddi GS (2000) Platinum group metals (PGM) occurrence, use and recent trends in their determination. Trends Anal Chem 19 565-586 Rauch S, Lu M, Morrison GM (2001) Heterogeneity of platinum group metals in airborne particles. Env Sci Technol 35 595-599... 

Detection systems employed with hydride generation approaches are conventional AA spectrometers, usually fitted with intense electrodeless discharge or hollow cathode lamp sources. Quartz tube cells are of suitable dimensions to be compatible with the optical systems of all modem spectrometers. Background correction is usually achieved in double-beam optics using deuterium sources, and Zeeman-effect background correction can be implemented when the graphite furnace is used as the atomization cell. 

FIG. 2. Principle of Zeeman effect background correction, using a pulsed, longitudinal magnetic field at the atomizer, = emission line profile, (a) Magnetic field off. (b) Magnetic field on (Courtesy of Perkin-Elmer). 

In the early stages of development, the graphite atomizers suffered from relatively low analytical precision, severe chemical interferences and from the intense background signals. With the introduction of the L vov platform and Zeeman-effect background correction considerable improvements have been made with respect to these deficiencies. The L vov platform placed inside the graphite tube (first proposed by L vov in 1978) is mainly heated by atomization from the tube wall as the temperature increases. Atomization of the sample from the platform delays atomization until near isothermal gas-phase conditions are present... 

J.Y. Cabon and A.L. Bihan. Direct determination of zinc in seawater using electrothermal atomic absorption spectrometry with Zeeman-effect background correction effects of chemical and spectral interferences. Journal of Analytical Atomic Spectrometry 9 477-481,1994. 

The need for improved background correction performance has generated considerable interest in applying the Zeeman effect, where the atomic spectral line is split into several polarised components by the application of a magnetic field. With a Zeeman effect instrument background correction is performed at, or very close to, the analyte wavelength without the need for auxiliary light sources. An additional benefit is that double-beam operation is achieved with a very simple optical system. 

To compensate for the above effects background correction systems are introduced such as the use of Zeeman effect. Zeeman AAS uses splitting of atomic spectral lines... 

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