Background correction Zeeman-effect

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. 

Grobenski et al. [709] have reviewed methodology for the determination of these elements in seawater. Zeeman-effect background correction using an AC magnet around the graphite furnace corrects for nonspecific attenuation up to 2.0 absorbance and corrects for structured background. 

Maximum power heating, the L vov platform, gas stop, the smallest possible temperature step between thermal pretreatment and atomisation, peak area integration, and matrix modification have been applied in order to eliminate or at least reduce interferences in graphite furnace AAS. With Zeeman effect background correction, much better correction is achieved, making method development and trace metal determinations in samples containing high salt concentrations much simpler or even possible at all. 

Cabon and Le Bihan [711] studied the effects of transverse heated AAS and longitudinal Zeeman effect background correction in sub xg/l determination of chromium, copper, and manganese in seawater samples. 

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... 

Blood Diluted with 0.1% EDTA and 5% isopropanol GFAAS-Zeeman-effect background correction 0.09 pg/L No data Dube 1988... 

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. 

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. 

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. 

NRCC biological and sediment CRMs Sn Digest with HNO3/HF/HCIO4 [WDC] Inject with modifier into GFA, Zeeman-effect background correction [ETAAS] [WDC-ETAAS] Sturgeon et al. (1987)... 

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. 

Total arsenic in urine was determined by the graphite furnace with Zeeman effect background correction. Using matrix modification with 5% nickel nitrate, sampie volumes of 20 /tL, charring up to 1500 °C, atomisation at 2800 °C. and using the standard addition method was reported to achieve a detection limit of 10 hqIL if the urine dilution factor (2) was considered (Edgar and Lum, 1983). 

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... 

Figure 85 Principle of the transverse AC Zeeman effect background correction (Perkin Elmer Corp.)...

A method for direct Ag determination at ppb levels in blood plasma was developed, based on GF-AAS with Zeeman effect background correction . Selective preconcentration of several metal ions can be accomplished with poly(chlorotrifluoroethylene). Thus, after SPE of the complexes of Ag(I), Cd(II) or Cu(II) with bismuthiol II (14) at pH 2 and elution with tetrabutylammonium chloride in acetone, the eluate was directly determined by AAS. Sub ngL concentrations of Ag(I) may be preconcentrated by sorption on finely ground dithizone (12), filtration, dissolution of the dithizone in CHCI3 and end analysis by ET-AAS LOD 1 ngL with no interference by humic acids, fulvic acids or soluble siUca . Ag(I) in river bottom and sea floor was preconcentrated on activated carbon containing dithizone (12), at pH 1.5 a suspension of the carbon was injected into a metal furnace AAS LOD 0.05 pg AgL, for 100 mL samples at SNR 3 . 

Zeeman effect background correction is effective at any wavelength. There are, however, some disadvantages A slight decrease in the sensitivity can be observed (ca. 20 %) and a bending of the calibration curve ( rollover ) is also encountered. 

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