ETAAS background correction

Ag, At, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn ETAAS Metals are measured by ETAAS using the manufacturer s recommended conditions and an injection volume of 20 pL Applicable to surface, ground, tap, and waste water. A high CE concentration interferes. To minimize the matrix effect, the chemical modification, standard addition method, and background correction systems may be used. 105... 

ETAAS using deuterium as background correction was not considered to be suitable for the determination of Co since the absorption line of this element is close to the end of the deuterium continuum. A general remark was that AAS showed poor agreement for Co in this material. INAA and ICP-MS proved to be better suited for certification in this instance. 

The techniques of final determination are summarised in Table 11.1. Sample pretreatment methods were e.g. dry ashing or pressurised digestion with combination of acids. Techniques such as ICP-AES or ETAAS with Zeeman background correction were not yet popular at the time of the certification campaign [8]. 

ZETAAS ETAAS with Zeeman background correction... 

Analytical Methods and Speclatlon Electrothermal atomic absorption spectrophotometry (ETAAS), differential pulse adsorption voltammetry (DPAV), isotope-dilution mass spectrometry (ID-MS), and inductively coupled plasma mass spectrometry (ICP-MS) furnish the requisite sensitivity for measurements of nickel concentrations in biological, technical and environmental samples (Aggarwal et al. 1989, Case et al. 2001, Stoeppler and Ostapczuk 1992, Templeton 1994, Todorovska et al. 2002, Vaughan and Templeton 1990, Welz and Sperling 1999). The detection limits for nickel determinations by ETAAS analysis with Zeeman background correction are approximately 0.45 jg for urine,... 

Wood tissue Cu Fe Mn Slurry preparation with three different reagents [SP] Hot injection slurry introduction into GFA, modifiers and Zeeman background correction [ETAAS] [SP-ETAAS] Ehsan and Marshall (2001)... 

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)... 

Direct measurements of several trace metals by electrothermal atomic absorption spectrometry (ETAAS) have been reported. In general, sensitivities are inadequate for open-ocean waters, though in more metal-enriched environments (e.g., coastal waters and sediment pore waters) such analysis is possible careful corrections for the large and complex salt effects are necessary. The interferences can be minimized by the use of appropriate chemical modifiers, platforms in the graphite tubes, and sophisticated background correction schemes such as Zeeman. 

Urine chromium determined by ETAAS with Zeeman background correction and standard addition procedure outlined in this section has a reported detection limit of 0.1 p.g/liter. This is an outline of the method of Fleischer [46]. The reference provides detailed directions for this analysis. 

AAS is the most widely used analytical technique for the determination of lead in biological materials [57,58], The majority of AAS methods employ the electrothermal atomic absorption spectrometry (ETAAS) technique, using either Zeeman background correction or deuterium background correction for the determination of lead in biological fluids [55,59-65], Urine is less often employed as an indicator of exposure however, similar problems associated with AAS determination of lead exist for blood as well as urine (1) incomplete atomization (2) volatile lead salts (3) spectral interferences (4) buildup of carbonaceous residue reducing sensitivity and precision. These analytical problems are eliminated by optimal sample preparation, e,g., dilution, addition of matrix modifiers, deproteinization, and background correction and calibration by matrix-matched standards [66],... 

Background correction. Nowadays all ETAAS instruments are equipped with facilities for background correction. However, in many cases little attention is paid to whether the system actually corrects properly for background or not. Results for the analysis of two standards, containing the same concentration of analyte but with one also containing a potential spectral interference, should be compared. 

ETAAS. In ETAAS atomization takes place in an electrothermal atomizer which is heated to the appropriate temperature programme. The detection limits of the method are about two or three orders of magnitude better than FAAS. It is applicable to about 40 elements but generally for about 20 elements detection limits at the ng and pg level can be reached. Commensurable or better sensitivities have only INAA, ICP-MS and stripping voltammetry. Therefore ETAAS is widely used for environmental analysis. However the method suffers from serious interferences leading to systematic errors due to thermochemical processes in the atomizer. Background absorption is also a potential source for systematic errors. Spectral interferences are additive and cannot be corrected by the popular standard addition method. ETAAS is also not free of memory effects for refractory elements. 

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