Determination aluminum

Factorial Design in the Optimization of Preconcentration Procedure for Aluminum Determination by AAS... 

Coagulant. Stock solutions were 10"2Af in reagent grade A1(C104)3 and 10-1M in HC104. Aluminum determinations for the standardization of stock solutions were made by alkalimetric titration. The amount of residual dissolved aluminum in adsorption experiments was determined absorptiometrically using aluminon (14). The agreement between both... 

Fuchs C, Brasche M, Paschen K, et al. 1974. [Aluminum determination in serum by flameless atomic absorption]. Clin Chim Acta 52 71-80. (German)... 

Subra J-F, Krari N, Tirot P, et al. 1991. Aluminum determination in the skin of patients with and without end-stage renal failure. Nephron 58 170-173. 

Xie X, Yokel RA, Markesbery WR. 1994. Application of electron energy loss spectroscopy and electron spectroscopic imaging to aluminum determination in biological tissue. Biol Trace Elem Res 40 39-48. 

M. Plessi, A. Monzani, Aluminum determination in bottled mineral waters by electrothermal atomic absorption spectrometry, J. Food Comp. Anal., 8 (1995), 21-26. 

Table 8. Other contamination sources in trace aluminum determination... 

Table 9 summarizes procedures of blood collection for aluminum determination. Steps to avoid contamination, the analytical technique, and the aluminum levels found in the serum of healthy individuals are listed. It can be seen that, as a general procedure, plasticware was used, all materials that entered in contact with the sample were acid-washed, usually by nitric acid, and the analyses were carried out inside clean rooms. 

Domingo et al. [107, 108] used ultrapure nitric acid for sample digestion, performed all specimen manipulation in a laminar flow hood, carried out readings of a blank (reagents only) for each group of samples and, to minimize matrix effects, prepared the standard curves for aluminum determination by the standard addition method. 

Bohrer et al. [93] used microwave heating as an adjuvant to precipitate serum proteins prior to ETAAS aluminum determination. With this procedure, the concentration of TCA necessary to precipitate more than 99% of the proteins could be reduced to 10% of the amount needed without such microwave pretreatment. 

An example of the influence of extraneous aluminum in an in vivo study with animals can be seen in Fig. 16. The graph shows the results of aluminum determination in brain and liver of mice in a study of the effect of aluminum sulfate on delta-aminolevulinate dehydratase from these organs [110], before and after measures to avoid aluminum contamination had been adopted. In a first attempt to check the way to kill the animals and how to digest the samples, the animals were sacrificed with no measures taken to avoid contamination. The results from this experiment, when compared with those after controlling extraneous aluminum as much as possible, show an aluminum level at least 10 times higher. The results also show that, due to the extent and to the randomness of the distribution of the contamination, there are no significant differences between controls and Al-treated animals, when no attempts to avoid contamination are adopted. 

Electrothermal atomic absorption spectrometry (ETAAS) was in the past, and still is in the present, the most useful technique for total aluminum determination in biological samples. The technique is subject to contamination from dust, but by keeping the instrument under laminar flow conditions or setting the sample in the autosampler just before pipetting, contamination may be avoided. In recent years, chromatographic techniques have also been... 

If question 7 in Table 1 was answered ambiguously with a (don t know or don t care), then two answers, which in this case represent two methods, would be left unresolved. The KDS3 system would warn the user that insufficient information was provided to resolve the differences, as seen in Figure 4. Since only one method, either method 13050 or 13053, can be used at any one time this ambiguity would have to be resolved before the other modules in the ACexpert system, or the human technician, could complete the aluminum determination. 

Surface Tension and Viscosity. The surface tension of molten aluminum, determined by the method of maximum bubble pressure, is 0.86 0.2 N/m (860 dyn/cm) in the range of 700—750°C. The viscosity of 99.996% aluminum at these same temperatures is 1-1.2 mPas(= cP). 

Rate of Aluminum-Aluminon Color Development. The preparation of color solution for rate measurement was similar to the procedure for aluminum determination (9), but the following remarks are important ... 

If 2.50 g of aluminum metal is heated in a stream of fluorine gas, it is found that 5.28 g of fluorine will combine with the aluminum. Determine the empiri-cai formula of the compound that results. 

Total parenteral nutrition (TPN) can produce trace metal deficiency associated with different clinical symptoms. Therefore trace metal supplementation (Fe, Cu, Zn, Se, Cr, Mo, Mn) in TPN solutions is necessary to disclose complications [59]. In addition, hemodialysis treatment influences trace metal metabolism and may derange trace metal balance (Zn, Cu, Se, and Mg). Complications in hemodialysis caused by aluminum treatment to prevent hyperphosphatemia include dialysis encephalopathy, osteomalacia, and anemia. Aluminum determination in blood serum is one of most important tests in therapy monitoring [60]. 

Several authors have proposed graphite furnace AAS (GFAAS) methods for the determination of aluminum in biological materials [28,32,34-36]. These methods have improved considerably the aluminum determination in biological body fluids they were critically reviewed by Savory and Wills [19] and Taylor and Walker [22]. In the authors laboratories the following detailed working procedures are used for the determination of aluminum in plasma/serum or urine [37]. 

Interlaboratory intercomparison programs including the aluminum determination in urine and serum are provided from the German Society of Occupational Medicine and the Centre de Toxicologic du Quebec, Canada and others [41-43]. 

At this pH value, Tiron reacts only with aluminum and iron(III), hence this method for aluminum determination is very selective. The only disadvantage is the comparatively low extinction coefficient, e = 6000 L/(mol cm), of the resulting complex at 310 nm. A corresponding standard chromatogram of the separation of aluminum is illustrated in Figure 4.71 (see Section 4.5.3). 

Fluorimetric SIA system for aluminum determination. HC holding coil, RC reaction coil, SV selection valve. 

As example, Figure 5.18 shows an SIA system with a fluorimetric detector for the determination of aluminum with sodium 8-hydroxyquinoline sulfate [7]. Another example is an in-syringe dispersive liquid—liquid microextraction system for aluminum determination in seawater exploiting a special designed fluorescence detector and flow cell [8]. The detection cell comprised a glass mbe of 3 mm... 

The aluminum foil on a certain roll has a total area of 18.5 m and a mass of 1275 g. Using a density of 2.7 g per cubic centimeter for aluminum, determine the thickness in millimeters of the aluminum foil. 

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