AAS Measurements

When the AAS measurements have been completed, aspirate de-ionised water for several minutes to ensure thorough cleaning of the nebuliser-burner system. 

In a recently published study MiUer et al. describe similar phenomena in which XPS and AA measurements prove the incorporation of cations during the discharging of PPy. 

Haslam et al. [32] reported the determination of Al in polyolefins by AAS. Typical AAS tests on rubber compounds involve several steps. The sample is combusted, and the resulting ash is dissolved in distilled de-ionised water. The solution is then used for AAS [126]. AAS or EDS can also be used for element analysis of filler particles. In order to determine the uniformity of tin compounds in polychloroprene after milling and pressing, Hornsby et al. [127] have ashed various pieces from one composition. After fusion of the residue with sodium peroxide and dissolution in HC1, the Sn content was determined by means of AAS. Typical industrial AAS measurements concern the determination of Ca in Ca stearate, Zn in Zn stearate, Ca- and Zn stearate in PE, Ca and Ti in PE film or Al and V in rubbers. 

AAS measures a photon absorbed when a ground state atom is excited... 

AAS measures the discrete radiation absorbed when ground state atoms are excited to higher energy levels by the absorption of a photon of energy. The radiant power of the absorbed radiation is related to the absorption coefficient of the ground state atoms using the... 

Both AES and AAS can be used to Identify and quantify the elements present In a sample. AES measures the radiation emitted when excited electrons fall back to lower energy states. AAS measures the absorbed radiation needed to promote eiectrons to higher energy ieveis. 

Cesium can be analyzed by various instrumental techniques including atomic absorption and atomic emission spectrophotometry and various x-ray methods. The most sensitive wavelength for AA measurement is 852.1 nm. It imparts a reddish violet color to flame. It is identified by specific line spectra having two bright lines in the blue region and several other lines in the red, yellow, and green. 

The element may be analyzed in aqueous acidified phase by flame and furnace atomic absorption, ICP emission and ICP-MS spectroscopic methods. Also, at trace concentrations the element may be measured by x-ray fluorescence and neutron activation analysis. Wavelength for AA measurement is 240.7 nm and for ICP analysis is 228.62 nm. 

Silver metal and its contents in silver alloys and salts can be measured at trace levels by various instrumental techniques such as flame- and furnace-AA, ICP-AES, ICP/MS and x-ray fluorescence methods. It is solubilized by digestion with nitric acid prior to analysis. The AA measurement may be carried out at the wavelength 328.1 nm and ICP analysis at 328.07 nm. ICP/MS is the most sensitive technique while x-ray fluorescence is relatively less sen-... 

Tin can be measured readily at trace concentrations in aqueous solutions by flame or furnace atomic absorption spectrophotometry. For flame AA measurement, air-acetylene flame is suitable. The metal can be identified accurately at 224.6 nm. Tin also can be measured by other instrumental techniques such as ICP-AES, ICP/MS and neutron activation analysis. 

Zinc in trace amounts may be measured in solutions by flame-and fumace-AA, ICP-AES, and ICP/MS methods. It also can be identified by x-ray fluorescence and neutron activation analysis. Flame-AA measurement is done at 213.9nm using an air-acetylene flame. The ICP-AES measurement may be done at 213.86 nm or 206.20nm or alternative wavelengths. ICP/MS is the most sensitive method. 

Figure 1. Effect of initial sulfuric acid concentration on ferric ion yield (AA), measured after irradiating of standard ferrous-cupric dosimeter to approximately 400,000 rads...

Neon Lines That Must Be Resolved for Accurate AAS Measurements... 

Alpdogan and Sungur [50] developed an indirect atomic absorption spectroscopy method for the determination of mefenamic and flufenamic acids, and diclofenac sodium, based on the complexation with copper (II) amine sulfate. The complex was extracted into chloroform, and the concentrations of substances were determined indirectly by AAS measurement of copper after re-extraction into 0.3 N nitric acid solution. The developed method was applied to the assay of the substances in commercial tablet formulations. The results were statistically compared with those obtained by HPLC method by t- and F tests at 95% confidence level. Calculated t and F values were both lower than the table values. 

Calibration curves are based on AES or AAS measurements on at least five (preferably six) standards. The calibration curve, relating the average AES or AAS reading to concentration, is graphed either manually or by a suitable computer program. 

VIII. DETERMINATION OF SILICON BY AAS A. Procedure for sample decomposition and AAS measurement... 

FIG. 22. a) Calculated free (thick curve) and screened R= 9.3 a.u. thin curve) response oscillator strength distributions with a linewidth parameters F = 0.06 H. b) Experimental oscillator strength distribution aa measured by Burose et al. [175]. 

The contribution of the variance of the atomic absorption analysis to the total variance was calculated from duplicate AA analyses of the same extract, usually at the beginning and end of a series of AA measurements of a single metal. The variance of the AA method and the variance of all other factors, including the extraction itself, were calculated and are presented in Table VIII. It can be observed that the contribution to the total variance by the AA measurement is substantial for Cd, Ni, Pb, and Zn. The relative standard deviation from other sources, including the extraction technique itself, contamination, and variation between sup-... 

This e cpresslon Is useful since It contains measurable true and apparent absorbances (At and Aa) measurable volume fractions, V and only one unknown, the size parameter, Z. Some typical computational re-stilts are shown in Figure 6 where Aa/At values are plotted versus the size parameter, Z. Note that Aa approaches At for very large Z s, i.e., molecular dispersion. 

Monaghan MS, Olsen KM, Ackerman BH, Fuller GL, Porter WH, Pappas AA, Measurement of serum iso-propanol and the acetone metabolite by proton nuclear magnetic resonance application to pharmacokinetic evaluation in a simulated overdose model,... 

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