Flame atomic absorption analysis

Hobbins reported the following calibration data for the flame atomic absorption analysis for phosphorus. ... 

Experiment 29 Quantitative Flame Atomic Absorption Analysis of a Prepared Sample... 

The ASTM-EFA standard method of analyzing lead In gasoline requires extraction of alkyl lead Iodide complexes Into methyllsobutylketone and a subsequent flame atomic absorption analysis of the extract A more direct method has been proposed ( ) which uses Zeeman atomic absorption analysis after sample dilution. Both methods were used to analyze a set of five field collected samples. The results showed a bias (average difference between method results) of 0.0012 g/gal with the standard flame results higher. The correlation coefficient between the results was 0.9998 0.0009, and a pairwise t-test showed no difference between the methods (6). 

Tin is usually determined as the total metal, but it may also be measured as specific organotin compounds. Flame atomic absorption analysis is the most widely used and straightforward method for determining tin furnace atomic absorption analysis is used for very low analyte levels and inductively coupled plasma atomic emission analysis is used for multianalyte analyses that include tin. 

Recommended Wavelength, Flame Type, and Technique for Flame Atomic Absorption Analysis... 

The types of separation procedure described elsewhere in this book for the improvement of sensitivity and for matrix separation in flame atomic absorption analysis can, in principle, be employed for the same purposes before electrothermal atomisation. 

Carbonell, V., de la Guardia, M., Salvador, A., Burguera, J.L., Burguera, M. On-line microwave oven digestion flame atomic absorption analysis of solid samples. Anal. Chim. Acta 238, 417 21 (1990)... 

Table VI. Analysis of the Variation of Metal Emissions during a 24-hr Period by Flame Atomic Absorption Analysis (ng/va )...

Although the co-precipitation method was initially conceived with large volume extraction coupled with flame atomic absorption analysis in mind, its utihty may prove to lie in other areas. In particular, the introduction of improved fiameless atomizers will allow the determination of trace metals using much smaller sample volumes. We have combined pre-concentration by this method on 100 ml samples with use of a Perkin-Elmer HGA-2100 graphite furnace for the analysis of copper. 

The reference materials for calibration of the spectrophotometer for flame atomic absorption analysis were prepared from the copper standard solution by its dilution with nitric acid 1% solu-... 

Results of the analysis (C) are presented in Table 1. Usually the display of the Perkin-Elmer 5000 instrument in flame atomic absorption analysis is autozeroed for the blank solution. For this reason the values read visually from the display and those stored by GIRAF differ by the value of the blank, a fact that has no influence on the results of the analysis. The uncertainties of the results (U) are shown in Table 1 also. The uncertainties of the calculated analyte concentrations in the test solutions UtT described in the Reference materials section are approximately one third of the corresponding uncertainties of the results of the analysis (for sodium it is not obvious because of rounding), and so the use of the term true values in the context of the validation is permissible. All these data were used for calculation of the acceptance criteria A and B formulated in the Validation plan (see Table 2). The criteria are satisfied for both graphite furnace and flame analysis. 

In AAS, FIA has been applied to hydride generation and cold vapour techniques, microsampling for flame atomic absorption, analysis of concentrated solutions, addition of buffers and matrix modifiers, dilution by mixing or dispersion, calibration methods, online separation of the matrix and analyte enrichment, and indirect AAS determinations. 

Under the usual conditions, the relative error associated with a flame atomic absorption analysis is of the order of 1% to 2%. With special precautions, this figure can be lowered to a few tenths of a percent. Errors encountered with electrothermal atomization usually exceed those for flame atomization by a factor of. 3 to 10. 

Atomic absorption using either flame or electrothermal atomization is widely used for the analysis of trace metals in a variety of sample matrices. Using the atomic absorption analysis for zinc as an example, procedures have been developed for its determination in samples as diverse as water and wastewater, air, blood, urine, muscle... 

ASTM. 1998a. ASTME1613. Standard test method for analysis of digested samples for lead by inductively coupled plasma atomic emission spectrometry (ICP-AES). Flame Atomic Absorption (FAAS), or Graphite Furnace Atomic Absorption (GFAA) Techniques. American Society for Testing and Materials. 

Olsen et al. [660] used a simple flow injection system, the FIAstar unit, to inject samples of seawater into a flame atomic absorption instrument, allowing the determination of cadmium, lead, copper, and zinc at the parts per million level at a rate of 180-250 samples per hour. Further, online flow injection analysis preconcentration methods were developed using a microcolumn of Chelex 100 resin, allowing the determination of lead at concentrations as low as 10 pg/1, and of cadmium and zinc at 1 pg/1. The sampling rate was between 30 and 60 samples per hour, and the readout was available within 60-100 seconds after sample injection. The sampling frequency depended on the preconcentration required. 

Fang et al. [661] have described a flow injection system with online ion exchange preconcentration on dual columns for the determination of trace amounts of heavy metal at pg/1 and sub-pg/1 levels by flame atomic absorption spectrometry (Fig. 5.17). The degree of preconcentration ranges from a factor of 50 to 105 for different elements, at a sampling frequency of 60 samples per hour. The detection limits for copper, zinc, lead, and cadmium are 0.07, 0.03, 0.5, and 0.05 pg/1, respectively. Relative standard deviations are 1.2-3.2% at pg/1 levels. The behaviour of the various chelating exchangers used was studied with respect to their preconcentration characteristics, with special emphasis on interferences encountered in the analysis of seawater. 

Cabezon et al. [662] simultaneously separated copper, cadmium, and cobalt from seawater by coflotation with octadecylamine and ferric hydroxide as collectors prior to analysis of these elements by flame atomic absorption spectrometry. The substrates were dissolved in an acidified mixture of ethanol, water, and methyl isobutyl ketone to increase the sensitivity of the determination of these elements by flame atomic absorption spectrophotometry. The results were compared with those of the usual ammonium pyrrolidine dithiocarbamate/methyl isobutyl ketone extraction method. While the mean recoveries were lower, they were nevertheless considered satisfactory. 

Limit of detection The method you choose must be able to detect the analyte at a concentration relevant to the problem. If the Co level of interest to the Bulging Drums was between 1 and 10 parts per trillion, would flame atomic absorption spectroscopy be the best method to use As you consider methods and published detection limits (LOD), remember that the LOD definition is the analyte concentration producing a signal that is three times the noise level of the blank, i.e., a S/N of 3. For real-world analysis, you will need to be at a level well above the LOD. Keep in mind that the LOD for the overall analytical method is often very different than the LOD for the instrumental analysis. 

Quantitative analysis in flame atomic absorption spectroscopy utilizes Beer s law. The standard curve is a Beer s law plot, a plot of absorbance vs. concentration. The usual procedure, as with other quantitative instrumental methods, is to prepare a series of standard solutions over a concentration range suitable for the samples being analyzed, i.e., such that the expected sample concentrations are within the range established by the standards. The standards and the samples are then aspirated into the flame and the absorbances read from the instrument The Beer s law plot will reveal the useful linear range and the concentrations of the sample solutions. In addition, information on useful linear ranges is often available for individual elements and instrument conditions from manufacturers and other literature. 

A number of applications of flow-injection techniques have been made to flame atomic absorption spectrometry [22]. Although manifolds can be connected directly to the nebuhzer, the response of the spectrometer is dependent on the flow rate of the sample into the nebuhzer [23], and some adjustment to the manifold may be required. The optimum flow rate for maximum response when the sample enters the nebuhzer as a discrete sample plug can be different from that found for analysis of a continuous sample stream. 

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