Sensitivity atomic absorption spectroscopy

Bromo-2-pyridyla2o)-5-diethylamiQophenol (5-Br-PADAP) is a very sensitive reagent for certain metals and methods for cobalt have been developed (23). Nitroso-naphthol is an effective precipitant for cobalt(III) and is used in its gravimetric determination (24,25). Atomic absorption spectroscopy (26,27), x-ray fluorescence, polarography, and atomic emission spectroscopy are specific and sensitive methods for trace level cobalt analysis (see... 

Colorimetric procedures are often used to determine copper in trace amounts. Extraction of copper using diethyldithiocarbamate can be quite selective (60,62), but the method using dithhone is preferred because of its greater sensitivity and selectivity (50—52). Atomic absorption spectroscopy, atomic emission spectroscopy, x-ray fluorescence, and polargraphy are specific and sensitive methods for the deterrnination of trace level copper. 

Atomic absorption spectroscopy of VPD solutions (VPD-AAS) and instrumental neutron activation analysis (INAA) offer similar detection limits for metallic impurities with silicon substrates. The main advantage of TXRF, compared to VPD-AAS, is its multielement capability AAS is a sequential technique that requires a specific lamp to detect each element. Furthermore, the problem of blank values is of little importance with TXRF because no handling of the analytical solution is involved. On the other hand, adequately sensitive detection of sodium is possible only by using VPD-AAS. INAA is basically a bulk analysis technique, while TXRF is sensitive only to the surface. In addition, TXRF is fast, with an typical analysis time of 1000 s turn-around times for INAA are on the order of weeks. Gallium arsenide surfaces can be analyzed neither by AAS nor by INAA. 

Analysis of Corexit 9527. Corexit 9527 in natural waters can be analyzed. The method is based on the formation of a Z>w(ethylenediamine) copper(II) complex, extraction of the complex into methylisobutylketone, and atomic absorption spectroscopy [1564]. The method is suitable for a concentration range of 2 to 100 mg/liter, with a precision as low as 5% relative to standard deviation for samples in the middle- to high range. Only a small sample volume (10 ml) is required. The sensitivity may be substantially increased for trace analysis by increasing the sample volume. 

Over thirty different elements have been determined in medical and biological materials by atomic absorption spectroscopy. The popularity of the technique is due to a number of factors, including sensitivity, selectivity, and ease of sample preparation. With biological fluids, often no preparation at all is required. The techniques employed usually involve simple dilution of the sample with water or with an appropriate reagent to eliminate interference. Alternatively, the element to be determined is separated by solvent extraction. Either an untreated sample, a protein free filtrate, or an ashed sample is extracted. 

McCracken et al. 164) compared atomic absorption with the tetraphenyl-boron method for determining potassium in 1190 fertilizers, and very close agreement was found between the two methods. Hoover and Reagor 16S) also found good agreement between the two methods, and atomic absorption was far more rapid. They reported that the 7665 A potassium line was more subject to interference than the less sensitive 4044 A line. Temperli and Misteli 166> reported far better results for low concentrations of potassium in soil extracts by atomic absorption spectroscopy than by flame emission spectroscopy. 

High-performance liquid chromatography coupled with fluorescence detection [106, 107] or ion-exchange high-performance liquid chromatography with detection by graphite furnace atomic absorption spectroscopy [108] proved to be sensitive methods, but may lack from limitations in separation power and ease of identification of unknown products. 

The atomic absorption characteristics of technetium have been investigated with a technetium hollow-cathode lamp as a spectral line source. The sensitivity for technetium in aqueous solution is 3.0 /ig/ml in a fuel-rich acetylene-air flame for the unresolved 2614.23-2615.87 A doublet under the optimum operating conditions. Only calcium, strontium, and barium cause severe technetium absorption suppression. Cationic interferences are eliminated by adding aluminum to the test solutions. The atomic absorption spectroscopy can be applied to the determination of technetium in uranium and its alloys and also successfully to the analysis of multicomponent samples. 

Analysis. Atomic absorption, emission, and mass spectrographic separation are the most sensitive methods for the analysis of Si. Electrothermal atomization-atomic absorption spectroscopy ETAAS has a sensitivity of 10 ppb, ICPAES 1 ppb, and ICPMS 10 ppb. Colorimetric agents permit spectrometric analysis down to about 10 ppb. 

During in vivo studies under biologically relevant conditions, the cis-Pt loading of the DNA is much lower than for the above-mentioned in vitro studies. It has been calculated that mortality of HeLa cells occurs at an value of 10 5 (i.e., one bound cis-Pt molecule per 105 nucleotides) (64a). This excludes atomic absorption spectroscopy for identification of the in vivo adducts. Immunochemical techniques, however, have shown to be very promising, and high sensitivity and selectivity levels have been reached. At the moment, only a few studies in which antibodies are raised against cis-Pt-treated DNA (64) or against synthetic cis-Pt adducts with mono- or dinucleotides are available (64a). With the latter method, quantitation of the different platinum-DNA adducts formed under in vivo conditions is possible. At the moment, femtomole (10-15 mol) amounts of the adducts can be detected with competitive enzyme-linked immunosorbent assay (ELISA) techniques. It has been demonstrated in this manner that the GG-Pt adduct is also the predominant adduct under in vivo conditions. 

Atomic absorption spectroscopy is likewise a relatively new technique but one which has developed rapidly and for which a considerable choice of commercial equipment is available (12, 13). In this technique, the samples are vaporized in a flame, and the absorption of monochromatic light beamed through the flame from an external source is used to measure concentration. The sensitivity for many elements is excellent, and good quantitative results can be obtained. For a number of elements... 

Howlett and Taylor (1978) used an atomic absorption spectroscopy fitted with a micro-cup assembly (MCAAS) for determining silver levels in human whole blood. The MCAAS technique affords a rapid, precise, and relatively simple method for the measurement of silver in blood. Furthermore, this technique requires no sample preparation prior to analysis except pipetting and drying. A detection limit level of 0.27 pg/100 ml of blood sample was measured. Flowlett and Taylor (1978) noted that repeated measurement of silver in blood using a single nickel cup showed a gradual decrease in sensitivity. 

Ramirez-Munoz, J., N. Shifrin, and A. Hell Quantitative Sensitivity in Atomic-Absorption Spectroscopy. Microchem. J. 11, 204 (1966). 

Atomic Absorption Spectroscopy. One of the more sensitive instruments used to detect metal-containing toxicants is the AA spectrophotometer. Samples are vaporized either by aspiration into an acetylene flame or by carbon rod atomization in a graphite cup or tube (flameless AA). The atomic vapor formed contains free atoms of an element in their ground state, and when illuminated by a light source that radiates light of a... 

Me tals and metallic compounds are among the toxic substances most often found in workplace environments (1,2), Industrial hygienists and hygiene chemists must accurately determine the presence and amount of toxic metals and their compounds in the industrial environment. Accurate methods for the quantification of metals in biological and atmospheric samples are required for the industrial hygienist to properly evaluate the environment. Atomic absorption spectroscopy (AAS) has been the primary method of analysis for toxic metals because AAS is sensitive, specific, and rapid especially compared to colorimetric analysis. 

Thirty-two sherds representing five different examples of Kayenta Anasazi Pueblo II pottery (Tusayan Corrugated [TC], Medicine Black-on-Red [MB], Tusayan Black-on-Red [TB], Dogoszhi Black-on-White [DB], and Sosi Black-on-White [SB]) have been analyzed for the elements As, Ba, Co, Cr, Cm, Fe, Mn, Ni, Pb, Se, V, and Zn by using the techniques of flame atomic absorption spectroscopy (.FAA) and electrothermal atomic absorption spectroscopy (ETAA). Analytical procedures for the chemical analysis of ceramics afford accuracy and sensitivity and require only a modest capital investment for instrumentation. The sherd samples were collected at two sites, one in southern Utah (Navajo Mountain [NM]) and the second in northern Arizona (Klethla Valley [KV]). These sites are approximately 60 km apart. Statistical treatment of the data shows that only three clay types were used in the 32 sherds analyzed, and that only three elements (Fe, Pb, and Ni) are necessary to account for 100% of the dispersion observed within this sample set. 

The technique can be used with or without a flame. In the flameless technique several variations are possible, including a graphite furnace or cold vapour, all of which are more sensitive than flame photometry. Further details on atomic absorption spectroscopy are given in Chapter 27. 

Barrier-layer cells and photomultipher tubes have both been used for photodetection in atomic absorption spectroscopy. The use of barrier-layer cells of course is limited by their sensitivity and the diflBculty encountered in amplifying their output. They will suflBce where determination of the alkali elements is desired only. For most other work photomultiplier tubes are necessary. These are available for a broad spectral... 

While industrial or agricultural chemists for the most part have large samples available for analysis, the clinical chemist is faced with an ever increasing number of tests to be performed on a small single sample, for instance a few milliliters of serum. The sample size in atomic absorption spectroscopy depends on necessary sample dilutions, aspiration rate, and time of aspiration required to obtain one reading. These are a function of sensitivity and instrumental stability. Since a few seconds (usually 10-30) of sample aspiration suffice for one reading, the total... 

In the following subsections the application of atomic absorption spectroscopy to the determination of the more important elements of biological and clinical interest is presented, and special problems and interferences encountered with individual elements are discussed in detail. The resonance lines given at the beginning of each subsection are those showing greatest absorption, although many elements possess several resonance lines that can be used in analysis. The sensitivity limits quoted are the lowest reported in the literature, usually defined as that concentration of the test element in aqueous solution which produces 1% absorption. The reproducibility of results by most atomic absorption techniques lies... 

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