Atomic absoiption

MDHS 6/3 Lead and inorganic compounds of lead m air (atomic absoiption spectrometry)... 

Cobalt and cobalt compounds in air - Laboratory method using flame atomic absoiption spectrometry... 

Optical-Emission Spectrometer. Similar to flame photometer (atomic-absoiption photometer) except that an electric spark rather than a flame is used to vaporize (atomize) unknown samples. 

Calculated for a 20 kg child. b Analyzed by flame atomic absorption spectroscopy. cAnaIyzed by graphite furnace atomic absoiption spectroscopy. Includes 0.02 mg integumental loss/day. includes 0.03 mg integumental loss/day. Includes 0.01 mg integumental loss/ day. Submitted for publication. 

D2. David, D. J., Determination of zinc and other elements in plants by atomic-absoiption spectroscopy. Analyst 83, 655-661 (1958). 

Electrothermal atomizers, which first appeared on the market in about 1970, generally provide enhanced sensitivity because the entire sample is atomized in a short period and the average residence time of the atoms in the optical path is a second ormore. Also, samples are introduced into a confined-volume furnace, which means that they are not diluted nearly as much as they would be in a plasma or flame. Electrothermal atomizers are used for atomic absoiption and atomic fluorescence measurements but have not been applied generally to emission work. They are, however, used to vaporize samples in inductively coupled plasma emission spectroscopy. 

Atomic absorption spectroscopy (AAS) An analytical method that is based on atomic absoiption. 

Atomic absoiption spectroscopy (AAS) is probably still the most widely employed of all the atomic methods because of its simplicity, effectiveness and relatively low cost. A Tine source of radiation is required for AAS (they do not employ a continuous source of radiation) hence a complete spectrum is not obtained. The sources (which are changed depending on the element of interest) emit certain lines of radiation that have the same wavelength as that of the absorption peak of the analyte of interest. 

Katskov, D. A., Marais, P. J. J. G., and Tittarelli, P., Design, Operation and Analytical Characteristics of the Filter Furnace, a New Atomizer for Electrothermal Atomic Absoiption Spectrometry, Spectrochimica Acta Part B, Vol. 51,1996, pp. 1169-1189. 

Mbileni, C., Ngobeni, P., Katskov, D. A., and Panichev, N., Determination of Lead and Cadmium in Organic Solutions by Electrothermal Atomic Absoiption Spectrometry with a Transverse Heated Filter Atomizer, Journal of Analytical Atomic Spectrometry, Vol. 17, 2002, pp. 236-241. 

Protein, iron catd labile sufiir analysis Protein was quantified by a modified Lowry assay (12) on triplicate samples at 3 different sample amounts. Iron was analyz by atomic absoiption using deuterium arc background correction by the method of standard additions. AU samples for iron analysis were passed over Chelex resin io>Rad) to remove any unbound iron. Labile sulfur analysis was done according to the method of (13) except that CHQ3 was used for extraction of pigment acidification products. 

Atomic absoiption spectrometer with background correction Graphite furnace with autosampler and pyrolytically coated graphite tubes Monoelement aluminum hollow cathode lamp Aluminum standard, 1 g/Iiter (Al metal in 0.3 M HCl)... 

Atomic Absoiption Spectrophotometer (Perkin-Elmer Model 5100)... 

The ciystallisation run was as follows. One litre each of 14.7 g L calcium chloride and sodium sulphate solutions were placed in the crystalliser, the impeller was started and the whole system was left to equilibrate to the designated temperatures of 25, 35, and 45 C. A solution sample (which conesponds to t = 0 or zero time) was taken and prepared for the calculation of calcium ion concentration using atomic absoiption spectrometry (AAS) analysis (as discussed later, the gypsum crystallisation process was followed by measuring the decrease of one of the gypsum crystal components, i.e. the Ca. Eight grams of seed crystals (sized 53 to 90 micron) were added and the timer was started. Samples were taken for AAS analysis at 5,10,15,20, 30,40, 60 and 90 minutes respectively after the seed addition. 

Ogure has described a method for the determination of antimony trioxide in polypropylene powder by extraction with aqueous hydrochloric acid followed by atomic absoiption spectrometry. 

Both atomic and molecular emission and absoiption can be measured when a sample is atomized in a flame. A typical flame-emission spectrum was shown in Figure 24-19. Atomic emissions in this spectrum are made up of narrow lines, such as that for sodium at about 330 nm, potassium at approximately 404 nm, and calcium at 423 nm. Atomic spectra are thus called line spectra. Also present are emission bands that result from excitation of molecular species such as MgOH, MgO, CaOH, and OH. Here, vibrational transitions superimposed on electronic transitions produce... 

In addition, the atoms have large manifolds of excited states which are not present in the molecule. Thus the possibilities for energy absoiption is greater in the atoms, leading to deviations from the Bragg s rale. 

A very widely employed method for the measurement of spin-orbit state-specific rate constants is the time-resolved measurement of the concentrations of individual atomic levels after formation of these species from a suitable precursor, either by flash photolysis [13], or, more recently, by laser photodissociation. The concentrations of the various atomic reactant states are monitored by atomic absorption or fluorescence spectroscopy using atomic emission sources [14], or, for spin-orbit-excited states, by observation of the spontaneous infrared emission [15-18]. Recently, Leone and co-workers have utilized gain/absoiption of a colour centre and diode infrared laser to probe the relative populations of ground and spin-orbit excited halogen atoms produced in a chemical reaction [19] and also by photodissociation [20],... 

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