Absorption thallium

The attenuated total reflectance (ATR) technique is used commonly in the near-infrared for obtaining absorption spectra of thin Aims and opaque materials. The sample, of refractive index i, is placed in direct contact with a material which is transparent in the region of interest, such as thallium bromide/thallium iodide (known as KRS-5), silver chloride or germanium, of relatively high refractive index so that Then, as Figure 3.f8... 

A variety of therapies for thallium poisoning have been suggested by neutralising thallium in the intestinal tract, hastening excretion after resorption, or decreasing absorption. Berlin-Blue (fertihexacyanate) and sodium iodide in a 1 wt % solution have been recommended. Forced diuresis hemoperfusion and hemodialysis in combination results in the elimination of up to 40% of the resorbed thaHous sulfate (39). 

Kubaslk, N. P. and Volosln, M. T. "A Simplified Determination of Urinary Cadmium, Lead, and Thallium, with Use of Carbon Rod Atomization and Atomic Absorption Spectrophotometry . Clin. Chem. (1973), 19, 954-958. 

Machata, G. and Binder, R. "The Determination of Lead, Thallium, Zinc and Cadmium Traces in Biological Material with Flameless Atomic Absorption". Z. Rechtsmed. (1973),... 

Berndt et al. [740] have shown that traces of bismuth, cadmium, copper, cobalt, indium, nickel, lead, thallium, and zinc could be separated from samples of seawater, mineral water, and drinking water by complexation with the ammonium salt of pyrrolidine- 1-dithiocarboxylic acid, followed by filtration through a filter covered with a layer of active carbon. Sample volumes could range from 100 ml to 10 litres. The elements were dissolved in nitric acid and then determined by atomic absorption or inductively coupled plasma optical emission spectrometry. 

As discussed above, the measurement of characteristic y rays is very similar to the methods used in EDXRF. Early studies used a scintillation counter, typically a crystal of sodium iodide containing a small amount of thallium (Tite 1972). y ray absorption by these counters produces visible light, which is converted into an electrical pulse using a photosensitive detector. More recently semiconductor detectors have been used, either a lithium drifted germanium crystal, or, more typically, a pure ( intrinsic )... 

Actually the reaction of the dimer [Fe(bd bpza)Cl]2 (5) with thallium benzoylformate results in the purple benzoylformato complex [Fe(bd bpza)(02CC(0)Ph)] (6). The purple color is caused by a visible absorption at 544 nm (Fig. 8). 

The 2003 ACGIH threshold limit valuetime-weighted average (TLV-TWA) for thallium and soluble compounds is O.lmg/m , as Tl, with a notation for skin absorption. 

Of the above three s ions, most data have been obtained for Pb . The reason is that this ion gives the best Sq -> Pj absorption spectrum the bismuth(III) spectral band tends to be somewhat broad (see above) and the thallium (I) band often has a shoulder, or even consists of two distinct maxima, an effect which has been attributed possibly to the Jahn-TeUer effect in the excited state (75). From Eq. (2) and data in... 

Although both SH transients in Fig. 5.21 fall to a minimum at about the same time, their form is quite different and qualitative comparisons are useful. The isotropic contribution, /pp(/), decays as a single exponential, in agreement with previous measurements of submonolayer thallium deposition on polycrystalline electrodes [54]. The solid line in Fig. 5.21 a is an exponential fit with r = 10.7 msec. The exponential form suggests that the deposition occurs by an absorption, rather than a nucleation, mechanism [154]. The transient anisotropic response is not as simple. In fact, the initial fall in /ps( ) in Fig. 5.21 b is not a simple decaying exponential. The differing time dependencies for the isotropic and anisotropic responses suggests that f, the bulk anisotropic susceptibility element which is the only common element, is not the main source of the nonlinear response in either case. 

In an interlab oratory study involving 160 accredited hazardous materials laboratories reported by Kimbrough and Wakakuwa [28], each laboratory performed a mineral acid digestion on five soils spiked with arsenic, cadmium, molybdenum, selenium and thallium. Analysis of extracts was carried out by atomic emission spectrometry, inductively-coupled plasma mass spectrometry, flame atomic absorption spectrometry and hydride generation atomic absorption spectrometry. 

Atomic absorption spectrometry has been used to determine thallium in soil [220]. This element has also been determined in multi-metal mixtures by emission spectrometry (Sect. 2.55). 

Lopez Garcia et al., [24] suspended soil samples in water containing 5% (v/v) concentrated hydrofluoric acid before injection into an electrothermal atomic absorption spectrophotometric system. No modifier other than the hydrofluoric acid was required for the determination of lead, cadmium and thallium. 

Its absorption spectrum shows one band at 320 nm (e = 2900 M 1cm 1), assigned to the cti - ct2 transition localized in the Au-Tl moiety. The emission spectrum in the solid state at 77 K shows a band at 602 nm, which is attributable to a transition between orbitals that appear as a result of the metal-metal interaction. In this sense, Fenske-Hall molecular orbital calculations indicate that the ground state is the result of the mixing of the empty 6s and 6pz orbitals of gold(I) with the filled 6,v and the empty 6pz orbitals of thallium(I). In frozen solution, this derivative shows a shift of the emission to 536 nm, which has been explained by a higher aggregation of [AuT1(MTP)2] units in the solid state if compared to the situation in solution. 

The availability of strongly chelating extractant reagents for a number of metals has lead to the development of procedures in which the metal is extracted from minimally treated blood or urine and then quantified by atomic absorption analysis. The metals for which such extractions can be used include cobalt, lead, and thallium extracted into organic solvent as the dithiocarbamate chelate, and nickel extracted into methylisobutyl ketone as a chelate formed with ammonium pyrro-lidinedithiocarbamate. 

A. F. Silva, D. L. G. Borges, B. Welz, M. G. R. Vale, M. M. Silva, A. Klassen, U. Heitmann, Method development for the determination of thallium in coal using solid sampling graphite furnace atomic absorption spectrometry with continuum source, high-resolution monochromator and CCD array detector, Spectrochim. Acta, 59B (2004), 841. 

J. Cvetkovic, S. Arpadjan, I. Karadjova, T. Stafilov, Determination of thallium in wine by electrothermal atomic absorption spectrometry after extraction preconcentration, Spectrochim. Acta, 57B (2002), 1101-1106. 

Organic compoimds that contain nitrogen in a hmctional groi shoitid not be used with plates whidi are made of thallium bromide and thallium iodide (KRS-5 plates) as they pereact with the plates. Despite these disadvantages, the tedmique is still a most usefiti one for solid ugs. The advalkali halide is very low and the quantity of compound required is small. The disks can easily be stored for reference puqx>ses or the compound can be recovered if required. 

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