Selenium hydride

Hydrogen selenide (selenium hydride), HjSe, and hydrogen telluride (tellurium hydride), HjTe... 

Selenium Conversion of selenium into selenium hydride Selenium hydride swept into quartz tube at 400 °C, analysed by hydride generation Graphite furnace AAS 20 ng/1 [906]... 

Willie et al. [17] used the hydride generation graphite furnace atomic absorption spectrometry technique to determine selenium in saline estuary waters and sea waters. A Pyrex cell was used to generate selenium hydride which was carried to a quartz tube and then a preheated furnace operated at 400 °C. Pyrolytic graphite tubes were used. Selenium could be determined down to 20 ng/1. No interference was found due to, iron copper, nickel, or arsenic. 

Tin, antimony, and selenium hydrides, produced by the borohydride reduction technique, were found to chemiluminesce with ozone in an analytical detection scheme. Limits of detection were 35, 10, and 110 ng of Sn, Sb, and Se,... 

A custom-made Pyrex cell [169] was used to generate selenium hydride. The internal purge gas supply line to the furnace was routed through a stopcock made of Teflon that permitted the operator to select gas flow into either the bottom of the hydride cell or into the furnace, as illustrated in Fig. 12.11. 

Hydride generation AAS is a well-established technique for the determination of selenium because of its selectivity and sensitivity. The detection limits are improved by concentrating the hydride prior to the transfer to the spectrometer. Cryogenic condensation in a U-tube at liquid nitrogen temperature is a preferred method of pre-concentration. However, selenium hydride is formed essentially only from Se. The selectivity for Se has been combined with various chemical preparation steps to determine the sum of SeIV and Se and the total selenium content of samples. Se concentrations are measured by the difference between the (Se + Se ) and Se contents. The difference between total selenium and (Se + Se ) contents represents the concentrations of Se° and Se2- species. These methods have been used for determinations of selenium species in natural waters. Soluble organic matter in some groundwater samples interferes with the hydride generation determination of selenium. Isolation of humic substances by their adsorption on resins has overcome this problem. 

SYNS ELECTRONIC E-2 HTOROGEN SELENIDE, anhydrous pOp SELENIUM HYDRIDE... 

SELENIUM DISULPHIDE (DOT) see SBROOO SELENIUM DUST see SB0500 SELENIUM ELEMENTAL see SB0500 SELENIUM FLUORIDE see SBSOOO SELENIUM HEXAFLUORIDE see SBSOOO SELENIUM HOMOPOLYMER see SB0500 SELENIUM HYDRIDE see HICOOO SELENIUM METAL POWDER, NON-PYROPHORIC (DOT) see SB0500... 

ICP-MS detection of selenium is now favored because of its sensitivity even without HG or other forms of preconcentration. However, selenium can be seriously affected by matrix interferences when using ICP-MS. The polyatomic ArJ, with a mass of 80, overlaps with the most abundant isotope of selenium ( °Se). Even using hydrogen as a collision gas results in the formation of 2-5% of selenium hydride for which a correction must be applied. For routine analysis of selenium, the... 

The catalytic formation of hydrogen has been exploited as a means to reduce substrates by carbon monoxide/water. For example, selenium is converted into selenium hydride, SeH2, in the sequence of eqs. (7a-d) under high-pressure autoclave conditions [13]. 

Properties Black, shiny solid. D 6.8. Almost insoluble in water soluble in hydrochloric acid, evolving selenium hydride. 

Synonyms Registered trade name(s) Elemental selenium selenium base selenium dust colloidal selenium selenium homopolymerb selenium alloy C.l. 77805 VANDEXb Dihydrogen selenide hydrogen selenide [H2Se] selenium anhydride selenium dihydride selenium hydride selane Selenic acid, liquidD0Tb Monohydrated selenium dioxide selenous... 

Nitric-perchloric acid digestion HCI reduction sodium borohydride reduction measure selenium hydride HGAAS No data 33-73% Oster and Prellwitz 1982... 

SeVI to SelV add zinc to the acidified sample pass gaseous selenium hydride to AA hydride 270.3) ... 

SELENIUM HYDRIDE (7783-07-5) Flammable gas. A strong reducing agent. Reacts with moisture, acids, acid fumes, alcohols, evolving heat and flaiiunable hydrogen. Violent reaction with strong oxidizers, nitric acid. Incompatible with acids, alcohols, water, halogenated hydrocarbons. 

SYNONYMS dihydrogen selenide, electronic e-2, hydrogen selenide (anhydrous), selenium dihydride, selenium hydride. 

The introduction of atomic absorption spectrometry in 1955 by Walsh has brought about a preferred analytical technique among clinical chemists in the field of element determinations. Flame atomic absorption atomization techniques with solution aspiration is not sufficiently sensitive (detection limits varies from 0,05-3 mg Se/L for most clinical applications where sub-mg/L concentrations are encountered. The sensivity can, however, be improved by generation of volatile selenium hydride and subsequent atomization in argon-hydrogen flames or electrically heated quartz tubes. Electrothermal atomization of solutions in graphite tubes has developed rapidly since the analytical use was first proposed and studied by L vov (1961). For most clinical chemists this technique may be the most appropriate technique to analyze samples for low concentrations of selenium. 

Synonyms/Trade Names Selenium dihydride, Selenium hydride... 

Hydrogen selenide (selenium hydride) CASRN 7783-07-5 Odiferous colorless gas PEL 0.05 ppm IDLH 1 ppm... 

After a sufficiently large number of collisions with H radicals there is equilibrium between reactions (68), (69), and (70). The probability of the formation of free Se atoms from SeH2 is proportional to the number of collisions with free H radicals and the efficiency of atomization should increase with increasing number of radicals. Analogous conclusions can be drawn for atomization of selenium hydride and other volatile hydrides in hydrogen diffusion flames. 

A modification of the method described in Clesceri et al. (1998) was used to quantify the concentrations of selenite (Se(lV)) in the samples. An aliquot of the filtered sample was reacted with sodium borohydride to distill off any Se(lV) as selenium hydride. The concentration of selenium remaining in solution after the reaction was measured. The difference between original concentration (total dissolved) Se and residual Se in solution is taken as the value for Se(IV). Because of the high concentrations of organo-selenium compounds in the samples, attempts to separate Se(VI) and Se(IV) in the sample by this method (see Clesceri et al., 1998) were not successful. 

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