Hydride generator

In this manner an argon flow could be used to strip the generated hydride from solution and carry it out of the top of the cell where it was directed, via a 1mm i.d. xl.5mm o.d. quartz tube, into the sample introduction port of a... 

In general, the complexes shown in Tables 4 and 5 are hydrides or generate hydrides within the reaction medium. Some of these require further discussion since they can take part in cyclic hydrogen production or the catalyst can easily be regenerated from the product of hydrogen production. 

Water Generate hydrides with sodium borohydride, separate hydrides by boiling point... 

The disproportionation of NO into N2O and surface nitrates was investigated for CoO-MgO and NiO-MgO solid solutions by IR and EPR techniques (379). The heterolytic dissociation of H2 on Co2+ and O2 pairs present at edges and steps of CoO-MgO cubes to generate hydride and hydroxyl species has been shown by IR spectroscopy (380). The decomposition of N2O was also investigated (356). 

Addition of protons to anionic clusters to generate hydrides leaves the cluster electron count unaffected, yet the process is sometimes accompanied by structural changes. For example, both [Os6(CO)i8] (87) and [Os6(CO)igH] (88) have octahedral arrangements of metal atoms as predicted by Wade s rules. In the dihydride Osg(CO)i8H2, however, the metal atoms describe a capped square-based pyramid (87). 

Reaction (h) illustrates a limitation of the use of alkoxides for generating hydride ligands. A vacant coordination site must be generated so that the alcohol or alkoxide ion can attack the metal rather than any ligand [such as the hydrogen ligand in Eq. (h) or the carbonyl ligand in Eq. (k) ] subject to nucleophilic attack ... 

Hydride generation is a sample introduction technique exclusively for elements that form volatile hydrides (e.g. As, Se, Sn). An acidified sample solution is reacted with sodium borohydride solution, liberating the gaseous hydride in a gas-liquid separator. The generated hydride is then transported to... 

Blood Mineralize using HN03-HCI04 mixture, generate hydride, and atomize HGAAS 1x1 O 8 g/g No data Clinton 1977... 

NaBHjCN (sodium cyanotrihydroborate), or electrochemical reduction to generate hydrides of As, Se, Bi, Sn, Sb, Ge, and Pb. These are then swept into either a flame directly or into a flame- or electrically heated tube for atomization. Atomization of the gaseous hydrides occurs in argon (or nitrogen)-hydrogen diffusion flame, electrically-heated quartz tube, flame-heated quartz tube (quartz tube atomizers QTA), flame-in-tube (FIT) atomizer or a graphite furnace. Other techniques of chemical vapor generation can be as chlorides, Ni carbonyl, tetramethyl lead or chelates. 

Volatile analytes cryogenically preconcentrated at —78°C on the U trap species identified by retention time matching, elemental isotopic fingerprints, and ion trap MSn analysis Batch HG to generate hydride derivatives cryogenic preconcentration at — 196°C on the U-trap thermally desorbed into an ICP-MS identification of species based on comparison with standards or calculation of boiling point... 

Flush the generated hydrides Into the heated quartz cuvette (1000 °C) with simultaneously generated hydrogen Purge (whole system) with inert gas (approx. 1500 mL/min) 30... 

In addition to these online atomizers, the graphite furnace has also been used in its traditional role as an offline device for the analysis of conventional liquid samples of sequestered hydrides. Aliquots of absorbing solutions used to tap the generated hydrides are injected into the furnace, atomized and quantitated in the usual manner. 

Metalloid compounds are usually determined by flowing-stream techniques hyphenated with hydride generation (HG)-atomic absorption or atomic fluorescence spectrometry. The continuous operation mode inherent to flow injection is specially suited for the latter detection technique as the tetrahyd-roborate reagent is a potential source of hydrogen for supporting the flame. Analyte preconcentration is frequently needed to detect the typical levels of metalloid species found in water matrices. In this context, cold trap collection of generated hydrides, sorbent extraction microcolumn methods, sorption... 

In many other cases, oxidative additions of alkanes occur readily to transition-metal-alkyl complexes to generate hydride dialkyl intermediates that subsequently eliminate alkane and form a new metal-alkyl complex. For example, cations related to the alkyl hydrides of iridium formed by oxidative addition undergo reaction with alkanes at or below room temperature to generate new alkyl complexes (Equation 6.34). Cationic platinum complexes undergo similar reactions with substrates containing aromatic and aliphatic C-H bonds (Equation 6.35). " The C-H activation of the platinum complexes has been studied, in part, to understand and to develop systems related to the ones reported by Shilov that lead to H/D exchange, and oxidation and halogenation of alkanes. 

Building on these results, Hanessian and co-workers devised an efficient protocol for the isomerisation of terminal olefins with minimal self-dimerisation or cross-metathesis by employing methanol to generate hydride complex 33 in situ from its parent 10. The procedure was successfully applied to a variety of allylic compounds, including O- and A-allyl ethers, and cleanly afforded the corresponding propenyl species as EjZ isomeric mixtures, without any further isomerisation or conjugation in the cases of ketones, esters and lactams. 

Vapor Generation Hydride Generation Ouniuin TetTOxide Vapor Cold-Vipor Mercury ... 

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