Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Reviews
Mechanism of Volatile Hydride Formation and Their Atomization in Hydride Generation Atomic Absorption Spectrometry
A. RAMESH KUMARP. RIYAZUDDIN
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2005 Volume 21 Issue 12 Pages 1401-1410

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Abstract

The mechanism of volatile hydride generation (HG) and the formation of analyte atoms in the quartz cell atomizer used in the determination of hydride-forming elements (As, Bi, Ge, Pb, Sb, Sn, Te etc.) by atomic absorption spectrometry (AAS), have been critically reviewed. The nascent hydrogen mechanism failed to explain hydride generation under different experimental conditions when tetrahydroborate (THB), amineboreanes (AB) and cyanotrihydroborate (CBH) were used as reductants. Various experimental evidence suggested a non-nascent hydrogen mechanism, in which the transfer of hydrogen directly bonded to boron to an analyte takes place. In electrochemical hydride generation (EcHG), the reduction of the analyte species and subsequent hydrogenation was proposed. The mechanism of analyte atom formation in a quartz tube atomizer has been explained by the following hypotheses: thermal decomposition, oxidation by O2 and collisions by hydrogen free radicals. The free-radical mechanism satisfactorily explains most of the analytical implications. The significant variation in the experimental conditions required to generate different analyte hydrides makes it difficult to arrive at a generalized mechanism of hydride formation.

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© 2005 by The Japan Society for Analytical Chemistry
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