Mechanism of Volatile Hydride Formation and Their Atomization in Hydride Generation Atomic Absorption Spectrometry

Kumar, A. Ramesh; Riyazuddin, P.

doi:10.2116/analsci.21.1401

Cited by 38 publications

(5 citation statements)

References 161 publications

(171 reference statements)

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“…However, if the organoarsenical content is obligatory, a post-column reactor is essential to convert these compounds to hydride-forming species in a process that involves UV photolysis in the presence of an oxidant, which converts benign arsenic species, such as AsC and AsB, to As V before HG. , Cysteine is used to reduce As V to As III before the formation of arsine (AsH 3 ) . Kumar et al proposed that the As–cysteine complexes, where oxygen is replaced by a thioalkyl (SR) group, readily react with less sterically hindered BH – compared to As III . Cysteine permits lower acid concentrations to be used to obtain the same response for As III , As V , MMA, and DMA.…”

Section: Detection Techniquesmentioning

confidence: 99%

Analytical Methodologies for the Determination of Organoarsenicals in Edible Marine Species: A Review

Luvonga

Rimmer

et al. 2020

J. Agric. Food Chem.

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Setting regulatory limits for arsenic in food is complicated, owing to the enormous diversity of arsenic metabolism in humans, lack of knowledge about the toxicity of these chemicals, and lack of accurate arsenic speciation data on foodstuffs. Identification and quantification of the toxic arsenic compounds are imperative to understanding the risk associated with exposure to arsenic from dietary intake, which, in turn, underscores the need for speciation analysis of the food. Arsenic speciation in seafood is challenging, owing to its existence in myriads of chemical forms and oxidation states. Interconversions occurring between chemical forms, matrix complexity, lack of standards and certified reference materials, and lack of widely accepted measurement protocols present additional challenges. This review covers the current analytical techniques for diverse arsenic species. The requirement for high-quality arsenic speciation data that is essential for establishing legislation and setting regulatory limits for arsenic in food is explored.

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Section: Detection Techniquesmentioning

confidence: 99%

Analytical Methodologies for the Determination of Organoarsenicals in Edible Marine Species: A Review

Luvonga

Rimmer

et al. 2020

J. Agric. Food Chem.

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“…The arsenic hydride atomization in a heated quartz cell working at 1000˚K is presented in this section; the aim is to speculate the formation and the distribution of the produced free arsenic species through the examined atomizer. It is worth noting that the atomization of volatile hydride forming elements in a heated quartz cell has been described according to the following mechanism [13]:…”

Section: Study Of the Atomization Of Arsenic Hydride And The Distribumentioning

confidence: 99%

“…The decomposition of THB has been referred to be a second order reaction that might be last for few microseconds [1], whereas the generation and transfer of the hydrides from the liquid phase to the gaseous phase were considered to be a first order reaction [10]. On the other hand, the atomization process of the hydride has also been studied by many researchers [11][12][13][14] which raised several perspectives about the appropriate consistent mechanism. The general opinion supports the atomization by a thermal decomposition such as the case of electro-thermal atomization in a heated quartz tube.…”

Section: Introductionmentioning

confidence: 99%

“…Generally speaking, the hydrogen radicals are found to be the most effective factor on the atomization process. Moreover, the oxygen radicals are also found to be an important factor, in which the hydride decomposition would occur in the presence of oxygen radicals alone; nevertheless, no atomization could be achieved with temperatures below 1700˚C [13]. Furthermore, the OH radicals which accompany the hydrogen radical formation are reported to play a powerful catalytic role on the hydride generation process.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the inlet stream velocity was assumed to be 0.084 m/sec. The hydride molecule dissociation into the free atoms was considered to be an exothermic reaction accompanied by elaborating (-189 kJ/mol) [13]. This value has been adopted in this study in order to consider the effect of the generated heat.…”

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Computational Modelling of the Hydride Generation Reaction in a Tubular Reactor and Atomization in a Quartz Cell Atomizer

Abdul‐Majeed¹,

Zimmerman²

2012

JASMI

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In this study, we present a model whereby the centre of the atomization channel is shown to be the optimal location for the spectrometric data acquisition in a quartz cell atomizer. The study aims to explore the hydride generation technique which is normally coupled with efficient thermal source to apply determination of heavy metals in water samples via spectrometric analysis. The arsenic hydride generation process and the atomization of the generated hydride in a quartz cell atomizer were studied analytically as model case studies. The hydride generation (HG) process was analyzed by adopting two hypotheses, the nascent hydrogen and formation of intermediate hydroboron species, where the results based on the second hypothesis are found to be more realistic for design purposes. Moreover, the release of the generated hydride from the liquid phase and their transport to the gas phase is simulated in a helical tubular section, in which the actual tubular section length required for separation is deduced. The analytical results have been verified experimentally by measuring the signal intensity for the free arsenic atoms against several reaction tube lengths, in which increasing the tubular section length from 12 cm to 100 cm results in signal amelioration by no more than 6.6%. Furthermore, the atomization of the hydride and the distribution of the generated free atoms are deduced in two configurations of tubular quartz atomizers. The results obtained from both studied cases illustrate that a high concentration of the free analyte atoms is generated in the first part of the atomization channel, saturates to a maximum in a position at the atomizer centre, and dissipates at the inside wall of the tubular atomizer before reaching the atomizer outlet edge, which is found to be in total agreement with the current understanding of atomization mechanism in tubular atomizer and emphasizes the fact that the centre of the quartz cell atomizer is the best location for the spectrometric data acquisition

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Instrumentation

Iacobucci¹,

Suder²,

Bodzoń‐Kułakowska³

et al. 2019

Mass Spectrometry

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Mechanism of Volatile Hydride Formation and Their Atomization in Hydride Generation Atomic Absorption Spectrometry

Cited by 38 publications

References 161 publications

Analytical Methodologies for the Determination of Organoarsenicals in Edible Marine Species: A Review

Analytical Methodologies for the Determination of Organoarsenicals in Edible Marine Species: A Review

Computational Modelling of the Hydride Generation Reaction in a Tubular Reactor and Atomization in a Quartz Cell Atomizer

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