Influence of water on adsorption of organic compounds from its aqueous solutions on surface of synthetic active carbons

The anticipated diagnosis of various fatal diseases from the analysis of volatile organic compounds (VOC) biomarkers of the volatolome is the object of very dynamic research. Nanocomposite-based quantum resistive vapor sensors (vQRS) exhibit strong advantages in the detection of biomarkers, as they can operate at room temperature with low consumption and sub ppm (part per million) sensitivity. However, to meet this application they need to detect some ppm or less amounts of biomarkers in patients' breath, skin, or urine in complex blends of numerous VOC, most of the time hindered by a huge amount of water molecules. Therefore, it is crucial to analyze the effects of moisture on the chemo-resistive sensing behavior of carbon nanotubes based vQRS. We show that in the presence of water molecules, the sensors cannot detect the right amount of VOC molecules present in their environment. These perturbations of the detection mechanism are found to depend on the chemical interactions between water and other VOC molecules, but also on their competitive absorption on sensors receptive sites, located at the nanojunctions of the conductive architecture. This complex phenomenon studied with down to 12.5 ppm of acetone, ethanol, butanone, toluene, and cyclohexane mixed with 100 ppm of water was worth to investigate in the prospect of future developments of devices analysing real breath samples in which water can reach a concentration of 6%.

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Determination of Oxygen-Containing Organic Compounds in Aqueous Solutions by Vapor-Phase Extraction and Some Thermodynamic Regularities

Journal of Chemical & Engineering Data ◽

10.1021/je700458j ◽

2008 ◽

Vol 53 (4) ◽

pp. 905-909 ◽

Cited By ~ 1

Author(s):

Victor N. Bekhterev

Keyword(s):

Aqueous Solutions ◽

Organic Compounds ◽

Vapor Phase ◽

Phase Extraction ◽

Vapor Phase Extraction

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Steam-carbon gasification catalyzed by calcium: Assessment of the porous structure of active carbons from plum stones and synthetic active carbons

Adsorption ◽

10.1007/bf01650134 ◽

1997 ◽

Vol 3 (3) ◽

pp. 233-242 ◽

Cited By ~ 3

Author(s):

A. Dąbrowski ◽

Z. Fekner ◽

R. Leboda ◽

J. Goworek

Keyword(s):

Porous Structure ◽

Active Carbons ◽

Carbon Gasification ◽

Synthetic Active Carbons

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Some applications of polarography for investigation of equlibria in aqueous solutions of organic compounds

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2009121 ◽

2009 ◽

Vol 74 (11-12) ◽

pp. 1777-1789 ◽

Cited By ~ 2

Author(s):

Petr Zuman

Keyword(s):

Aqueous Solutions ◽

Organic Compounds ◽

Carbonyl Compounds ◽

Limiting Current ◽

Nitroso Compounds ◽

Primary Amines ◽

Acid Base ◽

Fast Reactions ◽

Half Wave

There are two possibilities how to follow equilibria of organic compounds established in aqueous solutions using polarography: for very fast reactions, information can be obtained from shifts of half-wave potentials. For slowly established equilibria, the changes in the limiting current are followed. In both cases variation of the half-wave potentials or limiting currents with concentration of a reactant, present in excess, is followed. The types of reactions, which had been followed in this way, are as follows: hydration–dehydration equilibria, additions of hydroxide ion to carbonyl and nitroso compounds, the role of slowly established acid–base equilibria involving C-acids; further also reactions involving the addition of ammonia, primary amines, hydroxylamine, and hydrazine to carbonyl compounds.

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