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Sensitivity and long-term stability of an amperometric enzyme gas sensor for formaldehyde

Title data

Hämmerle, Martin ; Falkner, Tamara ; Hilgert, Karin ; Achmann, Sabine ; Moos, Ralf:
Sensitivity and long-term stability of an amperometric enzyme gas sensor for formaldehyde.
Event: Biosensors 2010, 20th Anniversary World Congress on Biosensors , 26.-28.05.2010 , Glasgow, UK.
(Conference item: Conference , Other Presentation type)

Abstract in another language

Amperometric enzyme gas sensors can broaden the applicability of chemical gas sensors as they possess the intrinsic possibility to increase the specificity of the sensor based on the substrate specificity of the incorporated enzyme. Various examples of enzyme based gas sensors can be found in the literature and sensors for analytes such as formaldehyde, formic acid, ethanol, phenol, carbon monoxide, choline or sulfur dioxide in air have been reported.

In the present work two sensor characteristics are the focus of the investigation: the sensitivity and the long-term stability, exemplarily for a formaldehyde sensor based on formaldehyde dehydrogenase and electrochemical NADH detection. In previous works, the operation stability of gas sensors for formaldehyde, ethanol, and phenol at permanent exposure to a constant gas concentration was already reported. This protocol represents a high demand for the sensor, which is not necessarily required for practical applications, e.g. when the sensor is used as an alarming device. Thus, in this work the gas exposure protocol was changed in order to investigate the long-term stability over days and weeks when the sensor is only intermittently exposed to the analyte gas. This was realised by integration of the sensor in an automated flow injection system. Furthermore, it is known that the stability of the formaldehyde sensor is limited by the stability of the mediator used for electrochemical NAD recycling. Thus, another system for NAD recycling using diaphorase together with other mediators than formerly used was tested, also in combination with various electrode materials (gold, platinum, carbon).

In order to increase the sensor sensitivity, the enzyme formate dehydrogenase was additionally integrated into the sensor. Formaldehyde is oxidised by formaldehyde dehydrogenase to formic acid, which is further on oxidised by formate dehydrogenase to carbon dioxide. Thus, two moles NADH are produced per mole formaldehyde instead of one using formaldehyde dehydrogenase alone, and accordingly, the sensitivity should be doubled.

Further data

Item Type: Conference item (Other)
Refereed: Yes
Institutions of the University: Faculties > Faculty of Engineering Science
Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos
Faculties > Faculty of Engineering Science > Chair Functional Materials
Profile Fields > Advanced Fields > Advanced Materials
Research Institutions > Central research institutes > Bayreuth Center for Material Science and Engineering - BayMAT
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Central research institutes
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 26 May 2015 11:23
Last Modified: 07 Sep 2023 08:39