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Electrochemical enzyme biosensor for gaseous formaldehyde

Title data

Hämmerle, Martin ; Lauterbach, Anja ; Schumacher, Matthias ; Moos, Ralf:
Electrochemical enzyme biosensor for gaseous formaldehyde.
Event: The Eighth World Congress on Biosensors , 24.-26. Mai 2004 , Granada, Spanien.
(Conference item: Conference , Poster )

Abstract in another language

Formaldehyde is an ubiquitous air pollutant in indoor and outdoor atmospheres. Possible sources are disinfectants, paints, resins, particle boards, tobbaco smoke and combustion processes. It is used in large amounts in the plastics manufacturing industry. The German government has set the maximum allowed workspace concentration, MAK-value, to 0.5 ppm (v/v). For non-occupational indoor environments 0.1 ppm (v/v) are recommended. Traditional systems for the determination of formaldehyde in air consist of a sampling step (e.g. washer, adsorber) followed by a quantification step (optical, enzymatic, or titration). There are only few reports where formaldehyde is determined directly in the gas phase in one step. We present an electrochemical enzyme biosensor that can detect gaseous formaldehyde directly without a separate sampling step. NAD-dependent formaldehyde dehydrogenase converts formaldehyde to formic acid. The formed NADH is oxidised by a redox mediator (e.g. naphthoquinone). The latter is electrochemically reoxidised at an electrode (+0.2 V vs. Ag/AgCl). The measured current is related to the formaldehyde concentration in the gas phase. The aqueous phase where these redox reactions take place is separated from the gaseous sample phase by a gas permeable Teflon membrane. The sensor is characterized according to response and performance. For a gas phase concentration of 0.5 ppm (v/v) the current is about 0.9 μA. The detection limit (3 sigma) is about 0.05 ppm (v/v), the response time (t90%) at 0.5 ppm (v/v) is about 6 min. The sensor response is constant during continuous operation at 2 ppm (v/v) for at least 10 h. The life time of the sensor at room temperature and continuous operation is a few days. Additionally, a model of the processes in the sensor is presented. The sensor performance and possible design improvements are discussed according to this model.

Further data

Item Type: Conference item (Poster)
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 > Research Centres > Bayreuth Center for Material Science and Engineering - BayMAT
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited: 29 Jun 2015 11:50
Last Modified: 05 Apr 2016 06:52