title: A biosensor for monitoring formaldehyde using a new lipophilic tetrathiafulvalene-tetracyanoquinodimethane salt and a polyurethane membrane.
abstract: A format for a disposable screen-printed biosensor was investigated for monitoring formaldehyde. The screen-printed sensor format comprised a working electrode (WE) modified with platinised carbon, a new lipophilic tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) salt as mediator, a plasticised polyurethane membrane (TECOFLEX SG80, PU) with anionic sites and the enzyme (formaldehyde dehydrogenase FOH) and co-factor (beta-NAD(+)). The new lipophilic TTF-TCNQ salt gave a smooth, robust electrode surface rather than microcrystalline deposits of the salt observed with TTF-TCNQ salts. Entrapment of the enzyme and co-factor behind a plastcised PU membrane with anionic sites enhanced the sensitivity and stability of the sensor. A linear response between 10(-3) and 10(-4) mol dm(-3) was observed. To demonstrate the feasibility of the use of the screen-printed sensor to monitoring formaldehyde in ambient air, preliminary experiments were carried out in the vicinity of a local medium density fibreboard factory and its performance compared to that of a biosensor made from the same platinised carbon and enzyme system, but without the lipophilic TTF-TCNQ and membrane, using a commercial 'Rank' cell. Samples were collected using a Molspin 'Super-sniffer'.
authors.affiliation: Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK.
authors.forename: R
authors.initials: R
authors.lastname: Kataky
authors.forename: M R
authors.initials: MR
authors.lastname: Bryce
authors.forename: L
authors.initials: L
authors.lastname: Goldenberg
authors.forename: S
authors.initials: S
authors.lastname: Hayes
authors.forename: A
authors.initials: A
authors.lastname: Nowak