On-line detection of atmospheric formaldehyde by a conductometric biosensor.
Atmospheric formaldehyde (CH(2)O) was detected under continuous flow conditions by an on-line system comprising of a wet scrubber for a continuous transfer of the pollutant to an aqueous solution, a micro-reactor containing immobilized formaldehyde dehydrogenase (FDH) and a conductometric transducer. By this system atmospheric formaldehyde concentrations in the range 0.05-2 ppm were detected with a sensitivity of 20 microS/ppm. In this concentration range the immobilized enzyme oxidized all the sampled formaldehyde molecules to formic acid, avoiding cumbersome calibration procedures. The operational stability of the biosensor was at least 3 months, working continuously 10 h/day at room temperature.
Vianello
Fabio
F
Department of Biological Chemistry, University of Padua, Viale G. Colombo 3, 35121 Padova, Italy.
Boscolo-Chio
Raffaella
R
Signorini
Stefano
S
Rigo
Adelio
A