Biopolymers and cell. 2005; 21 (5): 425 - 432

Enzymatic conductometric sensor for formaldehyde detection in model samples

O. O. Soldatkin, O. F. Sosovskaya, I. V. Benilova, M. V. Gonchar, Y. I. Korpan

Thin-film planar electrodes and formaldehyde dehydrogenase from Pseudomonas putida have been used for the development of formaldehyde-sensitive enzyme conductometric biosensor. A new approach to create a biologically active sensor membrane has been proposed. This approach allows to detect formaldehyde concentration without usage of exogenous NAD in the analyzed sample since the biomembrane contains NAD at high concentration (100 mM). Moreover, because of this the formaldehyde concentration can be measured many times with the same transducer without NAD regeneration. The time of formaldehyde analysis in the solution is no longer than 2 min and 10 s in steady-state and kinetic modes of the biosensor signal measuring, respectively. The linear dynamic range of the sensor output signals corresponds to 1-50 mM formaldehyde concentration. The optimal values of pH, buffer capacity and ionic strength have been determined. Operational stability, storage stability and selectivity of the developed conductometric biosensor have also been analyzed.

Key words: biosensor, formaldehyde dehydrogenase, conductometry.