Development of highly selective and stable potentiometric sensors for formaldehyde determination.
Two types of biosensors selective to formaldehyde have been developed on the basis of pH-sensitive field effect transistor as a transducer. Highly or partially purified alcohol oxidase (AOX) and the permeabilised cells of methylotrophic yeast Hansenula polymorpha (as a source of AOX) have been used as sensitive elements. The response time in steady-state measurement mode is in the range of 10-60 s for the enzyme-based sensors and 60-120 s for the cell-based sensor. When measured in kinetic mode the response time of all biosensors developed was less than 5 s. The linear dynamic range of the sensor output signals corresponds to 5-200 mM formaldehyde for highly and partially purified alcohol oxidase, and 5-50 mM formaldehyde for the cells. The operational stability of the biosensors is not less than 7 h, and the relative standard deviation of intra-sensor response is approximately 2 and 5% for the enzyme- and cell-based sensors, respectively. When stored at 4 degrees C, the enzyme and cell sensor responses have been found stable for more than 60 and 30 days, respectively. Both types of biosensors demonstrate a high selectivity to formaldehyde with no potentiometric response to primary alcohols, including methanol, or glycerol and glucose. The possible reasons of such unexpected high selectivity of AOX-based FET-sensors to formaldehyde are discussed. The influence of the biomembrane composition and the effect of different buffers on the sensor response to formaldehyde are also discussed.
Korpan
Y I
YI
Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv. ya_korpan@yahoo.com
Gonchar
M V
MV
Sibirny
A A
AA
Martelet
C
C
El'skaya
A V
AV
Gibson
T D
TD
Soldatkin
A P
AP
D000429:Alcohol Oxidoreductases / Q000378:metabolism; D015374:Biosensing Techniques; D002138:Calibration; D005557:Formaldehyde / Q000032:analysis*; D011199:Potentiometry
D005557:Formaldehyde; D000429:Alcohol Oxidoreductases; C019643:alcohol oxidase