Designing an amperometric thick-film microbial BOD sensor.
Thick film oxygen electrodes manufactured by screen print method have been used as a transducer for a biochemical oxygen demand (BOD) sensor. The kinetics of the immobilized yeast, Arxula adeninivorans (Arxula) has been studied. The apparent KM of immobilized Arxula (> 100 microM) is higher than free cells of Arxula (70 microM). The increase in KM caused by the effect of immobilization extends the linear range of the sensor. End-point measurement and quasi-kinetic measurement have been studied comparatively as measurement procedures with a good correlation. The Vmax for end-point measurement is 790.7 microM/s and that for quasi-kinetic measurement is 537.3 microM/s. The limit of detection is calculated 1.24 mg/l BOD. Using the quasi-kinetic measurement, instead of end-point measurements, the measuring time can be reduced from 5-30 min to 100 s. The sensor layer thickness or increase in the layer of covering gel can increase the KM that is accompanied with the extension of the linear range of the sensor. Nevertheless, increase in the layer of covering gel will not increase the saturation signal. Domestic wastewater was checked by the thick film BOD sensor and the results are satisfactory.
Chan
C
C
Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon.
Lehmann
M
M
Chan
K
K
Chan
P
P
Chan
C
C
Gruendig
B
B
Kunze
G
G
Renneberg
R
R
D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D015374:Biosensing Techniques; D005782:Gels; D010101:Oxygen Consumption; D012680:Sensitivity and Specificity; D012722:Sewage; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015003:Yeasts / Q000378:metabolism
D005782:Gels; D012722:Sewage; D014874:Water Pollutants, Chemical