| 1. |
- WHITE, SF, et al.
(author)
-
INVESTIGATIONS OF PLATINIZED AND RHODINIZED CARBON ELECTRODES FOR USE IN GLUCOSE SENSORS
- 1994
-
In: Electroanalysis. - : John Wiley andamp;amp; Sons, Ltd. - 1040-0397 .- 1521-4109. ; 6:8, s. 625-632
-
Journal article (peer-reviewed)abstract
- Graphite electrodes were modified by the electrodeposition of either platinum or rhodium, using cyclic voltammetry. Following only brief periods nf treatment, plantinized carbon electrodes were able to directly oxidize glucose at a potential of +350 mV (vs. Ag/AgCl). By narrowing both the potential range of deposition (-450 to -500 mV) and cycling period (50 seconds at a scan rate of 10 mV s(-1)), the effects of direct glucose oxidation could be significantly: reduced. Detection of H2O2 at +400 mV was possible; glucose enzyme electrodes were constructed, with glucose oxidase immobilized in hydroxyethylcellulose and operated at this potential. These sensors had a linear range of 0.1 to 25 mM glucose and a slope of 8 nA/mM. Other electrodes were prepared by the electrodeposition of rhodium. These base electrodes proved to be insensitive to glucose and produced higher currents (compared to low platinum electrodes) to H2O2. Glucose sensors were constructed using rhodinized electrodes. Again operating at +400 mV, these sensors had a linear range from 0.1 to 20 mM and a slope of 21 nA/mM glucose.
|
|
| 2. |
- WHITE, SF, et al.
(author)
-
LACTATE, GLUTAMATE AND GLUTAMINE BIOSENSORS BASED ON RHODINISED CARBON ELECTRODES
- 1994
-
In: Analytica Chimica Acta. - : Elsevier Science B.V., Amsterdam.. - 0003-2670 .- 1873-4324. ; 295:3, s. 243-251
-
Journal article (peer-reviewed)abstract
- Amperometric enzyme sensors for lactate, glutamate and glutamine were constructed using rhodinised carbon electrodes. All three sensors operated at a potential of +400 mV (Ag/AgCl). Lactate sensors were constructed using lactate oxidase immobilized in hydroxyethylcellulose, overlaid with a cellulose acetate membrane. Using a flow-injection system, the sensors had a linear range of 0.1 to 1.5 mM. Measurements of lactate concentrations from a mammalian cell culture were compared with results obtained from a commercial instrument. A correlation coefficient of r=0.982 (n = 15) was obtained. Glutamate and glutamine sensors were fabricated based on glutaraldehyde immobilization; the former by incorporating glutamate oxidase and the latter based on glutamate oxidase and glutaminase (both had a linear range of 0.1 to 1.5 mM). The feasibility of using these sensors, in conjunction with a previously described glucose sensor, for mammalian cell culture monitoring is discussed
|
|
| 3. |
- WHITE, SF, et al.
(author)
-
ONLINE MONITORING OF GLUCOSE, GLUTAMATE AND GLUTAMINE DURING MAMMALIAN-CELL CULTIVATIONS
- 1995
-
In: Biosensors & bioelectronics. - : Elsevier Science B.V., Amsterdam.. - 0956-5663 .- 1873-4235. ; 10:07-jun, s. 543-551
-
Journal article (peer-reviewed)abstract
- Amperometric biosensors (based on rhodinised carbon electrodes) for glucose, glutamine and glutamate were constructed. The sensors were incorporated into a three cell parallel FIA system and used to monitor the three analytes on-line during two mammalian cell perfusion cultures. All measurements were made simultaneously from undiluted media sample. Use of the FIA system enabled easy and rapid exchange of the sensors, during cultivation. The inclusion of a calibration step, regularly for all sensors, helped to maintain the accuracy of all measurements. Comparison with off-line measurements indicated that all three biosensors operated successfully, providing accurate information.
|
|
