MI-730 Micro-Oxygen Electrode (Dip-type)
MI-730 Micro-Oxygen Electrode (Dip-type)
The MI-730 Micro-Oxygen electrode features negligible oxygen consumption, fast response and requires less than a drop. Each electrode is supplied with 6 assembled membranes and a bottle of electrolyte solution.
SPECIFICATIONS
TOTAL LENGTH
8.6 cm LEAD LENGTH
2 m
BODY (Outer Diameter)
3 mm
TIP (Outer Diameter)
3 mm
RESPONSE TIME:
less than 20 seconds
DEPTH of IMMERSION:
0.1 mm
SENSITIVITY:
1700 pA in air at 25 C
TEMPERATURE RANGE:
-5°C to 100° C
REFERENCE ELECTRODES
TYPE: Solution & Electrode
3M KCI & Ag-AgCI
CALIBRATION
Calibration of the electrode requires the use of two standard gases with percent values that are close to the percent values of Oxygen to be measured. Common values used are 0% Oxygen for zeroing and 21% Oxygen (Ambient Air) for sloping or gain.
A. Calibration for gas samples:
When samples to be measured are gaseous, then calibration should be performed with humidified gases. Two possible setups for calibrating the electrode are shown below. Keep the tip of the electrode as far as possible from the surface of the water. The bubbling rate of the gas should be slow (3 - 6 bubbles per second). Although bubbling at a faster rate will flush the chamber more quickly, it will also cause a cooling effect on the electrode.
1. Bubble the 0% gas through the chamber and adjust the zero of the meter after a stable reading is obtained. It may take up to 15 minutes to de-gas the chamber of contaminants, however bubbling the gas vigorously will cause droplets to collect on the tip of the electrode. This will make the electrode response time appear to be slow.
2. Bubble the 21% gas (or any other percent value you decided to use for your application) through the chamber until a stable reading is obtained. Adjust the calibration control to 21%.
This procedure of alternating between the two gases should be continued until you become confident of stability and reproducibility. The electrode is now ready to use.
B. Calibration for liquid samples
To decrease calibration time, two separate calibration chambers should be used. One for the 0% gas and another for the sloping gas such as 21%. When setting up the calibration chambers initially, it will take up to 30 minutes to flush each chamber to obtain a steady state oxygen level and a constant temperature. Again the bubbling rate should be carefully regulated (3 - 6 bubbles per second) so that both calibrating liquids are at the same temperature.
Calibrating standards and samples must be at the same temperature for accurate Oxygen measurements.
1. Immerse the tip of the electrode into the 0% standard and adjust the zero of the meter after a stable reading is obtained.
2. Remove the electrode from the first standard and place it into the second standard. Adjust the calibration control to the value of the second standard (ex: 21%)
Alternate between the two standards until you become confident of stability and reproducibility. The electrode is now ready to use.
CLEANING
Using any electrode in solutions containing protein requires the electrode be rinsed with an enzyme cleaning solution.
After each use, we recommend cleaning our electrodes with Terg-a-zyme (Alconox, Inc.) or a chromic/sulfuric acid glass cleaning solution by submerging the electrodes for a couple of minutes in order to remove all protein from the glass and reference junction.
This will prolong the useful life of the electrodes.
STORAGE
Always clean the microelectrode before storing:
- Long-term (over 2 weeks): Return the probe to its original container and prepare it in the same condition in which you received it. Usually this means simply moistening the sponge located in the bottom of the protective glass tube with pH 4 buffer.
- Short-term: The probe can be left in an acid pH buffer solution (pH 4.01).