PASCO PS-2108 Dissolved Oxygen Sensor - Manual (Page 2)

Calibration with DataStudio Software
Setup and Calibration
Equilibrate the Probe in 100% Humidified Air:
1. Before performing any calibration, place 5 mL of deionized water into a clean
electrode storage bottle.
2. Loosen the lid to the electrode storage bottle. Insert the probe into the
electrode storage bottle and screw on the lid. Place the end of the probe
about 2 cm above the water (See Figure 1).
3. Vigorously shake the electrode storage bottle for about 10 seconds to saturate
the water. Shake off any large water drops from the membrane.
For a percent (%) saturation calibration:
1. Put the Dissolved Oxygen Sensor in water that is 100% oxygen saturated
(See the section above).
2. In DataStudio, click the Setup button to open the PASPORT Setup
window.
3. In the Setup window, click on the pull down menu to ensure the percent (%)
saturation unit is selected from the Dissolved Oxygen Sensor options.
4. Click the Calibrate button. The default is 100% saturation. When
the Calibration window opens, the current value displays under Dissolved
Oxygen.
5. When the current value settles, click the Set and OK buttons.
Note: For a mg/L calibration, see our web site (www.pasco.com) for documentation on
our Dissolved Oxygen sensors and/or contact PASCO’s Technical Support Dept.
Calibration with a PASPORT Xplorer
Check for large
water drops.
Shake bottle vigorously for
about 10 seconds.
Figure 1
CARD 2A
You can calibrate the Dissolved Oxygen in the field or connected to DataStudio.
For a percent (%) saturation calibration:
1. Turn on the Xplorer.
2. Plug the sensor into the Xplorer.
3. Press the Display button until “Calibrate” appears on the screen.
4. Press the Plus (+) button and select % as the measurement unit.
5. Put the Dissolved Oxygen Sensor in water that is 100% oxygen saturated.
6. Check the Xplorer display. When the % value displayed settles, press the
Check button.
7. Quickly press the Check button again to accept the new calibration.
8. To exit calibration mode, press the Display button.
Note: To calibrate in mg/L instead of %, see our web site for documentation on our
dissolved oxygen sensors and/or contact PASCO’s Technical Support Dept.
Equipment required: 1 PASPORT Dissolved Oxygen Sensor (PS-2108), 1 electrode
storage bottle (included with sensor), DataStudio software (version 1.5.3 or higher) or a
PASPORT Xplorer (PS-2000), and deionized water. [(Optional): Barometer (PS-2113)
and Temperature Sensor (PS-2125) for performing calibrations at a specific barometric
pressure and temperature.]
(Note: After plugging in the Dissolved Oxygen Sensor, you must allow 2 minutes for the
sensor to come to equilibrium.)
electrode
cable
012-07688C
• Always change the filling solution before calibrating the Dissolved Oxygen
sensor or when taking your first set of measurements with the sensor.
• For best results, always stir the solution before taking measurements. When
using the Dissolved Oxygen Sensor, it is important to move a steady flow of
test solution past the sensor’s membrane: while measuring, the sensor uses
up 0
2
molecules faster than they can diffuse back into the area. Use a
magnetic stir bar if available.
• Avoid placing the sensor in acidic or caustic solutions, or vapors. The sensor
was designed for use in aqueous solutions. Placing the sensor in caustic,
abrasive, or harsh solutions may damage the membrane and/or probe.
• When taking measurements, do not drag the probe or allow the membrane to
touch the bottom of a container or body of water. The membrane is fragile
and may become damaged or pop out with mishandling.
• We do not recommend using the the Dissolved Oxygen Sensor in
environments with rapidly changing temperature conditions. The sensor is
temperature-compensated, but large temperature changes may give false
readings.
• Avoid using the sensor in solutions with high salinity, such as ocean water.
Factors that may affect dissolved oxygen measurements include atmospheric
pressure, atmospheric temperature, air density, altitude, and the salinity in the
sample.
If you plan to take quantitative dissolved oxygen measurements in mg/L
instead of percent saturation, calibrate the sensor in mg/L units. A mg/L
calibration requires that you mathematically adjust for atmospheric pressure,
atmospheric temperature, and altitude. (Note: The percent saturation
measurement is recommended for comparative studies or when examining
relative changes in dissolved oxygen concentration.)
Calibration tables for mg/L units of dissolved oxygen can be found in the
following reference: Hitchman, Michael L. 1978. Measurement of Dissolved
Oxygen. In
Chemical Analysis, volume 49, edited by Elving and Winefordner,
196-199, New York: John Wiley and Sons, Inc.
CARD 2B Sensor Usage Tips - Please Read!
Factors Affecting Dissolved O
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Results