PASCO PS-2108 Dissolved Oxygen Sensor - Manual (Page 8)

PASPort Dissolved Oxygen Sensor Model No. PS-2108
4 ®
Equilibrate the Probe in 100% Humidified Air
1. Place about 5 mL (to a height of about 1 cm) of deionized
water into a clean soaker bottle. Slip the cap and O-ring of the
soaker bottle over the end of the probe.
2. Insert the probe into the soaker bottle and screw on the lid.
Adjust the height of the end of the probe to about 2 cm above
the top of the water (Figure 4).
3. Shake the soaker bottle vigorously for about 10 seconds.
Shake off any large water drops from the membrane.
Perform a Single-point Calibration (mg/l Dissolved O
2
)
1. Obtain current barometric pressure and temperature readings
for your location. You can use the PAPSPORT Barometer (PS-
2113) and Temperature Sensor (PS-2131), or the PASPORT Weather Sensor (PS-2154) to
take the necessary measurements.
2. Refer to the Solubility table 1 in Appendix C and find the appropriate dissolved oxygen
value for the temperature and barometric pressure at your location.
Example: At a temperature of 25ºC and a barometric pressure of 760 MM. Hg, 8.2 mg of oxygen will
dissolve in one liter of water at 100% saturation.
3. In DataStudio, click the Setup button on the toolbar. Make sure mg/L is selected next to
the Calibrate… button in the Dissolved Oxygen Sensor dialog.
4. With the DO
2
sensor equilibrated as described above, click the Calibrate… button.
5. Refer to the tables for the value of mg/l dissolved O
2
in saturated water at the temperature
and uncorrected barometric pressure at which you are measuring. (If you do not know the
barometric pressure, assume that it is 760 mm Hg.) Enter the value in the mg/l box. Click
OK.
Setup to Calibrate in Percent (%) Saturation
1. (DataStudio only) Click the Setup button on the DataStudio toolbar. Click the mg/L button
next to the Calibrate… button and select % from the drop-down menu
Note: Always calibrate the probe before measuring absolute (rather than relative) concentrations. Calibrate at or
close to the temperature and barometric pressure at which the test solution is to be measured.-
Note: Percent (%) saturation output is valid only at the temperature and barometric pressure at which the probe is
calibrated.
Note: Before taking measurements of dissolved oxygen (DO) concentration (rather than % saturation), change
Water level
Shake
vigorously
Soaker
Bottle
Figure 4
To equilibrate the probe, insert the
end of the probe into a clean soaker
bottle containing ~5 mL of deionized
water. Shake the probe vigorously for
about 10 Sec.