Calibration; Temperature; Dissolved Oxygen - VWR DO220 Manuel D'instructions

record. All records after the deleted record will shift up to keep the
records in sequential order. For example, if record 3 is deleted, record
4 will become record 3 and record 5 will become record 4. Press Mode
twice to return to the measurement mode.

Calibration

Temperature

All VWR DO220 cables have a built-in thermistor. Temperature calibration
is not available or required. To verify the temperature sensor, compare it
to a NIST traceable thermistor by touching the thermistors together and
observing the measurements.

Dissolved Oxygen

The DO220 sensor is an optical luminescent sensor which has greater
stability and is less susceptible to calibration drift than traditional
electrochemical sensors. This increased stability means the instrument
can hold its calibration for many months; however, calibration should be
verified regularly for highest data accuracy.
To verify the instrument's calibration, place the sensor in its calibration
environment and check to see that the DO% is reading its calibration
value based on the barometric pressure. Refer to Appendix A for the
DO% calibration values based on barometric pressure.
Calibration Requirements:
• The approximate true barometric pressure (in millibars [mbars]) of
the location at the time of calibration.
[Corrected BP mmHg] – [2.5 * (Local Altitude in ft. above sea level/100)]
• The approximate salinity of the water to be analyzed. Fresh water's
salinity value is approximate zero parts per thousand (ppt). Seawater
has an approximate salinity of 35 ppt.
1. Moisten the sponge in the gray storage sleeve with a small amount of
clean water. The moistened sponge creates a 100% water-saturated
air environment for the probe, which is ideal for calibration, transport,
and storage of the VWR DO220 probe.
2. Make sure there are no water droplets on the sensor cap or
temperature sensor and then install the storage sleeve over the
guarded probe. Make sure the DO and temperature sensors are
not touching the sponge or immersed in water. Turn the instrument
on and wait approximately 5 to 10 minutes for the storage sleeve
True Barometric Pressure (mmHg) =
mBar = mmHg *1.333
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