61
SECTION 7,
continued
Sampling and Storage
Collect samples in 300 mL glass BOD bottles. Fill completely.
Analyze immediately.
Accuracy Check
Checking Calibration Accuracy
Return the electrode to the calibration and storage chamber. The
chamber should contain a wet sponge or a small amount of water.
Allow at least 10 minutes for stabilization. Enter the current
barometric pressure and altitude into the meter according to
Sections 3.1.5 and 3.1.6. The meter should display
100%
saturation
. If not, recalibrate the meter.
Method Performance
Precision
In a single lab using one sample at 7.45 mg/L DO and one sample
at 5.10 mg/L DO, the electrode was moved between the two
samples with no rinsing in between. A single operator with a
single sens
ion
8 meter obtained a standard deviation of
0.03 mg/L DO.
Table 5 Adjusting Barometric Pressure and Altitude
Enter a new barometric pressure when the barometric pressure or the altitude of the instrument
changes using one of the methods below:
Using Sea Level Equivalent
Using True Barometric Pressure
1.
Obtain the sea level equivalent barometric
pressure from TV, radio, or a local airport.
1.
Obtain the true barometric pressure from a
nearby mercury barometer or use
2.
Enter this value into the meter according to
Section 3.1.5 Changing the Barometric
Pressure.
2.
Enter this value into the meter according to
Section 3.1.5 Changing the Barometric
Pressure.
3.
Enter the local altitude according to
Section
3.
Enter the altitude as
0
feet or meters
according to
Section 3.1.6 Adjusting the
