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Appendix D
Calculating Drift Per Sensor
Drift differs depending on the sensor formulation (FOXY, FOSPOR or HIOXY). See the table and
example below.
Stability (Continuous LED):
Lifetime Stability
(Tau):
Example: Calculate drift for a FOXY sensor probe while measuring a sample every 2.5 hours for 100
hours with the LED being lit for 1 minute:
New drift = reported drift * duty cycle on / duty cycle off
New drift = 0.01%/hr * (1 min / (2.5 hr*60 min/hr)) 2.5 * 60 converts hours into minutes,
so as to cancel out the dimensions
New drift = 0.01%/hr *(1 min/150 min)
New drift = 0.01%/hr * (.0066)
New drift = 0.000066 %/ hr
To run the experiment for 100 hours:
New drift = 0.000066%/hr * 100 hrs
New drift = 0.006%