UNISENSE HYDROGEN SENSOR User Manual page 13

magnetic stirring can introduce electrical
noise to the signal . The hydrogen in the
water will slowly escape to the atmosphere
and the concentration can only be
considered constant for a few minutes .
Hydrogen sensors respond linearly in the range of 0 to 100
% hydrogen and signals can be linearly converted to partial
pressure .
Check and repeat calibration at appropriate intervals to
ensure that all measurements can be calibrated to correct
concentrations . When the sensor is new, the appropriate interval
may be every 30 minutes; later it may be 24 hours . To minimize
the need for calibrations, keep the sensor polarized between
measurements, unless the time between measurements exceeds
several days or unless the picoammeter batteries are running out .
The membrane permeability of hydrogen microsensors changes
with time, so a change in signal of up to 50 % may occur over
months .
If the sensor functions according to the above procedure,
the seal and protective plastic tube can be carefully removed
before making measurements.
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