The HBOD Probe uses a fluorescence method to
measure the concentration of oxygen in the headspace of an HBOD test
tube. The system is based on an optical fiber that illuminates a
special thin-film coating at the end of the probe with blue light.
The coating fluoresces and is quenched in proportion to the
concentration of oxygen in the sample, and this signal is measured
using separate optical cable. The device is a low-power system that
is resistant to most interferences and is quite stable. Ordinarily,
the tubes must be kept in the dark during sampling (using a special
container drilled to fit the tubes). However, the probe can be made
to work in ambient light. However, this increases the response time
to one to two minutes (versus only seconds in the dark).
The HBOD probe specificiations:
Range: 0-100% oxygen in gas phase.
Response time: Uncoated tip: <1 s
Coated: 60-90 seconds
Interferences: None (from CH4, acetone, moisture, or CO2)
Resolution: 0.1% at high O2
0.01% at low concentration
Calibration: 2-point calibration (air; oxygen-free air)
Stability: <0.05% per day
Re-calibration: Beginning of a new HBOD Probe test
Probe temperature range: -80° C to +110° C
Storage conditions: no specific requirements
Probe lifetime: 1 year (reconditioning available)
- HBOD Probe and Software:
- Air Gage (to measure pressure, temperature and relative
- HBOD Tubes, tops, and crimper.
- Zero-air calibration tube
- Shaker table