Minifors 2 - Benchtop Bioreactor
Setup and Function
Page
38
of
214
07 February 2019
These approaches can also be combined.
pO
2
reduction
In anaerobic processes, the vessel can be gassed using nitrogen.
This displaces the oxygen dissolved in the medium.
3.8.1 Measurement System
The pO
2
measurement system is designed for use with HAMILTON
digital sensors:
pO
2
sensor with built-in opto-electronics
Type: Visiferm DO ARC
Manufacturer: HAMILTON
INFORMATION
The HAMILTON pO
2
sensors are pre-configured by the equip-
ment manufacturer, INFORS HT. Replacement sensors must be
configured before use.
For details on the technical data, maintenance and storage require-
ments for the pO
2
sensors, see the separate documentation pro-
vided by the sensor manufacturer. Read and follow the instruc-
tions.
Generally speaking, the following applies: Unlike measurements
such as pH, which are calibrated to absolute measurement values,
the oxygen measurement is always calibrated to a relative refer-
ence point. For this purpose, the calibration is set to 100 % relative
oxygen saturation, usually with air at max. stirring speed and maxi-
mum gas flow rate. The actual concentration of dissolved oxygen
in mmol/L may therefore vary at 100 % saturation, depending on
the process.
Calibration is always carried out
AFTER
autoclaving. This is done
using the operating panel. Depending on the specifications defined
by the user, the pO
2
sensor will be calibrated either before the ves-
sel is filled with medium or afterwards, in the prepared medium.
For more details on this procedure refer to main chapter “Opera-
tion”, chapter “Calibrating the pO
2
Sensor”.
For culture vessels with nominal widths of 90 and 145, pO
2
sen-
sors can be mounted directly into 12 mm/Pg13.5 ports. For culture
vessels with a nominal width of 115, an electrode holder is used.
