Sartorius BioPAT Trace - Dialysis Mode: Referencing at the Beginning; Of a Fermentation; Dialysis Mode: Referencing at Low Lactate; Concentrations

BioPAT
®
Trace | Multi Trace Operating Instructions 111
Operation
8.5.2 Dialysis Mode: Referencing at the Beginning of a Fermentation
It is crucial to perform reference measurements when using the dialysis
method to compare the permeability of the membranes inside the reactor
and outside the diffusion cell as well as to compensate for temperature
differences between both membranes. Thus, reliable determination of the
reference factor is very important for the quality of the measured values.
It is therefore recommended that you determine the reference value as soon
as possible at the start of the cultivation and do so in a phase without fluctua-
tions in the concentration of the medium. For this purpose, deactivate
auto-calibration and then set the measuring interval to 1. Afterwards, track
some measured values. If they do not spread too widely and are as constant
as possible, you can trigger reference measurement. Once the reference
measurements are completed, you should wait for some measurements and
check if the recalculated values meet your expectations. If necessary, you can
also repeat the reference measurement. As soon as you are satisfied with the
result, you can readjust the measurement parameters and start with the
cultivation.
8.5.3 Dialysis Mode: Referencing at Low Lactate Concentrations
In many cases, there is a surplus in glucose and the medium is (still) lactate-
free at the start of a cultivation. When performing reference measurements,
the BioPAT
®
Trace | Multi Trace suggests a value once the reference
measurement is completed. This value is usually overwritten by entering the
known value (known due to the media composition or determined with an
external analyzer). If the available lactate concentration is still very low, do not
yet overwrite this value (the reference factor for lactate is still 1.0). During the
course of the cultivation, the increase in lactate concentration can now be
observed more easily. In due course, a standard reference measurement
overwriting both values can be performed.