BioPAT
®
 Trace | Multi Trace Operating Instructions   79
  Operation 
8.1.4  Single Sample
This function can be used for a spontaneous unscheduled single point mea-
surement at a selected port (Multi Trace). This function is especially useful 
during long intervals, when for instance an actual value of a certain reactor is 
wanted. By this option, the running program does not need to be interrupted 
and the planned intervals remain unchanged.
The “Single Sample” command is only triggered, if there is enough available 
time for the measurement.
8.2  Reference (for Dialysis only)
A reference measurement must be performed to compare the permeability of 
the two diusion membranes in the diusion cell (which is only allowed 
contact with calibration solutions) and in the dialysis probe (which only has 
contact with the reactor contents). The relationship of the two membranes to 
one another is expressed by a reference factor used for calculating the 
measured values. 
You can conduct a reference measurement whenever you want, in particular 
when changes occur in the process that may influence the diusion speed 
(e.g. as a result of temperature changes).
Reference measurements can also be carried out at regular intervals, e.g. 
when samples are taken for external accompanying analysis. The measured 
value is only corrected with a new reference factor when the new reference 
value was entered and conrmed by pressing “Apply”. Up to then, measured 
values that were determined in the meantime are always calculated and 
displayed with the currently valid reference factor.
The device starts with a reference factor of 1.0. If the two membranes were 
permeable to the same degree, then this value would be correct. In practice, 
however, experience has shown that manufacturing-related and ambient 
conditions aecting the probe can lead to discrepancies.