BUCHI Fraction Collector C-660 - Manual (Page 26)

6 Operation
26 C-660 Operation Manual, Version F
Table 6-9: Parameters for configuration
Parameter Description
Detector 1 or 2 A detector must be selected and connected to the correct socket. This definition deter-
mines which detector signal will be evaluated for a fraction change. If no detector has
been selected, the peak collection function is turned off. The peak collection function is
automatically activated at the start when a detector is selected.
Threshold The threshold value defines the signal strength at which the peak collection function is
activated. The peak collection function is shut off at signal strengths below the threshold
value. The threshold value is entered as a % of the end-scale deflection (with a detector
signal of 1 V end-scale deflection,1% corresponds to a signal level of 10 mV) and serves
to suppress occurring noise signals. A tube change occurs each time the signal exceeds
or falls below the threshold value.
Change Here you can define whether a fraction change should only be triggered at a peak
minimum or both at peak minimum and maximum. A fraction change at the peak
maximum allows for an automatic division of peak into ‘front’ and ‘rear’ halves. Especially
in the case of only slightly separated peaks, this procedure allows the multiple extraction
of a fraction with sufficient purity for the subsequent analysis.
A tube change takes place when crossing the threshold line and at every
minimum.
A tube change takes place when crossing the threshold line and at every
minimum and maximum.
Mode Here you define whether the solvent of the entire chromatographic run or only the frac-
tions are collected in the prepared tubes during a peak. In the second case the solvent
is directed to the waste container between the peaks. The optional waste diverter valve
044964 is necessary for this function.
Collection occurs only during the detected peaks. The fractions between
the peaks as well as substances not detected are directed to the waste
container.
Collection occurs during and between peaks, meaning that all fractions are
collected.
Between peaks
(only mode
)
Fraction sizes between peaks (Signal<Threshold):
Serves to define different fraction sizes during and between the peaks.
The time defined in the main menu or the corresponding volume is the valid maximum
fraction size during a peak. Both times or volumes can differ. This makes it possible to
break a peak down into smaller fractions but still makes it possible to fill the tubes to the
maximum between the peaks.
Both times are independent of each other and must be defined individually.