Preparative separation chromatograph

A preparative separation chromatograph system, comprising:

• a) a chromatograph having a column configured to temporally separate one or a plurality of target components contained in a sample and a detector configured to detect each target component eluted from the column;
• b) a fraction collector configured to collect a target component exiting from the detector;
• c) a controller configured to execute controller-executable instructions to:
• store, in a storage section, sampling-rate information which relates a plurality of threshold values of an output signal from the detector to a plurality of sampling rates, the sampling-rate information being prepared so that a higher sampling rate is set for lower levels of the output signal, while a lower sampling rate is set for higher levels of the output signal;
• acquire a value of the output signal from the detector;
• determine a sampling rate corresponding to the acquired value of the output signal with reference to the stored sampling-rate information;
• determine a rate of change in the output signal in the determined sampling rate;
• command the fraction collector to initiate a collecting operation for the target component with reference to a point in time where the rate of change becomes greater than a positive predetermined reference value;
• and
• command the fraction collector to discontinue the collecting operation for the target component with reference to a point in time where an absolute value of the rate of change becomes smaller than an absolute value of a negative predetermined reference value after the rate of change turns negative.