Preparative liquid chromatograph

A preparative liquid chromatograph comprising:

• a liquid delivery pump that delivers a mobile phase at a set flow rate;
• an injector that injects a sample into the mobile phase fed by the liquid delivery pump;
• a separation column configured for separating components in the sample injected into the mobile phase by the injector from each other;
• an outlet flow path fluidly connected to an outlet of the separation column and through which eluate from the separation column flows;
• a branch flow path that branches from the outlet flow path and for extracting a part of flow of the eluate in the outlet flow path;
• a first detector fluidly connected to the outlet flow path and configured to output a first signal corresponding to a concentration of each component in the eluate;
• a second detector fluidly connected to the branch flow path and configured to output a second signal corresponding to the concentration of each component in the eluate supplied through the branch flow path;
• a fraction collector fluidly connected to an outlet of the first detector for collecting a desired portion of the eluate from the separation column in an individual collection container;
• and
• a control device configured to execute a set fractionation sequence by controlling operation of the liquid delivery pump, the injector, and the fraction collector,
• wherein the control device has an information storage area that stores initial setting information set before the fractionation sequence is started, the initial setting information includes a time difference information and a first delay time, the time difference information is information as to a time difference between a time required for a component eluted from the separation column to be detected as a peak in the first signal and the time required for the component eluted from the separation column to be detected as a peak in the second signal, and the first delay time is the time required for the component detected as a peak in the first signal to reach the fraction collector,
• during execution of the fractionation sequence, the control device is configured to apply the first delay time to control operation of the fraction collector in a first collection operation of collecting the component detected as the peak in the first signal to the collection container, and to apply a second delay time to control operation of the fraction collector in a second collection operation of collecting the component detected as the peak in the second signal in the collection container, the second delay time is the time until the component detected as the peak in the second signal reaches the fraction collector and is obtained by using the time difference information and the first delay time stored in the information storage area,
• the control device is further configured to execute a maintenance operation of the time difference information stored in the information storage area when a specific component detected as a peak in both the first signal and the second signal is injected into the mobile phase during execution of the fractionation sequence, and
• the control device is configured, in the maintenance operation, to calculate a difference between a first retention time from when the specific component is injected into the mobile phase until the specific component is detected as the peak in the first signal and a second retention time from when the specific component is injected into the mobile phase until the specific component is detected as the peak in the second signal, to execute peak determination as to whether or not the calculated difference falls within an allowable range set with reference to the time difference information, and when the calculated difference is out of the allowable range in the peak determination, to update the time difference information stored in the information storage area with the calculated difference.