Liquid chromatograph with improved defect elimination

A liquid chromatograph comprising:

• a liquid sending pump that sends a mobile phase;
• an analysis flow path having a separation column for separating a sample into components and a detector for detecting sample components obtained by separation in the separation column;
• a pressure sensor that detects a liquid sending pressure applied by the liquid sending pump;
• a sample injector for injecting a sample into the analysis flow path;
• a switcher for switching a state between the liquid sending pump and the analysis flow path to a connection state or a disconnection state;
• a liquid sending failure detector configured to compare a variation range of the liquid sending pressure detected by the pressure sensor with a preset threshold value, and detect a liquid sending failure caused by the liquid sending pump when the variation range of the liquid sending pressure exceeds the threshold value;
• an analysis operation executer configured to control operations of the liquid sending pump, the sample injector and the switcher, and execute an analysis by putting the state between the liquid sending pump and the analysis flow path in a connection state and injecting a sample into the analysis flow path, as a scheduled analysis in regard to all of samples scheduled to be analyzed in a preset analysis schedule;
• a purge operation executer, when a liquid sending failure is detected by the liquid sending failure detector during a sample analysis, configured to interrupt a sample analysis in execution, put the state between the liquid sending pump and the analysis flow path in a disconnection state and execute a purge operation of sending a liquid mobile using the liquid sending pump at a flow rate higher than a flow rate during the analysis for a preset purge time;
• a confirming operation executer configured to execute a confirming operation of confirming whether a liquid sending failure is detected by the liquid sending failure detector after the purge operation ends;
• and
• a non-injection analysis executer, when a liquid sending failure is not detected by the liquid sending failure detector in the confirming operation, configured to execute a non-injection analysis in which a mobile phase is sent into the analysis flow path by the liquid sending pump under a condition that enables removal of a sample in the analysis flow path, wherein
• the analysis operation executer is configured to restart the scheduled analysis after the non-injection analysis is executed.