Liquid Chromatograph and Liquid Delivery Method

A liquid chromatograph, comprising:

• a separation column incorporating a stationary phase;
• a liquid delivery device configured to deliver a liquid, which is a mobile phase, to the separation column;
• a sample injection device configured to inject a sample to be analyzed into the liquid delivered from the liquid delivery device to the separation column;
• a liquid supply device configured to supply the liquid to the liquid delivery device;
• and
• a control device configured to control operations of the liquid delivery device and the liquid supply device, wherein
• the liquid supply device includes
• a liquid storage container configured to store the liquid to be supplied to the liquid delivery device,
• a supply pipe configured to connect the liquid delivery device and the liquid storage container,
• a circulation pipe configured to connect an intermediate portion of the supply pipe and the liquid storage container and return the liquid delivered through the supply pipe to the liquid storage container,
• a flow passage switching valve provided on a connection portion between the supply pipe and the circulation pipe, and configured to selectively switch between a liquid delivery state in which the supply pipe on a liquid storage container side and the supply pipe on the liquid delivery device side communicate with each other and a circulation state in which the supply pipe and the circulation pipe on a liquid storage container side communicate with each other,
• a bubble detection device provided on the supply pipe between the liquid storage container and the flow passage switching valve and configured to detect presence or absence of bubbles of the liquid delivered through the supply pipe, and
• a circulation liquid delivery device provided on the circulation pipe and configured to deliver the liquid from a flow passage switching valve side to a liquid storage container side, and
• the control device is configured to switch the flow passage switching valve to the circulation state to perform a circulation liquid delivery by the circulation liquid delivery device, and switch the flow passage switching valve to the liquid delivery state when the bubbles of the liquid are not detected by the bubble detection device.