Ion chromatograph

An ion chromatograph comprising:

• a separation column that separates a sample that is included in an eluent. wherein the sample to be measured into ion species components;
• a three-way valve that has an input port, a first output port and a second output port, wherein in the three-way valve branches an electrode liquid to be introduced into the input port to discharge a first output port electrode liquid, and a second output port electrode liquid from the respective of the first output port and the second output port;
• an ion suppressor that includes an eluent flow path through which the eluent from the separation column passes, an anode-side flow path through which the first output port electrode liquid from the first output port passes and a cathode-side flow path through which the second output port electrode liquid from the second output port passes;
• wherein the ion suppressor performs ion exchange by electrolysis between an-the eluent that passes through the eluent flow path, the first output port electrode liquid that passes through the anode-side flow path, and the second output port electrode liquid that passes through the cathode-side flow path;
• a detector that detects the sample that passes through the eluent flow path and is separated by the separation column;
• and
• a backward flow of the second output port electrode liquid in the cathode-side flow path, wherein:
• the backward flow suppression mechanism includes:
• a first pipe that has a flow path resistance and that connects the first output port to an upstream portion of the anode-side flow path, and
• the flow path resistance of the second pipe is smaller than the flow path resistance of the first pipe to prevent the backward flow to the three-way valve of the second output port electrode liquid from the cathode-side flow path.