Two or more of the test object (preferably, the sulfur-containing compound) provides a method of analyzing simultaneously in a short time.
Step of flowing a measurement sample to the flow path P1 with the mobile phase (1), the step of flowing the mobile phase in the flow path P2 and the flow channel P3 containing no sample (2), and, by steps (1) and (2) two or more of the test object leaving the analytical column (preferably, sulfur-containing compounds) step of acquiring by the detector chromatograms (3) has a (where the flow path P1 is the pretreatment column as in the forward direction, then a flow path to the detector through the analytical column, flow path P2 is without passing through the pretreatment column, a flow path to the detector through the analytical column, the flow path P3 is through the pretreatment column in the opposite direction, without going through the analytical column, the detector also is the channel discharged without passing.), object to be examined of two or more in the step (1) is passed through the pretreatment column It begins steps (2) to exit the step (1) after, two How the above analysis of the test object.