Online sampling system

An online sampling system configured to collect a sample from a sample source and to inject the sample into a mobile phase flowing through an analysis channel of a liquid chromatograph, the online sampling system comprising:

• an injector including a first sample loop for temporarily holding a sample and an injection valve for switching between a state in which the first sample loop is incorporated in the analysis channel and a state in which the first sample loop is separated from the analysis channel;
• a sample supply channel fluidly connected to the injector and configured to supply the sample to the injector;
• a pump part configured to suck and discharge a liquid;
• a second sample loop provided separately from the first sample loop;
• a sample source channel communicating with the sample source;
• a path construction part including one or more switching valves, the path construction part being configured to selectively build multiple fluid flow paths in the online sampling system by switching the one or more switching valves, wherein
• the path construction part being configured to be capable of selectively constructing a sampling path and a sample supply path,
• the sampling path is configured so that the sample source channel and the pump part are fluidly connected to each other in a closed system with the second sample loop interposed therebetween and the sample is drawn from the sample source to the second sample loop using the pump part, and
• the sample supply path is configured so that the second sample loop is separated from the sample source channel while maintaining a closed system state of the sample source channel and the pump part or another pump different from the pump part and the sample supply channel are fluidly connected to each other with the second sample loop interposed therebetween and the sample held in the second sample loop is supplied to the injector through the sample supply channel using the pump part or the other pump.