Refractive index detector and liquid chromatograph

A refractive index detector comprising:

• a sample cell, made of a light transmitting container, including a sample cell inlet through which a liquid flows in, and a sample cell outlet through which a liquid flows out;
• a reference cell, made of a light transmitting container, including a reference cell inlet through which a liquid flows in, and a reference cell outlet through which a liquid flows out, the reference cell being arranged adjacent to the sample cell across a light transmitting partition wall;
• a measurement section including a light source for emitting light in such a way that the light passes through both of the sample cell and the reference cell from a side of one of the cells, and a photodetector for detecting displacement of the light which has passed through the sample cell and the reference cell;
• a liquid inlet port that leads to the sample cell inlet;
• a first outlet port for discharging a liquid;
• a second outlet port for discharging a liquid, provided separately from the first outlet port;
• and
• a switching mechanism including a reference liquid supply mode for forming a channel for connecting the reference cell outlet to one of the first outlet port and the second outlet port while connecting the sample cell outlet to the reference cell inlet, and an analysis mode for forming a channel for connecting the sample cell outlet to one of the first outlet port and the second outlet port while sealing the reference cell outlet;
• wherein a recycle channel for returning a liquid to a liquid supply section is to be connected to the second outlet port, and
• wherein the switching mechanism includes, as the reference liquid supply mode, a reference liquid normal supply mode for connecting the reference cell outlet to the first outlet port while connecting the sample cell outlet to the reference cell inlet, and a reference liquid recycled supply mode for connecting the reference cell outlet to the second outlet port while connecting the sample cell outlet to the reference cell inlet, and includes, as the analysis mode, a normal analysis mode for connecting the sample cell outlet to the first outlet port while sealing the reference cell outlet, and a recycle analysis mode for connecting the sample cell outlet to the second outlet port while sealing the reference cell outlet.