The EcoSEC GPC system and earlier Tosoh GPC models feature dual flow RI detection for enhanced baseline stability, unaffected by significant changes in temperature and atmospheric pressure.

Refractive Index detectors measure the difference in refractive index between a sample and a reference cell. Most RI detectors are of the single flow type, in which the reference cell is statically filled with solvent rather than the solvent flowing through the cell, as in the dual flow design. In a single flow design, the properties of the solvent in the reference cell slowly change over time. Since the solvent flows through the reference cell in a dual flow RI detector, the changes over time become insignificant. The figures below demonstrate that the improvement in baseline stability obtained with a dual flow detector far outweighs the cost of adding a second pump.