The JASCO Model RI-2031 RI detector is a microcomputer based Differential Refractometer which combines a high-quality optical system with advanced electronics and microcomputer control/programming capabilities. The RI-2031 is the latest addition to the new high-performance, easy-to-use and extremely compact LC-2000 Plus series HPLC modules.

The RI-2031 can easily be interfaced with the JASCO HPLC system using the ChromPass Software.

Highly Reliable Optics
The RI-2031 optical design is based on Snell's Law of Refraction utilizing a prism flow cell. Two flow cells, i.e., the sample and the reference cells having triangle cross section, form a pair of liquid prisms. The beam from the light source is directed to the prism cell through the collimator lens and passes through the sample and the reference prism cells where refraction occurs in accordance with the difference in the refractive indices between the sample and reference liquids. This refracted beam is then reflected by the plane mirror located behind the flow cell back through the cell where the second refraction takes place and is focussed on a photodiode. The refraction angle representing the refractive index difference is monitored as a movement of the image on the photodiode pair which outputs corresponding electrical signals.

Advanced Electronics
The difference and sum of analog signals from the photodiode pair are converted into digital signals and sent to the CPU. Then, the CPU computes the difference of refractive indices between the sample and reference liquids with compensation of the intensity fluctuation of the light source and the light absorption of the sample solute by using the sum signal. This digital signal is displayed on the high-contrast backlit LCD, and is also sent to the analog output via a D/A converter.

High Stability
A high-sensitive Refractive Index detector requires an extremely rugged optical bench which maintains perfect alignment over the entire life. JASCO has achieved such optics and realized the RI-2031. To ensure this stability, the RI-2031 is designed with careful consideration of the system's overall thermal balance by utilizing very effective heat exchangers and precise control of temperature at both the sample and reference cells.

Maximum Flow Rate of 50 mL/min
Maximum flow rate is 50 ml/min (Solvent: H20). Wide dynamic range and extended maximum flow rate enables semi-preparative applications.

Time Programming Capability
The RI-2031's on-board microprocessor allows time programmed change of the detector range and reference cell solvent replacement, thereby optimizing peak detection and facilitating unattended solvent replacement of reference cell.