WANTED: Wyatt Optilab DSP interferometric refractometer. The Optilab DSP Interferometric Refractometer measures the difference in refractive index (RI) between a current sample and a liquid, usually a clear solvent, that is stored as a reference. The RI is measured at a fixed wavelength and temperature. The RI can be read on the front panel display, the analog output channels or through the serial port interface. Please contact us for complete Wyatt HPLC details.