Differential Refractometer for Precise dn/dc Determination

Testa Analytical Solutions e.K. has added the AYE Differential Refractometer to its existing line of high-performance instruments for chromatographic measurements.

The AYE is a flexible differential refractometer that may be used in either static or dynamic mode. In static mode, the specific refractive index increment (dn/dc) of dissolved samples can be easily and precisely determined in just a few minutes. The specific refractive index increment is a critical parameter required to determine absolute molecular weight using static light scattering (SLS) detectors. This is because a relatively small error in dn/dc determination will lead to twice the error in calculating molecular weights. It is important also to determine the dn/dc value at the same wavelength as the SLS detector laser or a further error will be introduced, as dn/dc is strongly dependent from wavelength.

The AYE differential refractometer offers a large number of wavelength options to enable precise matching of your SLS detector laser operating wavelength, thereby ensuring reliable and reproducible results every time.

Where the dn/dc value of the sample is already known, the AYE differential refractometer can be used for precise and sensitive concentration determination. The amount of sample used for this can also be easily recollected and therefore utilized for further investigations.