MULTIANGLE LIGHT-SCATTERING AND VISCOMETRIC DETECTOR FOR SIZE-EXCLUSION CHROMATOGRAPHY

A new miniaturised Light Scattering (LS) apparatus coupled with a capi llary viscometer has been developed which analyses sequentially small size fractions of eluent (1 cm(3)). The apparatus can be used in an au tonomous manner in order to obtain the weight-average molar mass (M(W) ), the z-average radius of gyration (R(g)), the second virial coeffici ent (A(2)), the intrinsic viscosity ([eta]) and the Huggins constant ( Ic) by analysing a given polymer sample at different concentrations. T he device can be coupled to a standard Sire-Exclusion Chromatography c hain in which the detector not only provides mean values, but also the evolution of [eta], M(W) and R(g) as a function of elution volume (V- e). Specific calibration curves (log(M(W)) = f(V-e)) can be constructe d for any sample, and then be used without the combined detector. In t his way the molecular weight dependence of [eta] and R(g) is readily o btained. Moreover, the special design of the detector allows simple co llection of fractions. A number of problems which need to be solved in order to allow an efficient use of the detector are discussed. Result s on polystyrene standards illustrate the good performance of the appa ratus.