A photometer for the measurement of elastically scattered light from macromolecules in solution

In this paper a description of a low-cost and compact light scattering photometer with a precision temperature control is provided. The instrument can span an angular range from 10 to 160 degrees by means of a step-motor driven acquisition optics, and the signal is brought to a single photon counter by means of an optical fiber. The high sensitivity of the system allows measurements of light scattered from dilute polymer solutions with a temperature control with a stability of 0.01°C and a tolerance less than 0.03°C. The performances of the photometer were checked on different macromolecular systems in aqueous solution as well as in organic solvents. The results obtained with this instrument are reproducible within ±1% in the measurements of the light scattered by pure liquids and within ±2% for macromolecular solutions regardless of the type of solvent used