| Developed in the 1970's, dynamic light scattering has become a popular noninvasive method of particle size analysis. Within the last 10 years, systems have been developed to analyze highly concentrated samples exhibiting multiple scattering. Of the three main system setups designed to suppress multiple scattering, the one-beam method was used for the research in this thesis. This method involves using two detectors at a small angle from one another (3 to 4 milliradians) to measure the scattering intensity. The signals are then cross correlated and multiple scattering is eliminated. The two main objectives of this thesis were to find and test a method for analyzing polydisperse samples, and to then apply the method to test protein samples supplied by Dr. Middaugh's pharmaceutical chemistry lab.; The DLS setup was first modified by adding a cooling bath for the sample such that testing could be carried out at a constant known temperature. Once the system was ready for testing, monodisperse polystyrene samples were tested to verify the accuracy of the system. (Abstract shortened by UMI.)... |
