Abstract: A system for emitting and detecting electromagnetic radiation of multiple wavelengths to observe the motion of particles in a polydisperse solution in order to size the particles is provided. The system includes a first and second light sources constructed to emit a first and second beams of electromagnetic radiation at substantially a first and second wavelength, respectively. The beams are directed to a specimen chamber such that a portion of the beams scatter when illuminating the particles, and wherein the scattered portion of the beams are directed to a sensor. The first and second wavelengths are different from each other and a recorder is connected to the sensor. At processor controls the light sources in a time-division fashion, and from the resulting images the size of particles can be determined by tracking the motion of the particles.

Abstract: A system for determining the growth/dissolution rate of colloidal particles is disclosed and includes multiple light sources and multiple sensors. A light source is constructed to emit a beam of electromagnetic radiation at a specimen chamber that holds the colloidal particles. The chamber allows a portion of the combined beam to scatter perpendicularly or at some other angle to the combined beam. The scattered portion of the beam is directed to a sensor that detects electromagnetic radiation. The sensor is connected to processor that activates the light source and obtains an image from the sensor. Multiple images are taken at a time interval and for each image taken, and a total image intensity level is calculated and normalized. A formula is then calculated that fits the normalized values over time and a slope is determined from the formula.

Abstract: A system and method are provided to observe and count particles in polydisperse solutions with dark field microscopy while distinguishing among particles of different sizes and accurately counting particles. A calibration mask, calibration light source, and multiple wavelengths of light are used. Opaque calibration marks on the transparent calibration mask define a region of interest. Multiple beams of various wavelengths are combined into a beam or a light sheet and the perpendicular component of scattered light from the specimen particles is then split into separate wavelengths and detected by separate sensors attuned to each wavelength.

Abstract: A method for calibrating a dark field microcopy setup is disclosed. The method includes preparing a plurality of particle samples, each with a known concentration and particle size, the plurality having more than one particle size and, optionally, more than one refractive index and more than one diluent. For each sample in the plurality, the sample is measured in the setup and the scattered light intensity and number of particles is measured. From this data, a relationship between the scattered light intensity, particle size and calibrated investigated volume can be determined. The calibrated investigated volume is used to obtain the proper particle size distribution in a given diluent.

Abstract: A system and method are provided to observe and count particles in polydisperse solutions with dark field microscopy while distinguishing among particles of different sizes and accurately counting particles. A calibration mask, calibration light source, and multiple wavelengths of light are used. Opaque calibration marks on the transparent calibration mask define a region of interest. Multiple beams of various wavelengths are combined into a beam or a light sheet and the perpendicular component of scattered light from the specimen particles is then split into separate wavelengths and detected by separate sensors attuned to each wavelength.

Abstract: A special purpose cuvette assembly with features that create a small, restricted volume to minimize bulk movements of liquid and that minimize backscattering of light. The special-purpose cuvette assembly enables recording of Brownian movements of nanoparticles in a liquid when it is placed in a suitable optical device comprising a light sheet and an optical microscope attached to a video camera that is oriented perpendicular to the light-sheet plane.

Abstract: A special purpose cuvette assembly with features that create a small, restricted volume to minimize bulk movements of liquid and that minimize backscattering of light. The special-purpose cuvette assembly enables recording of Brownian movements of nanoparticles in a liquid when it is placed in a suitable optical device comprising a light sheet and an optical microscope attached to a video camera that is oriented perpendicular to the light-sheet plane.