Optical method for determination of minute amounts of opaque insoluble colored light absorptive substances

Abstract

A method for the rapid quantitation of minute amounts of particulate insoluble substantially opaque colored light absorptive substances is disclosed. The method may be employed to quantitate such particulates which are formed as an end product of an assay productive thereof. The method is practiced by bringing into contact particles to be quantified and an optical component or matrix formed of substantially water insoluble reflective granules of material which is substantially nonabsorptive of light and has a light scattering coefficient of at least about eighty. The opacity of the particles to be quantitated, when in contact with the component granules, masks and prevents any substantial light flow through the contacted granule surface areas which, with the absorptivity of light by the contacting particles, is effective rapidly and dramatically to reduce the light transmittance capability of the optical component. The particles to be quantitated may be formed in a fluid medium which is caused to flow in contact with the optical component during such formation. When this is done, measurement on a second-by-second basis, of the change in light transmittance capability of the optical component caused by contact of granules thereof and particles to be quantitated, provides a generally straight line time versus transmittance relationship, the slope of which is proportional to and indicative of the quantity of the contacting particles thus formed.

Dependencies are inferred from the claim text.