Abstract: This invention relates to an improved real-time scanning fluorescence electrophoresis apparatus for the electrophoretic analysis of fluorescently-labeled polynucleotide fragments. The apparatus is characterized by having an electrophoresis chamber containing an electrophoretic separation medium capable of accommodating multiple electrophoresis lanes arranged in a planar array, a fluorescence detector mounted on a translatable stage, a light source for exciting fluorescent molecules, and a computer for collecting data consisting of time, location, fluorescence wavelength and fluorescent intensity information. The improvements herein disclosed include, (i) using a spectral-array detector for detecting the emission light from the fluorescently-labeled polynucleotide fragments including the simultaneous detection of multiple fluorescent labels, and, (ii) a temperature control means to control the temperature of the electrophoretic separation medium during electrophoresis.

Abstract: A liquid boundary level detector employing an open-ended conduit which directs pressure waves toward a liquid boundary layer. The conduit is moved from a starting position toward the liquid boundary and, upon contact with the boundary, there is a change in acoustic impedance within the conduit. This change is monitored and a signal is generated indicative of such contact. Once the initial liquid boundary position is determined, that may become the reference position for subsequent liquid boundary measurements or motions.