Abstract: The separations resulting from capillary electrophoresis performed in a microbore capillary tube are detected on-line by focusing a light beam in the form of a line or sheet of light on the capillary passage in which the separations take place so that the width of the sheet of light encompasses the length of the passage in which separations of interest are expected to take place. The separations form concentration gradients in the capillary passage encompassed by the light beam and cause refraction of portions of the light beam and variations in the intensity of the light beam due to such refraction. Alternately, the separated components may absorb light of certain frequencies so if the light beam includes light of the certain frequencies, variation in the intensity of the light beam is caused by such absorbance.

Abstract: The separations resulting from capillary electrophoresis performed in a microbore capillary tube are detected on-line by focusing a light beam in the form of a line or sheet of light on the capillary passage in which the separations take place so that the width of the sheet of light encompasses the length of the passage in which separations of interest are expected to take place. The separations form concentration gradients in the capillary passage encompassed by the light beam and cause refraction of portions of the light beam. The variation in the intensity of light along the width of the light beam after passage through the sample is sensed and is indicative of the concentration gradients and separation occurring in the sample. An apparatus including a relatively short capillary tube with liquid reservoirs secured at each end may be used with the detector to perform various capillary electrophoretic separation techniques.

Abstract: The separations resulting from capillary electrophoresis performed in a microbore capillary tube are detected on-line by focusing a light beam in the form of a line or sheet of light on the capillary passage in which the separations take place so that the width of the sheet of light encompasses the length of the passage in which separations of interest are expected to take place. The separations form concentration gradients in the capillary passage encompassed by the light beam and cause refraction of portions of the light beam. The variation in the intensity of light along the width of the light beam after passage through the sample is sensed and is indicative of the concentration gradients and separation occurring in the sample. An apparatus including a relatively short capillary tube with liquid reservoirs secured at each end may be used with the detector to perform various capillary electrophoretic separation techniques.

Abstract: The sensitivity of refractive gradient detectors for detecting refractive index gradients in samples flowing through samples chambers is increased by detecting the gradients formed in the direction perpendicular to the direction of flow of the sample through the sample chamber and by detecting such gradients simultaneously intermediate the central axis and sides of the sample chamber on opposite sides of the central axis. A preferred detector uses two spaced, parallel probe light beams passing through the sample chamber between the central axis and sides of the chamber on opposite sides of the axis, with each beam preferably centered about half way between the axis and the respective side. A sensor detects relative movement of the probe beams caused by a refractive index gradient in the sample but preferably compensates for parallel movement of the parallel light beams caused by positional instability or mechanical movement of the light source.

Abstract: A differential, sequential detector, and method, for detecting refractive index gradients in a sample and for producing an output signal approximating a derivative of the refractive index gradient utilizes two closely spaced, parallel probe light beams passing through the sample with the beams separated along the direction of any expected gradient to be detected. A sensor is arranged to measure and produce an output signal proportional to the difference in movement of the two beams. The sensor is preferably arranged so that only complementing portions of each beam will fall on the sensing area of the sensor so that parallel movement of the beams will change equally the respective complementary portions sensed to maintain a constant output from the sensor, but movement of one beam relative to the other beam will produce a change in the sensor output proportional to the relative movement and approximating the derivative of refractive index gradient causing the relative beam movement.

Abstract: Concentration gradients in samples to be evaluated are detected by measuring the deflection of a probe light beam passed through the sample using the principals of Schlieren optics. Specific chemical compounds in a sample can be detected and identified by supplying excitation energy to the sample where such energy is selected to be absorbed by the chemical compound to be specifically identified and not by other compounds in the sample. The absorption of the excitation energy by the absorbing compound produces a temperature gradient within the sample which causes deflection of the probe light beam and signals representative of such deflection may be separated from signals representative of deflections caused by other refractive index gradient present in the sample. A light emitting diode may be used to generate the probe light beam.

Abstract: Concentration gradients in samples to be evaluated are detected by measuring the deflection of a probe light beam passed through the sample using the principals of Shlieren optics. Specific chemical compounds in a sample can be detected and identified by supplying excitation energy to the sample where such energy is selected to be absorbed by the chemical compound to be specifically identified and not by other compounds in the sample. The absorption of the excitation energy by the absorbing compound produces a temperature gradient within the sample which causes deflection of the probe light beam and signals representative of such deflection may be separated from signals representative of deflections caused by other refractive index gradients present in the sample. A light emitting diode may be used to generate the probe light beam.