Method and device employing time-delayed integration for detecting sample components after separation
First Claim
1. An apparatus for detecting analytes in a sample, comprising:
- means for separating said sample into migrating analyte bands migrating along a direction, said separation means comprising a capillary tube with an inlet and outlet in which a detection zone is located in the capillary tube, and means for applying a voltage across a portion of the tube;
means for generating radiation signals to indicate the presence of an analyte band in the detection zone;
an array of solid state detectors capable of collecting the radiation signals to produce charges, wherein the array is aligned with the detection zone in a sequence in the direction of the migrating analyte bands, so that when a migrating analyte band is in the detection zone the radiation signals indicative of said band are directed to each of the detectors in sequence as the band migrates across the detection zone, said array having an output;
means for shifting the charges from each detector to the respective adjacent detector in the direction of the migration at a shift rate that is synchronized to the movement of the band such that the charges corresponding to the radiation signals of an analyte band can be accumulated at the array output; and
readout means to read the accumulated charges from the array output.
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Abstract
This invention relates to a detection method and apparatus useful in capillary electrophoresis and capillary chromatography that employs an array of solid state detector such as a charge-coupled device operating in the time-delayed integration mode which allows more exposure time of the moving analyte zones. The CCD is synchronized so that after a normal exposure of the CCD, the charge information in every row of the CCD is shifted toward one end of the CCD and the charge/signal information in the last row is quantified. Applying the CCD and the time-delayed integration method in effect increases the effective sampling volume of the flow cell without introducing band broadening. Use of the CCD as a fluorescence detection in capillary electrophoresis separations allows analytes to be differentiated both in migration time and fluorescence emission, yielding detection limits for fluorophores in the 1-8×10-20 mole range.
198 Citations
40 Claims
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1. An apparatus for detecting analytes in a sample, comprising:
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means for separating said sample into migrating analyte bands migrating along a direction, said separation means comprising a capillary tube with an inlet and outlet in which a detection zone is located in the capillary tube, and means for applying a voltage across a portion of the tube; means for generating radiation signals to indicate the presence of an analyte band in the detection zone; an array of solid state detectors capable of collecting the radiation signals to produce charges, wherein the array is aligned with the detection zone in a sequence in the direction of the migrating analyte bands, so that when a migrating analyte band is in the detection zone the radiation signals indicative of said band are directed to each of the detectors in sequence as the band migrates across the detection zone, said array having an output; means for shifting the charges from each detector to the respective adjacent detector in the direction of the migration at a shift rate that is synchronized to the movement of the band such that the charges corresponding to the radiation signals of an analyte band can be accumulated at the array output; and readout means to read the accumulated charges from the array output. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for detecting analytes in a sample, comprising:
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means for separating said sample into migrating analyte bands migrating along a direction comprising a capillary tube with a stationary phase wherein separation is accomplished by chemical interaction between the stationary phase and the analytes; means for generating radiation signals to indicate the presence of an analyte band in a detection zone; an array of solid state detectors capable of collecting the radiation signals to produce charges, wherein the array is aligned with the detection zone in a sequence in the direction of the migrating analyte bands, so that when a migrating analyte band is in the detection zone the radiation signals indicative of said band are directed to each of the detectors in sequence as the band migrates across the detection zone, said array having an output; means for shifting the charges from each detector to the respective adjacent detector in the direction of the migration at a shift rate that is synchronized to the movement of the band such that the charges corresponding to the radiation signals of an analyte band can be accumulated at the array output; and readout means to read the accumulated charges from the array output. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus for detecting analytes in a sample, comprising:
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means for separating said sample into migrating analyte bands migrating along a direction in a detection zone; means for generating radiation signals to indicate the presence of an analyte band in the detection zone; means for transmitting said radiation signals to an array of solid state detectors capable of collecting the radiation signals to produce charges, wherein the array is aligned with the detection zone in a sequence in the direction of the migrating analyte bands, so that when a migrating analyte band is in the detection zone the radiation signals indicative of said band are directed to each of the detectors in sequence as the band migrates across the detection zone, said array having an output, wherein each detector comprises a linear row of detector elements that is arranged transverse to the direction of migration, and wherein the transmitting means is such that radiation signals transmitted to one detector element of a row are at different wavelengths from those of radiation signals transmitted to another detector element that is located on said row; means for shifting the charges from each detector to the respective adjacent detector in the direction of the migration at a shift rate that is synchronized to the movement of the band such that the charges corresponding to the radiation signals of an analyte band can be accumulated at the array output; and readout means to read the accumulated charges from the array output. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A time-delayed integration method for detecting analyte bands from a sample, comprising the steps of:
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separating said sample into migrating analyte bands along a direction; generating radiation signals that indicate the presence of the analyte bands as they move through the detection zone; transmitting said radiation signals to an array of solid state detectors capable of collecting the radiation signals to produce charges, wherein the array is aligned with the detection zone in a sequence in the direction of the migrating analyte bands, wherein the detectors are arranged so that when a migrating analyte band is in the detection zone the radiation signals indicative of said band is directed to each of the detectors in sequence as the band migrates across the detection zone, wherein said detector comprises a linear row of detector elements that is arranged transverse to the direction of migration, and wherein said signals are transmitted such that radiation signals transmitted to one detector element in a row of detector elements are at different wavelengths from those of radiation signals transmitted to another detector element that is located on said row; accumulating the charge by shifting said charge, one detector at a time, beginning from a first detector sequentially toward an array output wherein the shifting is at a specific rate that is synchronized to the movement of the migrating analyte bands; and reading the accumulated charge from the device output. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification