Automated optical alignment system and method using Raman scattering of capillary tube contents
First Claim
1. An optical alignment assembly for fluorescence detection, utilizing a capillary tube, comprisingan axially symmetrical concave reflector having a wall bounded by a rim, a bowl opposite the rim incorporating a vertex, a focal region, a set of tube guides defined by the wall, the tube guides allowing passage of the capillary tube through the reflector, and a beam guide means defined by the wall for directing an excitation beam such that a path of the beam intersects with the capillary tube within the reflector, a region of intersection emitting Raman scatter signals,means disposed for collecting and detecting the Raman scatter signals, andmeans connected to the detecting means for adjusting position of the beam relative to the capillary tube to maximize the detected Raman scatter signals.
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Abstract
A system and method are disclosed for optically aligning a capillary tube and an excitation laser beam for fluorescence detection applications by utilizing the Raman scatter signals of the capillary tube'"'"'s contents. For example, Raman scatter by an electrophoretic separation matrix may be used for alignment in a capillary electrophoresis system. Fluorescent material may be present and may also be used for alignment purposes, but is not necessary. The invention employs a parabolic reflector, having apertures through which the capillary tube and the laser beam are guided so that they intersect, preferably at right angles and at the focal point of the reflector. The Raman scatter signals of the material within the capillary tube are collected via a series of filters and this information is used to reposition, if necessary, a focusing lens that directs the excitation beam into the reflector and the capillary tube, so that the Raman scatter signals are maximized. Maximal Raman scatter signals indicate proper alignment of the capillary tube and the excitation beam. Other signals, such as fluorescence emission from the sample, may then be gathered. Adjustment of the focusing lens may be automated so that alignment of the capillary tube and the beam is maintained throughout analysis of the tube'"'"'s contents. Sequential alignment of an array of capillary tubes with an excitation beam is also disclosed.
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Citations
48 Claims
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1. An optical alignment assembly for fluorescence detection, utilizing a capillary tube, comprising
an axially symmetrical concave reflector having a wall bounded by a rim, a bowl opposite the rim incorporating a vertex, a focal region, a set of tube guides defined by the wall, the tube guides allowing passage of the capillary tube through the reflector, and a beam guide means defined by the wall for directing an excitation beam such that a path of the beam intersects with the capillary tube within the reflector, a region of intersection emitting Raman scatter signals, means disposed for collecting and detecting the Raman scatter signals, and means connected to the detecting means for adjusting position of the beam relative to the capillary tube to maximize the detected Raman scatter signals.
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28. A method for aligning a fluorescence excitation beam and a capillary tube comprising
providing a parabolic reflector having a wall bounded by a rim, a bowl opposite the rim incorporating a vertex, and a focal region incorporating a focal plane and a focal point, defining a set of oppositely-spaced tube guides near the focal region and a beam guide means through the wall of the reflector, guiding a capillary tube containing a matrix through the set of tube guides, directing an excitation beam through a focusing lens and then through the beam guide means to cause intersection of the capillary tube and the excitation beam at the focal region within the reflector, thereby forming a detection region with Raman scatter and fluorescence signals being emitted from the detection region, collecting and detecting the Raman scatter signals, shifting the relative positions of the beam and the capillary tube to maximize the Raman scatter signals, and then collecting and detecting the fluorescence signals.
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40. A method for aligning a fluorescence excitation beam and a capillary tube comprising
providing a parabolic reflector having a wall and a focal region, defining a set of oppositely-spaced tube guides through the wall of the reflector near the focal region and a beam guide means through the wall of the reflector, guiding a capillary tube containing a matrix through the set of tube guides, directing an excitation beam through a focusing lens and then through the beam guide means to cause intersection of the capillary tube and the excitation beam within the reflector, thereby forming a detection region with Raman scatter and fluorescence signals being emitted from the detection region, simultaneously collecting and detecting the Raman scatter and fluorescence signals with a dispersive element and an array-type detector, and shifting the position of the lens to maximize the Raman scatter signals and thereby align the beam and the capillary tube while collecting and detecting the Raman scatter and fluorescence signals.
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41. A method for sequentially aligning a fluorescence excitation beam and each capillary tube in a one-dimensional array of capillary tubes, the method comprising
providing a parabolic reflector having a wall and a focal region, defining a set of oppositely-spaced tube guides through the wall of the reflector near the focal region and a beam guide means through the wall of the reflector, guiding a one-dimensional array of matrix-containing capillary tubes through the set of tube guides, directing an excitation beam through a focusing lens and then through the beam guide means to sequentially intersect within the reflector with each of the capillary tubes of the array, thereby forming a detection region in each of the capillary tubes with Raman scatter and fluorescence signals being emitted from each of the detection regions, collecting and detecting the Raman scatter signals from each detection region while the excitation beam intersects each of the capillary tubes, shifting the position of the lens to maximize the Raman scatter signals from each detection region while the excitation beam intersects each of the capillary tubes, and collecting and detecting the fluorescence signals from each detection region while the Raman scatter signals are maximized.
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42. An automated optical alignment system for fluorescence detection comprising
a parabolic reflector having a wall, a vertex, a focal plane incorporating a focal point, a set of oppositely-spaced tube guides defined by the wall for guidance of a capillary tube containing a matrix through the reflector, and a beam guide means defined by the wall for guidance of a fluorescence excitation beam through the reflector transverse to the guided tube to intersect the guided tube, the guided beam causing emission of Raman scatter signals from the region of intersection, a lens disposed exterior to the reflector for focusing the guided beam into the guided tube, an automated positioner for shifting the relative positions of the guided tube and the guided beam, and means for collecting and detecting the Raman scatter signals from the region of intersection of the guided tube and the guided beam, the means for collecting and detecting the Raman scatter signals being in communication with the positioner in order to shift the relative position of the guided tube and the guided beam as necessary to maximize the Raman scatter signals, thereby aligning the guided tube and the guided beam for fluorescence detection.
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48. Art automated optical alignment system for fluorescence detection comprising
a parabolic reflector having a wall, a focal region, a set of oppositely-spaced tube guides defined by the wall for guidance of a capillary tube containing a matrix through the reflector, and a beam guide means defined by the wall for guidance of a fluorescence excitation beam through the reflector transverse to the guided tube to intersect the guided tube, the guided beam causing emission of fluorescence signals from the region of intersection, an automated positioner for shifting the relative positions of the guided tube and the guided beam, and means for collecting and detecting the fluorescence signals from the region of intersection of the guided tube and the guided beam, the means for collecting and detecting the fluorescence signals being in communication with the positioner in order to shift the relative positions of the guided tube and the guided beam to maximize the fluorescence signals.
Specification