Analytical device with lightguide illumination of capillary and microgroove arrays
View Patent ↗An analytical cell including a lightguide with a plurality of conduits filled with a migration medium. The medium, the lightguide and a surrounding medium have refractive indices selected such that light entering the lightguide is internally reflected within the lightguide to provide substantially uniform illumination of the conduits.
1. An analytical device, comprising:
a lightguide consisting of a solid block of a transparent or a translucent material, wherein the lightguide comprises an array of close-packed conduits extending therethrough such that all the conduits touch each other in a plane of the array, and a migration medium in the conduits;
a first light source outside the lightguide, wherein the first light source emits a first light beam in a first direction with an optical axis substantially coplanar with and normal to the longitudinal axes of the conduits,
a second light source outside the lightguide, wherein the second light source emits a second light beam in a second direction substantially collinear with and opposite to the first direction;
wherein the migration medium, the lightguide and a medium surrounding the lightguide have refractive indices selected such that light emitted by the first and second light sources is totally internally reflected within the lightguide to illuminate the migration medium in the conduits.
2. The device of claim 1 , wherein the longitudinal axes of the conduits in the array are substantially parallel and coplanar.
3. The device of claim 2 , wherein the longitudinal axes of the conduits in the array are at a substantially equal pitch to one another.
4. The device of claim 1 , wherein the conduits have a substantially circular cross section.
5. The device of claim 1 , wherein the conduits have a substantially square cross section.
6. The device of claim 1 , wherein the conduits are capillary tubes.
7. The device of claim 1 , further comprising a detector optically coupled with the lightguide.
8. The device of claim 1 , wherein at least one of the first and second light beams are decollimated.
9. The device of claim 1 , wherein the beams from the first and second light sources diverge in a direction normal to a plane containing the conduits.
10. The device of claim 9 , wherein at least one of the first and second light beams has a divergence half angle of at least about 20° in a direction normal to a plane containing the conduits.
11. The device of claim 9 , wherein at least one of the first and second light beams has a spread of no more than about 1° in a plane parallel to a plane containing the conduits.
12. The device of claim 1 , wherein the lightguide is made of a glass selected from the group consisting of fused silica and borosilicate.
13. The device of claim 1 , wherein the lightguide is a polymeric material selected from the group consisting of polycarbonate, polymethylmethacrylate, polymethylpentene, and cycloolefins.