Patent ID: 8268249

Claim:
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.