Methods and apparatus are provided to resolve analytes within a fluid path using isoelectric focusing, gel electrophoresis, or other separation means. Materials within the fluid path that are compatible with these separation means are used to attach resolved analytes to the wall of the fluid path. Attachment results from a triggerable event such as photoactivation, thermal activation, or chemical activation. In accordance with a further aspect of the present invention, the material in the capillary may also be disrupted, by either the triggerable event or a subsequent event such as melting or photocleavage. Thus, an open lumen or porous structure may be created within the fluid path, allowing unbound analyte materials to be washed from the fluid path, and detection agents to be washed into the fluid path. The separation-compatible materials may be polymerizable monomers, gels, entangled polymers or other materials.