Systems for Microchip Capillary Electrophoresis Absent Electrokinetic Injection
Microchip capillary electrophoresis (CE) utilizing a sample injector based on a mechanical valve rather than electrokinetic injection can provide improved sample injections, enhanced capabilities, and can eliminate the need for changing the electric field in the separation channel to induce sample injection. In one instance CE electrodes continuously apply an electric field for CE separation along a separation channel. A sample channel is connected to the separation channel at an intersection and has a sample pressure that is greater than that which is present in the separation channel near the intersection. The sample channel does not have electrodes that apply voltages for electrokinetic injection. A sample injector in the sample channel or at the intersection comprises a mechanical valve to control sample injection from the sample channel to the separation channel.
1 . A microchip capillary electrophoresis (CE) system comprising:
A separation channel and CE electrodes configured to continuously apply an electric field for CE separation along the separation channel during operation;
A sample channel connected to the separation channel at an intersection, the sample channel during operation having a sample pressure greater than that of the separation channel at the intersection, and lacking electrodes associated with electrokinetic-based injectors; and
A sample injector in the sample channel or at the intersection comprising a mechanical valve, and not an electrokinetic-based injector, to control sample injection from the sample channel into the separation channel.
2 . The system of claim 1 , further comprising:
A plurality of discrete injections of a sample from the sample channel to the separation channel in a rapid, pseudo-random sequence, the sample comprising a plurality of components;
A detector at the end of the separation channel detecting the discrete injections after CE-induced overlap, which comprises mixing of at least one component from at least one of the discrete injections to another discrete injection; and
A processing device programmed to deconvolute the CE-induced overlap.
3 . The system of claim 1 , further comprising:
One or more discrete injections of a sample from the sample channel to the separation channel, the sample comprising a plurality of components;
A plurality of CE channels within the separation channel; and
A manifold within the separation channel distributing the one or more discrete injections among the plurality of CE channels
4 . The system of claim 3 , further comprising an electrospray ionization (ESI) emitter at the end of each CE channel.
5 . The system of claim 1 , further comprising a liquid chromatography column connected to the sample channel and providing liquid chromatography separation of the sample prior to injection into the separation channel.