Microfluidic devices connected to capillaries with minimal dead volume

摘要

A method is provided for joining a microchip device to a capillary tube. The microchip device has a capillary channel opening onto an edge surface of the device. A short hole is drilled into the edge surface, aligned with the capillary channel. The drilling is done with a flat bottom, preferably by a two-step drilling process. Then, the end of the capillary can be inserted into the hole so that its end is substantially flush with the flat bottom of the hole, thereby eliminating dead volume. Testing has shown that this connection provides very little band broadening of samples transported through the capillary channel into the capillary tube. The tip of the capillary tube can be tapered, so that it is suitable for use as an electrospray source for a mass spectrometer.