IMPROVEMENTS IN OR RELATING TO MICROFLUIDIC SAMPLE PREPARATION AND MASS SPECTROMETRY

摘要

An electrospray ionisation probe (100) which comprises a piezoelectric micropump for receiving two liquid components, mixing them to form a sample and ejecting them into a capillary needle which, in turn, emits the mixture as an ionised spray to a mass spectrometer for analysis. The drive voltage for the piezoelectric micropump can be varied to vary the mixing parameters. Temperature regulation of the sample is provided by a thermoelectric device in the probe. Bath gas can be passed through channels of an aluminum block attached to the thermoelectric device to provide temperature controlled gas which is supplied to an apron surrounding the sampling cone of the mass spectrometer. This provides temperature regulation of the sample. Another aspect of the invention provides a method of collecting macromolecular assemblies by using a time-of-flight mass spectrometer in which the ion beam containing packet, containing the macromolecular assemblies is diverted by an orthogonal accelerator (910). The diverted ions are collected on a collector plate (920) which can be an EM grid or X-ray plate, to be used for further analysis. A double isolation valve arrangement is used so that the collection plate (920) can be removed without venting the interior of the mass spectrometer. Macromolecules can be detected and collected intact by admitting gas into the mass analyser to effect collisional cooling namely reducing the internal energy of the ionized macromolecular assemblies.