Improvements in and relating to the production and control of ions

摘要

A nebulized fluid is formed by injecting a liquid comprising a solvent into a vacuum system 107connected to a mass analyzer directly at supersonic speeds. Liquid droplets are entrained within a gas stream 109 also injected into the vacuum system. The droplets are ionized by an electrode ring 217 although it is envisaged that non-charged droplets may be produced and ionized within an ion optics system. The solvent subsequently evaporates during transit through an ion optics system to provide a stream of ions to a mass analyzer. Secondary or primary ionization of the ions/molecules may be provided using a UV source arranged in the ion optics system. The droplets/ions produced by the nozzle are directly injected into the mass analyser vacuum system so differential vacuum pumping systems are not required. The nozzle configuration with direct injection into a vacuum enables reduced droplet sizes and increased droplet dispersion that enhances desolvation whilst at the same time allowing high flow rates. Also, the ion optics system provided converts the supersonic jet injected into the system into a subsonic laminar flow of ions, and because the ion flow is laminar the loss of ions in the ion-optics system is reduced.