Mass spectrometer interface

An apparatus for providing ionized particles of a target sample to a mass spectrometer, said ionized particles having characteristic mass to charge (m/z) ratios, said apparatus comprising:

• a channel providing a guide path for guiding a flow of gas from an inlet to an outlet;
• an expansion orifice to expand a flow of gas into said channel thereby increasing the gas' velocity;
• a roughing pump to reduce pressure in said channel to below atmospheric pressure;
• an ionizer within said channel for forming ionized particles from analyte;
• geometry for slowing said flow of gas, said outlet being provided at proximate a channel section in which flow of said gas has been slowed to be generally laminar to sample ionized particles from said flow.

A method of providing ionized particles of a sample to a mass spectrometer, comprising:

• introducing a mixture of gas and said sample into a channel;
• ionizing within said channel at least some of said sample to form said ionized particles;
• wherein said channel provides a tortuous path for said mixture of gas creating a region of disturbance for said gas within said channel to aid in liberating at least some of said ionized particles from impurities in said mixture;
• slowing said gas within said channel, downstream of said region of disturbance to provide a substantially laminar flow proximate an exit of said channel;
• sampling said ionized particles proximate said exit, for analysis in said mass spectrometer.