Atmospheric pressure ion lens for generating a larger and more stable ion flux

An ion source apparatus for generating ions from an analyte sample, the apparatus comprising:

• an ion source;
• at least one counter electrode mounted opposite the ion source;
• and,
• an ion lens mounted adjacent to the ion source, wherein, during use, a potential difference is applied between the ion source and the at least one counter electrode to generate a plurality of ions, and to cause the plurality of ions to move towards the at least one counter electrode, and a constant potential is applied to the ion lens to chance the equipotentials adjacent to the ion source to stabilize the spray of ionized droplets and to focus and direct the ions in a desired axis of ion propagation.

A method for generating ions from an analyte sample, the method comprising the steps of:

• 1) supplying the analyte sample to an ion source;
• 2) providing at least one counter electrode spaced from the ion source;
• 3) providing a potential difference between the ion source and said at least one counter electrode to generate a plurality of ions;
• and,
• 4) providing an ion focusing element and applying a potential to the ion focusing element to change the equipotentials adjacent to the ion source to focus and direct the plurality of ions in a desired axis of ion propagation.

An ion source apparatus for generating ions from an analyte sample, the apparatus comprising:

• an ion source:
• at least one counter electrode mounted opposite the ion source;
• and,
• a plurality of ion focusing elements mounted to substantially surround the tip of the ion source,
• wherein, in use, a potential difference is applied between the ion source and the at least one counter electrode to generate a plurality of ions, and to cause the plurality of ions to move towards the at least one counter electrode, and potentials are applied to the plurality of ion focusing elements to change the equipotentials adjacent to the ion source to stabilize the spray of ionized droplets and to focus and direct the ions in a desired axis of ion propagation.