Ion funnels are a well-established means of improving sensitivity in mass spectrometers. These funnels collect and transfer diffuse ion plumes from ion sources using a combination of radio frequency direct current fields applied to a series of ring electrodes. The relatively large entrance of the funnel followed by progressively smaller inner diameters focus the ions. In even the most advanced ion funnels, however, ion plumes are accompanied by expanding gas that contains partially dissolved ions, droplets, and neutral particles. When large amounts of this gas are present, the non-ionic particles significantly impact the performance of the ion funnel as well as the downstream ion optics. These non-ionic particles also stick to the sides of the funnel, necessitating downtime for periodic funnel cleaning.

PNNL's novel bent ion funnel uses a non-linear approach to separate ions from non-ions. Typical ion funnels have a straight line of sight from entrance to exit. PNNL’s newest patented ion funnel features a center axis that is bent, curved, or angled so that it is offset in a certain direction or plane, breaking the line of sight. Ionic and non-ionic species introduced into the device separate into two paths; only ions follow the curved center axis, while non-ionic species get pumped away from between the electrodes. This approach has been proven to improve the limit of detection for direct mass spectrometry analysis of low-abundance peptides by more than four-fold compared to a standard triple quadrupole interface.

The easy-to-clean device offers enhanced sensitivity and improved longevity and reproducibility. It can be used with mass spectrometry to increase analysis performance.