Advancements in Atmospheric-Vacuum Interfaces of Mass Spectrometers with Increased Gas Throughput and Enhanced Sensitivity

Charged analyte-solvent clusters created in the atmospheric pressure ion (API) source flow into the mass spectrometer through a small diameter tube, heated to liberate molecular ions. Increasing the throughput by enlarging the diameter of the tube improves the sensitivity of the mass spectrometer, but this trend is constrained by the limited radial heat transfer during the short transfer time and fragmentation of fragile species at elevated temperatures. With the implementation of a high capacity transfer tube (HCTT) with a slotted cross section, in combination with an electrodynamic ion funnel (EDIF) operated at elevated pressures, larger throughputs are attainable while maintaining the desolvation characteristics of smaller throughput round bore tubes. This poster demonstrates enhancements in suppression of chemical noise by a combination of anisotropic supersonic expansion and blocked line of sight.