Rational inlet design for a portable atmospheric pressure ionization–mass spectrometer (API–MS)

Equations are derived that describe the gas-dynamic flow through three types of high pressure inlets into a vacuum system: (1) a sonic orifice inlet, (2) a sonic capillary inlet and (3) a pulsed sonic capillary inlet. These equations can be used for rational inlet design for portable atmospheric pressure ionization–mass spectrometers (API–MS) taking into account the optimum operating pressure of the mass filter and the pumping characteristics of the system.

Equations are derived that describe the flow through three types of gas inlets: (1) a sonic orifice, (2) a sonic capillary, and (3) a pulsed sonic capillary.Figure optionsDownload high-quality image (80 K)Download as PowerPoint slideResearch highlights▶ Equation for predicting the molecular flow through a sonic orifice sampling atmospheric pressure gas. ▶ Equation for predicting the molecular flow through a sonic capillary sampling atmospheric pressure gas. ▶Equation for predicting the molecular flow through a pulsed sonic capillary sampling atmospheric pressure gas.