An improved ion sampling tube designed to increase the amount of current delivered into the vacuum system of a mass spectrometer or other gas-phase ion or particle detectors or collectors. A device and method is disclosed that utilizes a tube with a high flow of ion entrained gas passing through the said tube. Said ions are directed from the tubular gas flow through an ion selective aperture and into an adjacent region and subsequently directed into a lower pressure region for detection or collection. The method is useful for enhancing the detection of analytes in solutions that are either nebulized or electrosprayed, and analytes present in gases. The method is also useful for isolating ionic species from the ion source from neutral gases and particles that may interfere or interact with analyte species. The method also decouples the high flow of the atmospheric pressure ion source from the low flow ion transmission into vacuum.