An interface for mass spectrometers. The interface uses non coaxial sampling pathways of the analyte ion beam prior to entering the entrance of a mass spectrometer for decreasing chemical background, and can be done in such a way as to permit multiple sprayers, increasing sample throughput and sensitivity for LC/MS (liquid chromatography/MS). The interface includes an ion source having an exit from which a beam of analyte ions are emitted, a curtain plate and an aperture in the curtain plate member, an orifice plate having an orifice therein. The orifice plate is being spaced from the curtain plate member defining a flow passageway therebetween, and the aperture in the orifice plate is aligned with a sample entrance to a first vacuum stage of a mass spectrometer maintained substantially lower than atmospheric pressure. The aperture in the curtain plate member is non coaxially aligned with the orifice in the orifice plate and the interface includes a gas flow mechanism for directing a counter flow gas into the flow passageway.