Abstract: In a liquid chromatography apparatus, a stream of fluid flows at uninterruptedly high-pressure through a valve structure into a chromatographic column. The valve structure comprises an entrance port and a check valve through which a quantity of sample fluid can be introduced into the high-pressure carrier fluid stream. The entrance port of the valve structure is configured to mate in leak-tight sample fluid communication with an exit port on a high-pressure sample fluid delivery device. In a preferred embodiment, the high-pressure sample fluid delivery device is configured as a hand-gun, with a piston disposed in the barrel thereof to eject a quantity of sample fluid from the muzzle thereof. In this embodiment, the barrel of the gun is received within the entrance port of the valve structure so as to form a high-pressure seal.

Abstract: A high pressure sample injector for liquid chromatographs is disclosed. The apparatus includes structure defining a cylindrical dispensing chamber for receiving the sample to be injected into the flow path of a high pressure stream of carrier fluid in a liquid chromatograph. Control structure is interposed between the dispensing chamber and the flow path of the carrier stream for preventing liquid flow from the carrier stream to the dispensing chamber, and for enabling flow in the opposite direction only when the pressure in the dispensing chamber at least equals the carrier stream pressure. A pressurizing apparatus is connected to the dispensing chamber to raise its pressure, when desired, to a value at least equal to that of the carrier stream, in order that the sample may be injected into the carrier without reducing the carrier stream pressure.