Automated sampler-injector apparatus and method for sampling a quantity of sample and testing portions of said quantity

An automated sample-injector apparatus for use with a liquid chromatograph column, comprising:

• I. carousel means adapted to hold a plurality of sample containers in a substantially horizontal plane, having at one location thereon an aperture;
• II. means for removing a quantity of sample from one of said sample containers, and injecting a portion of said quantity directly into a multi-port injection valve means, comprising:
• (a) an elongate, hollow injector tube having a substantially flat tip lying in a plane perpendicular to the axis of said tube;
• (b) means for rotating said carousel means to allow positioning of a selected one of said sample containers vertically beneath said injector tube and to allow positioning of said aperture vertically beneath said injector tube;
• (c) means for lowering said injector tube from an original position to a first position and for raising said injector tube back to said first position and for lowering to a second position within a tube-receiving passage in said injector valve means;
• (d) syringe means operable by an electric motor;
• (e) tubing means connecting said syringe means to said injector tube to allow said syringe means when activated by said electric motor to draw a quantity of sample from said sample container into said injector tube and tubing means;
• and
• (f) means to activate said electric motor to cause said syringe means to inject said portion of said quantity through said injector tube directly into said injector valve;
• III. said injector valve means adapted to receive said injector tube in said tube-receiving passage and further receive said injected portion of said quantity of sample and transfer said portion to said liquid chromatograph column to be analyzed, comprising:
• (a) a non-rotatable first element having said tube-receiving passage extending therethrough along a straight line to a face thereof;
• (b) a second element rotatably mounted on said first element and having a face axially adjacent to and in bearing contact with said face on said first element;
• (c) rotating means for rotating said face on said second element relative to said face on said first element to switch the injector valve means from a load position to an inject position;
• (d) a first port in said second element for connection at one end thereof to one end of a sample loop, said first port at its other end being narrower than the flat tip of the injector tube whereby the flat tip can lie flush against the face of the second element;
• (e) a second port in said second element for connection at one end thereof to said other end of said sample loop;
• (f) a third port in said second element for connection at one end thereof to a pressurized supply of liquid solvent;
• (g) a fourth port in said second element for connection at one end thereof to said liquid chromatograph column;
• (h) a fifth port in said second element for connection at one end thereof to a discharge tube;
• wherein said second element, when rotated relative to said first element to said load position by said rotating means has said first port aligned with said tube-receiving passage so as to be in fluid communication therewith, said second port in fluid communication through said first element with said fifth port, and said third port in fluid communication through said first element with said fourth port;
• and
• wherein said second element, when rotated relative to said first element to said inject position by said rotating means, has either of said first port or said second port in fluid communication through said first element with said third port, and said other of said first port or said second port in fluid communication through said first element with said fourth port.

A method for automatically sampling a quantity of sample and injecting in consecutive sequence portions of said quantity into a liquid chromatograph column for analysis, from each of a plurality of sample containers, comprising the steps of:

• (a) positioning a carousel member containing a plurality of sample containers so that a selected one of the sample containers is disposed vertically beneath an injector tube connected by tubing means to a syringe means;
• (b) lowering said injector tube from an original position into the selected sample container, and operating said syringe means to draw up a quantity of said sample through said injector tube into said tubing means;
• (c) raising said injector tube to its original position, and removing the selected sample container from beneath said injector tube so as to expose a multi-port injector valve vertically beneath said injector tube;
• (d) switching said multi-port injector valve so that one end of a sample loop, connected to a first port on a second element of said valve, is aligned and in communication with a tube-receiving passage located in a first element of said valve;
• (e) lowering said injector tube into said tube-receiving passage;
• (f) operating the syringe means to force a portion of the quantity of sample contained in said tubing means through said injector tube and into said sample loop, said sample loop connected at its said other end to a second port on said second element of said valve;
• (g) rotating said second element of said injector valve relative to said first element so that a means for flushing said portion of sample from the sample loop, connected to a third port on said valve, is in fluid communication with one of said ends of said sample loop, and a liquid chromatograph column connected to a fourth port on said second element is in fluid communication with said other of said ends of said sample loop, thereby flushing the sample from the sample loop and into said chromatograph column;
• (h) repeating steps (d), (f) and (g) at least once;
• (i) raising said injector tube to said original position;
• and
• (j) positioning said carousel member so that a further selected one of the sample containers is disposed vertically beneath said injector tube.