| 摘要 |
1,272,732. Sampling for gas chromatography. BECKMAN INSTRUMENTS Inc. 9 Jan., 1970 [15 Jan., 1969], No. 01085/70. Headings B1X part B. [Also in Division B8] Apparatus for injecting metered amounts of liquid samples of predetermined volume into analytical instruments comprises a needle section 11 open at one end 14 and communicating at the other end with a plunger section 17, and a plunger 19 slidably engaging the bore 13 in the plunger section 17 and adapted to seal the other end 16 of the bore 13 in the needle section 11, at the same time sealing a port 22 in the plunger section of the needle bore 13. In use the needle section 11 is inserted through the rubber septum of a pressurised container (not shown). After the plunger is moved to open the port 22, liquid sample flows up the bore 13 and spills from the port 22. The plunger 19 is returned to seal the bore 13 and the needle and plunger sections is then inserted, for example, into a selfsealing cap 42 on a G.L.C. (Fig. 4), the shoulder 15 of the needle section 11 restricting penetration of the needle 11 into a hot carrier gas conduit 36a of the G.L.C. instrument. Heaters 45 warm the carrier gas as it flows through the inlet 46 and also heat the blocks 37, 47. The plunger 19 is then moved to open the port 22 and the build-up of carrier gas pushes the liquid sample from the needle 11 which is then withdrawn to allow the gas to carry the vapourised sample through the column 38 and into the detector 39 of the instrument. |
