PNNL

Abstract

A novel injection technique for high-speed gas chromatography (HS-GC) is demonstrated. Synchronized dual-valve injection is demonstrated to provide peak widths as low as 1.5 ms (width-at-half-height) for the unretained analyte using a 0.5 m DB-5 column with an internal diameter of 100 ?m and a film thickness of 0.4 ?m using a head pressure of 70 psi at a temperature of 150 °C, for a resulting dead time of only to =26 ms (~1900 cm/s., 26 mL/min). Using the DB-5 column in a 1.0 m length under the same instrumental parameters, with a resulting linear flow velocity of 935 cm/sec (12.7 mL/min of carrier gas, to=117 ms), a minimum peak width of 3.3 ms was obtained. For these 0.5 m and 1.0 m column experiments, the resulting band broadening data is limited almost entirely by the band broadening terms in the Golay equation, and not by extra-column band broadening due to the injection process. During an isothermal separation, ten analytes were separated in a time window of 400 ms.