High Column Efficiency in Gas Liquid Chromatography at Inlet Pressures to 2500 p.s.i.

Unified chromatography: Fundamentals, instrumentation and applications†

“…In recent years, as technology has advanced, devices that can be operated at high pressures and temperatures utilizing low flows are becoming commercially available. Studies have been performed to develop separation techniques that would combine the advantages of LC and GC, such as high efficiency and shorter analysis time, and the analysis of a wide range of compounds, as anticipated decades ago with the high inlet pressure gas chromatography .…”

“…The trend in chromatography is the miniaturization of analytical systems, and the use of capillary columns in unified chromatography is necessary as new detectors and their interfaces are being adapted for use with miniaturized systems . In addition, the use of capillary columns with reduced internal diameters allows faster separation without significant loss in the resolution . This is usually done by raising the column temperature, utilizing smaller diameter particles thus generating higher pressures, or both .…”

“…In addition, the use of capillary columns with reduced internal diameters allows faster separation without significant loss in the resolution . This is usually done by raising the column temperature, utilizing smaller diameter particles thus generating higher pressures, or both . To take the best advantage from such a system, the instrumentation has to support high pressures and temperatures, permitting faster linear velocity.…”

Electrically heated cold trap inlet system for computer-controlled high-speed gas chromatography

“…The recognition that optimal performance of short columns could only be achieved if injection plug widths approached a few milliseconds has led to a number of devices and studies aimed at achieving the goal of rapid sample introduction. Advances in this area in the past few years have included the use of high-speed mechanical valves or fluid logic gates (2)(3)(4)(7)(8)(9)(10)(11). The use of cold trapping for the collection of airborne samples and the rapid reinjection of collected vapor or liquid samples has also resulted in the development and investigation of many effective systems (6,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21).…”

“…However, the preparation of enzyme electrodes using gas sensors is complicated by the difficulty in attaching the enzyme to the fluorocarbon membrane. In most cases, the enzyme is immobilized onto a support membrane, e.g., nylon net (5), pig intestine (6), or cellulose acetate (7), which is physically held over the gas-permeable membrane of the sensor. Alternatively, covalently cross-linked enzyme membranes, prepared with glutaraldehyde and bovine serum albumin, are held on the gas sensor by means of a dialysis membrane (8,9).…”