Most modern GC autosamplers employ high-speed actions by default.

Computerized pneumatic control adds a very capable multipurpose tool to the chromatographer's tool belt.

In this month's "GC Connections" instalment, John Hinshaw discusses computerized pneumatics for gas chromatography. This is the first of a two-part series that reviews computerized pneumatics and some important considerations that arise in the course of normal use.

This month's instalment of "GC Connections" discusses factors that can help determine which type of liquid injection technique is appropriate for specific samples, including having to use existing inlet systems that are on-hand in the laboratory with samples for which they might not be ideally suited.

Setting realistic expectations requires a good working knowledge of an instrument's capabilities in terms of the sample requirements as well as an understanding of the effects of real-world samples and their matrices on long-term instrument performance.

The accuracy and precision of results in gas chromatography and other analytical techniques are highly dependent upon the sample and its preparation, the instrumentation, accessories and operating conditions, as well as on operator skill and experience. For these reasons, accuracy and precision for a specific methodology can be expected to vary from one laboratory or operator to another. This month, we look at statistical analysis as a diagnostic tool.

Thermal conductivity detectors have been in use since before the beginning of gas chromatography. Essential for fixed-gas detection — no substitute has the same ease of use and stability — thermal conductivity detectors are also employed when the auxiliary or combustion gases required by flame ionization or other detectors are unsafe or impractical. Although they cannot match the sensitivity of ionization detectors, thermal conductivity detectors are the third most used detector, surpassed only by flame ionization and bench-top mass-spectrometry detectors. This month's instalment of "GC Connections" takes a look at the operating principles and inner workings of the thermal conductivity detectors.

Overall FID sensitivity depends upon the combustion gas flow-rates, the carrier-gas flow-rate, the flame jet exit diameter, the relative positions of jet and collector and, to a lesser degree, the detector temperature.