Gas Chromatography (GC)

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

September 2006. 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.

The fundamental aim of any computerized system validation should be to define its intended use and then test it to demonstrate that it complies with specification.

September 2006. In analytical chemistry, the continual quest for enhanced sensitivity and specificity - in gas chromatography (GC), this can be equated to separation power - remain the common goal in the development of new analytical methodologies. Today, GC is still the most widely used method for the analysis of volatile and semivolatile organic compounds. When coupled with the right choice of detector for the specific application, a wide linearity range and low limit of detection (LOD) can be met. For GC analyses, many approaches can be used to achieve greater sensitivity and lower LOD. They can be classified broadly into four categories: improved sampling (sample preparation) strategies; sample introduction methods; improved chromatographic performance; and alternative (selective–sensitive) detection transducers. This article provides an up-to-date review of existing and emerging chromatographic innovations, based upon these four strategies, that will improve sensitivity and detection limits of trace..

Analytical technologies have been applied to many problems of the modern world, though usually in the domain of the laboratory or to regulate production on the factory floor. However, modern instrumentation can provide valuable information in many other settings as well. Security applications demand sensitive information, accurate information and fast information. These are precisely the kinds of problems that instrumentation has been solving in the research setting for decades. The application of analytical technology to the security of nations, facilities, and people has become an important segment of the industry.

Researchers are using a method called gas chromatography, a process by which they will extract fish tissue and identify organic based compounds and pollutants in the tissue, especially flame retardants, of which traces have been found in the breast milk of women.

In the most general sense, validation refers to a process that consists of at least four distinct components or steps: software, instruments, methods or procedures, and system suitability.

The two questions to ask when considering the validation of computerized laboratory systems are "Do I need to validate the system?" and,if so,"How much work do I need to do?" This article provides a simple framework to answer these questions at the system level.

Validation is one of the most critical issues facing today?s chromatographers and spectroscopists. With developments in this area moving for-ward at a staggering pace, it is more critical than ever that scientists have the most up-to-date information possible on validation.

Gas chromatography-mass spectrometry using a single-quadrupole instrument is the workhorse technique of the environmental lab. It normally falls short for applications that require high mass accuracy. It is shown here that with proper calibration techniques, this technique can indeed readily obtain high mass accuracies to within a few millidaltons and become a powerful tool for unknown compound identification.

This article describes the current situation in FDA-regulated areas, as well as characterization of these products. Finally,the author discusses the various stages of early- and late-phase product developments.

In the second of a two-part series, Marlin K.L. Bicking continues to explain his work concerning integration errors in peaks with approximately equal sizes (small peak ratios).

The Stephen Dal Nogare award is one of the oldest and most prestigious awards given in chromatography. Little has been written about Stephen Dal Nogare "the man" or his contributions to scientific knowledge, including his unique contributions to separations science. This article describes his scientific career and how it has influenced the practice of chromatography.

Globally, 2005 sales of pharmaceuticals have been estimated at approximately $550 billion. A significant fraction of this amount was due to the top pharmaceutical companies in the world. The top five companies alone were responsible for total revenues of $168 billion, or 30% of the entire market.

In his annual installment, John Hinshaw takes a look at the new gas chromatography instruments and accessories that were on display at Pittcon this year.

Guest columnist Walter Jennings reflects on the early days of capillary gas chromatography (GC) and how chromatographers become experts in the technology by constructing their own columns, thereby achieving a more thorough understanding of the chromatographic process.

This article looks at current practices in bioanalytical chemistry by examining and critically assessing the various parameters that can be altered to achieve high-speed results with high resolution in LC–MS applications. The decision to opt for gradient or isocratic elution is also discussed.

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.

This month's installment of "Column Watch" is the conclusion of a two part series in which Ron Majors examines the trends in columns and sample preparation at Pittcon 2006.

In part I of a two-part series, the author introduces several methods to reduce error in your chromatographic analyses.

Exciting new uses for gas chromatography and its hyphenated forms show that there is an uncharted territory of applications and that there are limitations that still need to be overcome. The Tuesday afternoon oral session at Pittcon 2006, "GC-MS: Developments and Applications," gave the audience an idea of advances in GC and some new areas for the technique's application. John Chalmers of VS Consulting (Stokesley, United Kingdom) presided over the session.

At a session entitled "Atomic Emission Detection for Gas Chromatography," several speakers discussed applications of coupling gas chromatography and atomic emission detection (GC-AED).

This month's installment of "Column Watch" is the first of a two-part series in which Ron Majors examines the trends and highlights in columns and consumables at Pittcon 2006.

Capillary gas chromatography (GC) is a well-established separation technique. Rick Parmely reviews some of the capillary column basics by investigating a standard test mixture and observing some of the chromatographic effects that can affect peak response, peak shape and column bleed. He provides guidelines for obtaining the best performance from a capillary column. He discusses peak tailing, column overload, ghost peaks and column bleed and speculates on "when to give up." He concludes with a set of fundamental steps to be used in achieving better GC analyses.