Gas Chromatography (GC)

Capillary extraction (CEx) is used to study the solventless in-tube extraction of naphthalene, acenaphthene, phenanthrene, fluoranthene, chrysene, benzo(a)pyrene and coronene in aqueous samples prepared by analyte spiking into clean waters or, as an alternative, by using the generator–column method of sample preparation. Analysis of laden extractors is conveniently performed by high-resolution gas chromatography (GC), with a flame-ionization detector (FID). Extraction set-ups and main extraction variables are investigated from a practical point of view. For 2- to 4-ring polycyclic aromatic hydrocarbons (PAHs), equilibrium times are within a few minutes, analytical sensitivity is in the parts-per-billion (ppb) range and reproducibility is better than 10% relative standard deviation (RSD) (n = 6). Coronene behaviour is unique and presumably determined by extreme hydrophobicity and thus very negligible aqueous solubility: in-tube extraction of coronene seems possible only if starting from..

The environmental market peaked about fifteen years ago when the United States government passed a large body of new environmental laws and strengthened existing ones, dramatically increasing the number of mandated tests. As a result, the analytical instruments market received a boost in new instrument sales. While growth from the environmental market has slowed considerably since, the total market is still quite significant.

You have purchased a new gas chromatograph. Your company's safety office has completed a review of your lab's supplies. Before setting up your gas chromatograph, you read the instructions and familiarize yourself with the instrument. You might even give some thought to the exposure risks for the various substances in your samples. Yet, what about the less visible risks inherent in the gas delivery system that makes this a gas chromatograph?

The analysis of peptides and additives using a new HPLC innovative column technology, Pathfinder, was shown. For the analysis of flavours in lemon juice GC–MS with a new MS library, FFNSC, with linear retention indices was used.

Soft drink formulas often include preservatives, artificial sweeteners, flavours or caffeine in their list of ingredients. Using the Acclaim OA column, as many as eight common additives may be determined in a single run. Many of these additives are hydrophilic organic acids for which this column was designed. Notably, benzoate and sorbate, which do not resolve on C18 columns at low pH, are fully separated.

Column lifetime is a more and more important issue when developing an analytical method for HPLC. Besides sample treatment, column cleaning and storage, operational parameters of the analytical method will have an influence on column lifetime. This question may not always be addressed early enough in the methods development process.

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.

In a good laboratory practice (GLP) environment, data-handling software cannot be used until it is validated. This even applies to the most simple program that performs calculations or stores data. A detailed documentation of the set-up and the performance of the software - called software validation - is required. The development and validation requirements are described in this article and illustrated with a software for robustness testing (SRT), which guides the user step-by-step through the experimental set-up and interpretation of robustness tests. This software was developed in an Excel (Windows XP) environment and is used as part of method validation in laboratories that require compliance with GLP and 21 CFR Part 11. The software was subjected to software validation regulations and is compliant with electronic records and signature rules (21 CFR Part 11) as it creates, delivers and stores electronic data. The validation tests are based on the computerized system validation (CSV) -..

This article assesses the advantages of including certified reference materials in collaborative method validation studies in food analysis. A recently conducted collaborative trial on the determination of acrylamide in bakery and potato products is described to illustrate this.

Since the first Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy was held in 1950, Pittcon, as it is called today, has become a key meeting place where renowned scientists present their pioneering research and developers showcase the latest instruments that make many of those research scientific breakthroughs possible. This two-part article series will present a historical perspective on just a few of the significant scientific advancements that were discussed and demonstrated at Pittcon over the years. Part I will focus on new instruments and techniques that were presented at Pittcon from 1950 to 1980, and Part II will discuss a few of the many notable scientists and their discoveries that have been enabled by advances in mass spectrometry, capillary electrophoresis, and other instrumental techniques since 1980.

November 2006. This month, John Hinshaw addresses questions of instrument capabilities and chromatographers' expectations. In subsequent issues, he will discuss adjustment of hardware settings, optimization of column parameters, and data-handling issues. This is the first article in the recently released "GC Connections Resource Guide."

The laboratory life science and analytical instrument industry is comprised of a large, diverse group of organizations that manufacture and distribute their products worldwide. However, overall industry sales are concentrated among a small set of companies. Approximately 950 firms are included in the industry, but only about 100 companies have sales above $50 million.

October 2006. This brief review introduces the GCxGC technique and its advantages, hich primarily lie in the area of ncreased separation power for volatile chemical analysis.

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.