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Valco Instruments Co., Inc. For more information, visit the company's website at www.valco.com.

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Vanessa R. Kinton, Gerstel, Inc., Kevin Goodner, USDA, Citrus and Subtropical Products Laboratory

In the first of this new column, Michael Balogh takes a look at source design and the strengths of multimode ionization, such as its ability to switch at high speeds between electrospray and atmospheric-pressure chemical ionization.

This article establishes the estimation of the uncertainty associated with the chromatographic determination of biogenic amines. The authors identify and estimate each source of uncertainty to establish the accuracy of results and to obtain a better understanding of the method. Thus, measurement uncertainty was split into two sections: uncertainty related to the working conditions, which considers the equipment used, and inherent uncertainty, which includes the chemical stages indicated in the procedure as well as calibration sources, taking into account the existence of the matrix effect. Recovery studies also were made to quantify the contribution of bias to the overall uncertainty. This parameter was calculated for the determination of biogenic amines in different types of samples.

This article describes the basis of OPLC and its instrumentation, and provides brief details of recent applications for which this technique is suited.

The authors describe a system for automated analytical temperature-rising elution fractionation that uses the built-in differential refractometer of a commercial gel-permeation chromatography instrument and a stop-flow method for sample crystallization.

The guest authors describe an in-tube SPME system coupled with capillary GC for the trace analysis of organic contaminants in water.

Leslie Ettre discusses four major application fields in which GC changed the way chemists carry out analyses.

John Dolan discusses system-related causes of peak broadening in isocratic reversed-phase LC.

Guest author Steve Scheuring suggests ways to choose and use gases in laboratories.

Second column in a series that reviews impurity method validation guidelines.

2003 index of authors and subjects.

This month's column looks at several possible causes of peak splitting and presents some guidelines for isolating its source.

Products and literature for separation science.

Majors discusses low-dispersion columns, describes how to modify HPLC systems to work with the small-volume columns, and provides guidance about obtaining the optimum capabilities from these columns.

Advanced Chemistry Development, Inc. For more information, visit the company's website at www.acdlabs.com.

In this article the authors describe the benefits of on-line coupled LC?GC using a series of applications. The pros include shorter analysis times, better reproducibility and improved detection limits.

This article illustrates the use of multiplexed microemulsion electrokinetic chromatography with UV detection to develop a rapid approach for obtaining log POW values of neutral and basic compounds.

The authors descrive the use of GC–MS to isolate and identify potentially toxic compounds in concentrated extracts of sewage treatment plant effluents.

John Hinshaw explores how to perform solid-phase microextraction and discusses the advantages provided by the technique.

The guest authors provide an overview of tissue sample preparation by discussing and comparing conventional extraction technologies an novel approaches.

The authors show how several factors can contribute to a chromatogram's appearance.

Appendix for "Separation of Toxic Coplanar PCB Congeners . . ."

This new column looks at the current importance of electrospray ionization and emerging approaches for samples that require ionization by other means, including a new technology, multimode ionization.