February 2000

The efficiencies of microbore-2 columns, which are prepared from blanks that have a wide variety of inner surface roughness, drop sharply when the size of individual surface roughness features approaches the particle size of the packing material. The results suggest that two categories of packed column structure relate to the surface features and yield high and low efficiency columns. This installment of "Column Watch" discusses this conclusion in terms of the stability of an agglomerated layer of packing particles on the blank wall when subjected to shear forces during column packing.

Adapting the organic solvent strength and type can be an effective way to improve an isocratic separation.

In the first of two "GC Connections" columns, Hinshaw responds to reader questions about the signal-to-noise ratio and what it means in practical terms.

A second installment of "GC Connections" answers a reader's question about dual-column gas chromatography systems and their proper maintenance.

Column editor McDowall discusses electronic records and signatures and the effects of legislation regarding their use within the pharmaceutical industry.

The authors describe a method of reductive chlorination that enables the determination of total PCB content by gas chromatography with flame ionization detection.

The authors investigated the two most popular types of interfaces for benchtop LC–MS systems – the particle interface and the atmospheric-pressure ionization interface – to learn how the information obtained separately from the two can be complementary.

In the second installment of this series, the author looks at the first phase of the life cycle of a new chromatography system, bringing together a number of elements of the workflow and the functions as they are used in the laboratory.

The authors demonstrate a new detection method for various anions of weak acids separated by ion chromatography and point out the main advantages of this method.