LCGC Europe-06-01-2006

Higher productivity and faster analyses are two of the driving forces for continued improvement in high performance liquid chromatography (HPLC) column technology. Reduction in the average particle size of HPLC porous column packings below 2 ?m has resulted in sub-1.0 min separations in the gradient and isocratic modes. In this instalment of "Column Watch", Ron Majors traces the development of particle technology from the beginning of HPLC to the present, discusses why small particles are desirable, and probes some of the difficulties to be encountered, including extracolumn band broadening, pressure restrictions, and instrumental considerations. Finally, he shows a wide variety of fast- and ultrafast applications examples from commercial products in the sub-2 ?m range. Speculation on future directions in HPLC in particle technology concludes the column.

Conjugation catalysed by the UDP-glucuronosyltransferase (UGT) superfamily of drug-metabolizing enzymes is an important mechanism of anticancer drug resistance in colon cancer cells. The mechanism manifests itself by a reduction in the intracellular concentrations of the parent drug through increased export of the glucuronide metabolites to the extracellular compartment. Modulation by an inhibitor of UGT inhibits the formation of metabolites and restores intracellular concentrations of the drug. This article describes a screening method using HT29 human colon cancer cells and based on HPLC methodology that allows the identification of effective modulators of the glucuronidation mechanism of drug resistance. A rapid solid-phase sample preparation technique using C2-bonded 40 ?m silica particles was developed for the extraction of cell lysates and culture media without degradation of unstable parent compounds and their glucuronides or artefactual in situ formation of metabolites.

New ways of envisioning scientific data are constantly being developed in data rich research environments. Researchers at the University of California, Irvine's Center of GRAVITY (Graphics, Visualization and Imaging Technology), USA have developed a new display for this data rich market. They have developed the Highly Interactive Parallelized Display Wall or HIPerWall. It is a massively tiled, grid-based display built using fifty 30-inch Apple cinema displays and twenty-five Power Mac G5 computers. This powerful display system allows researchers to view and manipulate their data sets at extremely high resolutions and collaborate with other scientists in new and exciting ways.

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.

Infotrieve has announced that the University of Pittsburgh School of Medicine and Acacia Research's CombiMatrix Molecular Diagnostics (CMD) group have each adopted the company's electronic laboratory notebook (ELN). This software solution is said to be the first enterprise-wide ELN to receive the full endorsement of the collaborative electronic notebook systems association (CENSA).

In terms of practical use of the results, resolution is generally more critical than retention.