Successful Gas Chromatography Using Fused-Silica Capillary Columns
March 1st 2006Capillary 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.
LC workshops – something for the spring
March 1st 2006Two LC workshops will be held between 8?10 May at The Rubens at The Palace Hotel, London, UK. The courses are aimed at improving method development and providing solutions to common problems that occur with LC methods. The courses are brought by LC Resources and LCGC Europe, and sponsored by Hichrom.
Single Calibrant Quantification with HPLC — Fact or Fantasy?
This article assesses the extent to which some familiar HPLC detectors can provide reliable quantitative analytical measurements when no suitable primary reference standard exists. The advantages and limitations of two candidate detector schemes are discussed ? evaporative light-scattering detection (ELSD) and chemiluminescent nitrogen detection (CLND). It was found that when the ERETIC (Electronic REference To access In-vivo Concentrations) method in proton NMR was used as a "gold standard" reference procedure the ability of CLND to provide reliable single calibrant quantification is superior to ELSD. Furthermore, ELSD showed bias towards underestimation of chromatographically-resolved impurities, resulting in an overestimation of analyte purity.