Discussion of the origins of the retention gap, a length of uncoated tubing used to focus large volume injections and prevent band broadening. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
The rule of using empty liners with splitless injection was developed in the days of manual injections. Does it still hold true? Sample evaporation is explored. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Proper sample evaporation in the injection port cannot be assumed. Principles governing evaporation are discussed. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Even validated methods run on certified equipment are unlikely to be foolproof. Real quality assurance needs to be based on direct verification using internal standards and control samples. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Micropacked columns are 1-2 meter, 0.75-1.0mm ID packed stainless steel columns with performance characteristics intermediate between conventional packed columns and capillary columns. They are inexpensive, very durable, and easy to install and operate. They have a wide range of applications, but are especially useful for analyses of gas mixes, including sulfur compounds or light hydrocarbons, for which a packed column is needed to obtain baseline separations of sample components.
Learn what de-wetting is, and how to avoid it, by using an Aqueous C18 column, instead of a conventional C18, when analyzing polar compounds by HPLC.
Scaling down column size is simple to do and can help reduce solvent use. Here is an easy-to-follow example that teaches you how to reduce column internal diameter.
A basic understanding of gas flow principles is fundamental to obtaining accurate flow measurements. This primer contrasts mass flow and volumetric flow regimes, and illustrates the effect of flow impedance and loading on the flow source in gas chromatography.
Recovery of a 17 ppbv test standard of hydrogen sulfide exceeded 85% after 54 hours in a Sulfinert-treated cylinder; recoveries of methyl mercaptan, ethyl mercaptan, carbonyl sulfide, and dimethyl disulfide exceeded 90%. A Sulfinert-treated sampling/transfer system can assure accurate sulfur content data for natural gas, beverage-grade carbon dioxide, or other samples.
The analysis of synthetic cannabinoids and their metabolites can be a difficult and challenging task. Keeping up with the ever-growing list of synthetic cannabinoids that illicit drugmakers produce further complicates the analysis. As shown here, the retention and selectivity of the Raptor Biphenyl column allows new drugs to be added to an existing method, providing labs with an important vehicle for improving efficiency and productivity.
