Why 5 cm syringe needles for capillary GC?
A detailed discussion of how syringe needle length impacts quantitative analysis. Includes optimal needle lengths for different scenarios. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Why Uncoated Capillary Precolumns Enable Injection of Large Volumes
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
Sample Evaporation in Splitless Injection
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
Sample Evaporation in Hot GC Injectors
Proper sample evaporation in the injection port cannot be assumed. Principles governing evaporation are discussed. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Assuring Accuracy of GC Results
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
Using Micropacked Columns
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.
Tech Tip: Why do I Lose Retention on my C18 in Highly Aqueous Mobile Phases?
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.
Reducing Column Internal Diameter
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 Primer on Gas Flow
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.
How to Condition a New Capillary GC Column
Proper conditioning is essential for optimal performance from a capillary GC column, but inexperienced chromatographers might not know the proper procedures for installing and conditioning a new column. Here, we summarize our recommendations for installation and conditioning procedures.
