Using clean, high-quality tubing is essential when setting up a new GC or when replumbing an existing gas delivery system, especially for carrier and detector gases.
“Clean” tubing often only means that it has been processed according to ASTM B280 or CGA G-4.1. However, in our experience, tubing prepared by these methods alone is not clean enough for chromatography applications. Residual drawing oils and other manufacturing artifacts may still be present and can easily contaminate an instrument after installation.
Whether you are beginning method development or running a routine procedure, chances are good that you are using a 1-, 5-, or wax-type gas chromatography (GC) column. These general-purpose columns are the cornerstone for safety, quality, and purity testing in many industries including clinical, environmental, food safety, food quality, forensic, petrochemical, and more. From measuring trace-levels of pesticide residues to quantifying drug impurities, 1, 5, and wax fused silica columns are the laboratory workhorses that GC analysts depend on to deliver accurate, reliable results.
What is DiatoSorb-W?
Diatomaceous earth (DE) is a type of siliceous earth that is made up of the fossilized silica exoskeletons of single-celled algae called diatoms. It was discovered in Germany in the 1830s and since then these humble fossils have grown to play a critical role in many industries and are specified in numerous procedures including many ASTM and USP compendial methods. Since the 1960s, those using packed column methods have depended heavily on diatomaceous earth brands (e.g., Chromosorb) as the solid support material in their packed columns. These original materials worked well, but due to unpredictable availability and quality, today’s analysts face long delays and inconsistent product performance.
As all inlet liners gradually become dirty and the surface becomes active they become unsuitable for most sample analysis.
Some laboratories adopt the risky practice of cleaning and then deactivating their liners.
Regardless of whether the liner has visible deposits, charring or discolouration, the process of cleaning will involve the use of solvents such as Methanol, Methylene Chloride, and Hexane. As for deactivation, many labs use Dimethyldichlorosilance in dry Toluene. Most of those chemicals are category 1 and 2, and some of the long term exposure will cause damage to organs, reproductive toxicity, and aspiration hazards. In addition to the hazardous nature of those chemicals, they are costly to purchase and equally expensive to dispose.