Archive for 2020

FDA Issues Second Warning on Methanol Based Hand Sanitizers

The U.S. Food and Drug Administration has placed methanol containing hand sanitizers on an import alert (1). These products do not list this ingredient and some are incorrectly labeled “FDA approved.” Currently, 87 hand sanitizers have been found to contain methanol (2). Methanol (methyl alcohol Cas# 67-56-1), known as wood alcohol, is commonly found in […]

LPGC – Fast way to your pesticide analysis!

Throughput is one of the most important parameters in the lab. The more samples we can analyze in a day, the sooner we can get home. Enter Low Pressure GC (LPGC) – this is an invention from our brilliant Jaap de Zeeuw [1-2], where a relatively short analytical column (10 – 15 m) with large […]

Water, can’t live without it so how can we deal with it (and adsorbent columns)

Often the gas samples contain some water vapor. Although we are usually not interested in the amount of moisture present in the sample, if we don’t dry it, the water will be injected onto the column with our sample. Alan, in his blog, has previously discussed the effects of water on capillary columns with liquid […]

Thermo Trace 1310 Inlet Temperature Profile vs Agilent 7890 for Split/Splitless Injectors

Several years ago, my colleague Scott Grossman wrote an excellent article entitled “It’s a Matter of Degrees, but Do Degrees Really Matter?”  He measured the temperature profile across various Agilent inlets, demonstrating different gradients in temperature exist across inlets, depending on the type of inlet and even among the same inlet type.  One consistent finding […]

Did you know you can manage jagged bleed with a controlled cooling program?

GC column bleed sounds like one of those old problems people used to have. The XLB was developed to lower detection limits by minimizing bleed. Now, virtually all polysiloxane GC columns are low bleed, with thick film and high polarity phases being the exception. Modern GC-MS instruments are so sensitive that I’m rarely concerned about […]

The New U.S. EPA Method TO-15A Blog Series-Part4: Clean Lines for Clean Air

In previous blogs (Part 1, Part 2, Part 3) we’ve covered the need to use air instead of nitrogen as a fill gas, the new lower blank requirements, and how these increase the importance for very clean lab air for canister filling. We’ve shown that using high quality gas filters or generators will get you […]

How I clean a GC injection port

Recently I have been asked by several customers how to clean an injection port.  My initial answer is always the same, you should clean the injection port according to the manufacturer’s recommendations.  But what instructions do I provide when the injection port was manufactured by Restek?  I usually provide the same response but then I […]

The new U.S. EPA Method TO-15A blog series – Part 3: Use CLEAN air on a CLEAN analytical system!

From the start of this blog series, I have been teasing you with how to take your canister blanks from the following red trace down to the blue trace: In this post, I shall finally stop dragging it out. BUT FIRST… (Come on now, you had to have known this was coming) I shall digress […]

Accounting for Atmospheric Pressure When Using EZGC Method Translator and Flow Calculator and the ProEZGC Chromatogram Modeler

Modern GC’s are equipped with advanced pneumatics controls, which allow for accurate control of flow rates and pressures.  In order to accurately control or calculate flow rates, atmospheric pressure must be measured by the GC, since this determines the outlet pressure of non-vacuum detectors. Restek’s free tool, the EZGC Method Translator and Flow Calculator, has […]

Hydrocarbon Ranges of Natural Gas and Petroleum Products

Sometimes customers need to analyze natural gas and petroleum products, whether it is to confirm the purity of the product by looking for the impurities which may be present, or for an environmental reason such as a spill or leak.  In order to choose the correct GC column and reference standards, one needs to know […]