PFAS分析に必須のディレイカラムの重要性と効果
Sometimes I hear this from customers: I don’t need a delay column. I haven’t had any trouble without it so far.” It might be true. You may not have any issues without the delay column, especially when your samples are,…
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GC compounds – poor peak shapes and missing peaks
One of the most common questions I am asked by customers is “Why is my peak shape so poor?” Another is “I do not see a peak for my compound, what should I do?” Sometimes they are developing a new…
Simple Analysis of Bile Acids by GC-MS
Bile acids are a group of steroidal acids with carboxyl and hydroxyl groups on the side. They are the major metabolic products of cholesterol. Bile acids play important roles as biomarkers for early diagnosis and therapeutic monitoring of many diseases,…
High Source Temperatures and Meeting EPA Tuning Criteria
My first blog here at Restek was a demonstration of how increasing the source temperature could improve the raw response of 2,4-dinitrophenol while maintaining the relative response. Four years later I’m here with the promised follow-up on the elevated source…
Several things you may not know about our Super-Clean Gas Filters
Recently one of the designers of the Super-Clean Gas Filters spent some time with technical service and we were able to ask him a few common questions we get asked by customers. I thought I would share this information with…
It’s All in the Split Vent Trap
Recently I came across a situation where I wanted to make a series of constant flow GC-FID runs, during which, the inlet pressure would increase from 2 to 6 PSI over the temperature program. I also wanted to use split…
Peak Capacity in Capillary GC
Peak Capacity in capillary gas chromatography is different than sample loading capacity, which is something I’ve posted on multiple times recently in ChromaBLOGraphy. Peak capacity is simply the number of theoretical peaks that can “fit” inside a chromatogram under some…
Need help finding the correct ferrule to install your GC column? Part 1: Agilent GC ferrules
You’re ready to install a column into your GC and realize you do not have ferrules to do the job. But which ferrule do you choose? The parameters to consider when choosing the correct ferrule are instrument make and model,…
Fatty Acid Methyl Esters (FAMES) – converting % by weight to µg/mL
The first time I was asked by a customer about how to convert % by weight of one of our FAME reference standards to µg/mL, I needed to ask for some help. Because we (tech service) occasionally get asked this…
Do reverse phase HPLC columns really need conditioning?
Well, it’s partly a matter of semantics sometimes, but there is usually nothing drastic that you need to do to get your HPLC column going if it is new. There is no baking at high temperatures involved like you…
