Archive for the ‘Miscellaneous’ Category

Choosing an Internal Standard

Adding an internal standard (IS) to an assay can be an excellent way to often improve method precision and accuracy. An IS can account for signal suppression (or enhancement), that may be caused by the sample matrix. When using an IS, the response of your target compound(s) is compared to the response of the IS. […]

Finding Reference Standards Just Got a Lot Easier

The range of reference standards available from Restek is very wide, which is great. But finding a particular formulation among all those options can be a challenge. And, let’s face it, filling out a form to inquire about a custom mix can be a pain in the neck. That’s why we built our new Reference […]

Even More Technical Service “Red Flags” – GC

My third installment of Technical Service Red Flags contain six more situations that cause us to pay attention and ask questions.  I hope you find these helpful. Using a liquid leak detector to locate gas leaks instead of using an electronic leak detector. Or worse yet, using both at the same time.  We have, unfortunately, communicated […]

More Technical Service “Red Flags” – GC

Just like in my original post, Technical Service “Red Flags” – GC, this post contains several additional Red Flags we look (email) and listen (phone) for in technical service. Trying to set the carrier gas flow rate for a packed column without using a flow meter. You may want to review this previous post. Verify your […]

How do I order a dip tube?

  A dip tube (also known as an outage tube) provides vapor space above liquefied gases in a sampling cylinder so that if expansion occurs with an increase in temperature, the pressure is not significantly increased. Basically, the length of the dip tube is used to determine the filling capacity of the cylinder. Outage is expressed as […]

You Don’t Know Jack!…but NACRW does

Congratulations, Jack! I am happy to share that Restek’s own Jack Cochran has recently been awarded the North American Chemical Residue Workshop (NACRW) George and Wilma Fong Award. This award is given to individuals in recognition of their service to the workshop. This service award is named after the founders and organizers of the meeting, […]

Technical Service “Red Flags” – GC

For those of you not familiar with the term “red flag”, or phrase “It raised a red flag”, it basically means that something does not sound correct, or is very unusual or uncommon. In tech service, we listen for these “red flags” and if we hear one, we will either offer a cautionary statement if […]

Electronic Cigarettes Part X: Vapor Analysis – Application Note

With the last installment of this blog series garnering some comments/questions, I thought it would be appropriate to post the following link to our application note, which has been featured in a lot of these blogs:    

Electronic Cigarettes Part IX: Vapor Analysis – What does all this mean?

Sorry for the two month blog delay, but by now you know we were utilizing multi-bed thermal desorption (TD) tubes to collect and analyze electronic cigarette vapor (see our last blog here). You also know that we found some interesting volatile organic compounds (VOCs) like formaldehyde, acetaldehyde, acrolein, xylenes, as well as siloxanes in electronic […]

My GC capillary column was not sealed when I received it!

Traditionally, GC capillary column manufacturers have used several different methods to seal their products while in transit and storage. These sealing options include septa, silicone plugs, flame sealing, and press-fit caps.   I’m not going to discuss the advantages and disadvantages of these various approaches in this post. However, what I would like to address […]