Author Archive

Does that SPME Arrow come with a free lunch?

Here at Restek our company has a core value referred to as “In the Light.” For me, I like to think of it as no skeletons in the closet. So, time for me to shine a little light. I already introduced you to the SPME Arrow. I also addressed the SPME Arrow’s larger diameter and […]

Excellent question Hailey!!!

Last time, I told you I hunt for organic compounds with SPME Arrows, as opposed to the traditional SPME fibers, because I greatly appreciate the mechanical robustness and increased phase volumes afforded by the SPME Arrow. That blog has since received the following excellent comment/question from Hailey: The “sheath” part of the Arrow looks to […]

I hunt with arrows… SPME that is!

When you say “I hunt with arrows” in central PA, you better be prepared for a long conversation about whitetail deer. So, I better clarify that I am talking about hunting for organic compounds with a SPME Arrow. What is all this I am talking about? Time for a brief history lesson: Janusz Pawliszyn (University […]

Making a TO-15 Working Standard: Part 2 How-To Video

Last time we learned that in order to make a TO-15 working standard from our stock standard we need to determine our stock standard concentration, canister volume, stock standard injection volume, and final canister pressure. We covered how to go about deriving all of the aforementioned, the associated math, and I even provided you with […]

Making a TO-15 Working Standard: Part 1 – The Super Standard Calculator – V2.01

We already learned how to calibrate our TO-15 system, what our concentration units mean, and how to properly read our vacuum gauge while pressurizing samples. We are clearly going out of order here, because I have never covered how to prepare a working standard (necessary for calibrations) from a stock standard. Therefore, the following multi-part […]

“Absolute” Pressure (psia) vs “Gauge” Pressure (psig)

Here is the scenario: You have just received your brand new Ashcroft Test Gauge. Why??? Because you know that the gauge on your canister is not accurate enough for making reliable quantitative dilutions. You notice that your brand-spanking-new Ashcroft Test Gauge is not reading zero, like so: Now you are starting to FREEAAK OUT!!! Because […]

Concentration Units for Air Folks

A couple of customers have recently asked about standard concentrations and converting from ppmv to mg/m³. Honestly, I have no clue how I have never blogged about this subject, especially considering how fundamental and critical this topic is. So here we go: Air concentrations at ppm are parts per million by volume and should therefore be […]

NJDEP-SRP Low Level TO-15 Series: Part 6 – Carryooooooover…

I recently received some feedback on the previous posts in this blog series and was asked the question “what kind of carryover am I seeing?” The truth of the matter is that I struggled to answer this question. I believe this question needs to be qualified a little bit in order for me to answer […]

NJDEP-SRP Low Level TO-15 Series: Part 5 – Method detection limits…

If you recall from part 1 of this blog series, NJ LL TO-15 listed MDLs as being one of the items they modified from U.S. EPA Method TO-15. HOWEVER, the only “modification” I see made is that NJ LL has outlined “specific criteria that the laboratory must meet regarding the MDL and an MDL study […]

NJDEP-SRP Low Level TO-15 Series: Part 4 – How to calibrate your system Joisey style… with no digression

In the last installment of this series, we talked about optimizing the internal standard (ISTD) responses on the Markes CIA Advantage™. This is a critical step on the road to meeting the NJ LL TO-15 calibration criteria of a 5-point curve from 0.2 to 40 ppbv, for most of the target analytes. I say “most,” because […]