Some phys-chem properties of the components for GC.

Discussions about GC and other "gas phase" separation techniques.

4 posts Page 1 of 1
Good afternoon, dear colleagues.
Sorry for may be easy question or the wrong question. But for this, and there are forums, is not it?;)

Help me please, I find the optimum mix of compounds for the GC separation. It is necessary for the internal operations in the laboratory.

so, I decided to examine the next question:
I understand that the best compounds for the GC - a volatile, low molecular weight and don't high polarity (PAH, ethers PCBs).
But I did not once meets with the data, which also affect such an indicator as the LogP. Tell me please, what is the physical and chemical values you use to confirm the detection of compounds in the GC or HPLC?

May be logD, pKa, Polar Surface Area or Polarizability may be...

I select pesticides.
It's easy to see the article and just believe it, but it is interesting to find an answer and have a theoretical experience. :oops:

With best regards
Dmitry
When the path is over and passed successfully, it's nice to remember even the mistakes ...
I hope not to sound harsh, but I do not really understand what you want to ask
dRima wrote:
Tell me please, what is the physical and chemical values you use to confirm the detection of compounds in the GC or HPLC?



You run a sample of a known substance and a known amount and get a peak at a certain retention time. You then compare that peak to your sample which should also elute at the same time.

Another way to confirm would be by using a mass spec detector.
You can also confirm identity by using separation by a different polarity column which will give different retention time orders. For PAH by LC I use both UV and Florescence detection to confirm the identity of the analyte.

Other properties would be good if you have a pure substance that you are working with, including boiling point, melting point, refractive index, IR spectrum and such, but so often most of us only have trace amounts to work with and need to use variations of separation and detection techniques.
The past is there to guide us into the future, not to dwell in.
4 posts Page 1 of 1

Who is online

In total there is 1 user online :: 0 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: No registered users and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry