Porapak Q Sorbent Tube Conditioning and Extraction

Discussions about sample preparation: extraction, cleanup, derivatization, etc.

6 posts Page 1 of 1
Hi all,

Earlier this week I was gifted about 50 new Porapak Q sorbent tubes, however they did not come with any instructions as how to use them. The ones I have are manufactured by SKC (part number: 226-115) and can be found here: http://www.skcltd.com/index.php/sorbent-tubes/9-uncategorised/188-porapak-sorbent-tubes.

I have looked through the literature on the website and cannot find any information how to condition the tubes once the glass seal has been broken or which solvents would be useful (and volumes) to extract any entrained VOCs. Has anyone had any experience of using these previously?

Best wishes,

Joe
Hi Joe

I am flying blind on my reply because I don't have experience of Porapak Q solvent tubes and others might

However

a) Obviously different sorbents will have different selectivities

b) you say that wish to do solvent rather than thermal desorption - solvent extraction will add another layer of selectivity

c) My experience of sealed sorbent tubes is that they are pre-conditioned.
However if you look on the link that you provided

* Limited shelf-life; contact SKC for more information
‡ Tubes are chemically conditioned before shipping; use within 30 days or recondition. Restocking fee applies.
§ Each tube has a flow direction arrow and unique number.
• Limited shelf-life; refrigerator/freezer storage may be required. Contact SKC for more information.


Their comments may be just to cover their backside with those disclaimers. If sealed in glass (as I have had with charcoal tubes) I don't really see a problem. Have you tried contacting them?

d) there is some information here that might be useful

https://www.ncbi.nlm.nih.gov/pubmed/15974063 I don't have access to the full paper

http://link.springer.com/article/10.1007/BF02276852

e) it might be worth checking out searching under the equivalent Chromosorb Century series of adsorbents - I can't remember the Porapak Q equivalent.

f) It might be worth contacting Markes International for more information although they are more thermal desorption.

Being pragmatic - at the end of the day, because of my understanding of Porapak Q's limited selectivity, just dump them.

I fully appreciate not wanting to waste a free gift but my concern is that it may cause you to divert time that you don't really have.

If it was that good you would find far more references.

If you really wish to go down this route consider charcoal or Tenax

Regards

Ralph
Regards

Ralph
GOM wrote:
Hi Joe

I am flying blind on my reply because I don't have experience of Porapak Q solvent tubes and others might

However

a) Obviously different sorbents will have different selectivities

b) you say that wish to do solvent rather than thermal desorption - solvent extraction will add another layer of selectivity

c) My experience of sealed sorbent tubes is that they are pre-conditioned.
However if you look on the link that you provided

* Limited shelf-life; contact SKC for more information
‡ Tubes are chemically conditioned before shipping; use within 30 days or recondition. Restocking fee applies.
§ Each tube has a flow direction arrow and unique number.
• Limited shelf-life; refrigerator/freezer storage may be required. Contact SKC for more information.


Their comments may be just to cover their backside with those disclaimers. If sealed in glass (as I have had with charcoal tubes) I don't really see a problem. Have you tried contacting them?

d) there is some information here that might be useful

https://www.ncbi.nlm.nih.gov/pubmed/15974063 I don't have access to the full paper

http://link.springer.com/article/10.1007/BF02276852

e) it might be worth checking out searching under the equivalent Chromosorb Century series of adsorbents - I can't remember the Porapak Q equivalent.

f) It might be worth contacting Markes International for more information although they are more thermal desorption.

Being pragmatic - at the end of the day, because of my understanding of Porapak Q's limited selectivity, just dump them.

I fully appreciate not wanting to waste a free gift but my concern is that it may cause you to divert time that you don't really have.

If it was that good you would find far more references.

If you really wish to go down this route consider charcoal or Tenax

Regards

Ralph


Hi Ralph,

Thanks for such a detailed response, it is much appreciated. I will address the points you have listed sequentially:

a) I am aware that different sorbents have different selectivities, but the colleague I have acquired the Porapak Q tubes from used them for analysing plant volatiles, etc. This is the kind of work my lab wants to move into, as it compliments the entomological work we do. I have found a paper that seems demonstrate this application quite well: https://www.ncbi.nlm.nih.gov/pubmed/12033802.

b) Ideally TD would be the preferable method of desorption, but I don't believe these tubes are compatible with the TD unit as I have to cut the sorbent tubes to open them. I don't have a suitable tool for cutting glass so will be resorting to scoring the tubes with glass and snapping them. The stainless steel tubes that I currently use with the TD unit do contain tenax.

c) I had briefly looked on the manufacturer's website and noticed that the tubes are preconditioned. However, they were manufactured and packaged in 2010, so would most likely need to be reconditioned - how one would go about this I have no idea.

d) Thanks for the paper links, I had seen the chemical weapons one previously as I have been researching biofumigation of potato cyst nematodes in potato crops using mustard - allyl isothiocyanates seem to reduce populations substantially.

With regards to you being able to access papers, there is a way to access any published scientific article. I'm not sure how you feel about publishers, but this website does not benefit them: http://sci-hub.cc. All you need to do is copy and paste the URL of the paper into the search bar and you should have instant access to the paper.

e) It appears that Chromosorb 102 is interchangeable with Porapak Q. I'm still not certain as to whether this is suitable to my labs needs as the Chromosorb website doesn't make it very clear...when I say website I actually mean this document: http://www.advancedminerals.com/pdf/Chromosorb_century_polymer_supports.pdf

f) Markes International are the manufacturer's of the TD unit we currently have, although I'm not sure how much help they'd be willing to give me on an item they don't manufacture.

Thanks again Ralph!

Cheers,

Joe

EDIT: I have also found these papers:

1) http://link.springer.com/article/10.1023/A:1022442818196
2) https://www.jstor.org/stable/3547045?seq=1#page_scan_tab_contents
Hi Joe

Great - thanks for the extra information - it is looking more promising than I thought.

If it is in sealed glass I would be tempted just to give it a try using your colleagues conditions (and run one as a control)

I may be wrong but if it is in all glass sealed tubes and kept out of light it should be active for many years and not need extra conditioning

I have used older all glass sealed activated charcoal tubes without detriment

A standard lab glass cutter will do the job for scoring. Just wet the score mark with water ( or some saliva :-) - an old trick that helps to propagate the crack and produce a clean break

I recall trying the ceramic wafer used for capillary column cutting for scoring but don't remember if it was successful on thick walled tubing :-(. It was on thin walled tubing like Pasteur pipettes. But don't try to use that wafer on capillary columns afterwards :-)

Regards

Ralph
Regards

Ralph
GOM wrote:
Hi Joe

Great - thanks for the extra information - it is looking more promising than I thought.

If it is in sealed glass I would be tempted just to give it a try using your colleagues conditions (and run one as a control)

I may be wrong but if it is in all glass sealed tubes and kept out of light it should be active for many years and not need extra conditioning

I have used older all glass sealed activated charcoal tubes without detriment

A standard lab glass cutter will do the job for scoring. Just wet the score mark with water ( or some saliva :-) - an old trick that helps to propagate the crack and produce a clean break

I recall trying the ceramic wafer used for capillary column cutting for scoring but don't remember if it was successful :-(

Regards

Ralph


Hi Ralph,

I hope you're having a nice weekend despite the rarther abysmal weather?

I intend to give it a go tomorrow whilst i'm in the lab, I'll let you know how it works out for me.

Ah, thanks for the tip about wetting the cut!

Cheers,

Joe
Hi Joe,

McCormick et al. rinse their poropak with 200ul of DCM to desorb the compounds, you could check out their work (McCormick's time with the Unsicker lab mostly, so 2014-2019 ish)
6 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