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How to do Nitrogen blow down
Posted: Tue Oct 29, 2013 12:53 am
by sami6
Hi all,
I am new to chemistry but a botanist.
I have an issue of concentration with my plant extract samples. I need to concentrate them since they are more diluted. I have found that Nitrogen blow down can help me. Can somebody please tell me the steps of how to do the process practically. This is totally new to me.
Re: How to do Nitrogen blow down
Posted: Tue Oct 29, 2013 2:46 pm
by Consumer Products Guy
Set up a supply of nitrogen (such as: from a nitrogen cylinder) with a small step-down regulator and route the slow nitrogen flow through a tube to a disposable glass pipet directed at your extract. Some extracts can be warmed on a steam bath while doing this.
Obviously, using nitrogen for this instead of dry air gets oxygen out of the picture.
Re: How to do Nitrogen blow down
Posted: Tue Oct 29, 2013 3:43 pm
by Steve Reimer
In general, the nitrogen flow show dimple the surface but not splash. The rate you can reduce the volume will depend on the boiling point of the solvent and how volatile the components are looking for are.
Be careful of the tubing if you are going to have any GC analysis done on the extracts. Phthalates from many kinds of tubing will transfer into the extract. If you are unsure, test before committing valuble samples to the system.
Re: How to do Nitrogen blow down
Posted: Wed Oct 30, 2013 1:06 am
by sami6
Many thanks to both of you. I did a test trial using a glass pipette as you have mentioned.
Do I have to insert the tip of the pipette into the sample or have to keep it above the top level of the sample? In my trial I inserted the tip, but I feel it is not the way.
I am going to analyse the samples on HPLC.
Re: How to do Nitrogen blow down
Posted: Wed Oct 30, 2013 12:44 pm
by Don Shelly
Many thanks to both of you. I did a test trial using a glass pipette as you have mentioned.
Do I have to insert the tip of the pipette into the sample or have to keep it above the top level of the sample? In my trial I inserted the tip, but I feel it is not the way.
I am going to analyse the samples on HPLC.
Above the sample. To quote Steve, "In general, the nitrogen flow [should] show [a] dimple [on] the surface but not splash".
Re: How to do Nitrogen blow down
Posted: Wed Oct 30, 2013 6:30 pm
by Consumer Products Guy
Do I have to insert the tip of the pipette into the sample or have to keep it above the top level of the sample?
Wow, thought my response in the earlier post was clear, stating "directed at your extract":
...route the slow nitrogen flow through a tube to a disposable glass pipet directed at your extract...
Re: How to do Nitrogen blow down
Posted: Wed Oct 30, 2013 8:06 pm
by oscarBAL
Re: How to do Nitrogen blow down
Posted: Fri Nov 01, 2013 12:11 am
by MSCHemist
I have a crude setup with nitrogen, a regulator, and 1/4" Cu tubing branched into 8 branches each connected to some tygon tubing and ending with a pasteur pippette. I have a hot plate with a metal rack for 22ml headspace vials. I set it to heat at 70 deg. The capsaicinoid aren't going anywhere.
I mainly use it for scoville heat units. I use the ASTA method which is extract with ethanol, sent through c18 cart, then I blow down to dryness and redissolve in 1ml MeCl2 with hexacosane ITSD. Then GC-FID.
