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using HFIP in mobile phase
Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.
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Hello, dear collegs! I'm trying oligonucletides analysis on LCMS. We have Waters UHPLC system associated with LTQ XL Orbitrap Thermo Sсientific. Mobile phase contains HFIP which is very toxic, especialy in vapor. The problem is that some HFIP vapor which is creating in ion source could spreading away in lab. So, I know one ot the solutions is using a condensate collector on an ion source. Is this enough safety for such kind of analysis? How do you work with HFIP in mobile phase?
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Why are you using Hexafluoroisopropanol? It has a close link to a 'nerve gas'.
What is your molecular target? What is your sample matrix? What are your chromatographic conditions?
Put some 'meat' on the bones!
What is your molecular target? What is your sample matrix? What are your chromatographic conditions?
Put some 'meat' on the bones!
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HPLC chemist wrote:
Why are you using Hexafluoroisopropanol? It has a close link to a 'nerve gas'.
What is your molecular target? What is your sample matrix? What are your chromatographic conditions?
Put some 'meat' on the bones!
Thanks, answer your questions.
The sample is 22-mer ssDNA. The LC-MS conditions:
Mobile phase A: 15mM TEA, 400mM HFIP, pH=7.9
Mobile phase B: 15mM TEA, 400mM HFIP in water/methanol (50:50 v/v)
We use Hexafluoroisopropanol becouse it's a commonly used ion-pairing agent for oligonucleotides. The HFIP is used to increse MS signal.
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TEA is not good for the MS. It is difficult to clean out of the MS. In addition once you use an ion pairing agent you have to dedicate the column since its selectivity has been changed.
I would develop a 'new' HPLC method using a more modern hydrophobic column (high Carbon load). No one in the West uses ion pairing anymore particularly since there are newer methods. Check the Waters, Agilent, and Phenomenex websites.
I would develop a 'new' HPLC method using a more modern hydrophobic column (high Carbon load). No one in the West uses ion pairing anymore particularly since there are newer methods. Check the Waters, Agilent, and Phenomenex websites.
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Thank you! But both waters and agilent offer TEA and HFIP in mobile phases in the methods for theirs columns.
So, I'll try to find a new ion-pairing agent.
But what about HFIP? Do you know any information about using this in mas-spec?
So, I'll try to find a new ion-pairing agent.
But what about HFIP? Do you know any information about using this in mas-spec?
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If the molecule insists on being soluble in water I would try HILIC MS/MS. See article below;
http://www.chromatographyonline.com/hil ... gy-part-ii
http://www.chromatographyonline.com/hil ... gy-part-ii
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Besides all of the warnings above....
Do not use HFIP in your VACUUM DEGASSER! It will damage it and contaminate your entire HPLC and MS system.
An Often Ignored HPLC & LC/MS Contamination Source. Did you check your Vacuum Degasser? :
https://hplctips.blogspot.com/2015/08/an-often-ignored-hplc-lcms.html
Do not use HFIP in your VACUUM DEGASSER! It will damage it and contaminate your entire HPLC and MS system.
An Often Ignored HPLC & LC/MS Contamination Source. Did you check your Vacuum Degasser? :
https://hplctips.blogspot.com/2015/08/an-often-ignored-hplc-lcms.html
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I would 'seriously' look around for anything to replace HFIP! I am a proponent of electron theory (and their interaction with the analyte) in the composition of mobile phases. While Fluorine is a 'small' atom that is electron rich, it can be replaced (Oxygen, Nitrogen...).
In addition, you only have to demonstrate that your HPLC method is selective and not the full 'nine yards' as shown in various chromatograms by manufacturers (they don't tell you the concentrations, or what they replaced afterwards). If merxRNA doesn't appear in your 'soup' why look for it?
In addition, you only have to demonstrate that your HPLC method is selective and not the full 'nine yards' as shown in various chromatograms by manufacturers (they don't tell you the concentrations, or what they replaced afterwards). If merxRNA doesn't appear in your 'soup' why look for it?
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morozovae wrote:
Thank you! But both waters and agilent offer TEA and HFIP in mobile phases in the methods for theirs columns.
So, I'll try to find a new ion-pairing agent.
But what about HFIP? Do you know any information about using this in mas-spec?
I use HFBA on a regular basis. I agree with the poster who said TEA is not good for the MS and would add TFA to the list of things to stay away from. I also use only enough to get the retention I need, typically 0.05-0.1% in my A channel only.
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Thank you for yours answers! I've found an information about usong di-n-buthylamine in DNA LC/MS. Have you ever used that? Is that dangerous and harmful for mass-spec? I can't find enough information.
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