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Re: thanks for all column suggestion
Posted: Wed Aug 05, 2009 2:00 pm
by Bryan Evans
I do not have RI detector but i have ELSD...if sugar is comming in void volume i can not see it for sure will try to buy suggested column..but i am not sure the activity is due to sugars or any very hydrophillic compound which is not retaining in column ...
Bryan ,,its a aqueous part of methnolic extract of a leaves ( i used partition chormatography to fractionate methanolic extract)..i do not know what kind of sugars are there..there are sugars i can tell buy looking at the water eluted fraction of aqueous part which i got using HP-20 separation..
Can somebody will help how to extract highly water soluble compounds
Hi mk12 - are you using ODS (C18 phase)? If so, it will not retain your
sugars. As I said, given your solutes of interest (sugars) and detectors
(ELSD and MS), I believe NH2 (+ guard column) is a viable option.
Posted: Wed Aug 05, 2009 2:05 pm
by Bryan Evans
Hey, isn't it funny how everyone who works for a column manufacturer knows THE best column for sugars. Funny, too, how THE best column is always made by their employer.
Yes, thank you. I agree.
Silicycle, it is usually best to support claims with scientific data
rather than post comments like "column xyz is the best..." ect.
Posted: Wed Aug 05, 2009 2:11 pm
by Vlad Orlovsky
Here is another alternative - HILIC:
http://www.sielc.com/application_175.html (sugars)
http://www.sielc.com/pdf/Sugars%20on%20 ... column.pdf (sugars)
http://www.sielc.com/application_183.html (sugars, amino acids, carboxylic acid)
Methods use ELSD as detection technique.
These are not amino columns and you will not have problem with stability of stationary phase. You can also use RI (might require mobile phase modification)
You can also try just bare silica column (the cheapest alternative) with the same conditions.
Posted: Wed Aug 05, 2009 2:25 pm
by Noser222
As someone who used to do a lot of monosaccharide analysis, I'll speak from my experiences...
You can go with the ligand exchange columns that have a mobile phase of 100% water. Easy method, but may require de-ashing of your sample.
You can go with the amino phase columns using Acetonitrile/Water in some ratio near 80/20.
Since you have ELSD sensitivity won't be an issue, but with the ligand exchange columns you'll get decent sensitivity with RI.
I've used amino phase columns from Zorbax, Shodex, and Imtakt. For my application, the Imtakt was the best in terms of stability and selectivity of the monosaccharides of interest.
Re: thanks for all column suggestion
Posted: Wed Aug 05, 2009 5:11 pm
by SiliCycle
Silicycle, it is usually best to support claims with scientific data
rather than post comments like "column xyz is the best..." ect.
Sorry guys, but I using HPLC since 1980 (closed to 30 years experience), I worked for of differents suppliers during many years (Waters, Agilent, etc...) and I also worked for doping control lab for International Olympic Commitee, lots of differents pharma as method development and validation and so far. It is enough fair to say something based on my HPLC experiences. How many years experiences, you have in HPLC, and which areas did you work for HPLC (suppliers, CRO, pharma etc...) I believe that forum was for experienced people and good place to share nice informations. The Sugar D COSMOSIL is not my HPLC column this one is from Nacalai Tesque.
Posted: Thu Aug 06, 2009 6:23 pm
by HW Mueller
SiliCycle, is it fair to say that your 30 years of experience put you in a position to know very well how to optimize conditions for your columns, which means that those conditions are usually not optiml for columns of the competition.
Posted: Thu Aug 06, 2009 8:47 pm
by SiliCycle
SiliCycle, is it fair to say that your 30 years of experience put you in a position to know very well how to optimize conditions for your columns, which means that those conditions are usually not optiml for columns of the competition.
I just want to share my experiences. Not more.
Posted: Fri Aug 07, 2009 10:14 am
by HW Mueller
There are other experienced people on this forum, and we know what you are doing.
Posted: Sat Aug 08, 2009 2:13 pm
by Don_Hilton
I wait for the referee to call “Halt!â€
Posted: Tue Aug 11, 2009 9:51 am
by lmh
Don's inspired me to a bit of customer feedback for column vendors:
I personally like very much vendors who've developed methods with their columns and who offer me guidance. The ones I get on with best are the ones that follow the "Phenyl columns are good for... our phenyl column has this feature which is useful for....because...." approach. It helps me understand where I can apply their column chemistry, and how it compares to existing things I might have in the lab. Strangely, I trust the vendors best who take the trouble to know the characteristics of their competitors' columns, and who appreciate that the competitors' columns are also possibly quite good.
I don't get on well with reps who can't explain why their column is better than anyone else's, but merely assert that it IS.. I am definitely NOT grateful one jot to people who flog me a new reverse phase column that does polar things really well (honest, guv!) that turns out to be almost identical to all the other such columns I've accumulated over the years, and really not a lot better than a standard C18.
Posted: Fri Aug 14, 2009 3:33 pm
by Bart Poulsen
As another near 30 year industry veteran working for column manufacturing companies (Interaction Chromatography, Transgenomic, Benson Polymeric) specializing in ligand-exchange gel columns for sugar analysis, I felt compelled to weigh in on Mr. Levesque’s bold statement that the Sugar-D COSMOSIL column is the best sugar analysis column. Our company would like to proclaim that our columns are the “bestâ€
Posted: Fri Aug 14, 2009 5:18 pm
by Jade.Barker
... Everyone who works for a column manufacturer ...THE best column is always made by their employer.
...Silicycle, it is usually best to support claims with scientific data
rather than post comments like "column xyz is the best..." ect.
My 2 cents:
Basically it looks like a rep shared his opinion like it was fact, and got "called out" to prove it. The problem is that scientists are generally experts on empirical proof and usually fond of logic as well. Another thread asks what Chromatographers do in their spare time? I recommend taking up argumentation - it’s great for strengthening those critical thinking skills and catching a logical fallacy. In this case, the group asked for empirical proof, and was answered with the fallacy of “Appeal to authorityâ€
Posted: Fri Aug 14, 2009 11:20 pm
by Don_Hilton
A 30 year pro selling an LC column or my neighbor over the vence telling me what he used to get rid of mildew. You listen, you nod - take what you can use and move on. You get some additional information from another user, a demo, or even a sample. (I've been listening to those 30 year pros for... 30 years!) But, I got to the bottom of this thread hoping to learn something about running sugars....