Chromatography Forum

Hi all.
I just got the green light to get a new column, but not much budget at all to work from($300-400 range). My criteria for what I'm looking for are as follows:
1) Needs to be a RP, C18, 4.6mm ID, preferably 250mm
2) needs to operate from slightly below pH 2 to pH 10
3) needs to survive through six months of heavy use, mostly with 0.1% TFA and phosphate buffers as aqueous and ACN/MeOH as organic.

I'm a recent college grad doing QC for a small research chemical supplier and all I want is to be able to show my boss some nice chromatograms at the end of the week! What should I get?

Thanks for the suggestions,
Chris

Hmm... Since you are working in a QC department, shouldn't you have long-term reproducibility on your list of desired column properties?

Yeah, long-term reproducability would be great too- I certainly don't want it losing half of it's retention capacity in a year, or to have peaks start tailing off heavily after a bunch of uses. But since this will be one of the 2 columns I get to use for analyzing hundreds of different chemicals, I'd be willing to trade pretty much any other quality for the ability to operate under a wide range of conditions without killing it.

Up until this point, I've been using a really old cosmosil MS-II C18 4.6x250 that was probably great in its prime, but now it should really be put out to pasture because stuff just passes right through it. I need something that will do at least as good of a job as it used to, but since I'm a newbie I have no idea what $350 will get me.

Thanks again for your suggestions.

Chris

To my mind a Kromasil C18 can be a good choice, it's cheap enough, good peak shapes, good mecanical properties.... and for the pH range there's no problem, 0.1% aq TFA is about pH=2 so....

Luna C18(2) is a good one that might meet your requirements. I've also had good luck with Betasil C18 but I don't know if it's rated to pH 10. Neither should be expensive.

andy2922;

Why not show your boss how smart you really are! Macherey-Nagel is having a buy one column get one free column. As a world leading in chromatography, I would suggest to order MN's 3um and 5um Gravity column. This column is our workhorse column for your requirements. Call MN at 888-321-6224 to place your order. Even the call is free!

I guess to ask this question is a good way to find out who the column manufacturers are on this board...

My recommendation would be to look at the Symmetry line from Waters who has been proven to exhibit the highest reproducibility in the world.

Of course, I am from Waters, but you may have guessed....

FACT CHECK... FACT CHECK... FACT CHECK

Uwe Said: [/quote]"who has been proven to exhibit the highest reproducibility in the world".

Besides a Water's brochure can you give a site and source of your comments?

I believe you said in another post "You should not give advice if the advice is wrong"

I believe Uwe is talking about the column to column reproducibility of the Symmetry line, comments made on the fact they say they have the industry tightest manufacturing specs for this brand. Does one typically get access to the raw data behind the graphs given in a manufacturer's brochure? Steve - is MN commonly asked by consumers or competitors to provide theirs?

I'm not certain how having tight manufacturing specs leads to rugged chromatography under stressing conditions though, and I could not find comments that the Symmetry line is happy to be used at pH 10.

The data on the Symmetry line are public. The complete data set including the specifications are on every Certificate of Analysis that comes with every column. In addition, I have written about its reproducibility myself in an article in J. Chromatogr.. Kele and Guiochon have published specifically on this subject in J. Chromatogr. as well. Newer data are of course compiled in the plant and can be accessed as well.

Symmetry is a silica-based packing, and is not useful at alkaline pH. Other packings such as the inorganic/organic hybrid packing lines have been specifically developed for stability at pH 10 and above.

References: Neue et al., J. Chromatogr. A 849 (1999) 87-100 and 101-116 and Kele and Guiochon, J. Chromatogr. A 830 (1999) 41-54 and 55-79

I would also like to wish the original poster good luck "analyzing hundreds of different chemicals" (presumably not all ultra-pure) with a single phase type

I guess to ask this question is a good way to find out who the column manufacturers are on this board...

My recommendation would be to look at the Symmetry line from Waters who has been proven to exhibit the highest reproducibility in the world.

Of course, I am from Waters, but you may have guessed....

Not touting Sunfire this week? Is that line more expensive than Symmetry?

I've used & liked Phenomenex (prodigy), Waters Symmetry, Zorbax (Varian) StableBond, Kromasil and others...

The possibility of going to higher pHs also... may elicit other suggestions too.

That sounds like the ultimate column. If you find one, I'll buy a bunch as well. What kind of molecules are you looking at? What is the typical purity (are you looking for only one peak) of your compounds? How many injections are you looking at?

Every column has their advantages and disadvantages. A 25 cm column may be a little overkill. What are your methods typically like?

I think the answers to those questions will lead you to a "perfect" column.

DR: I am not touting the newest product lines of Waters, if I think that another product line might serve better. Ande2922 asked for something that is useful in a QC department. There, one usually wants to get the same results over and over again. This is why I recommended Symmetry.

If the higher pH is essential, my recommendation would be XTerra.

I might offer you a slightly different solution in a column. Try a polymeric reverse phase column like the Transgenomic RPSep PRX-1 Column. It is a Polystyrene DivinylBenzene polymer and works in the entire pH range. It is available in a 4.6 x 250 mm length. It is also low cost and has proven very reliable for much of our work. I have successfully used it in place of C18 phases and it might work well for you. They have two other polymeric RP columns but I think this one would be my recommendation.

Sincerely,
Jeff Brewer