Chromatography Forum

Hi, there!
Many thx 4 all u have answered to my post.t

Still I’ve gotta problems with this fucking Econosil NH2 column. After a full epopeea, I take column to initial shipping condition (hexane:ethanol=95:5). Testing this column in normal phase mode works very well. When I swithced to reverse phase and tried to separated some sugars I’ve gotta nothing but a bull shit. It seems any sugar passed through column with any retention (RI detector). More than that, when I have injected water and I’ve gotta a very fine peak at 3.2 min (and any sugar I have injected into column give the same peak at 3.2 min). Before this, I washed the column succesivelly with n-propanol, acetonitrile, 10mM NH4OH and acetonitrile:water=80:20. What the hell is going on? I do not know how it sounds in English but in my language it souds very well: “I’ve turn into a chronically palsy”.
Any suggestions will be appreciated,
Thx,
darth.anghel

My first advice would be to clean up your "scientific language".
Second, you might want to try another amino column, these columns has tendency to die quickly due to hydrolysis. Washing it with ammonia might accelerate the decay. Try to inject two sugars which have way different retention and see if column still works. May be going to ELSD detection be a better choice. Whatever you see is a change in refraction index. Inject you sugars dissolved in the mobile phase, and see if peak at 3.2 minutes is not solvent related.

Anytime you buy something with the"Econo" in the name you are taking your chances (I wouldnt by EconoDish Soap!). Pay the extra few bucks and buy a brand name next time. Now, get on the phone and return what is appently a defective product. This assumes that you bought it from a reputible company, oh yes, thats the other thing you get when you buy a brand name.

BTW, better watch your language, you lose resepect if you cant express youself without throwing in an F-bomb or two.

Dont panic, buy a decent column and get the job done.

Language!

I've had a harrowing week too, trying the impossible - glucosamine and chondroitin on the same column. Carbo separations take a lot of patience, and they can be frustrating.

I fully agree with SIELC - your problem could be column related, so try two different carbohydrates, and check. Seems to me you're consistently getting a solvent peak at 3.2 mins. We had the same problem too, and we solved it by dissolving the sample in the mobile phase, and by running a blank first.

Initially, we had some very bad results too and we got no retention at all, until we realised that our NH2 column had gone bad (it was a good brand, but it had been badly treated). So, we bought a new one. I wouldn't want to promote any particular brand on this forum, but we bought a Kromasil NH2, 5 um, 250x4.6, and it has performed very well.

Take your pick, there are several good brands around.

Good luck. Stay cool.

First of all I apologize for my un-academic language. I'll be carefully in the future.
It seems I have to buy another column. But, I wonder if the water may be the cause. I shall try DI water instead of distilled one before I throw out this column. Many hthx for ur suggestions.
darth.anghel

If you do buy another column, get one that says its for carbohydrates and is shipped to you in acetonitrile. It will save you a few headaches, as I have learned the hard way.