Hello all,
I have been working the whole day to get some flow truh my system. I finaly get the system to work after changing the "inlet check valve".
I have had this problem earlier a short time after I used my buffer solution?? KH2PO4 pH-2,3.
Is there some one who have some "golden rules" after using buffer. to clean the system.
Is it common to swich to pure water and ry to get rid of ions??

The best way is to be sure to flush the system with water/organic in approximately the same proportion as used in your mobile phase. Chase this with a ~80%organic/20%water solution. At least 5 column volumes of each right after the last analysis should keep things clean.

I use 20mM KH2PO4 at a pH of 4, and I flush my system for an hour with 100% water after using this "buffer". It may be overkill, but I haven't had any problems from the salt yet!
Lisa
PS--my column is fully compatible with 100% aqueous mobile phases, but if yours isn't, you wouldn't want to use this flushing method!

Remember please that if you use a high organic modifier concentration, the inorganic buffer will likely crystalize. Perhaps the crystals stuffed around the Anonymous' inlet check valve?
Better check possible crystalizing before you use the phase in your system, and remember about the pump piston flushing also.
I agree with DR that use of similar proportion of water/organic as mobile phase is a good choice, however, I would be more concerned about crystalizing if it was 80% MeOH (using phosphate). Using 30% MeOH/water would be safer, I believe.
By the way, Lisa, do REALLY believe your C18 column (even if it's claimed to be 100% compatible with H2O) will not collapse in pure water? C18 chains are long enough to stick to each other, especially when they are densely bound on the silica surface.

Greeting to all of you,

Maciej Turowski
KIT, Japan

Maciej,
Remember that there are other phases out there, not just C18! My column is NOT a C18, it's a "short chain" column (Micra Scientific's SCD-100). It can and does perform beautiful separations even in 100% buffer!!

Something strange is going on with the server of this forum. I have posted (in fourth attempt) my message once and it has dissapeared from this page after I came back in 2 hours...
Anyway, Lisa, you are right, sorry. C18 automatically comes to my mind anytime the exact column type is not mentioned, as it is very fundamental phase for me.
Greets,
Maciej

I had the same problem this morning (and I *work* here!). I think what happened is that I clicked on the my browser's "back" button after posting, but I've passed a note along to the adminstrator to check for network problems. It seems late for diyttrium potasside problems, but who knows.


-- Tom Jupille / LC Resources

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Hi,
My name is Joke and I'm working on the purification of MAbs (thesissubject). Therefor I use the 'Streamline XL 25'(Pharmacia). To clean the column properly there are some 'clean in place' procedures. In one of the cleaning buffers, we use sarcosyl 5% to eliminate the lypopolysaccharides, which is needed because the purified protein will be used for therapeutic goals. Anytime I clean the column with sarcosyl-containg solution, the fluid above the column becomes all troubled and its filled with flocculents. Most of it can be removed by flushing water trough it but some restants remain in the column. Although this method is recommended by the supplier I doubt teh effectiveness of the use of sarcosyl.