Chromatography Forum

Hi,
I am using a Shimadzu XR-ODS II UPLC column, with the following specifications:
Size: 3.0 mm x 150 mm
Particle size: 2.2 µ
Pore size: 80 angstrom
Carbon load: 20.2%
Endcapping: Yes

I am looking for a better replacement with nearly the same specification, but I could not find any. Please help.

Per the USP Column Equivalency tool (http://www.usp.org/USPNF/columnsDB.html) the closest equivalent in their database is the Capcell C18 UG 80. However, the database is limited by the number of columns it contains.

I would guess that in order to replace your column, depending on what you are doing, you may want to ask the major manufacturers if they have applications on UPLC columns for your analysis already, and if not ask if they can assist you in the method development. There are so many different C18 columns out there, even in UHPLC formats, that to buy and test them all would be nearly impossible.

If you post your application (if possible) maybe another Forum member might have experience with it and be able to recommend a different column.

My interest is to analyze pomegranate polyphenols, namely anthocyanins, anthocyanidins, ellagic acid and ellagitannins, namely punicalagins all in a single run. I use phosphoric acid/acetonitrile gradient system.

can you give details of retention times for the compounds?
capacity factors?
resolutions?
a picture of the shimadzu column would help also

are some of the peaks coming off the void volume right at the start of the chromatogram?

I am looking for a better replacement with nearly the same specification, but I could not find any.

What is the problem with your current column?

It is the life of the column. The column seem to have lost its resolution too soon. The flow rate we use is 0.7 ml/min and the back pressure achieved is 54-61 MPa.

Does anyone have any experience with HALO Fused-Core UHPLC columns?

It is the life of the column. The column seem to have lost its resolution too soon.

How soon is "too soon"? Are you talking about 10 injections? 100? 1000?

Well, close to 900-1000 injections. We had other non-UPLC columns where we had injected more number of times and have received consistent results. Even out of the near 1000 injections, 300-400 were done after connecting the column in the reverse directions, since the peak sharted to show trailing.

You're kind of on the "ragged edge" as far as lifetime is concerned. If this were my problem, I'd look at my expected column costs over then next 12-18 months (assuming something like 700 injections per column) and figure out how much it would cost me (counting my time!) to find an alternate column and revalidate the method.

Columns are cheap, your time is valuable!

What's your sample injection size on uplc and hplc columns, and dimension of your HPLC column? I believe column lifetime must be related to the total amount of samples loaded on a column and the amount of column packing material. For example, if you are comparing a 3x150mm column with a 4.6x250mm column, the former is only 1/4 of the latter - in terms of column packing material. Even if you reduce injection size to half (from HPLC to UPLC), you still doubled overall sample loading on the UPLC column. However, I must admit, what I have just said is only based logic thinking, not real first-hand experience ...

It is the life of the column. The column seem to have lost its resolution too soon. The flow rate we use is 0.7 ml/min and the back pressure achieved is 54-61 MPa.

Good day.
The mechanical strength of silica gel for long-term compression of about 40 MPa. Short-term course of silica gel beads can withstand the double pressure -around with the same result as the Fukushima reactor ...

If you want your column "lived happily and longilyty" (many years) o not push phase under super high pressure.Or put up with its rapid destruction of its (superpressure) cause . This is not a movie, you do not VanDamme.

PS
Let me remind you that the first classical UPLS - Mili-chom-1 (USSR 1968-1983) was originally designed to pressure of 5 MPa, using column 2 X 64 mm.

what type of UHPLC system are you using?

the stuff to check in order to prolong column live is:
the mobile phase, filterded at 0.2u and generally should have a lot shorter "shelf life" if using buffer.
sample should be fitlered at 0.2u
put a small 0.2u SST filtered at the head of the column.

remember that UHPLC is more sensitive, for both the good and bad that it brings.

your column is propably a polymeric type silica column.
a column with 100-120A pore size with at least 19-19.5% carbon loading would work for you
most columns are encapped these days

This is a problem all sorbents. At high pressures, they are destroyed. In UPLS it just manifests itself early, as column is shorter and the pressure gradient on it anymore. The best way out - to establish a flow rate that the pressure does not exceed 75% of the rating the strength of the sorbent. For the pore size of silica gel 80 Å is in the 320-380atm for the pore size of 130 angstroms - 250-300 atm.

500 atmospheres, and not every steel stand...

Thank you people for all your help.