Are these columns available as an "off the shelf" item now then?
The reason I ask is that I inputted a part number of one of these new columns into our internal ordering system "SciQuest Marketplace" and it couldn't finf the part number. Perhaps I should speak to Waters column reps locally in the UK.
Yes, the columns are available for sale. I forwarded your message onto our data services group and as soon as I hear back from them I will let you know.
In the interim, your suggestion/question about contacting your local Waters Chemistry Specialist is the best approach. I will also let my UK-based colleagues know, OK?
I am told that the SciQuest catalog will be updated to include the new ACQUITY CSH and XSelect columns part numbers by next week. If for some reason you are still unable to order columns in your 'SciQuest Marketplace' next week, please email me directly: [email protected].
Thanks for the update Doug - I'll keep an eye out next week to see if those part numbers can be found in SciQuest on-line catalogue next week.
Thinking of applications for these types of columns, I attended an interesting talk about oligonucleotide separations with HPLC/UHPLC employing ion pair reagents. Could these columns be used for oligonucletide applications without the need for ion pair reagents at all. If so have Waters perfomed any work on these columns detailing such applications?
My apologies in not responding sooner. I checked around and unfortunately no oligo work has been performed on the CSH columns. Theoretically, there should not be enough positive charge on the CSH surface to eliminate the need for the ion pairing agent. Everyone agrees that it would be something worth looking into but those same people just don't have the lab bandwidth to properly do the work any time soon.
If you would like to try this, I would be more than happy to provide you a column or two. Just let me know.
BTW, are the PNs now available in your SciQuest catalog? They should be.
Just checked our SciQuest system through our electonic sourcing and procurement eSP system here in the UK and still can't find these columns.
I am searching by part numbers.
I probably need to get hold of the column rep. here in the UK to find out what the crack is.
Could you please give me the specific part number(s) that you are trying to find? I've asked a couple people to pursue your problem and they need the part number(s) in question.
We tried the new CSH column on our UPLC Acid method.
25 real samples were run on the new column type (a CSH C18), and the peak shape results were compared (admittedly "by eye") with our current column (BEH C8). We run using 0.1% Formic acid in Water, ACN only, & a linear gradient.
The new CSH gave better peak shapes for 20 samples, the same for 4, and was worse for 1.
So, judging by these results we are going to move over to the CSH C18 for our Acid runs.
I have also tested the new CSH column for several peptides using TFA containing eluents (0.02 and 0.05% TFA in ACN/H2O). The results are similar. The peak shape is much better than with the BEH 130 PST C18 column, that is comparable with the CSH C18 column.
But I also made some "negative" experiences:
Do you also had such phenomenons?
Could you please elaborate on your first bullet point? I am unsure what that means.
Regarding your second point, I have not seen nor have I heard of such behavior using CSH columns. Please share the data and conditions if possible. Or contact me directly.
In general, when comparing a CSH 18 column vs. any modern C18 column, there will be little difference in peak shape for basic compounds if you are using: 1) a buffer; 2) TFA. Both have high ionic strengths and provide good peak shape for basic compounds. However, when you are using an acidic, low ionic strength additive alone such as 0.1% formic acid, acetic acid, phosphoric acid, etc., you will likely see improved peak shape for basic compounds with the CSH columns. That, along with different selectivities as described below, is why CSH columns were developed. The CSH Technology White Paper located here provides more detail.
Selectivity differences/similarities are tough to predict but allow me to generalize. As compared to BEH C18 columns, CSH C18 columns will retain basic compounds less, acidic compounds more and neutral compounds about the same. Again, these are generalizations and I am sure there are exceptions, but this behavior is what we most commonly observed when we developed the CSH columns.
Thanks for your feedback,
here are the details, methods and overlay chromatograms.
Thanks + regards
here is the same problem with the baseline drop after the main peak with the next CSH C18 column. Up to now it has been used since 4 weeks and about 300 injections have been performed. The working conditions were always in within the specified range. For me, this problem is serious.