Chromatography Forum

I'm looking into fast/high resolution chromatography systems. I'd like to know if you are happy with the UPLC instrumentation, is it easy to use if you're competent in HPLC? Also is the communication with the data system OK? Which data system do you have?

Thanks
Phil

I am very satisfied with my UPLC system. Running times of 3 and 5 minutes are just great. The only thing is that I had to get empower 2 for my lab.

I bought an Acquity system for 5-6 months ago. And I’m pretty satisfied with it.
Yes, I think it’s easy to operate, and I haven’t experienced any major problems.
The communication with CDS is OK – I use Empower 2 for the purpose.

A small, but quite annoying problem – for me anyway – is that the cooling fans of the autosampler and the column oven are always on, even when you switch off the modules. It’s just unnecessary energy consumption and wears the devices out.

But the overall evaluation must be OK/good.

You should be aware though that other vendors can supply similar instruments e.g. Thermo and Agilent.
They are not built to generate/resist as high presser as the Acquity, but I’m not sure that pressure as high as 15000 psi is that suitable for chromatography of any and every compound. I’m not going into this discussion here and I’m sure that some people will argue with me on this one, but it’s just my opinion.

Just check the prices and most importantly be sure to buy a system controllable by the CDS you have in house. I don’t think it’s worth it to buy completely new CDS (for your lab anyway) just to control a single or a few UPLCs.

Best Regards

I have just ordered a column from Sigma Aldrich or Supelco, whatever they call themselves(!), that claims to offer low backpressures but the efficiencies of a sub 2um column - and I can use it on my Agilent 1100!! Looking forward to testing this column, has anyone else tried, are the claims correct? It is called Ascentis.

Thanks for your replies and also for advising about other manufacturers, I'll have to look them up. My only experience with Waters software has been with MassLynx. This software is difficult to operate and the communication often fails. Am I right in thinking that the Empower system is more reliable/user friendly?

hi developer - I have not used the Ascentis but we have been using a 2.5 micron column from Phenonenex to get faster run times with an Agilent 1100. The limitations are the pressure limit of the pump and the data collection rate of the detector. But you can certainly explore and get some of the advantages with traditional HPLC instrumentation.

Hi lamond1973,

I’ve tried – that is before I both the Acquity system – a Zorbax 1.8 μm particle size column (50 X 4.6 mm) on a traditional Waters system and it performed very, very well. The pressure was appr. 2500 psi with 1.5 mL/min flow rate.
I understand you are familiar with Chemstation, so maybe the best solution for you is an Agilent 1200 system. It can generate and withstand 600 bar pressure and the system volume can be reduced to a minimum indeed. The detector operates with up to 80 Hz sampling rate, although 40 Hz (the 1100 detector) should be more than enough for most application I can imagine.
For the sake of the comparison it should be mentioned that an Acquity column 50 X 2.1 mm will raise the pressure to about 500 bar with 0.5 mL/min flow rate. So if you calculate the linear velocity you will find it fast enough to reduce your runs 4 times or something like that, provided you chose to get Agilent 1200 and still try the Acquity columns. But there are many vendors out there that provide sub 2 μm particle columns.

Best Regards

I just did two presentations on fast HPLC for our department's Analytical Forum discussion. Seems to me the interest level is very high elsewhere too. We have mostly Agilent 1100 HPLC, a couple 1200 and one UPLC. What Danko said about the CDS is very true. We are going to implement Chromeleon in 2Q2007, and will have to leave the UPLC out of the CDS. We haven’t use the UPLC extensively, because most people in our department are not familiar with Empower.

Most column vendors supply sub 2 um particle columns these days, mostly only up to 50 mm or 75 mm length due to pressure limits. We’ve started to use the small columns for initial column screening, such as Zorbax 1.8 um, Synergy 2 um, Xbridge 2.5 um, Halo 2.7 um, and Alltech Platinum 1.5 um. For most applications, these columns can provide sufficient efficiency for the desired separation on our existing instruments. Teh fact these columns are shorter provided 2-3 times savings in run time. However, the practical flow rate is usually less than 2 mL/min due to pressure limits on the 1100 (400 bar) or 1200 (600 bar) systems. We also tried the monolith column, but it didn’t provide enough plate counts.

To Developer1974,

I think you meant “Ascentis Expressâ€

Hi jzt -

How did you measure plate count? Unless my math is wrong,
600,000 plates/m seems a little on the high end...

I'm sure I saw a similar product from Shimadzu several months back. They had a 2.2 um particle column - and were also claiming some kind of manufacturing technology that gave a very narrow size range.

It seemed very clever to me. In the last week or two I tried to find information about this. But had no luck.

Does anybody know what happeded? Did they sell the technology to someone else?

Thanks

Bryan,

All the plate counts listed were from ChemStation Performance reports, which happened to be the half width method. for the HALO 4.6 x 100 mm column, the plate count by tangent method is 35979, by 5 sigma method is 31868.

Hi Jzt, yes you are right it is the ascentis express column - see http://www.sigmaaldrich.com/Area_of_Int ... press.html

The Halo column looks pretty interesting. I'll check it out.

I have to agree with Bryan though, on those plate counts. I would expect a perfectly packed 50 mm long column (with dp of 1.8 uM) to have a plate count of around 10,000 at optimum conditions. Anything over 8000 would be pretty impressive.

Hi jzt -

How did you measure plate count? Unless my math is wrong,
600,000 plates/m seems a little on the high end...

I have to agree.

jzt: You did do the column comparison using an isocratic separation?

cheers,

According to mac-mod site, using naphthalene in 60:40 CH3CN:H2O at 24C, their Halo column yields 215,000 N/meter, versus 100,000 N/meter for a similar 5 um, and 143,000 N/meter for a 3.5 um, column.

They note that the Halo column has slightly more back pressure than a similar 3.5 um column, but still can be used on most existing HPLCs.

Bruce Hamilton