UPLC

[zo]

Dear all,

I'm looking for a UPLC system. Theoretically it's look good to compare with HPLC. My question is what're disadvantages.



Thanks in advance for all answers

[tom jupille]

Good gravy!

Start by doing a search of the Forum (the "Search" link is near the upper left of your screen); there have been several threads on the pros and cons of UPLC in the past several months. If you don't find the information you need in those threads, post some specific questions and you'll probably get more feedback.

[malaka50]

price is major disadvantage. since it is a new technology, there are still a few "bugs" that need to be sorted out with the current manufacturers. we tried a system, but too many issues with software, so gave up on it.

main advantage is to shorten run time i guess? the better options are to look at using alternative columns rather than a new system as the solution. monolithic columns such as phenomenex onyx reduce run times significantly whilst maintaining separartion and resolution. you can also look at smaller particle sizes and shorter columns, ie. 2u 50x2mm, 50x4.6mm etc.

it's a lot cheaper to try a few different columns than to buy a whole new system.

[Uwe Neue]

While you are correct that to buy a column is cheaper than to buy a new system, you also will not get the performance of a UPLC column form a monolith. The performance of a monolith is roughly as good as a 3 to 5 micron column. The advantage over such columns is the lower backpressure. But this does not compare with what you can get out of 1.7 micron columns.

[bartjoosen]

....main advantage is to shorten run time i guess? ....

Not only shorten runtime.
If this is the goal, the UPLC will full fill your expectations.
Another goal can be increased selectivity (wether or not in combination with decrease in retention time), increased sensitivity, faster method development,...

When buying a new system, I think its worth to think about

Bart

[Bryan Evans]

Have you tried 3 micron columns? They are a great option
for your current HPLC - great resolution but not at the
expense of all the back pressure.

[pve]

Hi,
It's a very good idea to look for an UPLC system.
In our lab (Quality control and method dev.), we have about 20 HPLC and 2 UPLC. We bought our first UPLC in jan 2005, the second in june, and now these two apparatus are very occupied by the technicians.
With this system, building a new method goes very fast. We transfered "old" methods of 70 mn in HPLC to 15 nm methods in UPLC -the validation of these news methods is on going.
we work on pharmaceutical products (MW # 300), we have no experience on sugars. About Macrolids (MW #800), the transfert of the method is quite strange, and we are working on this point.
I wish my opinion will hepls you

pve

[Rafael Chust]

I generally agree with Uwe and Bryan concerning the size of particle.

In my opinion, the breakthrough of Ultrahigh Pressure LC systems is to allow the use smaller particle size columns without being worried with high backpressure - not the opposite.

Therefore, if you can run your HPLC at continuous pressure over 4000 psi with 2 or 3 µm columns, them you should have the same performance as Waters UPLC and Agilent 1200 series.

[Uwe Neue]

You can get decent performance from 3-micron particles on an HPLC, but it is sloooooooow.

You can get the same or better performance from 1.7 micron particles using UPLC, but about 4 times faster. So if you go from a 20 minute analysis to a 5 minute analysis, I think most of us will be able to tell the difference.

[Bryan Evans]

Our colleagues in Japan (Imtakt) have done
some exciting things using 3 micron technology.
I think data is a lot more telling than words - so here's
some high throughput/high resolution data.
(all done on existing HPLCs):

High throughput:
http://www.imtakt.com/TecInfo/TI202E.pdf
http://www.imtakt.com/TecInfo/TI203E.pdf

Separation of Isomers:
http://www.imtakt.com/TecInfo/TI151E.pdf

[zo]

Thanks for everybody.
Another question: how about the column (conventional vs. 1.7 micron particles) life time?

[Rafael Chust]

Depending how good and concious you are concerning sample prep...

Rule of thumb: the smaller the particle, higher the sensitivity, more demanding the sample prep... otherwise you will clog your column very fast!

Anyway, without any particular experience with UPLC, I would bet it's comparable.

[Chris Pohl]

zo,

I've seen a number of papers in the past year by users of UPLC and none reported more than 500 injections per column even with filtering of samples with a 0.22 micron filter. I think it's safe to say that column lfe in the best case is significantly worse.

[A.Nonymous]

I have had a column with 1,500 injections, but also with 200 injections (very dirt samples). I also know people with over 10,000 injections on a single column.

Perhaps there are some undiscovered factors which play a major role.
I have heard about the same applications for the same samples in the first lab 5,000 injections/column, where another lab only get 500.

[Chris Pohl]

A.Nonymous

In my previous post I wasn't trying to address the general issue of column life as it relates to sample preparation. I understand that column life can vary widely depending on the types of samples and how the samples are processed before injection. I was simply trying to make the point that there are specific column life issues associated with the particle size of the chromatographic media packed into a given column. Let me be more explicit: a rough rule of thumb is that the maximum allowable diameter of particles present in your sample should never be more than 10% of your chromatographic media particle diameter. This is a relatively lenient guideline which is certainly no guarantee that you won't have column plugging with such samples. But even if we take this guideline as fact, consider the implications for various chromatographic media. For 5 µ particle size chromatographic media the sample should be filtered with a 0.45 µ filter in order to avoid column plugging problems. Even this is no guarantee since most filter media will allow particles larger than the nominal particle retention value to pass right through which is why it is probably safer to use a 0.22 µ filter. For 3 µ particle size chromatographic media the sample should be filtered with a 0.22 µ filter. For sub-2 µ particle size chromatographic media the sample should be filtered with a 0.1 µ filter. Filter media of this sort is generally difficult to work with and is not widely available so many early adopters of UPLC have been using 0.22 µ filters. However, such filters are inadequate for preventing plugging problems. This is why I don't think you can say column life can be expected to be identical to larger particle size media (and why I have seen multiple presentations on the topic mentioning column life in the range of 70-350 injections). I think you'll agree this is unusual for most larger particle size media.