Chromatography Forum

Hi there

we're just in the discussion/decision for a new UPLC, so I'm looking for fast answers...

Does anybody already have some experience with the Aglient 1290?

Are there any pro/cons vs. the Waters Acquity (beside the higher pressure limit, higher flow rate possibility, higher sampling rate of the PDA)?

Are these features really needed in UPLC method develompent or are these more to impress the customers? E.g. how much of column performance do I trade of for the higher flow rate? Would it then not be possible to use a smaller column?
Are the particle going to be smaller than 1.7 µm in the near future?

What about the "adjustable" dwell volume of the 1290? The presentation says that this is for the compatibility of different systems. Is this really physically adjusted or is this just an inbuild calculative correction of the gradient table, which can also be done manually (if one knows the theory)?

Thank you for your opinions.

Interesting post, I'm surprised no one has commented thus far. I guess the reason for this is because not many individuals have managed to get their hands on a 1290 yet.

In my opinion, I would just use UHPLC with 2.1/3.0 mm columns so extended flow rates beyond 2.0 mlL/min are not really that important to me. I think the big advantge that the 1290 may have over the Acquity is in the detector performance - we'll just have to wait and see if this manifests itself.

PS. As far as I'm aware, the adjustable dwell volume of the 1290 isn't fully rolled out yet but will be a future feature of the instrument.

it would be really nice to hear from user of this equipment about their experiences

Hollow, any decisions made?

If I were to choose I would go with the agilent, versality being main factor

The feature which I like about the 1290 is the optional low volume mixture. We use TFA containing mobile phases and the baseline look better with the new mixer.

What is the longest column allowed on these systems?
The 250mm length column can be useful for difficult separations.

Hi all,

The feature which I like about the 1290 is the optional low volume mixture. We use TFA containing mobile phases and the baseline look better with the new mixer.

Actually one would expect less efficient mixing with a low volume chamber compared to a larger volume ditto. Maybe it’s a question of design as well. But I remember Waters recommending a larger volume mixing chamber (mixer) when noise and unstable baseline is an issue – and accidentally the TFA containing eluents were mentioned as a typical example.

Best Regards

http://www.chem.agilent.com/Library/use ... _ebook.pdf

See the section on the "Jet Weaver" for a description of the mixing capability of the system. Larger volume is recommended for "...demanding situations such as the use of TFA in UV detection." (p. 28 of e-book manual).

May I ask why you consider only the UHPLC systems from Waters and Agilent? I think there are some more interesting systems on the market worth to consider as well.

I have always been critical to the baseline noise achieved with Waters Aquiety. It simply cannot mix mobile phases containing acetic or formic acid without terrible noise (even in the 0.1% range) . And that is with their largest mixer installed. The Aquiety is best used directly coupled to an MS.

Comparing S/N values between different instruments (Waters, Dionex and Agilent), I found that Waters Alliance with a dual-wavelength detector is the best. And that is a 15 year old instrument.... Not only the music was better before.

I think it’s important in this particular context to find a way of distinguishing noise related to mixing (whether it’s TFA containing mobile phase or whatever) from noise caused by other sources (electronics for instance). Maybe all this talk about mixer volumes isn’t always relevant?
Mattias, it looks like you’re the only one (nearby who has done some comparative studies between Waters, Agilent and Dionex. So, I’m curious as to whether your tests only included gradient mixing or isocratic ditto as well. Because there could be huge differences between these two modes! Finally, did your test include determination of noise under no mixing flow, or mixing of two identical eluents (2 portions of the same eluent)?
I’m convinced that these modes would result in different outcomes depending on the conditions mentioned above.
Please don't get me wrong – I’m not defending any of the brands. It’s just that I think it’s nice to know where the devil lies. After all that is the first step to a possible solution.


Best Regards

There are so many parameters that influence the noise in a particular situation. I tested this by injecting a QL solution (a 0.03% solution of one of our drugs) in a standard water/TFA/Acetonitrile gradient - no premixing. Same solutions used on all instruments. I did not try isocratic elution.

The S/N achieved (purchase year):
Waters Alliance dualwavelength (1996): 65
Waters Alliance DAD (1999): 54
Dionex Summit (2003): 36
Agilent 1100 (1999): about 20
Aquiety (2008): just a hint of a peak (S/N < 3)

I think that there are big differences how the signal is processed in the different instruments also. But it is clear that we cannot use Aquiety for any trace analysis in low UV (230 nm).

very interesting results indeed

How did you changed gradient and injection vulume?

Mattias,

Your observations are very interesting. Can you tell us which wavelength you were working at with your QL solution? I presume it is below 230 nm?

What are the dimensions of the detector cell you use in the Acquity?

You seem to be suggesting that this is a mixing problem. Have you proved this by pre-mixing a mobile phase and eliminating the problem or not (if not with the QL test you referred to, but perhaps with some other test?). Is it possible that it is not a mixing problem but higher noise due to the high background absorbance of some mobile phases (like formic acid) at low wavelength? In this case the problem would not go away with a pre-mixed eluent. I could see different detector designs giving different results with a pre-mixed eluent.

The chromatograms were recorded at 220 nm, and I just moved the old 5 µm column around and did not change flow or injection volume. All systems uses "analytical cell".

I will have to come back regarding the premixed mobile phases, I just used one bottle of water and one bottle of ACN (containing 0.2% TFA each).

May I ask why you consider only the UHPLC systems from Waters and Agilent?

Yes, we are already equiped with Agilent and Waters systems (two departments).

We had tested the Acquity some time ago but only know the specs and presentations from Agilent. So I thought I would like to ask, if someone has already some practical comparison.

@grzesiek:
personally yes, Acquity, cause we have some other Waters systems and are using and familiar with Empower 2, so we don't have to use two CDS in the same lab.

I think, with the actual columns and particle on hand, the pressure limits are most given by this, than of the system. Therefore I regard these two systems as "equivalent" in daily work.
I made some exemplary calculation, that I should be able to transfer some 40 minutes gradient method (4,6x100mm, 3.5µ) to 9.7 min (only transfer, 2.1x50, 1.7µm), and further speed up to 4.15 min on the Acquity and down to 3.5 min on the 1290.
For some, this extra speed would made the difference, but this is not the main criteria for us.