Orbitrap or QTOF

[Edde]

I am currently using the Shimadzu IT-TOF bought a few years ago and now my laboratory is planning to find a sensitive exact mass analyzer capable of performing MSn and structural elucidation to replace the aged IT-TOF.

My target analytes are small molecules, drugs and metabolites and toxicology unknown identification.

We are considering the Orbitrap and QTOF (AB 5600, Agilent 6500, ?Waters G2). My considerations are:

1. price (heard that Orbitrap is more expensive than the top QTOF model, ? how much more)
2. resolution and mass accuracy at high scan rate compatible with UPLC
3. mass stability
4. hardware maintenance
5. software user-friendliness

Any comments are welcome and heartfelt appreciated.

[CE Instruments]

Which Orbitrap ? There is a range both in price and performance. Looking at Q-TOFs but no mention of Bruker ? What are you looking for in terms of resolution , sensitivity etc ?
I'm biased as ex Bruker but I would be looking at MaXis Impact with Smartforula3D software.

[Edde]

Orbitrap does not have MS/MS capability (please correct me if I am wrong). So I mean Q-Orbitrap. But I think the price should be way higher than top end QTOF.

I did not mention Bruker instrument because I heard from a peer user that the software is not user friendly (also, please correct me if it is not true) and the service support in my locality is not satisfactory.

As user, I certainly want to have an instrument with the best resolution, mass accuracy and scan rate at the best price.

Thanks.

[leadazide]

The Orbitrap does have MS/MS capability.. Both the "original" Orbitrap family and also the Exactive series have the possibility in different ways.. With the Q Exactive (Q-Orbi) there is a mass filtering Quad followed by an HCD cell for fragmentation before scans are done in the Orbitrap.. With the Exactive Plus there is also the possiblity of having an HCD cell but with no dass filtering Quad data interpretation can be tricky.. But is is upgradable to a Q Exactive later on..

[CE Instruments]

With all systems ease of use is both a function of existing knowledge and experience , the vendors software and how well you have been trained/supported to use it.
Smart Formula software was developed in conjunction with Pfizer in the UK. With any high resolution system you can generate a molecular formula match however even with small molecules that list can still be quite long. There are two solutions , firstly throw more resolution at the job , a million plus from an FT ! secondly Bruker TOFs give good reproducable fine isotope data. The 3D software takes the accurate mass data for the molecular ion , the daughter ions and the fine isotope for both molecular and daughter ions to generate the molecular formula. Pfizer found that this reduced the most common lists from 50+ compounds to about 5

Link to Bruker technical note TN-26

[Edde]

It is interesting. I should take into consideration the Bruker instrument as well

Thanks leakazide. Seems the Exactive plus needs more operator expertise and experience.

[Prim]

Xevo (Waters q-tof) is a nice instrument to use, works hard and doesn't break much. I haven't used the orbitrap, but I have used Thermo products (LTQ) - and again they don't break much either.

I think my personal preference is Waters, but I do believe the orbitrap has better sensitivity etc. You could always ask them for a demo....I've been to a few

Prim

[leadazide]

Seems the Exactive plus needs more operator expertise and experience.

Not as such... It is really streamlined for user friendliness.. Not much to tune/optimize. But as with all instruments/software there will always be a learning curve.

[Edde]

Thanks all for sharing.
I also heard from Agilent engineer that a new model will be out within 2 years!

[lmh]

Post ASMS, you will probably find that the price of low-end orbitraps has gone down enormously, now Thermo have introduced their new high-end orbitrap. Get all the manufacturers to demonstrate what they can do. If you are looking for Q-ToF-like characteristics, probably the Q-exactive is the nearest direct orbitrap substitute, because it's built for fast postive negative switching, and the aim was to provide high scan-speeds (normally not an Orbi's greatest strength) with simple quadrupole filter on the way in (SRM's and MS2 possible, but MS3 and beyond isn't). The ion-trap Orbis can do MSn, but check scan-speed for each model. They can all do blisteringly fast scan-speeds in the ion-trap bit, but with no mass accuracy - it is the Orbi part that limits scan speed (and pos/neg switching). Never assume an instrument is out of your price-range.

[Edde]

lmh, I appreciate your useful comments. I surely will obtain more information with regards to the Orbitraps.

Many thanks.