Hi
I have money to buy one of these for both metabolomics and proteomics. How stable are these instruments especially the 5600 model as regards mass accuracy?
Thanks
Brendan
Hi Brendan,
We use TripleTOF 5600+ since 2013 for untargeted environmental screening. This is a very powerful and robust machine. As for mass accuracy, it depends on the ambient temperature stability. If we do not worry about it, the mass scale stability is within 5 ppm during several hours. To obtain a very good accuracy we use automatic recalibration befor each run (~ 1 hour), in this case the typical errors are of 0-3 ppm. Thus, I strongly recommend to purchase the instrument with CDS (calibrant delivery system) accessory. In any case you should take into account that mass accuracy is also affected by m/z value - mass scale stability is much better for heavier ions when compared with m/z ~ 50-100 where the error can achieve 10 ppm and more (also due to the calibration problems in extremely low mass range). Other factors affecting mass accuracy are the signal intensity and the dynamic range. The latter means that you cannot measure absolutely precisely the m/z of low intensity ions with the simultaneously presence in spectrum very intense (for example 3 orders of magnitude higher) peaks of other ions. The very useful function of Analyst software is the possibility to recalibrate mass scale of already spectrum using the internal standards (peaks with known accurate masses). In this case the m/z errors can be reduced down to 1 ppm and less.
Before purchase, I strongly suggest you book a few days at the vendor's application lab to try out their system with your own samples.
Some systems look great on paper, but you may find that you do not like their software or some subjective aspects of their system. If possible, try a few different systems (brands/models) before purchase and try and keep an open mind. Resist being biased against a particular brand or method. Also, bring an experienced scientist with you to these meetings too. Nothing like a second set of eyes, ears and hands to soak in the information and ask questions.
This advice is given to all of my consulting clients and it is one of the best ways to gets some hands-on time and experience with their own scientist on hand to give you advice too.
What I should suggest you is not only take a look to the mass spec. Also see how you will handle the sample separation through the LC, considering the fact that could be different flow scales. What chromatography system will be upstream of the mass spec is important and how frequently you will perform either proteomics or/and metabolomics. You can switch easily at the mass spec but at the LC it will take more time.
- Badges
- Science topic
- Similar topics
- Chemistry
- General Biochemistry
- Proteomics