Analytical Services Talks 2009 “The Mass Spectrometry Service”

School of EPS Support Services Dr Roderick Ferguson EPS IT Service (see separate powerpoint on chemistry website) powerpoint Mass Spectrometry Service (I used to run this…)

Mass Spectrometry Service School of Engineering and Physical Sciences Perkin Building – Chemistry!! Lab WP G.10, ground floor, spine.

Mass Spectrometry Service WP G.10 is on the right…

Mass Spectrometry Service Was ran by Mr Gerry Smith Sadly, Gerry died at the end of April this year, and the School management are in the process of getting a replacement technician trained up…

Mass Spectrometry Service Current arrangements for running Mass Spec samples? Until training is complete, we are sending some samples out to Edinburgh Uni for analysis… For further info contact Dr Georgina Rosair as she is now managing the MS Service.

Mass Spectrometry Service Two important questions to ask: What can it do for you? What do I need to know in order to use this service?

What is Mass Spectrometry? Measure the mass/charge ratio (m/z) of a molecule, and also of any fragment ions. Equipment used? Double Sector Mass Spectrometer Quadrupole Mass Spectrometer

Spectrometer – Kratos Concept

Console and Computer Workstation

Benchtop Mass Spectrometer (Quadrupole / Electrospray source)

Uses of Mass Spectrometry? Many books have been written about this … Forensic Science Space exploration (Life on Mars?) Archaeology (eg dating studies) Chemical Analysis

Mass Spectrometry We can do TWO main experiments:- 1.Electron Impact (on the Kratos instrument) 2.Electrospray (on the Benchtop instrument) Both of these are Operator Only techniques

Sample Purity? A useful WARNING - Just like the other services, we cannot run samples that are mixtures! This means that you first need to do some work to clean up your product… especially if it is an unknown! You might need to remind your supervisor!

The EI Experiment:- Used with solid compounds which melt below 200 ºC and are soluble in either Dichloromethane or Methanol (for sample preparation). Upper mass limit depends on getting a good calibration (m/z = 800 Daltons) with PFK. Low resolution, gives weak molecular ion and lots of fragment peaks.

The EI Experiment:- We can also do Accurate Mass work Can be useful for product identification along with NMR (and when you can’t use CHN!) Again, the upper mass limit depends on getting a good calibration (m/z = 800 Daltons) with PFK. However, it does takes longer to do, and it doesn’t always work(!)

The ESI Experiment:- Polar compounds (eg Peptides) or Organic Salts in solution. Upper mass limit is 1400 Daltons. Can use Methanol for sample preparation, but not dichloromethane!!! Ions are generated from electrically charged droplets of a solution; hence the term ‘ElectroSpray’

The ESI Experiment:- Molecular ions are much easier to detect using this ‘soft ionisation’ technique. No fragment Peaks! It is a Low Resolution technique (No accurate mass possible) Only possible on the Benchtop MS

Mass Spectrometry Service How to submit samples … How much sample is needed? Just 2-3 mg(!), in a properly labelled, small, screw-top sample vial.

A ‘good’ sample vial… Screwtop lid and labled!

How we make up your sample

Loading sample into the MS…

a) EI Source without sample b) with sample loaded

Using a Mass Spectrometer As you can see from the previous slides, there are a lot of fiddly and very delicate manipulations that are required in order to use an older Mass Spectrometer… This is why we don’t offer a “self service” facility for MS! i.e. it’s an ‘operator only’ service.

Back to filling in a Sample Form OK – next question: How do I complete the Mass Spec Sample Form?

Mass Spectrometry Service How often should I submit samples for MS analysis? Submit samples regularly (eg on a weekly basis)

Mass Spectrometry Service Please do NOT leave submitting MS work until the end of your Project or PhD! 1.This is bad practice! 2.It is inconsiderate towards other users! 3.It is also a bad use of both staff and service time!

A filled in sample form …

A filled in sample form (continued)

The Low Res EI Mass Spectrum …

How much per sample? Older rates (up to April this year) Low res EI and Electrospray High res EI (your supervisor is charged these fees) = £2 per sample = £4 per sample

Edinburgh Uni. MS rates Rates for samples ran at Edinburgh Uni. are £15 for an ordinary sample (Low Res EI/ESI) and £30 for High Res EI (i.e. a Low Res & a High Res expt) (Ask Dr Rosair for specific details)

Mass Spectrometry Service Website: NB - this covers all of the Analytical Services…!

Mass Spectrometry Service “A satisfied customer, dear … we should have him stuffed!” Basil Fawlty – Guide to successful hotel management.

Mass Spectrometry Service The End … … but not for AIT students!