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)

• 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 ServiceCurrent arrangements for runningMass Spec samples?

Until training is complete, we are sending some samples out to Edinburgh Uni for analysis…

For further info contact Dr Georgina Rosairas 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 dosome 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 goodcalibration (m/z = 800 Daltons) with PFK.

• Low resolution, gives weak molecular ionand 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

How we make up your sample

Loading sample into the MS…

Loading sample into the MS…

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 theMass Spec Sample Form?

Mass Spectrometry ServiceHow often should I submit samples for MS analysis?

• Submit samples regularly (eg on a weekly basis)

Mass Spectrometry ServicePlease do NOT leave submitting MS workuntil 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 EIand 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:

www.che.hw.ac.uk/research/services.html

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!