Spectroscopy In a Suitcase

Royal Society of Chemistry

Aims of this workshop

• To provide a hands-on experience with Spectroscopic equipment that is found in a University Lab (IR/NMR/UV-Vis)

• To problem solve with real spectra

• To talk to Undergraduate and Postgraduate Chemistry students about life at University

What is Spectroscopy?

• ‘Spectroscopy is the study of the interaction between light (electromagnetic radiation) and matter.’

• We can characterise matter by the way it interacts with different frequencies of radiation

Which Techniques?

• Infra Red (IR)

• Mass Spectrometry (MS)

• Nuclear Magnetic Resonance (NMR)

• UV / Visible (UV/Vis)

• With a combination of these techniques you can identify the structures of unknown substances

Infra Red (IR) Spectroscopy

http://www.rsc.org/learn-chemistry/resource/res00001041/spectroscopy-videos#!cmpid=CMP00001771 then select IR video

Infra Red (IR) Spectroscopy

https://www.youtube.com/watch?v=xITzGUjongU then select IR video

Infra Red (IR) Spectroscopy

• Information obtained = Functional groups present

Applications of IR Spectroscopy

Forensics/law enforcement

• Many ‘breathalysers’ used to collect evidence to determine levels of alcohol in breath are IR spectrometers

• Several Police forces use portable IR spectrometers at music festivals (e.g.Glastonbury) to identify illegal drugs

• IR spectroscopy is approved by the Home Office for identification of Ketamine and Mephedrone

Applications of IR

Quality control• Major concern in chemical,

pharmaceutical, polymer and automotive industries

• Compare to reference IR spectrum by a correlation function

Wine analyser• Can use IR to determine quality-

related wine parameters such as alcohol, acid and sugar content, density, pH and to monitor maturation

IR Spectroscopy and Formula 1

• Most commonly used for ‘fault finding’

• Lubricant oil analysis can prolong the life of a gearbox

Mass Spectrometry (MS)

• Does not use electromagnetic radiation, therefore is called Mass Spectrometry but often called Mass Spectroscopy!

• Molecules are ionised then fragmented

• Information obtained = mass of molecule (RMM) and often molecular structure

Mass Spectrometry (MS)

http://www.rsc.org/learn-chemistry/resource/res00001041/spectroscopy-videos#!cmpid=CMP00001768

Mass Spectrometry (MS)

Propanone

Body in Lab

Background: • You come back to the lab to find your colleague lying lifeless

on the floor.

• You additionally notice a faint smell of almond that wasn’t

there when you left earlier.

• On approach, you notice his face is an unusual reddish

colour and again notice the almond smell but this time on his

lips.

• The decease was earlier that day complaining of chest pains

and had a cold.

Evidence: As you look around the lab you notice various things:

• There are a several tablets lying on the bench.

• Three beakers have been knocked over with the liquids

from each mixed together.

• There is a small amount of original liquid left in each

beaker. The beakers are labelled; sulphuric acid,

C7H6O and C3H3NO.

• The first page of a paper from the Journal of the

Chemical Society.

What are your

thoughts?

Activity: • In your groups use the FT-IR to identify the tablets

(reference IR and mass spec are also given for these

tablets)

• Using the IR spectra given suggest the structures of

the compounds C7H6O and C3H3NO from the beakers.

• From all the evidence, give a possible scenario into

what has happened to your colleague.

Now present your theory

on what happened to your

colleague

Summary:• The tablets were analysed and found to be Aspirin. The deceased was taking

them for his chest pains and/or cold and therefore not the cause of death.

• C7H6O is Benzaldehyde. This accounts for the almond smell but Benzldehyde

would not have killed your colleague either.

• Notice the peaks on the Benzaldehyde IR at 2700-2800cm-1 that don’t appear

on the Asprin IR. This is due to the C-H on the aldehyde.

O

H

OCH3

O

O

OH

• The C3H3NO is Acetyl Cyanide which is

deduced from the IR

• Finally you remember the report on your

colleague desk and take another look:

You see that acetyl cyanide undergoes

hydrolysis to form HCN in acidic conditions and

there was sulphuric acid on the bench as well!

CH3

O

N

Conclusion• Now you remember that your colleagues skin was

slightly red, a symptom of cyanide poisoning

• An almond smell is also a symptom of cyanide poison

but the Benzaldehyde threw you off the trace as it also

smells of almonds

• The deceased accidentally spilt the bottles of acetyl

cyanide and sulphuric acid on the bench which reacted

and produced HCN and he has collapsed and died!

Royal Society of Chemistry Resources

• Spectraschool – Videos, theory, real spectra• http://www.rsc.org/learn-chemistry/collections/spectroscopy

• ChemNet – http://www.rsc.org/Membership/Networking/chemnet/• Free support and advice for chemistry students 14-18 yrs• Help with your studies and exam revision from Dr ChemNet

and chat to others studying chemistry• Student magazine, ‘The Mole’• Guidance and events on career opportunities and university

choices

• Careers: http://www.rsc.org/careers/future/