Instrumental Methods

Question 1

Modern instruments advantages:

Answer 1

Quicker
More accurate
More sensitive
Can analyse very small samples
Need less people to run

Question 2

Modern instrument disadvantages:

Answer 2

More expensive
Results need to be compared
Special training is needed to use the machine and read the spectra

Question 3

What is FES (flame emission spectroscopy) used for:

Answer 3

Drugs tests
Discovering new elements
Monitoring water for toxic metal ions
Checking hip replacements - if bad, titanium in blood of patient

Question 4

What does FES test for:

Answer 4

Metal ions

Question 5

How does FES work:

Answer 5

Electrons get excited and jump to the next shell up/out
When they lose energy, they release light energy
Each element gives out light energy at different wavelengths to make different colours
The spectrometer analyses the wavelength to see if there are metal ions
It produces a line spectrum to compare with the database to identify the metal ions present
The spectrum also tells you the concentration by the intensity of the light, more intense = more metal

Question 6

How to work out the concentration:

Answer 6

Moles = mass x rfm (mass number)

Concentration =
Moles
——-
Volume