1. Shellfish are particularly good at concentrating heavy metals in seawater. A sample 
from scallops was analyzed for cadmium using atomic absorption spectroscopy and the 
following results were obtained:
Cd Standard Concentration (ppm)          Absorbance
0                               
0.00
2                               
0.10
4                               
0.20
6                               
0.30
8                               
0.40
10                             
0.50
a) Construct a Calibration Curve. 
b) One of the scallops was removed from its shell and chopped finely in a food processor.
A 2.0g portion was digested on a hotplate with 10ml nitric acid. The mixture was then 
analyzed using AAS.
An aliquot of this digest of scallops gave an absorbance of 0.42. Determine:
i) The concentration of cadmium in the 10ml solution (in ppm) 
ii) The amount of cadmium in the 2.0 g sample of scallop 
iii) Express the amount of cadmium in mg per gram sample of scallop (ppt).
2. Explain (briefly! A few sentences ONLY!) why a continuous spectrum source lamp is 
a good source in molecular absorption spectroscopy, but not in atomic absorption 
spectroscopy.

3. Graphite furnace atomizers are renowned in Atomic Absorption Spectrometry for their 
exceptionally low detection limits (10­12 g and lower for many elements). Why are 
detection limits so much better with graphite furnaces than with flame atom cells in 
AAS?

4. The Raman spectrum of SO2 has a peak at 1325 cm­1. When excited by an argon­ion 
laser at 514.5 nm, at what wavelengths (nm) will the Stokes and anti­Stokes Raman lines 
for this spectral feature be measured? Which of these is more intense (include your 
reasoning!)?

5.Given the EI mass spectrum below, what organic compound is this?

6. Give the species from the fragmentations (labeled masses) in the mass spectrum of 
butanone. Make sure you indicate radical cations, cations or radicals where appropriate. 
Include the masses of all fragments in the scheme.

7. What are three advantages and three disadvantages to a DESI type ion source for a 
Mass Spectroscopy system?