5 Atomic Methods - absorption

Question 1

what four techniques can atoms be detected by?

Answer 1

Absorption (Atomic Absorption Spectroscopy - AA)

Emission (Atomic Emission Spectroscopy – AES)

Mass Spectrometry (ICP-MS) Fluorescence (X-Ray

Fluorescence, XRF)

Question 2

in atomic absorbtion, how are aqueous solutions detected?

• name the type of equipment
• what detects the sample

Answer 2

flame atomic absorbtion detects aqueous solutions.

mixing a sample with fuel then oxigenating it. atoms are then detected using light

Question 3

in atomic absorbtion, how are solutions, liquids and solids detected for?

Answer 3

using a graphite furnace atomic absorbtion

place sample in graphie tube

incrase temp with heat and detect atoms with a light source

Question 4

compare a flame AA and graphite furnace AA

based on the way the sample is in the flame/analysed and the measurement time

Answer 4

flame:

• large amount of sample
• short time in flame

graphite furnace

• vaporises the sample quickly
• long measurement time

Question 5

why is calcium difficult to determine in the presene of phoshate or sulfate?

Answer 5

because calcium sulfate binds to calcium in the flame

Question 6

what are two solutions to determine calcium in water by atomic absorbtion if phosphate is present in the sample?

Answer 6

1. add a releasing agent
2. add EDTA to release calcium in the flame

Question 7

what are two examples of releasing agents that can release calcium in the presence of phosphate?

Answer 7

Sr2+ and La3+

Strontium and Lanthanum