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Ultraviolet absorption spectroscopy can be used in the quantitative analysis of some organic compounds (e.g - Leaving Cert Chemistry - Question i - 2007
Question i
Ultraviolet absorption spectroscopy can be used in the quantitative analysis of some organic compounds (e.g. drug metabolites and plant pigments). What is the underl... show full transcript
Worked Solution & Example Answer:Ultraviolet absorption spectroscopy can be used in the quantitative analysis of some organic compounds (e.g - Leaving Cert Chemistry - Question i - 2007
Step 1
What is the underlying principle of this analytical technique?
Answer
The underlying principle of ultraviolet absorption spectroscopy is that the absorbance of a substance is directly proportional to its concentration in a solution.
This can be expressed mathematically using Beer-Lambert Law, which states: A = rac{abc}{d} where:
- A is the absorbance,
- a is the molar absorptivity,
- b is the path length of the sample,
- c is the concentration of the substance,
- d is the thickness of the medium through which light passes.
Thus, as the concentration of the organic compound increases, the absorbance value also increases, allowing for quantitative analysis.