Scottish Highers Chemistry Chemical Analysis: Up to 10% of perfumes sold in th

Question

Up to 10% of perfumes sold in the UK are counterfeit versions of brand name perfumes.

One way to identify if a perfume is counterfeit is to use gas chromatography. Shown below are gas chromatograms from a brand name perfume and two different counterfeit perfumes. Some of the peaks in the brand name perfume have been identified as belonging to particular compounds.

**Brand name perfume**

- tinalool
- citrionellol
- geraniol
- eugenol
- anisyl alcohol
- coumarin
- benzyl salicylate

**Counterfeit A**

**Counterfeit B**

(a) Identify one compound present in the brand name perfume that appears in both counterfeit perfumes.

(b) Some compounds in the brand name perfume are not found in the counterfeit perfumes. State another difference that the chromatograms show between the counterfeit perfumes and the brand name perfume.

(c) The gas used to carry the perfume sample along the chromatography column is helium.

(i) Suggest why helium is used.

(ii) Apart from the polarity of the molecules, state another factor that would affect the retention time of molecules during gas chromatography.

(d) Many of the compounds in perfumes are molecules consisting of joined isoprene units.

(i) State the name that is given to molecules consisting of joined isoprene units.

(ii) Geraniol is one of the compounds found in perfume. It has the following structural formula and systematic name:

H   H   H   H   H
C---C---C---C---C=O
H   H   H   H

3,7-dimethylocta-2,6-dien-1-ol

(A) State the systematic name for linalool.

(B) Explain why linalool can be classified as a tertiary alcohol.

(e) Coumarin is another compound found in the brand name perfume. It is present in the spice cinnamon and can be harmful if eaten in large quantities.

The European Food Safety Authority gives a tolerable daily intake of coumarin at 0-10 mg per kilogram of body weight.

1 kg of cinnamon powder from a particular source contains 4.4 g of coumarin. Calculate the mass of cinnamon powder, in g, which would need to be consumed by an adult weighing 75 kg to reach the tolerable daily intake.

Up to 10% of perfumes sold in the UK are counterfeit versions of brand name perfumes - Scottish Highers Chemistry - Question 4 - 2015

Worked Solution & Example Answer:Up to 10% of perfumes sold in the UK are counterfeit versions of brand name perfumes - Scottish Highers Chemistry - Question 4 - 2015

Identify one compound present in the brand name perfume that appears in both counterfeit perfumes.

State another difference that the chromatograms show between the counterfeit perfumes and the brand name perfume.

Suggest why helium is used.

Apart from the polarity of the molecules, state another factor that would affect the retention time of molecules during gas chromatography.

State the name that is given to molecules consisting of joined isoprene units.

State the systematic name for linalool.

Explain why linalool can be classified as a tertiary alcohol.

Calculate the mass of cinnamon powder, in g, which would need to be consumed by an adult weighing 75 kg to reach the tolerable daily intake.

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