Question

A cosmetics company is interested in the development of a new analytical method for the analysis of an essential oil derived from plant extracts. They are specifically interested in quantifying carene (bp 168 oC), camphor (bp 209 oC), limonene (bp 176 oC), a-pinene (bp 155 oC), and residual ethanol (bp 78 oC) from the extract. a. What chromatographic technique would you use for this separation? b. What is the basis for separation in the technique you selected? c. Name and briefly discuss the operating principle of a suitable detector you would use for this separation. d. Why did you select this particular detector? e. If the detector you selected in part b was unavailable, what other could you use? Why?

Answer 1

(a)The question clearly states that the chromatography technique is used to separate and detect essential oils which are volatile. Thus, observing the nature of oils, and based on their volatile nature, we can use Thin Layer Chromatography. TLC can be used for its simplicity, economy in materials, simultaneous analysis of a large number of samples.

(b)The basis of separation is the volatile nature and the difference in the boiling points of the liquids of the given sample. In case the difference in boiling point is too less in the sample, we may use a sophisticated method of TLC known as High Performance Thin Layer Chromatography.

(c)The detector best used to determine the components is Ultra Violet light. This is of high use because, viewing under it, we can distinctly observe as many compontnts of the mixture.