Can chromatography be used for volatile substance?
Paper chromatography is a useful technique because it is relatively quick and requires only small quantities of material. The stationary phase is the water trapped between the cellulose fibers of the paper. The mobile phase is a developing solution that travels up the stationary phase, carrying the samples with it.
Disadvantages of Paper Chromatography This technique is not suitable for the separation of volatile substances such as hydrocarbons and volatile fatty acids. Not suitable for quantitative analysis. Not as accurate as HPLC and TLC. Chromatograms cannot be saved for a longer period of time.
Paper chromatography is used to separate mixtures of soluble substances. These are often coloured substances such as food colourings, inks, dyes or plant pigments.
A paper chromatogram can also be used to identify substances by comparing them with known substances. Two substances are likely to be the same if: they produce the same number of spots, and these match in colour. the spots travel the same distance up the paper compared to reference spots (have the same R f value)
TLC tends to produce more useful chromatograms than paper chromatography, which show greater separation of the components in the mixture – and are therefore easier to analyse. The distance a sample travels can depend on the size or the polarity of the molecules involved.
Paper chromatography is a technique which is used to separate low-molecular-mass compounds based on their distribution between stationary phase and mobile phase. Due to its low cost and availability of various protocols for the separation of compounds, paper chromatography is considered a powerful analytical tool.
The term ‘volatile substances’ refers to gases or chemicals that evaporate at room temperature to form a vapour which can be inhaled. They are found in a whole range of legal, household products.
Distillation is a separation technique used to separate components of a liquid mixture by a process of heating and cooling, which exploits the differences in the volatility of each of the components.
Limitations of Paper Chromatography Large quantity of sample cannot be applied on paper chromatography. In quantitative analysis paper chromatography is not effective. Complex mixture cannot be separated by paper chromatography.
Paper chromatography has become standard practice for the separation of complex mixtures of amino acids, peptides, carbohydrates, steroids, purines, and a long list of simple organic compounds. Inorganic ions can also readily be separated on paper.
Volatile or complex substances cannot be separated using paper chromatography techniques. The method is not useful for testing a large number of samples and data is not as accurate as in the case of the TLC technique.
Chromatography cannot be used to purify volatile substances. Explanation: Chromatography can be used to purify volatile substances if the carrier fluid, operating conditions and right adsorbent material are employed.
