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Thin film chromatography
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| Chromatography is an analytical technique that separates inks into their component dyes. A coloured pattern is formed called a chromatogram. Many inks or dyes form a unique pattern and therefore can be identified according to this pattern. | ||
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We can identify
the different inks according to their Rf values. Each component dye moves
a different distance up the paper. The Rf value is calculated by dividing the distance the ink has moved up the paper by the distance the solvent has moved up the paper. Take the red component of the chromatogram on the left. The ink has moved up 4 cm while the solvent has moved up 10cm. The Rf value for this particular red dye is 0.4. Calculate the Rf value of the green dye. |
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The animation on the left shows the chromatogram of a black ink being developed. Calculate the Rf value of each of the component dyes. | |
