Chromatography
Separating dissolved solids using chromatography Chromatography works because some of the colors dissolve more easily in water than others. colors that dissolve more easily travel further up the paper. A chromatogram with different samples of ink.
Chromatography is a method of separating mixtures of substances that can dissolve in water.
This is especially easy when the dissolved substances have different colors. An ink or food coloring is usually made from more than one color. Chromatography can be used to find out the colors in ink or food coloring.
There are two ways to do chromatography:
Standard chromatography
The photo shows an example of a paper with different colors from standard chromatography.
Four samples of ink were used. Looking at the photo from left to right, the first sample on the left is a mixture of colors (yellow and orange). The other three samples are single colors (blue, pink and yellow).
Radial chromatography This is done by putting water on a spot of ink in the middle of a piece of filter paper. The colors spread out as they move away from the middle, rather than moving up as in standard chromatography. Comparing chromatograms
Another way to separate colors in an ink is radial chromatography.
Chromatography is often used to see if an unknown mixture has the same colors as pure pigments. This helps scientists to identify the colors in the mixture. Pure pigments that are used for this purpose are called standard reference pigments.
The piece of paper that is left after a chromatography experiment is called a chromatogram. A chromatogram shows the colors that were in the mixture.
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