chromatography

Everyday

1. (science) A way of separating a mixture into the different substances in it, by letting a liquid or gas carry them along paper or another material at different speeds. tree →
2. Paper chromatography is a simple school experiment that shows the different colours hidden in an ink. tree →

In the lessons

In science lessons you draw a felt-tip dot on filter paper, dip the edge in water, and the water carries the colours up at different speeds, splitting black ink into blue, yellow and pink. Scientists and police labs use chromatography to test food, medicines and crime evidence. The result is a «chromatogram».

Examples

• In chromatography, we saw black ink split into blue and orange. tree →
• The water climbed up the paper and carried the colours with it. tree →
• Police labs use chromatography to test evidence. tree →
• Chromatography shows that one ink can contain many colours. tree →
• Our chromatography experiment used coffee filter paper. tree →
• Draw the line in pencil, because pencil does not run in chromatography. tree →

Note

Say «kroh-muh-TOG-ruh-fee». chroma (colour) + graphy (writing). Uncountable. Use a pencil line for the start, because pencil (graphite) does not dissolve.