A chromatograph is an analytical instrument used to separate and analyze mixtures of substances. It works by passing a sample through a medium, where different components move at different rates, allowing them to be separated. This technique is widely used in chemistry, biology, and environmental science to identify and quantify various compounds. There are several types of chromatographs, including gas chromatography and liquid chromatography. Each type uses different methods and materials to achieve separation. The results are often displayed as a graph, where peaks represent the presence and concentration of individual components in the sample.