MODEL RELEASED. HPLC analysis. Researcher, Matteo Girardi, using a high-performance liquid chromatography (HPLC) machine. He is analysing chlorophyll and carotenoid pigments. HPLC is used to separate components from a mixture dissolved in a liquid. Separation takes place on beads packed inside a column inside the instrument, coated with a waxy substance that exerts a varying attraction on the components of the sample as it is pumped through the column under high pressure. The varying attraction results in the components emerging at differing rates from the end of the column. Photographed at the Centre of Alpine Ecology, Trento, Italy.