90 likes | 333 Views
AP Bio – Plant Pigments and Chromatography. Materials Needed Per Grou p. Chromatography vial, with cap Wax pencil Disposable transfer pipet mL Chromatography paper strip S harp pencil Ruler (metric) Pair of scissors Piece of fresh (pre-soaked) spinach Coin Pair of forceps. Procedure!.
E N D
Materials Needed Per Group • Chromatography vial, with cap • Wax pencil • Disposable transfer pipet • mL Chromatography paper strip • Sharp pencil • Ruler (metric) • Pair of scissors • Piece of fresh (pre-soaked) spinach • Coin • Pair of forceps
Procedure! • Get a chromatography paper strip and measure 1.5 cm from one end. Mark this point with a pencil. • Use scissors to cut the corners of the strip below the mark you made to create a point. • Taking a pre-soaked spinach leaf and place it over the mark you made. Roll a coin over the mark to transfer some of the pigment onto the paper. (5-10 times).
Procedure! NEXT STEPS ARE DONE IN THE HOOD! • Place 1 ml of chromatography fluid into vial • Place chromotography paper in vial so that tip is immersed. • Cap the vial and let the chromotography fluid travel up the paper carrying the various plant pigments.
Procedure! • Because the solvent evaporates so quickly mark the top of where the solvent and each pigment traveled to in pencil. • Use a ruler to measure the distance each pigment traveled. Measure to the middle of the band. • Calculate the Rf value for each pigment
Rf value • Rf is calculated by; Distance pigment traveled/the distance the solvent traveled. • Units are in cm.
Analysis questions • What factors are invovled in the separation of pigments? • Would you expect the Rfvalue of a pigment to be the same if a different solvent was used? Explain. • What type of chlorophyll does the reaction center contain? • What are the roles of the other pigments found in the spinach leaf?