Chromatographie von Pflanzenpigmenten

Trennung von Chlorophyll und Carotinoiden durch Papierchromatographie

Qualitative Analysis Intermediate (High School) 60 Min. ~$8,00

Ziel

Pflanzenpigmente durch Papierchromatographie trennen und identifizieren sowie Rf-Werte für jedes Pigment berechnen.

Hintergrund

Paper chromatography separates mixtures based on differential affinity for the stationary phase (paper) and mobile phase (solvent). Plant leaves contain multiple pigments: chlorophyll a (blue-green), chlorophyll b (yellow-green), xanthophylls (yellow), and carotenoids (orange). These pigments have different polarities, causing them to travel different distances up the paper as the solvent front advances.

Sicherheitswarnungen

  • Acetone and petroleum ether are highly flammable — no open flames
  • Work in a well-ventilated area or fume hood
  • Avoid inhaling solvent vapors
  • Petroleum ether is a skin irritant

Erforderliche PSA

goggles gloves lab_coat

Materialien

  • Fresh spinach leaves (5–10 leaves)
    Or other dark green leaves
  • Acetone or isopropanol (50 mL)
    Extraction solvent
  • Petroleum ether (30 mL)
    Chromatography solvent
  • Chromatography paper (2 strips)
    Whatman No. 1 or equivalent
  • Sand (1 teaspoon)
    For grinding

Ausrüstung

Mortar and pestle Beaker (250 mL) with watch glass cover Pencil (not pen) Ruler Capillary tube Scissors

Durchführung

1

Grind spinach leaves with a pinch of sand and 5 mL acetone in a mortar until a deep green extract forms.

5 Min. Acetone is flammable
2

Draw a pencil line 2 cm from the bottom of the chromatography paper. Apply the extract using a capillary tube in a small spot. Let dry and reapply 3–4 times to concentrate.

10 Min.
3

Pour petroleum ether into the beaker to a depth of about 1 cm. Suspend the paper strip so the origin line is just above the solvent level.

5 Min. Work in fume hood
4

Cover the beaker with a watch glass and let the solvent rise by capillary action. Do not disturb until the solvent front is 1–2 cm from the top.

25 Min.
5

Remove the paper, immediately mark the solvent front with pencil. Let dry completely.

5 Min.
6

Identify the colored bands: carotenoids (orange, highest Rf), xanthophylls (yellow), chlorophyll a (blue-green), chlorophyll b (yellow-green, lowest Rf). Calculate Rf values for each band.

10 Min.

Erwartete Ergebnisse

Four or more colored bands should be visible. Carotenoids (orange) travel farthest (Rf ≈ 0.9–0.95). Xanthophylls (yellow) at Rf ≈ 0.7. Chlorophyll a (blue-green) at Rf ≈ 0.5. Chlorophyll b (yellow-green) at Rf ≈ 0.4.

Aufräumen

Allow all solvents to evaporate in the fume hood. Dispose of paper in general waste. Clean mortar and pestle thoroughly.

Details

Kategorie
Qualitative Analysis
Schwierigkeit
Intermediate (High School)
Dauer
60 Min.
Geschätzte Kosten
$8,00
Schritte
6
Materialien
5

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Frequently Asked Questions

What is the objective of Chromatographie von Pflanzenpigmenten?
Pflanzenpigmente durch Papierchromatographie trennen und identifizieren sowie Rf-Werte für jedes Pigment berechnen.
How difficult is Chromatographie von Pflanzenpigmenten?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Chromatographie von Pflanzenpigmenten?
Key safety precautions include: Acetone and petroleum ether are highly flammable — no open flames; Work in a well-ventilated area or fume hood; Avoid inhaling solvent vapors.
What materials are needed for Chromatographie von Pflanzenpigmenten?
The main materials required are: Fresh spinach leaves, Acetone or isopropanol, Petroleum ether, Chromatography paper, Sand.
What results should I expect from Chromatographie von Pflanzenpigmenten?
Four or more colored bands should be visible. Carotenoids (orange) travel farthest (Rf ≈ 0.9–0.95). Xanthophylls (yellow) at Rf ≈ 0.7. Chlorophyll a (blue-green) at Rf ≈ 0.5. Chlorophyll b (yellow-green) at Rf ≈ 0.4.