Хроматография растительных пигментов

Разделение хлорофилла и каротиноидов бумажной хроматографией

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

Цель

Разделить и идентифицировать растительные пигменты методом бумажной хроматографии и рассчитать коэффициенты Rf для каждого пигмента.

Предпосылки

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.

Предупреждения по безопасности

  • 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

Требуемые СИЗ

goggles gloves lab_coat

Материалы

  • 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

Оборудование

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

Процедура

1

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

5 мин 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 мин
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 мин 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 мин
5

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

5 мин
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 мин

Ожидаемые результаты

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.

Уборка

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

Детали

Категория
Qualitative Analysis
Сложность
Intermediate (High School)
Продолжительность
60 мин
Прим. стоимость
$8,00
Шаги
6
Материалы
5

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Frequently Asked Questions

What is the objective of Хроматография растительных пигментов?
Разделить и идентифицировать растительные пигменты методом бумажной хроматографии и рассчитать коэффициенты Rf для каждого пигмента.
How difficult is Хроматография растительных пигментов?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Хроматография растительных пигментов?
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 Хроматография растительных пигментов?
The main materials required are: Fresh spinach leaves, Acetone or isopropanol, Petroleum ether, Chromatography paper, Sand.
What results should I expect from Хроматография растительных пигментов?
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.