TLC Stains/Dips

• Ultraviolet: Look at the plate under the light first when working with compounds with conjugated double bond systems.
• Iodine: Shake with powdered I2. You can then heat the plate to remove the iodine stain, and use a liquid TLC stain as usual. It is best to keep the iodine from touching the plate as this can leave unwanted colorations on the plate.
• Anisaldehyde (great for carbonyl groups). Dip, dry and heat on hot plate to develop.
  1. EtOH (200 mL); H₂SO₄su (10 mL);p-anisaldehyde (10 mL)
  2. EtOH (250 mL); H₂SO₄su (2.5 mL);p-anisaldehyde (15 mL)
  3. EtOH (425 mL); H₂SO₄su (16 mL);p-anisaldehyde (8-12 mL); HOAc (5 mL): mix everything but p-anisaldehyde, which you add when the mixture has cooled to rt. Store refrigerated. If you add the anisaldehyde to the warm solution, it will turn bright pink and will not stain TLC plates properly.



For low-functionalized molecules, anisaldehyde has different colors for different molecules (yellow, green, blue, brown,…). It is best to photograph the plate, or note them down for your specific compounds. This can be helpful especially during column chromatography.

• Ceric Ammonium Molybdate (great for hydroxy groups). Dip, dry and heat on hot plate to develop.
  1. Ce(SO₄)₂ (cerium sulfate: 5.0 g);(NH₄)6Mo₇O₂₄.4H₂O (ammonium molybdate: 25.0 g); conc. H₂SO₄ (50 mL); H₂O (450 mL)
  2. Ce(NH₄)₄(SO₄)₄ 2H₂O (ceric ammonium sulfate: 4.0 g); ammonium molybdate (10 g); conc. H₂SO₄ (40 mL); H₂O (360 mL)
  3. Ceric ammonium sulfate (0.5 g); ammonium molybdate (12 g); conc. H₂SO₄ (15 mL); H₂O (235 mL)
• Ninhydrin (great for amines): Dissolve 0.3g ninhydrin in 100 ml of n-butanol; add 3 ml AcOH.
• Phosphomolybdic Acid (generally useful): 10% in Ethanol. Dip, dry and heat on hot plate to develop.
• Potassium Permanganate (generally useful). Dip, dry and heat on hot plate to develop.
  1. KMnO₄ (1g); Na₂CO₃ (2g); H2O (100 mL)
  2. KMnO₄ (3g); K₂CO₂ (20g); 5 percent NaOH (5 mL); H₂O (300 mL)

See Also:

1. Stains for Developing TLC Plates (.doc)
2. For an extensive list of TLC stains, and the compounds stained best by each one, see this list from the Adronov group at McMaster University
3. For descriptions of the chemistry behind common stains, and other helpful notes see: images of TLC plates showing the stain colors (in ninhydrin) of all 20 amino acids!