Todd:TLC Stain Recipes
Stains are very useful for visualizing TLCs where certain compounds may be difficult to see under UV. Stains can also reveal different functional groups clearly. Keep all the stains together in one hood/area, with a heat gun to hand. Always wipe the back of the plate with paper towel before heating to prevent excess stain dripping everywhere.
- Anisaldehyde: 9.2 mL p-anisaldehyde, 3.75 mL AcOH, 338 mL 95% ethanol, 12.5 mL conc. H2SO4.
- Potassium Permanganate: 3 g KMnO4, 20 g K2CO3, 5 mL 5% NaOH (aq), 300 mL water. Good idea to stir the mixture for ~10 min before transferring to a jar. The permangenate takes a while to dissolve.
- PMA: 35 g phosphomolybdic acid, 1 pint 95% ethanol
- Ceric Ammonium Molybdate (Goofy's): 40 mL conc. H2SO4, 360 mL water, 10 g ammonium molybdate, 4 g ceric ammonium sulfate
- Vanillin: 3 g vanillin, 50 mL 95% ethanol, 15 mL 2 M H2SO4
- Ceric Sulfate: 8 g Ce(SO4)2.2H2SO4, 100 mL 15% H2SO4 (aq)
- 2,4-DNP: 12 g 2,4-dinitrophenylhydrazine, 60 mL conc. H2SO4, 80 mL water, 200 mL 95% ethanol
- Copper Sulfate: 3% cuSO4 (aq), 15% H3PO4 (aq)
- Ninhydrin: 0.3 g ninhydrin per 100 mL EtOH