Simple and rapid detection of aromatic amines using a thin layer chromatography plate

Aromatic primary amines with electron donors can be detected in the nanomolar range using cinnamaldehyde as reagent on thin layer chromatography plates (TLC plates). It was found that a yellow color spot appeared immediately when a colorless solution of amines mixed with a colorless solution of cinnamaldehyde on a TLC plate. Control experiments showed that no color change was detected when a substituted group of aromatic primary amines is changed from electron donor to electron acceptor. It also showed negative results when aromatic primary amines were replaced by aromatic secondary or tertiary amines as well as aliphatic amines. Sensitivity tests showed that the detectable limits for amines could be optimized, and the lower detectable limits of amines on TLC plate with cinnamaldehyde reagent are between 0.02 and 0.28 mu g.