Iodine‐Azide Detection System for Dipeptides in Thin‐Layer Chromatography

Abstract

Dipeptides were derivatized with phenyl thiocarbamyl (PITC) to sulfur‐containing compounds. The reaction was performed directly on the chromatographic plate in normal phase chromatography. The detection system was based on an iodine‐azide reaction that was induced by sulfur compounds. The procedure involved spraying the developed plate with sodium azide and starch solution and, subsequently, exposing the plate to iodine vapor. Due to the catalytic effect of C˭S bonds, white spots appeared on the violet‐gray background. The method was found to be competitive with the other detection techniques and its sensitivity range was as low as pmol per spot.

Keywords:

• Iodine‐azide reaction
• Phenyl isothiocyanate
• Dipeptides
• Detection
• Separation
• Thin‐layer chromatography

Acknowledgment

This work was supported by Grant No. 505/708 from the University of Łódź, Poland.