Detection and Separation of Amino Acids as Butylthiocarbamyl Derivatives by Thin‐Layer Chromatography with the Iodine‐Azide Detection System

Abstract

Protein amino acids were derivatized to butylthiocarbamyl derivatives by prechromatographic reaction at 40°C for 30 min with butyl isothiocyanate. The iodine‐azide reaction was employed as the detection system for sulphur‐containing derivatives. In practice, the plates were sprayed with a mixture of sodium azide and starch solution and then exposed to iodine vapour. The spots became visible as white spots on violet‐grey background. The iodine‐azide system enabled detection of quantities in the range of 2–90 pmol per spot. R_F values of BTC‐derivatives in several solvent systems were established in order to carry out separation. The obtained data were applied to resolution of three 7‐component mixtures of BTC‐derivatives. Additionally, BTC‐leucine and isoleucine were successfully distinguished.

Keywords:

• Amino acids
• Butyl isothiocyanate
• Iodine‐azide reaction
• Thin‐layer chromatography (TLC)

Acknowledgment

This work was supported by grant No 505/678 from the University of Łódź, Poland.