Application of improved iodine–azide procedure for the detection of thiouracils in blood serum and urine with planar chromatography

The application of iodine–azide reaction for the determination of thiouracils in thin-layer chromatography and high-performance thin-layer chromatography is described. The developed plates were sprayed with a freshly prepared mixture of sodium azide, adjusted to a proper pH, and starch solution, and exposed to iodine vapour for 5 s. The detection limits were established at pmol level. The factors depending on the detection limits were described. A comparison of iodine–azide tests reaction with other procedures is presented. The developed method was applied to detection of thiouracils in blood serum and urine. The possibility of detection of a thiouracils mixture was demonstrated.