The detection of opiates by two-dimensional high-performance thin-layer chromatography

Detection of low concentrations of morphine and structurally related opiate s by thin-layer chromatography (TLC) is limited by the sensitivity of detec tion, which is 0.5-2 mu g per spot depending on layer quality and the spray reagent employed. High-performance thin-layer chromatography (HPTLC) has b een used to improve the performance of the method. Sensitivity of detection was tested for morphine, codeine, dihydrocodeine, and hydrocodone by use o f Dragendorff's and Marquis's reagent, fast blue B (FBB) and fast black K ( FBK), and for morphine as the dansyl derivative. Use of two-dimensional (2D ) HPTLC enabled further reduction of the detection limit by as a result of reduced background and matrix interference and good separation of the opiat es. Combination of 2D HPTLC with sensitive and/or specific detection proved a suitable and reliable method for detection of low concentrations of opia tes in urine samples. The detection limit was 20-100 times lower than for T LC, depending on the opiate.