Comparative verification study of silica gel-coated TLC and HPTLC plates\u2019 performances in separation of opium alkaloids on the basis of their physicochemical properties

Abstract

BackgroundThin layer chromatography (TLC) has been a conventional analytical method which is currently used for separation and detection of drugs in biological and non-biological samples. High-performance thin layer chromatography (HPTLC) has been claimed to have several advantages over TLC due to its smaller adsorbent particle size. Opium is the dried latex obtained from the opium poppy containing several alkaloids. Its precise and accurate detection in biological and non-biological samples is a matter of great importance in forensic and clinical toxicology.MethodsIn the present work, quality of commercial silica gel-coated TLC and HPTLC plates from the two best-known international manufacturers (Merck and Macherey Nagel) in separation of opium alkaloids were investigated and compared in the fluorescence quenching mode to propose the best plate for separation and identification of opium alkaloids. Particle size, zeta potential, specific surface, density, and scanning electron photomicrographs of silica gels, development time for 10 cm migration distance, number of theoretical plates (N), and resolution (R) were compared between all plates.ResultsMerck TLC plate showed the best separation of opium alkaloids. Although spherical-particle silica-coated Merck HPTLC plate showed narrower particle size distribution, it did not show better separation than Merck TLC plates.ConclusionsOn the basis of performance and price of TLC and HPTLC plates and great importance of precise and accurate detection of opium in forensic and clinical toxicology, the present work proposes conventional verified analytical TLC plates (for example Merck-TLC plate) for detection of opium alkaloids in biological and non-biological samples.