An High Performance Thin Layer Chromatography (HPTLC) Validated Method for the Determination of Ephedrine Alkaloids in Multi-Plant Formulations

Ephedrine is one component of a popular traditional Chinese multi-plant formulation used to treat asthma, fever, coughs and lately COVID-19. The aim of this study is to develop and validate a simple and rapid quali-quantitative High Performance Thin Layer Chromatography (HPTLC) densitometry method to detect ephedrine, the most abundant alkaloid of Ephedra plant, and to analyze free sale ephedra-based capsules. This quick, simple and low requirement method is cost-effective and allows screening up to 19 samples all together in a single layer. During the development of this method, an extraction solvent mixture composed of methanol/water (2:1, v/v) and a mobile phase constituted of ammonia/methanol/dichloromethane (1:10:40, v/v/v) gave the best results. The identity and purity of ephedrine peak were confirmed by matching Rf value and UV-spectrum with its reference standard. Lastly, samples were quantitated by densitometry at 500 nm after ninhydrin derivatization. Linearity was obtained in the concentration range of 0.062-0.146 μg/band. Limit of detection and limit of quantification (LOQ) were found to be 0.0020 μg/band and 0.0067 μg/band, respectively. This technique is useful to screen multiple samples at the same time with a limited use of solvents and reagents so that it can be considered a fast and simple procedure.