Evaluation of the Water and Organic Liquids Extraction Efficiency of Spirulina maxima Dyes Using Thermostated Micro Thin-Layer Chromatography

Abstract

Thermostated micro thin-layer chromatography was applied for separation and quantification studies of Spirulina maxima dyes isolated from pharmaceutical formulation by a simple one-step liquid extraction. The isolation process was performed using a number of liquids, including water; 10 mM water solutions of native alpha-, beta-, and gamma-cyclodextrin and their hydroxypropyl derivatives; and a number of common organic liquids characterized by different polarity, namely, methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, acetone, tetrahydrofuran, dichloromethane, toluene, and n-hexane. Chromatographic studies were performed on RP18W plates working inside a small thermostated horizontal chamber allowing a development distance of 45 mm. Using a mobile phase consisting of acetone-n-hexane (30 + 70, v/v) and 40 degrees C separation temperature, plate peak capacity of at least 15 spots/lane and developing time <5 min were obtained. Validation data indicated that under such conditions, with an office scanner used for chromatogram digitalization, spot quantification could be accurately performed within an analyte mass range of 2 factors. The raw quantitative data obtained from microchromatograms acquired under visible light conditions were explored using cluster analysis and principal components analysis. Chemometric investigations revealed that the best extraction liquids for isolation of dye mixtures from Spirulina samples were methanol, ethanol, tetrahydrofuran, and dichloromethane. Moreover, it was found that the liquids' parachor values could be used for estimation of the dye extraction efficiency from complex samples.