Medium-pressure solid-liquid extraction: A new preparative method based on the principle of counter-current

Abstract

SummaryA novel variant of continuous relative counter-current extraction, called medium-pressure solid-liquid extraction (MPSLE) is introduced as a new preparative separation method for laboratory purposes. This method is a special case of exhaustive extraction.On using MPSLE, the extraction column, i.e. a medium pressure liquid chromatographic (MPLC) column is filled with the fine-powdered solid phase to be extracted, and extraction solvent(s) is/are forced through the stationary bed by means of a pump. This method constitutes the relative counter-current extraction, and results in exhaustive and rapid extraction. By MPSLE, efficiency is achieved not just because the extraction solvent(s) is/are forced through the staying material to be extracted, but also clue to the overpressure in the extraction column and the suitable changes of the dissolution and diffusion periods of the process.The method can be used for the rapid extraction of various substance classes occurring as complex solid matrices. Experiments carried out with MPLC columns show that the exhaustive extraction of finely powdered plant material of 100-3000g can be extracted and concentrated with an automated equipment within a few hours. Further advantages of the environment-friendly process performed in closed system are full automation and operation with low qua ntil',/of extracta nt.