Centrifugal chromatography

This chapter describes two techniques, which are based on the use of centrifugal force: forced-flow layer liquid chromatographic technique—rotation planar chromatography (RPC; centrifugal layer chromatography) and forced-flow solid-liquid extraction technique—rotation planar extraction (RPE). The theoretical aspects of RPC, development and the state of the art of the instrumentation, characteristics of RPC techniques and practical aspects of RPC, preparation of chromatographic plates, circular, anticircular, and linear modes of the separations, as well as fully off-line, on-line, and mix mode separations are also discussed. Classification of different technical solutions, multiple developments, as well as several applications in the field of analytical, micropreparative, and preparative separations using planar layers and planar columns are also described. A multifunctional technical solution that enables the RPE, analytical and preparative separation of natural compounds from different plant matrices is also demonstrated.

This chapter describes two techniques, which are based on the use of centrifugal force: forced-flow layer liquid chromatographic technique—rotation planar chromatography (RPC; centrifugal layer chromatography) and forced-flow solid-liquid extraction technique—rotation planar extraction (RPE). The theoretical aspects of RPC, development and the state of the art of the instrumentation, characteristics of RPC techniques and practical aspects of RPC, preparation of chromatographic plates, circular, anticircular, and linear modes of the separations, as well as fully off-line, on-line, and mix mode separations are also discussed. Classification of different technical solutions, multiple developments, as well as several applications in the field of analytical, micropreparative, and preparative separations using planar layers and planar columns are also described. A multifunctional technical solution that enables the RPE, analytical and preparative separation of natural compounds from different plant matrices is also demonstrated.

Planar chromatography (PC) includes all analytical, micropreparative, and preparative separation methods where the mobile phase moves through the stationary phase in a planar arrangement. This chapter discusses various chamber types, development modes, and the newer forced-flow planar chromatography (FFPC) methods. PC can be classified according to (1) the flow of the solvent system/mobile phase, (2) the nature of the stationary phase, (3) the mechanism of the separation, (4) the polarity relation between the mobile and stationary phases, (5) the aim of the separation, and (6) whether the principal steps are performed as separate operations. The chapter describes the principles of PC methods. The driving force for solvent migration in classical thin-layered chromatography (TLC) is the decrease in the free energy of a liquid as it enters the porous structure of a layer; the transport mechanism is the result of the capillary effects. The chromatographic processes in analytical or preparative PC are basically the same, regardless of whether the driving force is a capillary action alone or augmented by additional forces.

This review covers salient features of planar layer liquid chromatography as applied to the analysis of inorganic pollutants present in a variety of complex matrices. The discussion is limited to classical planar chromatography (paper and thin-layer chromatography) as used in the analysis of real and synthetic environmental samples containing inorganic pollutants. The matrices from which inorganic pollutants have been isolated and analysed include: biological, food, geological, industrial, pharmaceutical, soil, water and wastewater. Eighty-nine references have been cited from the literature of the last twenty years. Over-pressured layer chromatography has not been utilized so far for the analysis of inorganic species present in natural environmental samples. In situ densitometry and spectrophotometry have been commonly used for the quantification of inorganic ions present in environmental samples.

This chapter focuses on planar chromatography (PC), a collective term that include all analytical, micropreparative, and preparative separation methods where the mobile phase moves through the stationary phase (paper or porous sorbent) in a planar arrangement. The movement of compounds to be separated by PC is the result of two opposing forces: (1) the driving force of the solvent system, and (2) the retarding action of the stationary phase. The chapter describes paper chromatograph, apart from discussing thin-layer chromatography (TLC) and high-performance TLC (HPTLC). Various chamber types and development modes that are only practicable in PC and the newer forced-flow planar chromatography (FFPC) methods are also discussed. Planar chromatography can be classified from different points of view such as (1) the flow of the mobile phase, (2) the nature of the stationary phase, (3) the mechanism of the separation, (4) the polarity relation between the mobile and stationary phase, and (5) the aim of the separation. The chromatographic processes in analytical or preparative PC are basically the same, regardless of whether the driving force is capillary action alone or augmented by additional forces. Among the factors that may influence PC separations, the chamber types and development modes are the most important.