First referred to in 1938 by Russian workers Izmailov and Shraiber, the method known as TLC today was used by American Chemists Meinhard and Hall in 1949 for separation of volatile oil components. Work of Kirchner and his associates and demonstration of its extensive utility by Stahl in 1958 gave impetus to the development of…
Experiments that led to the development of chromatographic methods traceable to the early 19th century works of C.S. Schonbein, F. Goppelsroeder, R.E. Liesegang, and A. Martin used paper as the stationary medium. Martin and his collaborators used filter paper strips as carriers for the analysis of amino acid mixtures. Soon the technique was being used for…
Chromatography refers to a broad range of physical methods for the separation and/or analysis of complex mixtures of compounds. Plant drugs being constituted of multitudes of phytochemical groups, chromatographic techniques find immense application in their separation, processing, purification, and in qualitative and quantitative analysis. Developments in the field of chromatography have facilitated parallel rapid advancement…
Resins may be identified based on their physical and chemical properties. In addition, they may be identified by individual chemical tests to detect the presence of specific chemical constituents.
General method of separating resins is dependant upon the plant part associated with the resin, its preferred use, composition and its physical properties. While resins directly collected from the plants are natural resins (mastich, benzoin), those prepared from the plant parts by processing are called prepared resins (Podophyllin, Jalap resin).
Resins when separated and purified are often hard transparent or translucent hard, brittle solids or slightly soft semi-solids. They are heavier than water and by the action of heat they soften and fuse, yielding clear, adhesive fluids. Specific gravity of resins varies from 0.9–1.25. They are usually transparent when pure and become opaque when water…
Resins are amorphous solid products of a complex chemical nature. They are a heterogenous group with certain well-identified physical, chemical, and solubility characteristics. Resins are formed in schizogenous or schizolysigenous ducts or cavities by cells, which secrete a fluid composed of substances constituting gums, essential oils, and resins. Resin is held in solution by volatile…
Essential oil identification and estimation of its quality is an important and integral process of its qualitative analysis. Their high economic value and extensive usage by various industries help in ensuring its quality, which is a significant aspect of its quality control. Today GC is an invaluable tool in the identification of essential oils. A…
Volatile oils are traditionally obtained by distillation of the plant parts containing the oil. Some volatile oils which undergo undesirable changes in the oil composition and organoleptic features due to distillation are separated by methods not involving heat application. In addition to these several newer methods such as super critical fluid extraction may now be…
Volatile oils are defined as oily liquids, which are entirely or almost entirely volatile without decomposition. They are also called essential oils as they are said to represent the essence of the odor constituents of the plants from which they are obtained. Volatile oils have been used in medicine, perfumery, and for flavoring since ancient…