Fresh biological material:
Fresh biological material consists of materials of active body of plants and animals. It is always hard to elucidate the chemical constituents of the plant materials. Information acquired from the study of the simple molecules cannot be essentially applied straight to heterogeneous system. In the study of like system indirect method has been applied e.g. done combustion, dilution effect, environmental effect etc. The DTA curves of four leave samples of different plant in oxygen exhibit two pronounced exothermic effect in the range 240-2700C region. The first peak is invariably smaller than second one at least in height always not in area apart from variation in peak temperature. The general similarity in these curves may be inferred that leaves of the plants have at least same micro-chemical composition.
The DTA curves for a few plant materials have also been acquired in a static or air or dynamic oxygen atmosphere, because it is hard to distinguish among decomposition and oxidation effects, which may overlap. Endothermic reaction such as dehydration or volatilization while exothermic accompany combustion under inert atmosphere condition, with oxidation reaction suppressed, such endothermic effect can be detected. Similarly the analytical method is useful for analysis of high energy materials, explosives, ceramic, cement and pharmaceuticals.