Occurrence of rubidium and cesium in Iqe coal, Qinghai-Tibet Plateau: Evidence from sequential chemical extraction experiment

The occurrence of Rb and Cs in coal samples from Iqe coalfield was analyzed by a sequential chemical extraction experiment. Five types of Rb and Cs were determined in the coal: water soluble, ion exchangeable, organic bonded, carbonate, and silicate. The results indicated that the occurrence of Cs is similar with Rb in coal, and nearly all Rb and Cs are distributed in silicate. The occurrence of Rb and Cs is most likely associated with silicate minerals in coal. With the high correlation between Rb, Cs, and K, and the high content of kaolinite and illite in these coal samples, it can be inferred that illite probably is the main carrier of Rb and Cs. Minor amounts of Rb and Cs may also be adsorbed by kaolinite in Iqe coal, and Cs may exist in other states, such as an exchangeable ion.

USE OF ION ASSOCIATION COMPLEX FORMATION FOR THE SPECTROPHOTOMETRIC DETERMINATION OF ITOPRIDE HCL IN BULK AND ITS PHARMACEUTICAL PREPARATIONS

Objective: The authors report two simple, accurate and economic spectrophotometric methods A and B for the determination of Itopride hydrochloride in bulk and dosage forms.Methods: The proposed methods are based on the formation of chloroform soluble ion-associates in the presence of acidic dyes namely BPB (Method A) and BCP (Method B) exhibiting lmax at 418 and 418 nm respectively.Results: Beer’s law is found to be obeyed in the concentration range of 2.0-10.0 µg/ml and 2.0-10.0 µg/ml. The molar absorptivities are found to be 1.42x104 and 9.61x103L/mol. cm for methods A and B. These methods are successfully applied for the assay of Itopride hydrochloride in pharmaceutical formulations.