RESUMEN
A novel, simple, sensitive and rapid spectrophotometric method for the determination of selenium(iv) in an acidic medium using rhodamine B hydrazide (RBH) has been developed. The method is based on the micellar mediated oxidation of RBH by Se(iv) in an acidic medium to produce a pinkish violet color of rhodamine B, which was monitored spectrophotometrically at λmax 585 nm. The sensitivity of the method was found to increase when the reaction was performed in a micellar medium. Beer's law was obeyed in the concentration range of 0.002-0.032 µg mL-1. The reaction variables such as time, temperature, reagent concentration, and acidity have been optimized for the reaction. Sandell's sensitivity and molar absorptivity for the reaction system were found to be 0.00004 µg cm-2 and 42.52 × 106 L mol-1 cm-1, respectively. The developed method was successfully applied for the determination of Se(iv) in several real samples with quantitative results.
RESUMEN
The thin films of CdS(1-x)Se(x) were successfully deposited over glass substrates by chemical bath deposition technique. Cadmium acetate, thiourea and sodium selenosulfate were used as source materials for Cd(2+), S(2-) and Se(2-) ions, while 2-mercaptoethanol was used as capping agent. The various deposition conditions such as precursor concentration, deposition temperature, pH and deposition time were optimized for the deposition of CdS(1-x)Se(x) thin films of good quality and the films were annealed at 200° and 300 °C. The structural, morphological, chemical and optical properties were examined by various characterization techniques and discussed in detail. The optical band gap of CdS(1-x)Se(x) thin film samples were estimated and found in the range from 2.11 to 1.79 eV for as-deposited and annealed thin films.