Application of CdS quantum dots modified carbon paste electrode for monitoring the process of acetaminophen preparation.

In this research article, a novel, selective, and sensitive modified carbon paste electrode (CPE) using CdS quantum dots (QDs) is presented. The highly stable CdS QDs were successfully synthesized in an in situ process using Na2S2O3 as a precursor and thioglycolic acid as a catalyst and capping agent. The synthesis of CdS QDs was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The synthesized CdS QDs were used for preparation of a modified carbon paste electrode (CdS/CPE). The electrochemical behavior of the electrode toward p-aminophenol (PAP) and acetaminophen (Ac) was studied, and the results demonstrated that the CdS/CPE exhibited good electrocatalytic performance toward PAP and Ac oxidation. The oxidation peak potential of each analyte in the mixture was well separated. As a result, a selective and reliable method was developed for the determination of PAP and Ac simultaneously without any chemical separations. Application of the fabricated electrode for monitoring the process of Ac preparation from PAP was investigated. The obtained results show that CdS/CPE has satisfactory analytical performance; it could be a kind of attractive and promising nanomaterial-based sensor for process monitoring via the electrochemical approach.

Determination of trace elements in soil, leaves and fruits of Quercus brantii grown in southwestern Iran by atomic spectroscopy.

Quercus brantii acorn is rich of some useful mineral elements such as K, Fe and Zn. The content of these mineral elements in Quercus are dependent on their region and environmental conditions. Q. brantii grown naturally in different regions of Iran especially in Kohgiloye va Boyer Ahmad province (southwestern of Iran). In this study total concentration of Fe, Zn and K elements were determined using atomic absorption and emission spectroscopy in fruits, leaves of Q. brantii and also in the soils where this plant was grown. Statistical evaluation (ANOVA test) was employed for all measurements. Results confirmed that the concentration of elements in fruit and leave depended on area which the plant is growth. The transport factor of elements was also considered.

Study on different forms and phosphorus distribution in the coastal surface sediments of Southern Caspian Sea by using UV-Vis spectrophotometery.

This paper presents distribution of phosphorus (total P, organic and inorganic P) in the southern of Caspian Sea sediments where collected from four sampling stations in the summer 2009. Several forms of the phosphorus in sediment were separated and extracted according to sequential extraction method. Then extracted phosphorus in each fraction was determined by UV-Vis spectrophotometery. Five forms of phosphorus were studied (i) loosely sorbed phosphorus, (ii) ferric-iron-bound phosphorus, (iii) authigenic phosphorus, (iv) detrital phosphorus, and (v) organic phosphorus. The total P contents were ranged from 124.5 to 328.2 µg g(-1). It was found that more than 98% of the total P is inorganic phosphorus (IP). Among the four forms of IP, loosely bound P, P-Fe, P-detrital and P-authigenic distribution ranges were 2.70-17.31%, 10.00-44.79%, 0.40-1.70% and 48.35-83.48%, respectively. Result also showed that the most abundant forms of phosphorus were authigenic phosphorus. Relative abundances of other forms of phosphorus follow the order: P-Fe>loosely bound-P>organic P>detrital P.

Silicon-29 diffusion-ordered NMR spectroscopy (DOSY) as a tool for studying aqueous silicates.

The first use of silicon-29 diffusion-ordered NMR spectroscopy (DOSY) is reported, in a study of the speciation of aqueous silicates.