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The purpose of the study was to develop an electrochemical method for detection of lead at low level of contamination in water samples using a carbon glassy electrode modified with the functionalized azulene: (2E)-2-(azulen-1-ylmethylidene) hydrazine carbothioamide (L) as a complexing polymer film. The modified electrodes were prepared in L solutions (1mM) in acetonitrile (CH3CN) containing tetra n-butyl ammonium perchlorate (0.1 M TBAP) as supporting electrolyte. The analyses were performed on Autolab PGSTAT 12 Potentiostat, all the reagents used were ultratrace quality. The electrochemical method include four steps: 1) polymeric film formation by controlled potential electrolysis (CPE) at 1.7V using a charge of 1 mC under argon atmosphere; 2) film conditioning in 0.1 M buffer acetate solution using cyclic voltametry; 3) complexation in a standard solution prepared from lead nitrate (II) using ultrapure water as matrix or a real sample; 4) stripping differential pulse voltammetry method (DPV) in acetate buffer at 5.5 pH, after 180 seconds reduction time at a reduction potential of -1.2 V. The determination time for a standard solution or real sample is arround 45 minutes. The calibration curve was ploted in the range 1 to 50 µg/L Pb (II). The precision experiments were performed at 10 µg/L Pb (II). The precision for polymeric film formation on the glassy carbon electrode was 13.5%, while the intermediate precision test indicated a value of 15.5%. Evaluation of the method performant parameters confirm that the proposed method is suitable to detect and quantify lead content in water samples. [ABSTRACT FROM AUTHOR]

In this work the tangent approach is valid on example of overlapping voltammetric peaks of Cd (II) and Tl (I) at their different concentration in a mixture. Height of the frame plotted by inflectional tangents to the inflection points on peak branches is used as a peak maximum for calibration curve plotting. It is founded that systematic errors are not significant for the measurement of Tl (I) peak. In case of the Cd (II) peak the significant systematic error arising from tailing of the ascending part of Tl (I) peak is observed. We propose a method of systematic errors compensation. Systematic errors are estimated by peak series modeling. We use six parametric peak model with help of a priory information about signal shape and real values of resolution criteria and ratios of peaks heights. Peak shape is determined by difference method and ratios of peak heights by calibration curve. [ABSTRACT FROM PUBLISHER]

Enhanced oxygen reduction reaction (ORR) on PdPt nanopartiles has been demonstrated after their synthesis using a simple co-precipitation method in presence of reducing agent like N-methylpyrrolidone. Enhancement in the ORR activity of PdPt over commercial Pt catalyst has been discussed based on formation of extent of deleterious oxygenated species on catalytic active sites and the same has been studied quantitatively using stripping voltammetry. An improved specific activity (Is) of 500 μA/cm².P for PdPt has been observed versus 200 μA/cm².Pt for Pt catalyst at 0.9 V. [ABSTRACT FROM AUTHOR]