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ELECTROCHEMICAL DETERMINATION OF LEAD IN WATER SAMPLES USING MODIFIED ELECTRODE BASED ON POLYAZULENE DERIVATES

M. E. Ungureanu, G. G. Vasile, G. L. Arnold, L. Birzan, G. O. Buica
Wednesday 13 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-08-9 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 51, 359-364 pp, DOI: 10.5593/sgem2017/51/S20.047

ABSTRACT

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.

Keywords: lead, water, stripping voltammetry, polymeric film, poly[(2E)-2-(azulen-1-ylmethylidene) hydrazine carbothioamide]