ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Investigation of 3-amino-1,2,4-triazole azodye derivatives as reagents for determination of mercury(II)

Abdalla M. Khedr

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt

E-mail: abkhedr2001@yahoo.com

Received: 2 October 2007  Revised: 21 March 2008  Accepted: 21 March 2008

Abstract: The reaction of mercury(II) with 3-(2,4-dihydroxyphen-1-ylazo)-1,2,4-triazole (HL¹), 3-(2-hydroxy-5-methylphen-1-ylazo)-1,2,4-triazole (HL²), 3-(2-hydroxy-5-ethoxycarbonylphen-1-ylazo)-1,2,4-triazole (HL³), 3-(2-hydroxy-5-acetylphen-1-ylazo)-1,2,4-triazole (HL⁴), 3-(2-hydroxy-5-formylphen-1-ylazo)-1,2,4-triazole (HL⁵), and 3-(2-hydroxy-5-bromophen-1-ylazo)-1,2,4-triazole (HL⁶) was studied. A new, direct, and simple procedure was suggested for the spectrophotometric determination of mercury(II) based on its complexation reaction with HL¹-HL⁶. The best reagent was found to be HL³ due to its high sensitivity and selectivity. In aqueous media of pH 9.0 containing 40 vol. % of methanol, Hg(II) reacts with HL³ to form a 1:2 (Hg(II) · HL³) complex having a sensitive absorption peak at 490 nm with the molar extinction coefficient of 3.31 × 10⁴ L mol⁻¹ cm⁻¹ using 4 × 10⁻⁴ M of the reagent. Beer’s law is obeyed over the range from 0.00 µg mL⁻¹ to 12.04 µg mL⁻¹ of mercury(II). The proposed method was applied in the determination of mercury(II) in tap water, seawater and synthetic seawater samples, without the need of prior treatment, with satisfactory results.

Keywords: azo-triazole - spectrophotometric determination - mercury(II)

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0071-6

Chemical Papers 62 (6) 541–546 (2008)