Synthesis of 6-(Phenanthrene-3-yl)-2,3-dihydro-1,2,4,-triazine-3-thione as a New Reagent for the Non-Extractive Spectrophotometric Determination of Cu(II)

A simple, sensitive, and non-extractive spectrophotometric method was developed for the determination of copper (II) using a newly synthesized chromogenic reagent, 6-(phenanthrene-3-yl)-1,2,4,-triazine-3-thione(PhDTT), in Tween 80 neutral surfactant. To synthesize the reagent (PhDDT), amyl nitrite was added to 3-acethylphenanthrene and refluxed for 26 hours to produce 2-oxo-2-(phenanthren-3-yl) acetaldehyde oxime (I). The reaction of compound (I) with thiosemicarbazide yielded the reagent (PhDDT). Copper (II) forms a red colored complex with 6-(phenanthrene-3-yl)-1,2,4,-triazine-3-tion which shows maximum absorbance at 460 nm in the pH range 9.0-11.0. Beer’s law was obeyed over the concentration range of 1.4-10 µg/mL Cu2+ with r2 = 0.999.  The limit of detection was 0.48 μg/mL of copper (II). The within-day and between-day precision values were in the range of 0.38-3.3%. The method was tested by analyzing the amalgam samples. The results were in good agreement with the atomic absorption.