Rapid and Sensitive Synergistic Extraction and Spectrophotometric Determination of Silver(I) using 1-(2′,4′-Dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol: Analysis of Real Samples

Abstract

A rapid, simple, reliable, sensitive, and selective extractive spectrophotometric method was developed for the determination of silver(I) using 1-(2′,4′-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydro pyrimidine-2-thiol, [2′,4′-dinitro APTPT] as a chromogenic reagent. The procedure is based on the synergistic extraction of silver(I) with 2′,4′-dinitro APTPT in presence of 0.5 mol L–1 pyridine. 2′,4′-Dinitro APTPT reacts with silver(I) to form an orange–red ternary complex (λmax 440 nm) in the presence of 0.5 mol L–1 pyridine having a molar ratio 1:1:1 (M:L:Py) in the pH range 2.7–4.3. The Beer’s law is obeyed in the concentration range of 1–11 μg mL–1 silver(I). The molar absorptivities and Sandell’s sensitivities of the complex in the chloroform are 1.131 × 104 L·mol–1·cm–1 and 0.010 μg cm–2 in the presence of pyridine, while they are 4.962 × 104 L·mol–1·cm–1 and 0.021 μg cm–2 in the absence of pyridine, respectively. A reproducibility of the method was checked by finding the relative standard deviation (RSD) (n = 5), which was 0.12%. The method is free from interferences due to the large number of cations and anions and has been successfully applied for the determination of silver in synthetic mixtures, ayurvedic samples, silver nano materials, photographic washing wastes (hypo solution), and waste effluent from silver refineries. It is also used for sequential separation of silver(I), copper(II), and gold(III) from their mixture. The accuracy was assessed using atomic absorption spectrometry (AAS), which tested the validity of the method.