Separation and pre-concentration of Pb and Cd in water samples using 3-(2-hydroxyphenyl)-1h-1,2,4-triazole-5(4H)-thione (HTT) and their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES)

Abstract

A new method for the separation, pre-concentration and accurate determination of trace amounts of Pb and Cd in water samples using Amberlite XAD-16 resin functionalized with a new chelating ligand, 3-(2-hydroxyphenyl)-1H-1,2,4-triazole-5(4H)-thione (HTT), Amberlite XAD-16-HTT and inductively coupled plasma atomic emission spectrometry (ICP-AES) is reported in the present study. Fourier transform infrared (FTIR) spectroscopy was used to characterize the chelating resin. The effects of analytical parameters such as the pH of the medium, amount of adsorbent, type and volume of eluent, flow rate of the sample solution, volume of the sample solution, and matrix interference on the retention of metal ions were investigated. Also, 1 M HNO3 was used for the elution of the sorbed metals, and ICP-AES was used for the analysis of elutes offline. The results indicate that pH 5 is the optimum pH for the sorption of Pb and Cd ions. The limit of detection was found to be 0.16 and 0.22 µg/L for Pb and Cd, respectively, by applying a pre-concentration factor of 50. The method was validated using the international water reference material (NIST 1643e). The developed enrichment method has a high selectivity, sensitivity, and reproducibility; this method was successfully applied for the determination of Pb and Cd in surface water samples collected in Nellore District, Penner River belt as well as Bay of Bengal, Andhra Pradesh, India.