Kisan Koirala, Jose H. Santos, Ai Ling Tan, Mohammad A. Ali and Aminul H. Mirza
This paper aims to develop an inexpensive, portable, sensitive and environmentally friendly electrochemical sensor to quantify trace metals.
Abstract
Purpose
This paper aims to develop an inexpensive, portable, sensitive and environmentally friendly electrochemical sensor to quantify trace metals.
Design/methodology/approach
A sensor was constructed by modifying carbon paste electrode for the determination of lead, cadmium and zinc ions using square wave anodic stripping voltammetry (SWASV). The modified electrode was prepared by inserting homogeneous mixture of 2-hydroxy-acetophenonethiosemicarbazone, graphite powder and mineral oil. Various important parameters controlling the performance of the sensor were investigated and optimized. Electrochemical behavior of modified electrode was characterized by cyclic voltammetry.
Findings
Modified carbon pastes electrodes showed three distinct peaks at −0.50, −0.76 and −1.02 V vs silver/silver chloride corresponding to the oxidation of lead, cadmium and zinc ions at the electrode surface, respectively. The highest peak currents for all the metal ions under study were observed in the phosphate buffer solution at pH 1 with a deposition time of 70 s. The sensor exhibited linear behavior in the range of 0.25-12.5 μg mL-1 for lead and cadmium and 0.25-10.0 μg mL−1 for zinc. The limit of detection was calculated as 78.81, 96.17 and 91.88 ng mL−1 for Pb2+, Cd2+and Zn2+, respectively. The modified electrode exhibited good stability and repeatability.
Originality/value
A chemically modified electrode with Schiff base was applied to determine the content of cadmium, lead and zinc ions in aqueous solutions using SWASV.
Details
Keywords
Nepal's political economy has been in the process of changing ever since the establishment of a unified kingdom on November 12, 1769, following the unification drive by the King…
Abstract
Nepal's political economy has been in the process of changing ever since the establishment of a unified kingdom on November 12, 1769, following the unification drive by the King of Garkha, Prithivi Narayan Shah. Although Nepal has never been colonized, her political economy has been largely influenced by changes in neighboring countries. Monarchs ruled the country from 1770 to 1845. At that point, Jung Bahadur Rana, taking full advantage of the ongoing conspiratorial politics in the king's palaces, decimated his foes and established himself as the Prime Minister of the country and turned the powerful king into titular head of state from 1846 to 1950. After a brief experiment of open and competitive politics following the 1950 revolution, the country fell back into a rule of absolutism from 1960 to 1990, then finally reverted to a constitutional monarchy and parliamentary system in 1990 following the Jana Andolan (People's Movement).