Detection of Trace Heavy Metal Ions Using Carbon Nanotube‐ Modified Electrodes

Abstract

A sensitive voltammetric method for detection of trace heavy metal ions using chemically modified carbon nanotubes (CNTs) electrode surfaces is described. The CNTs were covalently modified with cysteine prior to casting on electrode surfaces. Cysteine is an amino acid with high affinities towards some heavy metals. In this assay, heavy metals ions accumulated on the cysteine-modified CNT electrode surfaces prior to being subjected to differential pulse anodic stripping voltammetry analysis. The resulting peak currents were linearly related to the concentrations of the metal ions. The method was optimized with respect to accumulation time, reduction time and reduction potential. The detection limits were found to be 1 ppb and 15 ppb for Pb 2þ and Cu 2þ respectively. The technique was used for the detection of Pb 2þ and Cu 2þ in spiked lake water. The average recoveries of Pb 2þ and Cu 2þ were 96.2% and 94.5% with relative standard deviations of 8.43% and 7.53% respectively. The potential for simultaneous detection of heavy metal ions by the modified CNTs was also demonstrated.

Nanotechnology Solutions for Global Water Challenges

“…A limit of detection of 0.04 μg L -1 was reported. Cysteine coated CNTs were used in the construction of an electrochemical sensor for the simultaneous detection of lead and copper ions (152). Detection limits of 1 ppb and 15 ppb were reported for Pb 2+ and Cu 2+ respectively.…”

Nanostructure Restoration of Thermally Reduced Graphene Oxide Electrode upon Incorporation of Nafion for Detection of Trace Heavy Metals in Aqueous Solution

“…Recently, nanomaterials, such as carbon nanotubes (CNT) [10], graphene [11] and metal nanoparticles [12], have been employed in the fabrication of working electrodes. These nanomaterials possess a high specific surface area that is able to enhance the sensitivity of detection.…”

A Self‐assembled L‐Cysteine and Electrodeposited Gold Nanoparticles‐reduced Graphene Oxide Modified Electrode for Adsorptive Stripping Determination of Copper

“…Therefore, those methods often suffer from interference from other metal ions [9]. To achieve better selectivity, some researchers have performed the preconcentration at open circuit potential based on Cu 2 + complexation with some chelating agents [11][12][13]. Among different chelating agents, L-cysteine has received much attention to developed sensor for the determination of Cu 2 + [11,[14][15].…”

“…To achieve better selectivity, some researchers have performed the preconcentration at open circuit potential based on Cu 2 + complexation with some chelating agents [11][12][13]. Among different chelating agents, L-cysteine has received much attention to developed sensor for the determination of Cu 2 + [11,[14][15]. L-cysteine has a high binding constant for Cu 2 + by the coordination with its acidic carboxyl and amino functional groups [16].…”