Electrochemical Sensors for Heavy Metal Ion Detection in Aqueous

Overview

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Key numbers

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recent times, as shown in Figure 1. In the past decade, there their concentration range has a significant effect on human
potential for a wide range of technological applications. They 2.1.1. Atomic Absorption Spectrometry. In AAS, the
to portable low-cost sensors.24 However, they have their own in the sample using AAS, it is necessary that individual atoms
Table 1. Regulatory Limits, Sources, and Health Effects of Various Heavy Metals
arsenic (Ar) 0.01 ppm 0.2 ppm it can be released through volcanic eruptions and forest fires; it can be released from low-level exposure can result in symptoms including “pins and needles” in the hands and feet,
cadmium 0.005 ppm 2 ppm cadmium is present in all rocks and soils, including coal and mineral fertilizers; batteries, severe damage to lungs, irritation in stomach, kidney related disease, and fragile bones due to long-
chromium 0.05 ppm 0.1 ppm its compounds are usually found in sediments in water; it is mostly found in electroplating of short-term exposure can cause breathing problems like wheezing, asthma, nose ulcers, skin ulcers,
lead (Pb) 15 ppb 0.1 ppm lead can be found in air, water, and soil due to human activities like manufacturing, burning, long-term exposure leads to weakness in nervous system, increase in blood pressure and anemia
mercury 2 ppb 0.01 ppm it can be found in thermometer, power plants, dental fillings, etc. high-level exposure can damage kidneys, brain, and fetus development permanently; short-term
copper (Cu) 2 ppm 3 ppm it is found in electrical equipment, industrial machineries like heat exchangers etc. consuming copper in excess of what is advised on a daily basis, whether through food, drink, or
Table 2 is measured and recorded as a function of time. The
Table 2. HMI Detection by Analytical Methods
Chinese tablets AAS calcium, magnesium, iron, copper, 30
ppb.55−57 Nanomaterials are increasingly being employed for
linear calibration plot of peak current against arsenic concentrations from 0.1 to 10 ppb Insets in (a) and (b) are the enlarged views that correspond
to a range of 0.1−2 ppb. Reprinted with permission from ref 70. Copyright 2018 American Chemical Society.
realistic water environment. with a limit of detection of 1.2 ppb, which is found to be much
the bimetallic nanoparticles show better performance than Au ppb sensitivity and a detection limit of 0.0215 ppb. Figure 9
the sensing capabilities of electrodes with bimetallic gold SPCE in various concentration ranges from 0.1 to 10 ppb.
Table 3 presents a quick overview of reports of electro- 3.2. Research on Electrochemical Sensing of Cadmi-
Table 3. Electrochemical Sensing of Arsenic television picture tubes, solar modules, fluorescent probes in
SWASV Reduced graphene 0.05 1−10 72 of cadmium in drinking water is below 3 ppb. Thus, simple and
SWASV Fe3O4/SPCE 0.00185 2−14 82 ion detection has a linear detection range with a sensitivity of
SWASV MnFe2O4—AuNPs/ 3.37 10−110 89 the range of 40−1200 g/L.
electrode toward cadmium over the concentration range of (a) 0.1−1.9 μM by depositing for 120 s and (b) 20−60 nm by depositing for 30 min.
Table 4. Electrochemical Sensing of Cadmium
SWASV Bi−C nanocomposite 0.65 and 0.81 μg L−1 1−100 ppb 99
cadmium in the concentration range of 0.1−1.9 mM in 0.1 M concentration range of 20−60 nM by increasing the deposition
relation to cadmium concentrations, with a sensitivity of 13.86 sensitivity of 240 μA/μM and a lowest detectable concen-
optimal conditions, cadmium was directly and easily detected concentrations as low as 5 μg/L. The same method was used
over a wide linear range (1 nM−10 M) with low detection by Rosolina et al.126 to investigate the effect of carboxylated,
Table 4 presents a quick overview of the reports on the well as pyridinium-functionalized sol−gel thin films on the
below 0.05 ppb. Due to its widespread use in electroplating, 9 times when compared to the glassy carbon electrode, thereby
leather tanning, wood polishing and preservation, and artificial detecting chromium at 7.8 μg/L. Chen et al.128 developed an
chromium concentrations in natural waters is crucial.124 chromium ion concentrations as low as 1.04 μg/L.
electrodes show a lot of benefits, such as a higher ratio of for chromium detection at a concentration of 0.05 μg/L using
Table 5. Electrochemical Sensing of Chromium
polarography platinum 0.02 ppm 0.05−17.2 ppm 136
polarography mercury film electrodes 0.3 ppm 1−10 ppb 137
linear sweep voltammetry (LSV) platinum electrode modified with poly-3-methylthiophene 100 ppb NA 138
polarography mercury drop electrode modified with sodium pentamethylene 0.01 ppm NA 139
anodic stripping voltammetry mercury drop electrode modified with diphenylcarbazide complex 0.02 μg/L 0−10 nM 141

Methods (brief)

methods like atomic absorption spectroscopy, atomic fluorescence
caused by human activity, including air emissions from coal- for the analysis of low-concentration HMIs in samples from the
environment, samples from food and medicine, and biological emerging as an excellent technology because of their good
samples. selectivity and fast detection speed.25,26
samples, standard analytical techniques have been developed. methods to detect HMIs in aqueous medium as well as to
fluorescence spectrometry,14 and atomic absorption and the electrodes used in these methods. This Review covers the
HMIs in various samples has received significant attention in Metals are necessary for carrying out biological processes, but
keywords: electrochemical detection of heavy metal ion). sensing methods include atomic absorption and emission
Nanocomposite materials have recently emerged as an tion spectrometry (AAS), atomic fluorescence spectrometry
potential for a wide range of technological applications. They 2.1.1. Atomic Absorption Spectrometry. In AAS, the
and selectivity of the HMI detection using electrochemical metallic elements in a given sample. Figure 2 shows a block
sensors, electrode modifiers made of nanocomposite materials diagram of the general atomic absorption spectrometer. The
are employed.23 Many electrochemical devices make use of basic parts of AAS are light source, atomizer, monochromator,
to portable low-cost sensors.24 However, they have their own in the sample using AAS, it is necessary that individual atoms
limitations of lower sensitivity and detection limits compared or ions in the sample are well isolated from one another. Here
with the traditional analytical methods. In a similar manner, an atomizer is used to create the analytes from the sample.
Figure 2. Block diagram of an atomic absorption spectrometer.
excitation energy and atomic absorption spectroscopy can be processes for monitoring contaminated samples. Another

Implications

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised