Electrochemical Detection of Heavy Metals Using

Overview

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Key numbers

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tissues (4). It is estimated that more than 13% of the world’s arable land and almost 40% of
metals between 2020 and 2024 increased by over 114% compared to the previous five-year
sensors and biosensors (Table 1). This conditional subdivision facilitates reading; however,
156 Ω to 17 Ω), enabling femtomolar detection of Hg2+ (LOD = 0.16 fM) in milk samples.
SWASV at an accumulation time of 180 s. The thin (2 µm), highly hydrated 1 wt % Nafion
ultra-low detection limit and a wide linear range. The sensor was stable for 21 days, and
onto NH2 -UiO-66, forms stable EDTA complexes with Pb2+ and Cd2+ via its abundant
prolongs the analyses. The sensor is stable over 20 days and shows promising potential
material as it does not require long fabrication, is stable for at least 3 weeks, is cheap, and
an ultrasensitive LOD of 1 nM (0.001 µg·L−1 ) for Pb2+ and a wide LDR of 0.003–5000 nM
to dual ranges, cross-interference between Cd2+ and Cu2+ , and the long deposition time.
Table 1. Graphene-based electrochemical sensors and biosensors for heavy metal detection in real objects (food, water, human serum).
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
a —Cd2+ , b —Pb2+ , c —Cu2+ , d —Hg2+ , e —Tl2+ , and f —Zn2+ . Analytical characteristics. Advantages (Adv.): A low LOD; B wide LDR; C selective electrode; D high reproducibility; E
mental samples (Table 2). However, the widespread use of such sensors requires further
chemical sensors for the quantitative determination of heavy metals, as shown in Table 2.
heavy metals. Bao et al. (79) developed a portable system for detecting Hg2+ and Cu2+ in
electrode modification. Significant disadvantages include a high LOD (45.54 µM), poor
also demonstrated photocatalytic activity, degrading tetracycline with 90% efficiency within
has many advantages, namely selectivity, high reproducibility, and low LODs (0.58 nM
acteristics in two linear ranges of 0.2–250 nM and 250–3500 nM. The developed technique
showed that the LOD is about 0.04 nM, which is significantly less than the WHO Limits.
they have tunable electrochemical properties and stable oxidation states from I to III (77).
limits. In addition, GO/(Ru(bpy)3 )2+ /Au was shown to be easy to prepare, stable for at
least 30 days, and suitable for the determination of Cd2+ , Pb2+ , As3+ , and Hg2+ in Cau-
role in the binding of Hg2+ ions due to its unique ability to form stable complexes with
Thymine plays a crucial role in binding Hg2+ ions due to its ability to form stable complexes
and Cr6+ , respectively. Furthermore, an RSD < 4.5% indicates good reproducibility, while
field applicability (90). However, the high LOD for Cr6+ is disadvantageous compared to
Table 2. Graphene oxide-based electrochemical sensors for heavy metal detection in real objects (food, water).
MOF@GO15%-NF b Pb2+ b 1–150 b 0.07 A, B, C, E, F – I, J G, H (97)
a —Cd2+ , b —Pb2+ , c —As3+ , d —Hg2+ , e —Cu2+ , f —Cr2+ , g —UO 2+ , h —Zn2+ , and i —Cr3+ . Analytical characteristics. Advantages (Adv.): A low LOD; B wide LDR; C selective electrode;
successfully detected As3+ with an LOD of 0.24 ppb and a sensitivity of 1.24 µA/ppb in
Cd2+ in river water, honey, and orange juice (104). The combination of rGO and Au-Bi
This results in a wide LDR and low LODs of 0.05 µg·L−1 for Pb2+ and 0.02 µg·L−1 for
posit of Pb2+ and Cd2+ , enabling an ultrasensitive detection LOD of 0.45 µg·L−1 for Pb2+
and 1.69 µg·L−1 for Cd2+ with a linear dynamic range of 2.5–200 µg·L−1 for both ions.
changes of less than 8% for most common ions at environmentally relevant concentrations.
composites suitable for heavy metal detection in environmental samples (117). In 2020,

Methods (brief)

uid chromatography (HPLC) and spectrophotometry in the detection of heavy metals.
metals, unlike many atomic absorption/emission spectrophotometric approaches, which
for HPLC or inductively coupled plasma (ICP) spectrophotometry, allowing rapid in situ
their key performance metrics (LOD, LDR), comparative analytical performance grouped
156 Ω to 17 Ω), enabling femtomolar detection of Hg2+ (LOD = 0.16 fM) in milk samples.
samples for in situ heavy metal monitoring. For this purpose, a CO2 laser-induced porous
samples. The sensor achieved a low detection limit of 2.90 µg·L−1 for Pb2+ , 2.14 µg·L−1 for
the practicality for higher concentration samples and rapid field testing. Furthermore,
of Pb2+ in lake water samples using differential pulse voltammetry (DPV). The GNR-
bility remains untested beyond 12 days, and reliance on spiked samples may limit practical
efficiency, resulting in enhanced sensor performance. The sensor achieved low LODs
has a wide linear range for the analyzed heavy metals. Unfortunately, LOD and selectivity
sample, they interact with the DNAzyme and cause a conformational change that leads to
an ultrasensitive LOD of 1 nM (0.001 µg·L−1 ) for Pb2+ and a wide LDR of 0.003–5000 nM
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference
Electrode Sensing Materials (Accumulation LDR, µg·L−1 LOD, µg·L−1 Matrix Reference

Implications

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Verification notes

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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