Citation: Hu, C.; Pan, P.; Huang, H.;
Liu, H. Cr-MOF-Based
Electrochemical Sensor for the
Detection of P-Nitrophenol.
Biosensors 2022, 12, 813. https://
doi.org/10.3390/bios12100813
Received: 29 August 2022
Accepted: 28 September 2022
Published: 1 October 2022
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Communication
Cr-MOF-Based Electrochemical Sensor for the Detection
of P-Nitrophenol
Chao Hu
1,†
, Ping Pan
2,†
, Haiping Huang
1,
* and Hongtao Liu
2,3,
*
1
School of Chemistry and Chemical Engineering, Jiangxi University of Science and Technology,
Ganzhou 341000, China
2
Staff Hospital of Central South University, Central South University, Changsha 410083, China
3
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
* Correspondence: huanghp@jxust.edu.cn (H.H.); liuht@csu.edu.cn (H.L.)
† These authors contributed equally to this work.
Abstract:
Cr-MOF nanoparticles were synthesized by a simple hydrothermal method, and their mor-
phology and structure were characterized by SEM, TEM, and XRD techniques. The Cr-MOF modified
glassy carbon electrode (Cr-MOF/GCE) was well constructed and served as an efficient electrochemi-
cal sensor for the detection of p-nitrophenol (p-NP). It was found that the Cr-MOF nanoparticles had
significant electrocatalytic activity toward the reduction of p-NP. The Cr-MOF-based electrochemical
sensor exhibited a low detection limit of 0.7
µ
M for p-NP in a wide range of 2~500
µ
M and could
maintain excellent detection stability in a series of interfering media. The electrochemical sensor was
also practically applied to detect p-NP in a local river and confirmed its validity, showing potential
application prospects.
Keywords:
nanoparticle; modified electrode; electrochemical sensor; electrocatalytic activity;
detection limit
1. Introduction
Currently, nitroaromatic compounds are widely used in the chemical industry as raw
materials for the manufacture of various pharmaceutical compounds, pesticides, fungicides
and dyes. The extensive use of these chemical products results in their wide existence in the
environment [
1
,
2
]. However, even in trace concentrations, these compounds are harmful
to humans, animals and plants and may contaminate freshwater or marine ecosystems.
Among them, p-nitrophenol (p-NP) is one of the most common phenolic pollutants, which
not only harms our health but causes serious pollution to the environment [
3
,
4
]. Therefore,
in order to ensure the safety of our living environment, a simple and efficient detection
method to detect low concentrations of p-NP, whose concentration may be as low as
0.2 mg/L [5,6], becomes emergent.
Compared with other traditional techniques, electrochemical sensing methods have
the advantages of good selectivity, high sensitivity, simple operation, and fast response
time [
7
–
9
]. The detection performance of an electrochemical sensor depends on the chemical
properties of the modified materials used in the working electrodes [
10
,
11
]. Therefore,
the performance of the sensor can be improved by carefully designing the component and
structure of the electrode material in terms of selectivity, sensitivity and stability [
12
,
13
].
This can be satisfied by designing and developing a new material that can effectively
enhance the sensor’s response to p-NP.
Nanomaterials with metal-organic frameworks (MOFs) are currently among the hottest
materials studied by scientists in various fields. Because of their high specific surface area,
adjustable structure size, low density, and designability, they are all-in-one functional
porous polymeric materials [
14
,
15
]. Together with great progress for MOFs’ design and
Biosensors 2022, 12, 813. https://doi.org/10.3390/bios12100813 https://www.mdpi.com/journal/biosensors
