Citation: Kuang, Y.; Li, M.; Hu, S.;
Yang, L.; Liang, Z.; Wang, J.; Jiang, H.;
Zhou, X.; Su, Z. One-Step
Co-Electrodeposition of Copper
Nanoparticles-Chitosan Film-Carbon
Nanoparticles-Multiwalled Carbon
Nanotubes Composite for
Electroanalysis of Indole-3-Acetic
Acid and Salicylic Acid. Sensors 2022,
22, 4476. https://doi.org/10.3390/
s22124476
Academic Editors: Ki-Hyun Kim and
Deepak Kukkar
Received: 26 April 2022
Accepted: 10 June 2022
Published: 13 June 2022
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Article
One-Step Co-Electrodeposition of Copper Nanoparticles-Chitosan
Film-Carbon Nanoparticles-Multiwalled Carbon Nanotubes
Composite for Electroanalysis of Indole-3-Acetic Acid and
Salicylic Acid
Yiwen Kuang
1
, Mengxue Li
2
, Shiyu Hu
2
, Lu Yang
2
, Zhanning Liang
2
, Jiaqi Wang
2
, Hongmei Jiang
2
,
Xiaoyun Zhou
1,
* and Zhaohong Su
2,
*
1
College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China;
kuangyiwen@stu.hunau.edu.cn
2
College of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China;
limengxue@stu.hunau.edu.cn (M.L.); hushiyu@stu.hunau.edu.cn (S.H.); yanglu00@stu.hunau.edu.cn (L.Y.);
liangzhanning@stu.hunau.edu.cn (Z.L.); wangjiaqi@stu.hunau.edu.cn (J.W.); jhmndcn@hunau.edu.cn (H.J.)
* Correspondence: xyzhou71@hunau.edu.cn (X.Z.); zhaohongsu@hunau.edu.cn (Z.S.)
Abstract:
A sensitive simultaneous electroanalysis of phytohormones indole-3-acetic acid (IAA)
and salicylic acid (SA) based on a novel copper nanoparticles-chitosan film-carbon nanoparticles-
multiwalled carbon nanotubes (CuNPs-CSF-CNPs-MWCNTs) composite was reported. CNPs were
prepared by hydrothermal reaction of chitosan. Then the CuNPs-CSF-CNPs-MWCNTs composite
was facilely prepared by one-step co-electrodeposition of CuNPs and CNPs fixed chitosan residues
on modified electrode. Scanning electron microscope (SEM), transmission electron microscopy (TEM),
selected area electron diffraction (SAED), energy dispersive spectroscopy (EDS), X-ray diffraction
(XRD), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), electrochemical
impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) were used to characterize the
properties of the composite. Under optimal conditions, the composite modified electrode had a good
linear relationship with IAA in the range of 0.01–50
µ
M, and a good linear relationship with SA in
the range of 4–30
µ
M. The detection limits were 0.0086
µ
M and 0.7
µ
M (S/N = 3), respectively. In
addition, the sensor could also be used for the simultaneous detection of IAA and SA in real leaf
samples with satisfactory recovery.
Keywords:
carbon nanoparticles; copper nanoparticles; chitosan film; multiwalled carbon nanotubes;
electroanalysis of indole-3-acetic acid and salicylic acid
1. Introduction
Phytohormones are small molecular substances synthesized by plants themselves.
Indole acetic acid (IAA) and its derivatives are important plant growth hormones. They are
involved in the regulation of various biological processes such as plant cell elongation and
reproduction, leaf and flower withering, and plant vascular tissue decomposition. They
have different important functions in various stages of plant growth and development. Sali-
cylic acid (SA), another phytohormone, is involved in the regulation of many physiological
processes, such as flowering, heat production, senescence, and autophagy, and also plays
an important role in abiotic stresses such as low temperature, high temperature, and salt [
1
].
The content of IAA and SA in plants fluctuates, and the concentration of IAA is about
40–160 ng/g [
2
,
3
]. The concentration of SA is about 100~200 ng/g [
4
], which can complete
normal growth and development. External factors (salt, water, temperature, etc.) can lead
to abnormal levels of IAA and SA in plants, which can be regulated by applying exogenous
phytohormones to improve plant growth. Therefore, it is necessary to establish a method for
the determination of IAA and SA with high selectivity and sensitivity. The current detection
Sensors 2022, 22, 4476. https://doi.org/10.3390/s22124476 https://www.mdpi.com/journal/sensors
