Sensitive simultaneous electrochemical sensing of phytohormones indole-3-acetic acid and salicylic acid based on a novel poly(L-Proline) nanoparticles–carbon dots composite consisting of multiwalled carbon nanotubes was reported in this study. The poly(L-Proline) nanoparticles–carbon dots composite was facilely prepared by the hydrothermal method, and L-Proline was used as a monomer and carbon source for the preparation of poly(L-Proline) nanoparticles and carbon dots, respectively. Then, the poly(L-Proline) nanoparticles–carbon dots–multiwalled carbon nanotubes composite was prepared by ultrasonic mixing of poly(L-Proline) nanoparticles–carbon dots composite dispersion and multiwalled carbon nanotubes. Scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, energy dispersive spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry were used to characterize the properties of the composite. poly(L-Proline) nanoparticles were found to significantly enhance the conductivity and sensing performance of the composite. Under optimal conditions, the composite-modified electrode exhibited a wide linear range from 0.05 to 25 μM for indole-3-acetic acid and from 0.2 to 60 μM for salicylic acid with detection limits of 0.007 μM and 0.1 μM (S/N = 3), respectively. In addition, the proposed sensor was also applied to simultaneously test indole-3-acetic acid and salicylic acid in real leaf samples with satisfactory recovery.
The formation process of carbon dots (CDs) is mostly
polymerization; recently, studies
on the polymerization
of carbon families (graphene oxide and C60) have been receiving
exciting attention. Herein, a protocol of prepolymerization and electropolymerization
of monomer (melamine) and nanomonomer (CDs fixed melamine residues)
was proposed to prepare a nanocomposite for selective dopamine (DA)
and uric acid (UA) sensing. The nanomonomer was prepared by hydrothermal
prepolymerization of melamine, and then the nanocomposite was formed
in situ by electropolymerization of the CDs/carboxylated multiwalled
carbon nanotubes (MWCNTs-COOH)-modified glassy carbon electrode (GCE)
in KCl solution. Scanning electron microscopy, transmission electron
microscopy, energy-dispersive spectroscopy, X-ray diffraction, Fourier
transform infrared spectroscopy, cyclic voltammetry, electrochemical
impedance spectroscopy, and differential pulse voltammetry were used
to characterize the properties of the nanocomposite. Under optimal
conditions, the electrochemical sensor shows selectivity and a wide
linear range from 0.1 to 10 μM for DA and 0.1 to 200 μM
for UA, with the detection limit of 0.023 and 0.064 μM (S/N
= 3) in the presence of AA, respectively. In addition, the proposed
sensor was also applied to selectively test DA and UA in the presence
of 500 μmol/L AA in real samples with satisfactory recovery.
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 μM, and a good linear relationship with SA in the range of 4–30 μM. The detection limits were 0.0086 μM and 0.7 μM (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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.