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Methyl parathion (MP), an organophosphorus pesticide that is frequently used to control pests during the planting process of Chinese herbal medicine (CHM), has been used without sufficient control, leading to excessive residues on the surface of CHM, which has a serious impact on the quality and safety of CHM and their preparations. Consequently, it is crucial to carefully control MP during the cultivation, processing, and manufacture of CHM. Based on this, nitrogen-doped graphene (N-Gr) with a high conductivity and chitosan (CS) with good stability were used to modify the glassy carbon electrode (GCE). Subsequently, the prussian blue (PB) with catalytic activity and gold nanoparticles (AuNPs) with excellent biocompatibility were deposited by the electrodeposition method to form the AuNPs/PB/CS@N-Gr/GCE. Then, the acetylcholinesterase (AChE) was effectively immobilized on the electrode surface by covalent bonding between AuNPs and AChE through gold-sulfhydryl bonds. Finally, a rapid and easy procedure of enzyme biosensor (AChE/AuNPs/PB/CS@N-Gr/GCE) for sensitive detection of MP pesticide residues was fabricated. Herein, PB catalyzes the redox reaction of thiocholine, which is produced when acetylthiocholine iodide (ATCHI) undergoes efficient hydrolysis catalyzed by AChE. This process effectively promoted electron transfer, amplifying the sensor’s response signal. After the experimental conditions are optimized, the limit of detection (LOD) for MP is found to be 9.47 × 10−5 μg ml−1. Exhibits a good linear relationship within the concentration range of 1 × 10−3 μg ml−1∼ 1 × 101 μg ml−1. Significantly, the fabricated enzyme biosensor excels in swiftly and sensitively detecting trace amounts of MP in real examples. Furthermore, it exhibits robust stability and reproducibility. The excellent performance of this enzyme biosensor not only offers a rapid and easy way to identify and find minute amounts of trace MP pesticide residues in CHM, but also serves as a technical guide for the creation of new, portable, and on-site pesticide residue detection technology for law enforcement.

The hidden hazards of cardiovascular diseases (CVDs) are enormous, and there is a lack of early warning and prognostic risk assessment technologies. In this study, Cardiac troponin I (cTn-I), the “gold standard” for CVDs diagnosis, was selected as the target molecule, and chitosan functionalized graphene oxide composites (GO@CS) with excellent electrochemical performance were prepared as the electrode base material. Gold nanoparticles (AuNPs) were deposited on GO@CS by electrochemical deposition. Due to the large surface area, excellent electrical conductivity and good biocompatibility of GO@CS assembled with AuNPs provide abundant active sites for the immobilization of cTn-I antigen. Under the optimized experimental conditions, the fabricated immunosensor had a wide linear range of 2.44 × 10−2 ng ml−1to 2.50 × 10 ng ml−1and a low detection limit of 1.12 × 10−2 ng ml−1(S/N = 3). This study achieves the highly sensitive identification and detection of trace amounts of cTn-I in complex biological samples, providing a convenient and efficient method for the detection of CVDs-related markers. It also provides a scientific basis, new technologies and new methods for the development of objective early warning techniques for CVDs and the study of related pathological mechanisms.

After intensely ultrasonic cracking, activated carbon obtained larger specific surface area in the premise of the high electric conductivity being maintained, which has provided a prerequisite for the construction of highly sensitive electrochemical sensors. An electrochemical sensor for sensitive analysis of puerarin in Radix Puerariae was successfully constructed using the prepared ultra-micro activated carbon in this work. The electrochemical behavior of puerarin on the sensor was investigated by cyclic voltammetry and differential pulse voltammetry. Moreover, the conditions of sensor preparing and puerarin detecting were optimized. Under the optimal conditions, the oxidation peak current increased linearly with the concentration of puerarin in the range of 2.4 x 10[?]7 mol L[?]1[?]1.54 x 10[?]5 mol L[?]1, and the detection limit was 6.4 x 10[?]8 mol L[?]1. In addition, the proposed sensor also exhibited good reproducibility, stability and selectivity. With superior performance in sample analysis, the proposed method would not only provide a new way for rapid and sensitive detection of puerarin, but also give a new idea for the application of activated carbon materials in the field of electrochemical sensors.

In this study, a newfangled molecularly imprinted electrochemical sensor based on nanoporous carbon (NC) was constructed and applied to the sensitive determination of calycosin in complex Chinese medicine samples. Aniline as functional monomer and calycosin as template were used to assemble molecularly imprinted polymer (MIP), which was bonded to the surface of NC modified glassy carbon electrode (GCE) by electropolymerization. After characterization of the successfully prepared MIP/NC composite, the electrochemical performance of the proposed sensor (MIP/NC/GCE) was evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. The results proved that the sensor could accelerate electron transfer rate and heighten specific surface area. Under optimized conditions, the proposed sensor was used to detect calycosin, which displayed good reproducibility, stability and selectivity. The method demonstrated a liner range of 4.20 x 10[?]7[?]1.29 x 10[?]4 mol/L with the detection limit of 8.5 x 10[?]8 mol/L. Moreover, this study will provide a prospective exploration for the application of electrochemical analysis technology in the active ingredient detection of traditional Chinese medicine.

As hesperidin is a key indicator of some herbs and traditional Chinese medicine preparations, it is important to realize its sensitive, fast and high selective detection. In this work, prepared ultrafine activated carbon with high electrical conductivity was introduced as base decorated material of electrode, then with the use of self-assembly method and electro-polymerization method, the molecularly imprinted polymer was prepared on the electrode by using hesperidin as template molecular and o-aminothiophenol as functional monomer. Scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy were employed to characterize the morphological features and the stepwise modification of electrode, separately. The influence of pH, ratio of monomer to template, self-assembly time and so on were investigated and optimized. Under the optimized condition, the fabricated sensor exhibits a wide linear range from 85nM to 30uM with a low detection limit of 45nM. The decorated sensor has favorable selectivity, reproducibility and stability that could be used in real sample analysis.

Identification and quantification of epigoitrin (EP) in some herbs and traditional Chinese medicine (TCM) preparations are critical to pharmacokinetic study and pharmaceutical quality control due to its distinct antiviral activity. So, developing highly sensitive and selective method for detection of EP is essential for clinical treatment and drug development. In this study, a novel molecularly imprinted electrochemical sensor for detection of EP was firstly constructed. With acrylamide imprinting systems, surface imprinting on the polyaniline functionalized graphene oxide was employed to prepare molecularly imprinted polymer by electro-polymerization, which follow-up constructed afford specific binding cavities, endowing the exclusive recognition ability. Furthermore, the polyacrylamide chain is anchored to the polyaniline chain by covalent bonds, which is beneficial for raising electrochemistry signal. Under the optimized condition, the sensor demonstrates a linear wide range of 4.6 × 10−7mol l−1∼ 4.6 × 10−5mol l−1with a correlation coefficient of 0.9953 and a low LOD of 8.21 × 10−8mol l−1(S/N = 3). Additionally, the sensor showed good stability, repeatability (RSD 1.52%) and selectivity. The method was applied to analyze EP in the extraction from Isatidis Radixwith a recovery higher than 97.8% and RSD less than 1.81%. This work provided a novel strategy for on-site, real-time and rapid detection of indicator components from TCM.

After intensely ultrasonic cracking, activated carbon obtained larger specific surface area in the premise of the high electric conductivity being maintained, which has provided a prerequisite for the construction of highly sensitive electrochemical sensors. An electrochemical sensor for sensitive analysis of puerarin in Radix Puerariaewas successfully constructed using the prepared ultra-micro activated carbon in this work. The electrochemical behavior of puerarin on the sensor was investigated by cyclic voltammetry and differential pulse voltammetry. Moreover, the conditions of sensor preparing and puerarin detecting were optimized. Under the optimal conditions, the oxidation peak current increased linearly with the concentration of puerarin in the range of 2.4 × 10−7mol L−1∼1.54 × 10−5mol L−1, and the detection limit was 6.4 × 10−8mol L−1. In addition, the proposed sensor also exhibited good reproducibility, stability and selectivity. With superior performance in sample analysis, the proposed method would not only provide a new way for rapid and sensitive detection of puerarin, but also give a new idea for the application of activated carbon materials in the field of electrochemical sensors.

As hesperidin is a key indicator of some herbs and traditional Chinese medicine preparations, it is important to realize its sensitive, fast and high selective detection. In this work, prepared ultrafine activated carbon with high electrical conductivity was introduced as base decorated material of electrode, then with the use of self-assembly method and electro-polymerization method, the molecularly imprinted polymer was prepared on the electrode by using hesperidin as template molecular and o-aminothiophenol as functional monomer. Scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy were employed to characterize the morphological features and the stepwise modification of electrode, separately. The influence of pH, ratio of monomer to template, self-assembly time and so on were investigated and optimized. Under the optimized condition, the fabricated sensor exhibits a wide linear range from 85nM to 30μM with a low detection limit of 45nM. The decorated sensor has favorable selectivity, reproducibility and stability that could be used in real sample analysis.

In this study, a newfangled molecularly imprinted electrochemical sensor based on nanoporous carbon (NC) was constructed and applied to the sensitive determination of calycosin in complex Chinese medicine samples. Aniline as functional monomer and calycosin as template were used to assemble molecularly imprinted polymer (MIP), which was bonded to the surface of NC modified glassy carbon electrode (GCE) by electropolymerization. After characterization of the successfully prepared MIP/NC composite, the electrochemical performance of the proposed sensor (MIP/NC/GCE) was evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. The results proved that the sensor could accelerate electron transfer rate and heighten specific surface area. Under optimized conditions, the proposed sensor was used to detect calycosin, which displayed good reproducibility, stability and selectivity. The method demonstrated a liner range of 4.20 × 10−7∼1.29 × 10−4mol/L with the detection limit of 8.5 × 10−8mol/L. Moreover, this study will provide a prospective exploration for the application of electrochemical analysis technology in the active ingredient detection of traditional Chinese medicine.