Sensor and method for simultaneously detecting caffeic acid and dihydrotanshinone I

Abstract

The invention belongs to the technical field of compound detection, and particularly provides a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I. The sensor adopts an AuSe-BNPs / CFME electrode as a working electrode, wherein the AuSe-BNPs / CFME electrode is formed by modifying a carbon fiber electrode with gold-selenium composite nanoparticles through electro-deposition. A three-dimensional nanocluster structure is formed by the gold-selenium composite nanoparticles and is attached to a CFME interface, so that the specific surface area is remarkably increased, the surface activity of the electrode is enhanced, the contact opportunity between the electrode and substances in a solution is increased, and the electron transfer rate is favorably increased. The sensor is used for detecting caffeic acid and dihydrotanshinone I, has excellent stability and anti-interference performance, has relatively high electrochemical response sensitivity, is accurate in detection result and low in detection limit, can be applied to determination of the content of CA and DHT I in human serum, and has wide application prospects. The important application value is shown in the fields of disease marker detection, drug metabolism analysis and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of compound detection, and particularly relates to a sensor and method for simultaneously detecting caffeic acid and dihydrotanshinone I. Background Art

[0002] With the continuous advancement of natural product research, a growing number of plant-derived compounds have garnered widespread attention due to their unique pharmacological activities. Caffeic acid (CA) and dihydrotanshinone I (DHT I), two important natural products, have become research hotspots due to their remarkable antioxidant, anti-inflammatory, and anti-tumor properties. CA, chemically known as 3,4-dihydroxycinnamic acid, is a naturally occurring phenolic compound with a molecular structure consisting of two hydroxyl groups (-OH) and one carboxyl group (-COOH) on a benzene ring. Its chemical formula is C9H8O4, and its molecular weight is 180.16. Caffeic acid's aromatic core, conjugated double bonds, and hydroxyl structure impart antioxidant properties, enabling it to scavenge free radicals and modulate the cellular antioxidant defense system. Studies have shown that caffeic acid can inhibit the production of inflammatory factors and mitigate oxidative stress damage, thus showing broad application prospects in the treatment of cardiovascular diseases, neurodegenerative diseases, and cancer. DHTI is a diterpenoid compound extracted from the traditional Chinese medicine Danshen, with the chemical formula C 18 H 14 O3, molecular weight is 278.3. DHT I has significant cardiovascular protective effects and can exert its pharmacological activity through mechanisms such as inhibiting platelet aggregation, regulating blood lipid metabolism, and reducing inflammatory responses. In addition, DHTI also has anti-tumor activity, can induce cancer cell apoptosis, and inhibit the proliferation and migration of tumor cells. Although CA and DHT I have a wide range of pharmacological activities and use values, their practical application still faces many challenges. Since the concentrations of these two compounds in the body are extremely low and are easily interfered by environmental factors, the development of highly sensitive and highly selective detection methods is of great significance for revealing their metabolic mechanisms and evaluating their efficacy. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problems in the prior art that CA and DHT I have extremely low concentrations in complex biological matrices, are easily interfered by environmental factors, and are difficult to detect.

[0004] To this end, the present invention provides a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I. The sensor uses an AuSe-BNPs / CFME electrode formed by modifying a carbon fiber electrode by electrodeposition of gold-selenium composite nanoparticles as a working electrode.

[0005] The present invention also provides a method for preparing a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I, comprising the following steps: immersing CFME in an AuSe-BNPs solution for electrodeposition to prepare an AuSe-BNPs / CFME electrode.

[0006] Specifically, the CFME was immersed in the AuSe-BNPs solution and electrodeposited at +1.5 V using a constant potential method.

[0007] Specifically, the steps for preparing the AuSe-BNPs solution include: preparing a selenious acid solution, then adding a chloroauric acid solution and a trisodium citrate solution, mixing thoroughly, and continuously stirring to react to obtain the AuSe-BNPs solution.

[0008] Specifically, the deposition time of the CFME in the AuSe-BNPs solution is 5-40 min.

[0009] The present invention also provides a method for simultaneously detecting caffeic acid and dihydrotanshinone I: an AuSe-BNPs / CFME electrode formed by modifying a carbon fiber electrode by electroplating gold-selenium composite nanoparticles is used as a working electrode, and an Ag / AgCl electrode is used as a reference electrode. The electrodes are placed in a solution containing a supporting electrolyte and a sample to be tested, and the sample is detected using electrochemical scanning technology.

[0010] Specifically, the electrochemical scanning technique includes cyclic voltammetry and differential pulse voltammetry.

[0011] Specifically, the scanning range of the cyclic voltammetry test is -0.5V to 0.7V, the scanning rate is 50-500mV / s, and the sampling interval is 0.01V.

[0012] Specifically, the differential pulse voltammetry parameters are set as follows: initial potential -0.7 V, end potential 0.5 V, pulse amplitude 50 mV, pulse width 100 ms, and rest time 2 s.

[0013] Specifically, the supporting electrolyte solution is PBS with a pH of 2.0-4.0.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] The sensor for simultaneous detection of caffeic acid and dihydrotanshinone I provided by the present invention forms a three-dimensional nanocluster structure of gold-selenium composite nanoparticles and attaches it to the CFME interface. This significantly increases the specific surface area, enhances the surface activity of the electrode, and improves the contact between the electrode and substances in the solution, which helps to increase the electron transfer rate and lays an ideal foundation for the construction of ultrasensitive electrochemical sensors. The sensor is used to detect caffeic acid and dihydrotanshinone I, and exhibits excellent stability and interference resistance, high electrochemical response sensitivity, excellent stability and interference resistance, accurate detection results, and low detection limits. It can be applied to the determination of CA and DHT I levels in human serum, showing important application value in fields such as disease marker detection and drug metabolism analysis.

[0016] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of the experimental process of AuSe-BNPs / CFME detection.

[0018] Figure 2 : A, B, C are transmission electron micrographs of AuSe-BNPs at different magnifications; D, E, F are energy spectrum mapping images of AuSe-BNPs; G, H, I are scanning electron micrographs of CFME and AuSe-BNPs / CFME at different magnifications.

[0019] Figure 3 :A is the DPV graph of CFME, AuNPs / CFME, SeNPs / CFME and AuSe-BNPs / CFME for simultaneous detection of CA and DHT I; B is the electrochemical impedance spectroscopy of four different electrodes; C is the optimization of electrodeposition time of AuSe-BNPs / CFME, error bars, SD, n=3; D is the simultaneous detection of 1×10 -5 mol / L CA and 1×10 -6 mol / L DHT I CV graph; E is the linear relationship between the current and different scan rates during CV detection on AuSe-BNPs / CFME, error bars, SD, n = 3; F is the relationship between the redox peak potential and the logarithm of different scan rates, error bars, SD, n = 3; G is the relationship between the peak potential of AuSe-BNPs / CFME and 1×10 -5 mol / L CA and 1×10 -6 DPV detection of 1 mol / L DHT I; H, I are the relationships between the oxidation peak potential and the oxidation peak current and pH, error bars, SD, n=3.

[0020] Figure 4: Reaction mechanism of CA and DHT I on AuSe-BNPs / CFME.

[0021] Figure 5 :A and B are in PBS buffer at pH 3.0, 1×10 -5 3D and 2D graphs of DPV detection curves of mol / L CA and different concentrations of DHT I on AuSe-BNPs / CFME; C is the linear relationship between the oxidation peak current and the DHT I concentration, error bars, SD, n = 3; D and E are 1×10 -6 3D and 2D graphs obtained by testing different concentrations of CA while keeping the mol / L DHT I concentration constant; F shows the linear relationship between the oxidation peak current and CA concentration (error bars, SD, n = 3); G and H show the differential pulse 3D and 2D curves of different concentrations of DHT I and CA; I shows the relationship between the oxidation peak current and the concentrations of kaempferol and quercetin (error bars, SD, n = 3).

[0022] Figure 6 : A is the current value of AuSe-BNPs / CFME after 10 consecutive scans in the mixed solution; B is the comparison chart of the stability experimental data of the modified electrode, error bars, SD, n=3; C is the current signal when the interfering component coexists with the two target substances, error bars, SD, n=3. DETAILED DESCRIPTION

[0023] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Although the representative embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0024] The present invention provides a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I. The sensor adopts an AuSe-BNPs / CFME electrode formed by modifying a carbon fiber electrode by electroplating gold-selenium composite nanoparticles (AuSe-BNPs) as a working electrode.

[0025] The present invention also provides a method for preparing a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I, comprising the following steps:

[0026] Synthesis of AuSe-BNPs solution: Prepare selenious acid solution, then add chloroauric acid solution and trisodium citrate solution, mix thoroughly, and continue stirring to react to obtain AuSe-BNPs solution;

[0027] The CFME was immersed in the AuSe-BNPs solution and electrodeposited at +1.5 V using a constant potential method for 5-40 min to prepare an AuSe-BNPs / CFME electrode.

[0028] The present invention also provides a method for the simultaneous detection of caffeic acid and dihydrotanshinone I. An AuSe-BNPs / CFME electrode (formed by electrodeposition of gold-selenium composite nanoparticles to modify a carbon fiber electrode) is used as the working electrode, and an Ag / AgCl electrode is used as the reference electrode. The electrode is placed in a solution containing a supporting electrolyte and the sample to be tested, and the sample is tested using electrochemical scanning technology. After each test cycle, the electrode sample is rinsed with deionized water and ethanol to remove residual CA and DHTI.

[0029] Among them, electrochemical scanning techniques include cyclic voltammetry and differential pulse voltammetry; the scanning range of the cyclic voltammetry test is -0.5V to 0.7V, the scanning rate is 50-500mV / s, and the sampling interval is 0.01V; the differential pulse voltammetry parameters are set as: initial potential -0.7V, termination potential 0.5V, pulse amplitude 50mV, pulse width 100ms, and standing time 2s.

[0030] The effects of the sensor and method for simultaneously detecting caffeic acid and dihydrotanshinone I of the present invention are studied below through specific examples.

[0031] Example 1:

[0032] This embodiment provides a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I, which is prepared using the following method.

[0033] 1. Synthesis of AuSe-BNPs solution

[0034] Prepare 20 mL of a 1 mmol / L selenious acid solution, then add 800 μL of a 1% chloroauric acid solution and 10 mL of a 1% trisodium citrate solution. Thoroughly mix the three solutions, transfer them to a three-necked flask, and place them in a 40°C water bath. Stir continuously for 1 hour. After the reaction is complete, remove the mixture, cool it to room temperature, and then store it in a refrigerator at 4°C for later use.

[0035] 2. Preparation of AuSe-BNPs / CFME

[0036] A CFME with a diameter of 8 μm was selected as the working electrode. The CFME was repeatedly washed in deionized water and ethanol solution for 3 times, each time for 1 minute, and then naturally dried at room temperature for use.

[0037] The pretreated CFME was immersed in the AuSe-BNPs solution and deposited using a CHI660D electrochemical workstation by a constant potential deposition method at +1.5 V for 30 min to obtain AuSe-BNPs / CFME, which was then stored at room temperature.

[0038] 3. Characterization of AuSe-BNPs / CFME

[0039] Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the morphology and element distribution of AuSe-BNPs / CFME. Figure 2 As shown in AC, AuSe-BNPs present a monodisperse quasi-spherical structure with a particle size distribution of 5±0.5nm. Elemental energy spectrum scanning shows ( Figure 2 DF), Au and Se elements form composite nanoaggregates in the form of nanoclusters or are distributed in the sol in the form of single particles. SEM results show that the original CFME surface is smooth and flat ( Figure 2 G), with slight traces of flame burning. After electrochemical deposition, AuSe-BNPs formed a three-dimensional nanocluster structure attached to the CFME interface ( Figure 2 HI), successfully constructed an AuSe-BNPs / CFME composite electrode. This composite polymer provides a rich density of active sites, thereby accelerating the redox kinetics of the target compound.

[0040] Example 2:

[0041] To evaluate the electrochemical performance of AuSe-BNPs / CFME, electrochemical tests were performed on CFME, AuNPs / CFME, SeNPs / CFME, and the AuSe-BNPs / CFME electrodes prepared in Example 1 using a CHI660D electrochemical workstation. After each test cycle, the electrode samples were rinsed with deionized water and ethanol to remove residual CA and DHT I. All experiments were performed at room temperature (25 ± 1°C).

[0042] 1. Preparation of standard solution

[0043] CA standard solution: Accurately weigh 0.0018 g of CA standard (purity ≥ 98%) and dissolve it in 10 mL of anhydrous ethanol. Ultrasonic dispersion is performed for 30 min (power 100 W) to fully dissolve and remove dissolved oxygen. The solution is transferred to a 10 mL brown volumetric flask and the volume is adjusted to obtain 1.0 × 10 -3 mol / L CA stock solution was stored in aliquots at 4°C in the dark.

[0044] DHT I standard solution: accurately weigh 0.0028 g of DHT I standard (purity ≥ 98%), dissolve in 10 mL of anhydrous ethanol, and sonicate for 20 min (power 80 W). Dilute the solution to a 10 mL brown volumetric flask to obtain 1.0 × 10 -3 mol / L DHT I stock solution was divided into aliquots and stored at 4℃ in the dark for future use.

[0045] Mixed standard solution of CA and DHT I: Before use, take the CA and DHT I stock solutions and dilute them with PBS to mixed working solutions of different concentrations. Prepare and use them immediately to avoid oxidative degradation.

[0046] 2. Differential Pulse Voltammetry (DPV)

[0047] DPV is a highly sensitive electrochemical detection method that determines the electrochemical properties of the substance being measured by recording the change in response current at the working electrode as the voltage changes. This method combines pulse timing technology with controlled potential methods to effectively reduce background current and improve detection sensitivity.

[0048] In order to evaluate the electrochemical performance of AuSe-BNPs / CFME, DPV was used to characterize different electrodes. The parameters of the DPV test were set as follows: initial potential -0.7 V, end potential 0.5 V, pulse amplitude 50 mV, pulse width 100 ms, and rest time 2 s.

[0049] like Figure 3 As shown in A, different electrodes contain 1.0×10 -5 mol / L CA and 1.0×10 -6 Electrochemical determination was carried out in PBS buffer containing 0.1 mol / L DHT I. The results showed that the bare CFME electrode showed two weak signal peaks in the solution containing CA and DHT I. After modification with AuNPs and SeNPs, the electrochemical response was significantly enhanced. Compared with the above electrodes, the detection of the AuSe-BNPs / CFME electrode reached the maximum response, among which the oxidation peak current of CA was about 3.3 times that of the bare CFME, and the oxidation peak current of DHT I was about 2.8 times that of the bare CFME. There was no obvious shift in the peak position before and after modification, indicating that the AuSe-BNPs / CFME electrode can qualitatively detect these two targets. The DPV test results show that the AuSe-BNPs / CFME electrode has extremely high sensitivity in detecting CA and DHT I, providing a good electrochemical basis for the simultaneous quantitative detection of these two compounds.

[0050] 3. Electrochemical impedance spectroscopy (EIS) test

[0051] EIS is a nondestructive testing technique widely used in electrochemistry, enabling precise characterization of electrochemical processes and kinetic behavior at material interfaces. Four electrodes were subjected to EIS testing using this method over a frequency range of 0.01 Hz to 10,000 Hz. The test solution was a 10 mmol / L K₃[Fe(CN)₆] / K₄[Fe(CN)₆] solution containing 0.1 mol / L KCl.

[0052] Figure 3 B shows the EIS curves of CFME, AuNPs / CFME, SeNPs / CFME and AuSe-BNPs / CFME. As can be seen from the Nyquist Diagram, the EIS curve of the bare CFME electrode shows a larger semicircle, indicating that its charge transfer resistance (Rct) is higher and the charge transfer process is relatively slow. After modification with AuNPs and SeNPs, the Rct of the electrode is significantly reduced, indicating that the modified electrode has a weakened inhibitory effect on the charge transfer process. The EIS curve of AuSe-BNPs / CFME shows a smaller semicircle, indicating that its Rct value is the smallest. This shows that the modification of AuSe-BNPs significantly improves the electron transfer efficiency of the electrode, promotes the transfer of electrons at the electrode / solution interface, and thus increases [Fe(CN)6] 3- / 4- The electron transfer rate of the redox system. Furthermore, by analyzing the high-frequency semicircle and low-frequency linear portion of the EIS curve, we can further understand the electrochemical behavior of the electrode surface. The high-frequency semicircle corresponds to the charge transfer process, while the low-frequency linear portion is related to the diffusion-controlled process. The AuSe-BNPs / CFME electrode has a smaller semicircle in the high-frequency region, indicating a more efficient charge transfer process, while the low-frequency linear portion indicates that the diffusion process has less influence on the electrode performance.

[0053] Example 3:

[0054] In order to optimize the electrochemical performance of AuSe-BNPs / CFME, this example uses a constant potential deposition method to systematically investigate the effect of the electrodeposition time of AuSe-BNPs modified CFME on the electrode performance.

[0055] By immersing CFME in AuSe-BNPs sol, experiments were conducted with deposition times ranging from 5 min to 40 min to evaluate the effect of different deposition times on the electrode response. Figure 3 C shows that when the deposition time is 30 min, the electrode pair 1.0×10 -5 mol / L CA and 1.0×10 -6The DPV response of mol / L DHT I reached a peak, the oxidation peak current of CA reached a maximum of 13.97nA, and the oxidation peak current of DHT I also showed a significant enhancement. When the deposition time was extended to 40min, the oxidation peak current of CA decreased to 13.3nA, and the oxidation peak current of DHT I showed a greater downward trend. This phenomenon indicates that a deposition time of 30min is sufficient for AuSe-BNPs to form an efficient nanostructure on the CFME surface, promoting rapid electron transfer and efficient conversion of reactants. However, after more than 30min, the excessively thick nanoparticle layer may hinder the further transfer of electrons, resulting in a decrease in current response. Therefore, the electrodes in this experiment were used after 30min of deposition.

[0056] Example 4:

[0057] In this example, cyclic voltammetry (CV) was used to investigate the effect of scan rate on the redox peak current. The CV test had a scan range of -0.5V to 0.7V, a scan rate of 50-500mV / s, and a sampling interval of 0.01V.

[0058] like Figure 3 As shown in Figure D, with the increase of scan rate, the redox peak currents of CA and DHT I increased significantly. In the scan rate range of 50-500 mV / s, the oxidation peak currents of CA and DHT I showed a good linear relationship with the scan rate ( Figure 3 E). The linear regression equations are as follows.

[0059] DHT I:I pc1 (nA)=0.4633v+25.617,R 2 =0.993;I pa1 (nA)=-0.4221v-

[0060] 21.676, R 2 =0.992;

[0061] CA:I pc2 (nA)=0.0795v+5.8312,R 2 =0.993;I pa2 (nA) = -0.2257v-12.479,

[0062] R 2 =0.996.

[0063] The above results show that the electrode reaction of CA and DHT I on AuSe-BNPs / CFME is a typical adsorption-controlled process, which ensures the reversibility and stability of the electrode reaction. In addition, the logarithm of the scan rate (lgv) is closely related to the oxidation peak potential (E pa) and reduction peak potential (E pc ) also shows a good linear relationship ( Figure 3 F). The regression equations are:

[0064] DHT I:E pa1 =-0.0633lgv-0.0161, R 2 =0.993; E pc1 =0.0777lgv-0.2139,

[0065] R 2 =0.995;

[0066] CA:E pa2 =0.0277lgv+0.2214, R 2 =0.992; E pc2 =0.0649lgv+0.2185,

[0067] R 2 =0.998.

[0068] According to Laviron's equation, the electron transfer coefficient α and the electron transfer number n can be calculated by analyzing the relationship between the anode and cathode peak potentials and the scan rate in the electrochemical reaction. The specific formula is as follows:

[0069] E pc =E θ’ -2.3RT / (αnF)lgv, (1)

[0070] E pa =E θ’ -2.3RT / (1-αnF)lgv, (2)

[0071] Among them, E θ′ is the equilibrium electrode potential, R is the gas constant (8.314 J / mol·K), T is the temperature (298 K), F is the Faraday constant (96485 C / mol), and v is the scan rate. Fitting the above formula to experimental data yielded electron transfer coefficients α of 0.45 and 0.30 for CA and DHT I, respectively. The electron transfer number n is approximately 2 for both, indicating that the redox reaction in the detection process involves the transfer of two electrons and two protons.

[0072] In this example, 0.1 mol / L PBS was selected as the supporting electrolyte, and the effect of different pH values on the electrochemical behavior of the modified electrode in detecting CA and DHT I was investigated in the pH range of 2.0 to 4.0. Figure 3 As shown in G and I, AuSe-BNPs / CFME contains 1.0×10 -5 mol / L CA and 1.0×10-6 The DPV curves of 1 mol / LDHT I in different pH solutions show that the oxidation peak currents of both increase first and then decrease with the change of pH, reaching the maximum value at pH 3.0. Figure 5-4 It can be seen that the oxidation peak potential Epa of CA and DHT I shifts negatively with the increase of pH, showing a good linear relationship. The specific linear regression equations are:

[0073] CA:E pa (V)=-0.0761pH+0.503,R 2 =0.999;

[0074] DHT I:E pa (V) = -0.0757pH + 0.1018, R 2 =0.999.

[0075] These slope values are close to the theoretical value calculated by the Nernst equation (-59 mV / pH), indicating that the number of protons and electrons involved in the electrode reaction of CA and DHT I is equal, and the redox reaction of the two on the modified electrode is reversible. Based on the above results, it can be inferred that the reaction process of CA and DHT I is as follows Figure 4 shown.

[0076] Example 5:

[0077] This example uses DPV to explore the concentration detection of CA and DHT I. First, the concentration of one component is fixed and only the concentration of the other component is changed to achieve selective determination of DHT I and CA. Figure 5 As shown in AB, in the -5 The oxidation peak currents of CA and DHT I were detected in a mixture of 1.0×10 mol / L CA and different concentrations of DHT I. As the concentration of DHT I increased, its oxidation peak current increased significantly, while the peak current of CA remained basically unchanged. This indicates that the detection of DHT I in this system has high selectivity. -7 ~1.0×10 -6 mol / L concentration range, the oxidation peak current of DHT I shows a good linear relationship with its concentration, and the linear equation is I p1 (nA)=112.59c(μmol / L)+13.034, R 2 =0.991( Figure 5 C), the detection limit (LOD) was 0.0039 μmol / L (S / N=3). -6 mol / L DHT I and different concentrations of CA, such as Figure 5DE showed that the oxidation peak current of CA increased with the increase of its concentration, while the peak current of DHT I remained basically unchanged. -6 ~1.0×10 -5 mol / L concentration range, the oxidation peak current of CA is linearly related to its concentration, and the linear equation is I p2 (nA)=0.5179c(μmol / L)+14.395, R 2 =0.994( Figure 5 F), LOD was 0.33 μmol / L (S / N=3). In addition, the AuSe BNPs / CFME electrode also showed excellent performance in the simultaneous detection of these two substances. Figure 5 It can be seen from GH that with the continuous increase of CA and DHT I concentrations, the oxidation peak currents of the two are also increasing, and the oxidation peak current response is linearly related to their respective concentrations within a certain range. The equations are: CA:I p1 (nA)=1.2807c(μmol / L)+21.342, R 2 =0.993; DHT I:I p1 (nA)=140.05c(μmol / L)+29.662, R 2 =0.986( Figure 5 The AuSe-BNPs / CFME modified electrode exhibited excellent performance in the simultaneous detection of these two substances. Its wide linear range and low detection limit enabled highly sensitive and selective detection in complex samples, providing strong support for practical applications.

[0078] Example 6:

[0079] In order to evaluate the repeatability and stability of AuSe-BNPs / CFME in actual detection, this example used a concentration of 1×10 -5 mol / L CA and 1×10 -6 mol / L DHT I solution, the results are as follows Figure 6As shown. AuSe-BNPs / CFME was measured in a mixed solution for 10 consecutive times. The results showed that the current values of CA and DHT I did not change much, and their relative standard deviations (RSD) were 2.50% and 1.31%, respectively, indicating that the modified electrode had good reproducibility. Under the same experimental conditions, the response of the same electrode to CA and DHT I for 10 consecutive days was investigated. Compared with the first day, the oxidation peak currents of the modified electrode for detecting CA and DHTI decreased by 7.09% and 2.92% on the 10th day, respectively, and the oxidation peak potential did not change, indicating that the modified electrode had good stability. DPV was used to investigate the effects of common interfering substances on the detection of CA and DHT I. When the concentrations of CA and DHT I were 1×10 -5 mol / L and 1×10 -6 mol / L, 100 times the Na + , K + , Ca 2+ 、Zn 2+ , glucose (Glu), notoginsenoside R1 (NG-R1), ginsenoside Rg1 (G-Rg1), and ginsenoside Re (G-Re) had no significant effect on the detection of CA and DHT I, and the relative deviations of the currents were all within 3.43%. This indicates that the prepared AuSe-BNPs / CFME has good selectivity for the detection of CA and DHT I, and exhibits excellent stability, reproducibility, and anti-interference ability.

[0080] Example 7:

[0081] In order to verify the accuracy and application ability of AuSe-BNPs / CFME in the determination of actual samples, this example uses the standard addition method to detect CA and DHT I in human serum and calculate the recovery rate. The experimental results are listed in Table 1. AuSe-BNPs / CFME was selected as the working electrode, and 10 μL of human serum was added to 10 mL of phosphate buffer solution, followed by the addition of standard solutions of CA and DHT I, and the current response was recorded. The experiment was repeated three times, and the spiked recovery rate of the detection results was between 99.1% and 104.3%, with RSD≤1.39% (n=3). The experimental results show that the AuSe-BNPs / CFME biosensor constructed based on Au-Se bimetallic composite nanoparticles modified CFME can achieve simultaneous and accurate detection of CA and DHT I under complex matrix interference conditions, showing high accuracy and reliability, and verifying its application potential in actual sample detection.

[0082] Table 1 Determination of CA and DHT I in human serum samples

[0083]

[0084] In summary, this study innovatively developed an AuSe-BNPs-functionalized AuSe-BNPs / CFME-modified electrode and systematically investigated its electrochemical sensing properties for CA and DHT I. Electrochemical characterization results revealed that the nanocomposite modified electrode exhibited significantly enhanced synergistic electrocatalytic effects for CA and DHT I in a phosphate buffer system at pH 3.0, successfully enabling the simultaneous detection of both bioactive molecules. Quantitative analysis demonstrated good linearity for CA and DHT I over the concentration ranges of 1.0–10.0 μmol / L and 0.1–1.0 μmol / L, with LODs of 0.88 μmol / L for CA and 0.0055 μmol / L for DHT I, respectively. Electrode performance evaluation demonstrated excellent stability (current response retention greater than 95% after 10 consecutive scans) and reproducibility (RSD <10%). In serum sample testing, spike recovery rates remained between 99.1% and 104.3% (RSD ≤ 1.39%), validating the accuracy and reliability of the method. This study not only reveals the electrocatalytic mechanism of AuSe-BNPs but also provides new insights into the development of highly sensitive and selective dual-component biosensors, demonstrating significant application value in areas such as disease marker detection and drug metabolism analysis.

[0085] The above examples are merely illustrative of the present invention and do not limit the scope of protection of the present invention. Any design that is identical or similar to the present invention falls within the scope of protection of the present invention.

Claims

1. A sensor for simultaneous detection of caffeic acid and dihydrotanshinone I, characterized by: The sensor uses the AuSe-BNPs / CFME electrode formed by modifying the carbon fiber electrode with gold-selenium composite nanoparticles by electrodeposition as the working electrode.

2. A method for preparing a sensor for simultaneous detection of caffeic acid and dihydrotanshinone I, characterized in that: The following steps are involved: The CFME was immersed in the AuSe-BNPs solution for electrodeposition to prepare the AuSe-BNPs / CFME electrode.

3. The method for preparing a sensor for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 2, characterized in that: Electrodeposition was carried out at +1.5 V using a constant potential method.

4. The method for preparing a sensor for simultaneously detecting caffeic acid and dihydrotanshinone I according to claim 2, wherein: The AuSe-BNPs solution preparation step includes: preparing a selenious acid solution, then adding a chloroauric acid solution and a trisodium citrate solution, mixing thoroughly, and continuously stirring to react to obtain the AuSe-BNPs solution.

5. The method for preparing a sensor for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 2, wherein: The CFME deposition time in the AuSe-BNPs solution is 5-40 minutes.

6. A method for simultaneous detection of caffeic acid and dihydrotanshinone I, characterized in that: The AuSe-BNPs / CFME electrode formed by modifying the carbon fiber electrode by electrodeposition of gold-selenium composite nanoparticles was used as the working electrode, and the Ag / AgCl electrode was used as the reference electrode. The electrodes were placed in a solution containing a supporting electrolyte and the sample to be tested, and the sample was detected using electrochemical scanning technology.

7. The method for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 6, characterized in that: The electrochemical scanning technique includes cyclic voltammetry and differential pulse voltammetry.

8. The method for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 6, wherein: The scanning range of the cyclic voltammetry test is -0.5V to 0.7V, the scanning rate is 50-500mV / s, and the sampling interval is 0.01V.

9. The method for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 6, characterized in that: The differential pulse voltammetry parameters were set as follows: initial potential -0.7 V, end potential 0.5 V, pulse amplitude 50 mV, pulse width 100 ms, and rest time 2 s.

10. The method for simultaneous detection of caffeic acid and dihydrotanshinone I according to claim 6, characterized in that: The supporting electrolyte solution is PBS with a pH of 2.0-4.0.

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