An online floating ground electrochemical scanning electrospray mass spectrometry device

Abstract

This application discloses an online floating-ground electrochemical scanning electrospray mass spectrometry (FSMS) device, relating to the field of analytical chemistry, which can improve the efficiency and accuracy of electrochemical detection. The device includes: a reaction chamber with a three-electrode probe for holding the target solution to be detected; a floating-ground electrochemical controller, including: a high-voltage module, a power supply module, a floating-ground electrochemical measurement and control circuit, and the three-electrode probe; the high-voltage module raises the first potential of the floating terminal of the power supply module to a second potential; the power supply module converts the voltage of the floating battery into a preset voltage to power the floating-ground electrochemical measurement and control circuit; the floating-ground electrochemical measurement and control circuit controls the output of a continuous high-voltage signal or a continuous current signal from the three-electrode probe, which acts on the target solution to generate an electrochemical reaction and directly produce spray ions; the voltage and current during the electrochemical reaction of the target solution are detected using the three-electrode probe to obtain the detection voltage and detection current.

Description

Technical Field

[0001] This application relates to the field of analytical chemistry technology, and in particular to an online floating-ground electrochemical scanning electrospray mass spectrometry device. Background Technology

[0002] In chemical detection and analysis, electrochemistry, with its advantages of speed, sensitivity, and quantification, can effectively distinguish substances with significant differences in electroactivity. However, electrochemistry itself lacks structural analysis capabilities, while mass spectrometry (MS) excels in this area. Therefore, coupling electrochemistry with MS not only improves analytical efficiency and accuracy but also produces synergistic effects, enabling tasks that cannot be accomplished by a single technique. For example, electrochemistry can distinguish species with similar mass-to-charge ratios based on differences in electroactivity, while MS's structural analysis capabilities can reveal intermediates and products in electrochemical reactions. This combination provides significant assistance in studying electrochemical reaction mechanisms, further enhancing the application value of electrochemistry in analysis and synthesis. However, due to the significant differences in operating conditions between electrochemical and electrospray ionization (ESI) systems, effectively combining electrochemistry, ESI, and MS to construct an integrated co-operated device remains a critical issue that urgently needs to be addressed. Summary of the Invention

[0003] This application provides an online floating-ground electrochemical scanning electrospray mass spectrometry (FSMS) device, which can realize the combined use of electrochemistry, electrospray and mass spectrometry, and can improve the efficiency and accuracy of electrochemical detection.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] A first aspect of this application provides an online floating-ground electrochemical scanning electrospray mass spectrometry (FSMS) device, the device comprising:

[0006] A reaction chamber, in which a three-electrode probe is disposed, is used to hold the target solution to be detected, and the three-electrode probe is in contact with the target solution;

[0007] A floating electrochemical controller includes: a high-voltage module, a power supply module connected in series with the high-voltage module, and a floating electrochemical measurement and control circuit connected to the power supply module, wherein the floating electrochemical measurement and control circuit is connected to the three-electrode probe.

[0008] The high-voltage module is used to raise the first potential of the floating ground terminal of the power module to a second potential, the second potential being greater than 500V, so that the power module operates at the second potential.

[0009] The power module includes a floating battery and a voltage regulator circuit. The voltage regulator circuit is used to convert the voltage of the floating battery into a preset voltage to power the floating electrochemical measurement and control circuit.

[0010] The floating electrochemical measurement and control circuit is used to control the output of a continuous high-voltage signal or a continuous current signal in the three-electrode probe. The continuous high-voltage signal or continuous current signal acts on the target solution to generate an electrochemical reaction and directly generate spray ions. At the same time, the three-electrode probe is used to detect the voltage and current in the electrochemical reaction process of the target solution to obtain the detection voltage and detection current.

[0011] The output port of the reaction chamber is located near the input port of the mass spectrometer, which is used for the sprayed ions to enter the mass spectrometer.

[0012] As one possible implementation, the floating electrochemical measurement and control circuit includes: a main control chip, a voltage and current generator, a voltage detection module, a current detection module, and a synchronous triggering module. The main control chip is connected to the host computer via wireless communication.

[0013] The host computer is used to input electrochemical parameters into the main control chip and to receive, process, and display the electrochemical detection results obtained by the main control chip.

[0014] The main control chip is used to generate corresponding digital signals according to the electrochemical parameters and transmit the digital signals to the voltage and current generator;

[0015] The voltage and current generator is used to generate a corresponding continuous high voltage signal or continuous current signal according to the digital signal, and output the continuous high voltage signal or continuous current signal from the three-electrode probe;

[0016] The synchronous triggering module is connected to the main control chip, the voltage and current generator, and the mass spectrometer, respectively.

[0017] The main control chip is also used to control the synchronization trigger module to generate a synchronization signal before controlling the output of the continuous high voltage signal or the continuous current signal from the three-electrode probe;

[0018] The synchronization trigger module is used to send the synchronization signal to the voltage and current generator and the mass spectrometer, so that the voltage and current generator and the mass spectrometer start up after receiving the synchronization signal.

[0019] As one possible implementation, the three-electrode probe includes: a working electrode, a reference electrode, and a counter electrode, with the end of the working electrode close to the output port of the reaction chamber;

[0020] The voltage and current generator is connected to the working electrode, the voltage detection module is connected to the reference electrode and the working electrode, and the current detection module is connected to the counter electrode;

[0021] The voltage and current generator generates a continuous high-voltage signal or a continuous current signal, which is output from the working electrode. The voltage detection module is used to detect the comparison voltage signal of the working electrode relative to the reference electrode to obtain the detection voltage. The current detection module is used to collect the current signal generated by the counter electrode to obtain the detection current.

[0022] As one possible implementation, the voltage detection module includes a first analog-to-digital converter, and the current detection module includes a resistor and a second analog-to-digital converter;

[0023] The voltage detection module is specifically used to convert the comparison voltage signal into a first digital signal using the first analog-to-digital converter, and then transmit the first digital signal to the host computer through the main control chip to obtain the detection voltage.

[0024] The current detection module is specifically used to convert the current signal generated by the counter electrode into a voltage signal using the resistor, then convert the voltage signal into a second digital signal using the second analog-to-digital converter, and finally transmit the second digital signal to the host computer through the main control chip to obtain the detected current.

[0025] As one possible implementation, the high-voltage module includes a voltage regulation unit for adjusting the output voltage of the high-voltage module.

[0026] As one possible implementation, the power module includes a protection unit for preventing voltage breakdown of the power module by the high-voltage module.

[0027] As one possible implementation, the device further includes a first connecting component and a second connecting component;

[0028] The first connecting component is used to connect the reaction chamber and the mass spectrometer.

[0029] The second connecting component is used to connect the floating electrochemical controller and the reaction chamber.

[0030] As one possible implementation, the first connecting component includes a moving platform for adjusting the position of the reaction chamber along the input port direction of the mass spectrometer.

[0031] As one possible implementation, the reaction chamber is a nano-spray needle.

[0032] As one possible implementation, the host computer is also connected to the mass spectrometry device;

[0033] The host computer is also used to acquire the mass spectrometry detection results of the mass spectrometry device.

[0034] The beneficial effects of the technical solutions provided in this application include at least the following:

[0035] The online floating-ground electrochemical scanning electrospray mass spectrometry (FSMS) device provided in this application includes a reaction chamber containing a three-electrode probe. The reaction chamber holds the target solution to be detected, and the three-electrode probe is in contact with the target solution. A floating-ground electrochemical controller includes a high-voltage module, a power supply module connected in series with the high-voltage module, and a floating-ground electrochemical measurement and control circuit connected to the power supply module. The floating-ground electrochemical measurement and control circuit is connected to the three-electrode probe. The high-voltage module is used to raise the first potential of the floating terminal of the power supply module to a second potential, where the second potential is greater than 500V, so that the power supply module operates at a second voltage. The power module includes a floating battery and a voltage regulator circuit. The voltage regulator circuit converts the voltage of the floating battery into a preset voltage to power the floating electrochemical measurement and control circuit. The floating electrochemical measurement and control circuit controls the output of a continuous high-voltage signal or a continuous current signal from the three-electrode probe. The continuous high-voltage signal or continuous current signal acts on the target solution to generate an electrochemical reaction and directly generate spray ions. Simultaneously, the three-electrode probe is used to detect the voltage and current during the electrochemical reaction process of the target solution to obtain the detection voltage and detection current. The output port of the reaction chamber is close to the input port of the mass spectrometer for the spray ions to enter the mass spectrometer. The online floating electrochemical scanning electrospray mass spectrometry device provided in this application embodiment can realize online coupled detection of electrochemistry and mass spectrometry, and can simultaneously realize the detection of electrochemistry and mass spectrometry, which can improve the detection efficiency. In addition, a three-electrode system is introduced to continuously and accurately control the electrode potential during the electrochemical reaction process, and combined with mass spectrometry analysis, reactive intermediates in the process are captured and their structures are identified and analyzed. Furthermore, the power module uses a battery and is connected to a high-voltage module, which raises the first potential of the floating ground terminal of the power module to a high potential, thereby improving the portability of the online floating ground electrochemical scanning electrospray mass spectrometry device. Attached Figure Description

[0036] Figure 1 A schematic diagram of an online floating-ground electrochemical scanning electrospray mass spectrometry device provided in this application embodiment. Figure 1 ;

[0037] Figure 2 The structure of an online floating ground electrochemical scanning electrospray mass spectrometry device provided in this application embodiment Figure 2 ;

[0038] Figure 3Cyclic voltammetry curves of the device provided in this application embodiment and a commercial electrochemical workstation using a large electrode;

[0039] Figure 4 Cyclic voltammetry curves of the device provided in this application embodiment and commercial electrochemical workstations using microelectrodes in nanospray needles;

[0040] Figure 5 The reaction formula for the electro-oxidation of dopamine to produce dopaquinone provided in the embodiments of this application;

[0041] Figure 6 Electrochemical linear voltammetric scan curve of dopamine solution provided in the embodiments of this application Figure 1 ;

[0042] Figure 7 Electrochemical linear voltammetric scan curve of dopamine solution provided in the embodiments of this application Figure 2 ;

[0043] Figure 8 Mass voltammetry curves of dopamine and its oxidation product, dopamine o-quinone, provided in the embodiments of this application;

[0044] Figure 9 Mass spectrometry of the dopamine electrochemical reaction process provided in the embodiments of this application Figure 1 ;

[0045] Figure 10 Mass spectrometry of the dopamine electrochemical reaction process provided in the embodiments of this application Figure 2 .

[0046] Figure label:

[0047] 1-Reaction chamber, 2-Floating electrochemical controller, 3-Three-electrode probe, 4-First connecting component, 5-Mass spectrometer, 6-Second connecting component, 7-Host computer, 21-Main control chip, 22-Voltage detection module, 23-Synchronous triggering module, 24-Current detection module, 25-Voltage and current generator, 26-High voltage module, 27-Power supply module, 31-Reference electrode, 32-Working electrode, 33-Counter electrode; 271-Voltage regulator circuit, 272-Floating battery. Detailed Implementation

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0049] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0050] In addition, the use of “based on” or “according to” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” or “according to” one or more conditions or values ​​can in practice be based on additional conditions or values ​​beyond those conditions.

[0051] For decades, organic electrosynthesis has been widely used as a sustainable and green synthetic method, with outstanding advantages not only in sustainability and atom economy, but also in the possibility of preparing unique reaction intermediates in a controlled and predictable manner. As with any chemical reaction, mechanistic research is crucial. Current methods for studying reaction mechanisms mainly include electrochemical methods, spectroscopic methods, chromatographic techniques, and computational methods.

[0052] Cyclic voltammetry (CV) is one of the most widely used electrochemical methods, providing rich information for a given electrochemical process. While CV can determine the potential required to drive an electrochemical reaction and the appropriate potential window, offering advantages such as high sensitivity and convenience, relying solely on electrical signals to study complex redox reaction mechanisms remains a significant challenge. Mass spectrometry (MS), on the other hand, is a high-precision and high-accuracy analytical technique that directly obtains the mass-to-charge ratio (m / z) of the analyte. Furthermore, multistage tandem mass spectrometry can obtain characteristic fragments of relevant substances, enabling rapid identification of structural features. Therefore, MS, as a highly sensitive analytical tool, can provide structural information for electrochemical reaction products or intermediates. Consequently, the combined use of electrochemistry (EC) and mass spectrometry (MS) has become a powerful tool for studying electrochemical reaction processes.

[0053] In recent years, in some studies that utilize the electrochemical properties of electrospray ionization (ESI) or nano-electrospray ionization (nESI) sources for EC-MS coupling, the electrochemical reaction process and the electrospray process are often intertwined. However, since ESI sources usually operate at very high voltages (2-4 kV), the EC-MS system must float under the high voltage of ESI or be decoupled from the high voltage of ESI in some way. At the same time, the control of potential during the electrochemical reaction process is also very important, as it relates to whether the reaction can occur and the distribution of products or intermediates.

[0054] Electrochemical systems and electrospray systems differ greatly in their operating conditions and have poor compatibility in their circuit configurations. In order to eliminate their mutual interference and enable them to operate normally at the same time, so that EC-MS can continuously and accurately control the electrode potential of the reaction based on ESI.

[0055] Therefore, we propose an online floating electrochemical scanning electrospray mass spectrometry (ESP) device. By introducing a three-electrode system into a floating electrochemical scanning device, we can continuously and precisely control the electrode potential during the electrochemical (EC) reaction process, and combine mass spectrometry analysis to capture and structurally identify reactive intermediates in the process.

[0056] like Figure 1 As shown, this is an online floating-ground electrochemical scanning electrospray mass spectrometry device provided in an embodiment of this application. The device includes:

[0057] The reaction chamber 1 is equipped with a three-electrode probe 3. The reaction chamber 1 is used to hold the target solution to be detected, and the three-electrode probe 3 is in contact with the target solution.

[0058] A floating electrochemical controller 2 includes: a high-voltage module 26, a power supply module 27 connected in series with the high-voltage module 26, and a floating electrochemical measurement and control circuit connected to the power supply module 27. The floating electrochemical measurement and control circuit is connected to the three-electrode probe 3.

[0059] The high voltage module 26 is used to raise the first potential of the floating ground terminal of the power module 27 to a second potential, the second potential being greater than 500V, so that the power module 27 operates at the second potential;

[0060] The power module 27 includes a floating battery 272 and a voltage regulator circuit 271. The voltage regulator circuit 271 is used to convert the voltage of the floating battery 272 into a preset voltage to power the floating electrochemical measurement and control circuit.

[0061] The floating electrochemical measurement and control circuit is used to control the output of a continuous high-voltage signal or a continuous current signal in the three-electrode probe 3. The continuous high-voltage signal or continuous current signal acts on the target solution to generate an electrochemical reaction and directly generate spray ions. At the same time, the three-electrode probe 3 is used to detect the voltage and current in the electrochemical reaction process of the target solution to obtain the detection voltage and detection current.

[0062] The output port of the reaction chamber 1 is close to the input port of the mass spectrometer 5, which is used for the sprayed ions to enter the mass spectrometer 5.

[0063] Optionally, the reaction chamber 1 can be an electrolytic cell or a nano-spray needle, which can be made of high borosilicate glass tube. The three-electrode probe 3 is designed including a working electrode 32, a reference electrode 31, and a counter electrode 33. The substance generated by the working electrode 32 is ionized under high voltage and transported into the mass spectrometer. The reaction chamber 1 and the three electrodes can form an electrolytic cell for the electrochemical reaction.

[0064] In the three-electrode configuration, the working electrode 32 and counter electrode 33 are Pt wires, and the reference electrode 31 is an Ag / AgCl wire. The working electrode 32 (WE) is placed very close to the exit of the nESI nozzle to ensure rapid transfer of the electrode reaction products to the mass spectrometer. Notably, to prevent short circuits, both electrodes are pre-inserted into molten quartz capillaries.

[0065] It is understood that the online floating ground electrochemical scanning electrospray mass spectrometry device in the embodiments of this application can be combined not only with an electrospray ionization source, but also with other ion sources based on the principle of electrospray ionization, such as paper spray, desorption electrospray and droplet electrospray ionization sources. The basic connection method remains unchanged, only the electrolytic cell needs to be replaced from the nanospray needle with the corresponding paper, beaker and glass plate.

[0066] By connecting the floating ground terminal of the battery in the power module 27 of the floating electrochemical controller 2 to the high-voltage module 26, the three-electrode output voltage is made high, meaning the voltage and current between the three electrodes are low, which can control the generation of electrochemical reactions. However, since all three electrodes float above the high voltage, electrospray can be generated. The floating electrochemical controller 2 can realize voltage and current scanning functions under high voltage. By connecting the output and input terminals of the floating electrochemical controller 2 to the three-electrode probe 3, voltage and current detection can be realized.

[0067] Optionally, the floating electrochemical measurement and control circuit includes: a main control chip 21, a voltage and current generator 25, a voltage detection module 22, a current detection module 24, and a synchronous triggering module 23. The main control chip 21 is wirelessly connected to the host computer 7.

[0068] The host computer 7 is used to input electrochemical parameters into the main control chip 21 and to receive, process, and display the electrochemical detection results obtained by the main control chip.

[0069] The main control chip 21 is used to generate corresponding digital signals according to the electrochemical parameters and transmit the digital signals to the voltage and current generator 25;

[0070] The voltage and current generator 25 is used to generate a corresponding continuous high voltage signal or continuous current signal according to the digital signal, and output the continuous high voltage signal or continuous current signal from the three-electrode probe 3.

[0071] The synchronous triggering module 23 is connected to the main control chip 21, the voltage and current generator 25 and the mass spectrometer 5 respectively.

[0072] The main control chip 21 is also used to control the synchronous triggering module 23 to generate a synchronization signal before controlling the output of the continuous high voltage signal or the continuous current signal from the three-electrode probe 3;

[0073] The synchronization trigger module 23 is used to send the synchronization signal to the voltage and current generator 25 and the mass spectrometer 5, so that the voltage and current generator 25 and the mass spectrometer 5 start up after receiving the synchronization signal.

[0074] By using the comparison voltage signal and detection current signal obtained in real time, the potential change during the electrochemical reaction process of the target solution can be generated, and the electrochemical reaction process can be analyzed based on this potential change.

[0075] By using the comparison voltage signal and detection current signal obtained in real time, the potential change during the electrochemical reaction process of the target solution can be generated, and the electrochemical reaction process can be analyzed based on this potential change.

[0076] Specifically, the voltage detection module 22 includes a first analog-to-digital converter, and the current detection module 24 includes a resistor and a second analog-to-digital converter;

[0077] The voltage detection module 22 is specifically used to convert the comparison voltage signal into a first digital signal using the first analog-to-digital converter, and then transmit the first digital signal to the host computer 7 through the main control chip 21 to obtain the detection voltage.

[0078] The current detection module 24 is specifically used to convert the current signal generated by the counter electrode 33 into a voltage signal using the resistor, then convert the voltage signal into a second digital signal using the second analog-to-digital converter, and finally transmit the second digital signal to the host computer 7 through the main control chip 21 to obtain the detected current.

[0079] The specifications and parameters of the floating electrochemical controller 2 are shown in Table 1. Furthermore, the software control functions of the floating electrochemical controller 2 include: wireless communication with the control hardware circuit, electrochemical reaction parameter setting, mass spectrometry synchronous triggering, and electrochemical information acquisition and data processing.

[0080] Table 1. Specifications and parameters for the fabrication of a floating electrochemical controller

[0081]

[0082] Optionally, the high-voltage module 26 includes a voltage regulation unit for adjusting the output voltage of the high-voltage module 26.

[0083] Optionally, the power module 27 includes a protection unit for preventing the voltage of the high-voltage module 26 from damaging the power module 27.

[0084] Optionally, the device further includes a first connecting component 4 and a second connecting component 6; the first connecting component 4 is used to connect the reaction chamber 1 and the mass spectrometer 5; the second connecting component 6 is used to connect the floating electrochemical controller 2 and the reaction chamber 1.

[0085] The first connecting component 4 can be a fixing frame, used to fix the online floating electrochemical scanning electrospray mass spectrometry device provided in this application embodiment at the input port of the mass spectrometer, and can adjust the position of the floating electrochemical controller 2 in the Z-axis direction.

[0086] Optionally, the first connecting component 4 includes a moving platform, which is used to adjust the position of the reaction chamber 1 along the input port direction of the mass spectrometer 5.

[0087] The second connecting component 6 includes a slide plate and a three-dimensional moving platform. The slide plate includes a slide. The slide plate is located above the first connecting component 4 and can initially adjust the x-axis position of the nano-spray needle. The slide inside the slide plate can initially adjust the y-axis position of the nano-spray needle. Fine control of the nano-spray needle in three directions is achieved through the three-dimensional moving platform, thereby aligning the nano-spray needle outlet with the mass spectrometer inlet and enabling real-time detection of electrode reaction products.

[0088] Optionally, the host computer 7 is also connected to the mass spectrometry device 5; the host computer 7 is also used to acquire the mass spectrometry detection results of the mass spectrometry device 5.

[0089] This application provides an online floating electrochemical scanning electrospray mass spectrometry device that allows the electrolytic cell to float on the ground, enabling uninterrupted electrochemical processes in a three-electrode system while simultaneously ionizing substances. This allows for continuous and precise control of the electrode potential during the electrochemical reaction and monitoring of changes in material information during the electrochemical reaction using mass spectrometry.

[0090] This online floating-ground electrochemical scanning electrospray mass spectrometry (ESPMS) device includes a three-electrode output floating-ground electrochemical controller 2 for continuous three-electrode electrochemical measurement under high voltage; a three-electrode probe 3 for combining electrochemistry with mass spectrometry ionization, transferring substances generated on the working electrode 32 to the mass spectrometer via high-voltage ionization; and by controlling the movement of the three-electrode probe 3, aligning the high-voltage ionized substances from the working electrode 32 with the mass spectrometer inlet. Compared with previous electrochemical-mass spectrometry methods, the significant advantage of the online ESPMS device 5 is that it can achieve high-precision electrochemical control and electrochemical scanning under high voltage, while also providing excellent detection performance at nanoampere-level currents under microelectrodes, ensuring the versatility of redox reactions in different scenarios. Furthermore, the power module 27 uses a battery and is connected to the high-voltage module 26, raising the first potential of the floating-ground terminal of the power module 27 to a high potential, which improves the portability of the online floating-ground ESPMS device.

[0091] Based on the online floating ground electrochemical scanning electrospray mass spectrometry device (hereinafter referred to as "this device") provided in the embodiments of this application, this application conducts the following tests and verifications.

[0092] Example 1: This mainly verifies the differences between this device and commercial electrochemical workstations using traditional large electrodes for cyclic voltammetry testing.

[0093] Cyclic voltammetry of ferrocene was performed using a conventional large electrode (working electrode: platinum disk electrode Φ3mm, counter electrode: platinum sheet electrode 5*5*0.1mm, reference electrode: Φ0.1mm Ag / AgCl electrode wire). The electrochemical test results are as follows: Figure 3 As shown, according to Figure 3 It can be observed that the test results of this device on ferrocene are basically consistent with those of commercial electrochemical workstations.

[0094] Example 2: This example primarily verifies the differences between this device and commercial electrochemical workstations using microelectrodes for cyclic voltammetry testing in nanospray needles, and compares whether this device can perform electrochemical reactions under high voltage and whether high voltage affects the position of the electrochemical oxidation peak.

[0095] Electrochemical oxidation of ferrocene was tested using electrodes (working electrode: Φ0.2mm platinum wire, counter electrode: Φ0.2mm platinum wire, reference electrode: Φ0.1mm Ag / AgCl electrode wire) under a nanospray needle. The test results are as follows: Figure 4 As shown, the test results of this device on ferrocene are basically consistent with those of commercial electrochemical workstations. Furthermore, the use of smaller microelectrodes does not change the oxidation peak voltage of ferrocene, and the fluidity inside the nanospray nozzle under high voltage does not affect the oxidation peak potential of ferrocene.

[0096] Example 3: In positive ion mode, a voltage of 0.0 to 1.2 V was applied to monitor the oxidation of dopamine.

[0097] Example 3 mainly introduces the various electrochemical oxidation data of dopamine that can be observed when the applied voltage is 0.0 to 1.2V. Figure 5 The reaction formula for the electro-oxidation of dopamine to produce dopaquinone; such as Figure 6 This is the electrochemical linear voltammetric scan curve of a blank solution of dopamine. Figure 7 The electrochemical linear voltammetric scan curve of 1 mM dopamine (1 mM dopamine hydrochloride, 10 mM LiCl, MeCN / H2O = 1 / 1) is shown. Figure 6 and Figure 7 The scans were performed at a rate of 50 mV / s within the range of 0-1.2 V. The electrochemical linear voltammetric scan curves show that the electrochemical oxidation process of dopamine on the Pt disk electrode has a clear voltammetric response, with an initial oxidation potential of about 0.2 V and a peak potential of about 0.65 V.

[0098] Online EC-MS experiments were performed using this device under potential scanning, and mass voltammetric curves of dopamine and its oxidation product, dopamine-o-quinone, were plotted, as shown below. Figure 8 As shown, from Figure 8 It can be clearly seen that the initial oxidation potential of dopamine is approximately 0.2V. Furthermore, the strength of dopamine decreases with increasing potential, while the strength of dopamine-o-quinone increases with increasing potential. Figure 9 and Figure 10 High-resolution mass spectra at 0.1V and 0.8V are shown, revealing only the proton addition peak of dopamine ([M+H)) at the initial scan potential. + The intensity of the peak at m / z 154.0860 decreases with increasing potential, and the proton addition peak of dopamine-o-quinone ([M+H)) is observed. + The intensity of the ion (m / z 152.0710) begins to increase, and there is an ion with a relatively high intensity (m / z 137.0595) in the mass spectrum. This ion is a fragment ion generated when protonated dopamine loses a molecule of NH3 during ion transport.

[0099] Online scanning experiments on dopamine showed that the mass voltammogram can reflect the initial oxidation potential of the reactants, aiding in better monitoring the oxidation process. Furthermore, during this period, the electrochemical processes within the nESI source had virtually no impact on the electrochemical processes in the floating electrolyzer. Moreover, the dopamine intensity was not affected by the potential scan before the formation of dopamine-o-quinone, indicating that the electrochemical system also had minimal impact on the electrospray system.

[0100] The above examples fully demonstrate that the online floating electrochemical scanning electrospray mass spectrometry device provided in the embodiments of this application can monitor the electrochemical reaction process and capture and identify the active intermediates and products in the reaction process.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An online floating-ground electrochemical scanning electrospray mass spectrometry (FSMS) device, characterized in that, The device includes: A reaction chamber, in which a three-electrode probe is disposed, is used to hold the target solution to be detected, and the three-electrode probe is in contact with the target solution; A floating electrochemical controller includes: a high-voltage module, a power supply module connected in series with the high-voltage module, and a floating electrochemical measurement and control circuit connected to the power supply module, wherein the floating electrochemical measurement and control circuit is connected to the three-electrode probe. The high-voltage module is used to raise the first potential of the floating ground terminal of the power module to a second potential, the second potential being greater than 500V, so that the power module operates at the second potential. The power module includes a floating battery and a voltage regulator circuit. The voltage regulator circuit is used to convert the voltage of the floating battery into a preset voltage to power the floating electrochemical measurement and control circuit. The floating electrochemical measurement and control circuit is used to control the output of a continuous high-voltage signal or a continuous current signal in the three-electrode probe. The continuous high-voltage signal or continuous current signal acts on the target solution to generate an electrochemical reaction and directly generate spray ions. At the same time, the three-electrode probe is used to detect the voltage and current in the electrochemical reaction process of the target solution to obtain the detection voltage and detection current. The output port of the reaction chamber is located near the input port of the mass spectrometer, which is used for the sprayed ions to enter the mass spectrometer.

2. The apparatus according to claim 1, characterized in that, The floating electrochemical measurement and control circuit includes: a main control chip, a voltage and current generator, a voltage detection module, a current detection module, and a synchronous triggering module. The main control chip is wirelessly connected to the host computer. The host computer is used to input electrochemical parameters into the main control chip and to receive, process, and display the electrochemical detection results obtained by the main control chip. The main control chip is used to generate corresponding digital signals according to the electrochemical parameters and transmit the digital signals to the voltage and current generator; The voltage and current generator is used to generate a corresponding continuous high voltage signal or continuous current signal according to the digital signal, and output the continuous high voltage signal or continuous current signal from the three-electrode probe; The synchronous triggering module is connected to the main control chip, the voltage and current generator, and the mass spectrometer, respectively. The main control chip is also used to control the synchronization trigger module to generate a synchronization signal before controlling the output of the continuous high voltage signal or the continuous current signal from the three-electrode probe; The synchronization trigger module is used to send the synchronization signal to the voltage and current generator and the mass spectrometer, so that the voltage and current generator and the mass spectrometer start up after receiving the synchronization signal.

3. The apparatus according to claim 2, characterized in that, The three-electrode probe includes a working electrode, a reference electrode, and a counter electrode, with the end of the working electrode close to the output port of the reaction chamber; The voltage and current generator is connected to the working electrode, the voltage detection module is connected to the reference electrode and the working electrode, and the current detection module is connected to the counter electrode; The voltage and current generator generates a continuous high-voltage signal or a continuous current signal, which is output from the working electrode. The voltage detection module is used to detect the comparison voltage signal of the working electrode relative to the reference electrode to obtain the detection voltage. The current detection module is used to collect the current signal generated by the counter electrode to obtain the detection current.

4. The apparatus according to claim 3, characterized in that, The voltage detection module includes a first analog-to-digital converter, and the current detection module includes a resistor and a second analog-to-digital converter. The voltage detection module is specifically used to convert the comparison voltage signal into a first digital signal using the first analog-to-digital converter, and then transmit the first digital signal to the host computer through the main control chip to obtain the detection voltage. The current detection module is specifically used to convert the current signal generated by the counter electrode into a voltage signal using the resistor, then convert the voltage signal into a second digital signal using the second analog-to-digital converter, and finally transmit the second digital signal to the host computer through the main control chip to obtain the detected current.

5. The apparatus according to claim 1, characterized in that, The high-voltage module includes a voltage regulation unit for adjusting the output voltage of the high-voltage module.

6. The apparatus according to claim 1, characterized in that, The power module includes a protection unit for preventing voltage breakdown of the power module by the high-voltage module.

7. The apparatus according to claim 1, characterized in that, The device further includes a first connecting component and a second connecting component; The first connecting component is used to connect the reaction chamber and the mass spectrometer. The second connecting component is used to connect the floating electrochemical controller and the reaction chamber.

8. The apparatus according to claim 7, characterized in that, The first connecting component includes a moving platform, which is used to adjust the position of the reaction chamber along the input port direction of the mass spectrometer.

9. The apparatus according to claim 1, characterized in that, The reaction chamber is a nano-spray nozzle.

10. The apparatus according to claim 2, characterized in that, The host computer is also connected to the mass spectrometer; The host computer is also used to acquire the mass spectrometry detection results of the mass spectrometry device.

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