Method for improving heavy metal ion detection performance through vibration and detection system

Abstract

The invention relates to the field of heavy metal electrochemical detection, in particular to a scheme for simplifying the structure of a heavy metal electrochemical testing instrument. The enrichment of heavy metal ions to be detected on the surface of the screen-printed electrode is promoted by regulating and controlling the vibration of the interface part of the heavy metal detector and the screen-printed electrode. According to the scheme, the detection effects of the heavy metal detector under the vibration condition and the vibration-free condition are compared, it is found that the promotion effect similar to that of an external stirring device can be achieved by adjusting and controlling vibration of the detection port of the heavy metal detector, the actual requirement is met, the structure of a test instrument is simplified, the instrument cost is effectively reduced, and operation is more concise.

Description

Technical Field

[0001] This invention relates to the field of electrochemical detection of heavy metals, specifically a method and detection system for improving the detection performance of heavy metal ions by replacing traditional stirring with vibration. Background Technology

[0002] Electrochemical methods hold great promise for the qualitative and quantitative analysis of heavy metals. Compared to traditional mass spectrometry, they offer both high sensitivity and speed. However, the high sensitivity of electrochemical methods also presents challenges to the stability of their detection limits. Currently, commercially available instruments for heavy metal detection in grains can achieve detection limits as low as 20 ppb. The commonly used electrochemical method for heavy metal detection is stripping voltammetry. This method requires first reducing and enriching the analyte in the test solution onto the surface of an electrochemical sensor. Then, by applying a voltage, the reduced analyte enriched on the sensor is oxidized and dissolved. Quantitative analysis is performed based on the magnitude of the dissolution peak current, while qualitative analysis is performed based on the dissolution peak potential. During the analysis, if the dissolution peak current is too small, it will be susceptible to interference from environmental factors or other signals, leading to unstable results and excessively high detection limits for heavy metals, which cannot meet practical needs. The enrichment of analytes involves heterogeneous electron transfer and liquid-phase diffusion mass transfer. The diffusion mass transfer effect of the analyte directly affects the enrichment of the analyte, thus altering the dissolution peak current. Therefore, currently available heavy metal detectors using electrochemical methods employ external stirring devices to promote the diffusion mass transfer process of the analyte during enrichment, thereby significantly improving the dissolution peak current. However, this method requires a corresponding electrolytic cell (or solution cell), and also necessitates the addition of a stirring device or structure to the instrument. This not only makes operation more cumbersome but also increases the instrument's production cost. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for improving the detection performance of heavy metal ions through vibration. By causing local vibration of the heavy metal detector, the detection liquid can spontaneously and continuously mix in the droplet area of ​​the screen-printed electrode. Without the need for additional stirring structures or devices or electrolytic cells, the liquid phase diffusion mass transfer process can be promoted, the dissolution peak current of the analyte can be increased, and the detection limit of heavy metals can be reduced.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for improving the detection performance of heavy metal ions through vibration includes: By adding a vibration generator to the heavy metal detector, the electrode interface of the heavy metal detector can be locally vibrated. The detection liquid on the electrode inserted at the electrode interface can also vibrate in the dripping area on the electrode to promote the liquid phase diffusion and mass transfer process, so as to achieve the purpose of continuous mixing of the detection liquid. This increases the dissolution peak current of the analyte and enhances the intensity of the detection signal.

[0005] Furthermore, the vibration generator is a miniature DC vibration motor or an AC vibration motor.

[0006] Furthermore, the position of the vibration generator is adjustable to ensure that the solution in the electrode droplet area vibrates.

[0007] Furthermore, the vibration frequency of the vibration generator is controllable and can be selected based on the size and stability of the detection limit, achieving the lowest possible metal ion detection limit while ensuring stable detection results.

[0008] Furthermore, the electrode is a screen-printed electrode.

[0009] Furthermore, the intensity of the vibration can be controlled by adjusting the input current or voltage of the vibration generator.

[0010] Furthermore, the vibration generator is positioned at least one location on the detection host, corresponding to the left, right, or port position of the electrode interface.

[0011] The present invention also provides an electrochemical detection system for heavy metal ion detection, comprising: Detection host; Electrodes are used to hold the detection solution and carry out electrochemical reactions. A vibration generator is disposed within the detection host and / or integrated with the electrodes; The control unit is configured to control the vibration generator to apply localized mechanical vibration to the electrode during the enrichment and / or dissolution of heavy metal ions through the electrode.

[0012] Furthermore, the control unit is also configured to adjust the vibration frequency and / or intensity of the vibration generator.

[0013] Furthermore, the vibration generator is positioned at least one location on the detection host, corresponding to the left, right, or port position of the electrode interface.

[0014] The technical solution of this invention not only ensures the testing effect and meets the actual needs, but also simplifies the structure of the heavy metal tester, reduces the instrument production cost, and makes the operation process more streamlined.

[0015] The technical solution of this invention has at least the following beneficial effects: Compared with the prior art, in terms of the structure of the heavy metal detection instrument, the vibration part in this technical solution utilizes the original structure of the instrument without connecting any other devices, acting on the heavy metal detection electrode to indirectly promote the diffusion of detected ions in the detection solution, greatly enhancing the heterogeneous mass transfer effect within a fixed time. In other embodiments, the use of the heavy metal detection instrument requires an external stirring device, or it can act directly on the detection solution or on the container holding the detection solution. In terms of the usage process of the heavy metal detection instrument, after the heavy metal detection solution is prepared, the sample can be directly loaded onto the electrode for detection, which is simple to operate. In other implementation cases, in addition to installing the detection electrode, a stirring device is also required. In terms of the consumables required for the use of the heavy metal detection instrument, this technical solution only requires the detection electrode and the detection reagent. In other implementation cases, after removing the necessary electrode and reagent, a container for the detection solution used with the stirring and mixing device is also required. Compared with other current technical solutions, this solution reduces the cost of the instrument itself and the associated testing consumables. Attached Figure Description

[0016] Figure 1 This is a diagram showing the location of the local vibration points of the instrument selected to improve the detection performance of heavy metal ions, provided in an embodiment of the present invention; wherein: left side of the detection channel 11; detection channel port 12; right side of the detection channel 13; Figure 2 These are the current response values ​​of Example 1 under both vibration-free and vibration-free conditions; Figure 3 This is a schematic diagram of linear fitting of the test current values ​​of different concentrations obtained under conditions with and without vibration in Example 2; Figure 4 This is a graph showing the relationship between the vibration motor power and the detection current in Example 3. Detailed Implementation

[0017] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the present invention. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0018] This invention provides a technical solution for improving the detection performance of heavy metal ions through vibration, such as... Figure 1 As shown, we selected one or more of locations 11, 12, and 13 in the figure as the vibration points in our embodiment, and adjusted the vibration effect by setting different vibration parameters.

[0019] Example 1: like Figure 1 As shown, this embodiment uses a technique to improve the detection performance of heavy metal ions through vibration, by setting a local position 11 on the detection instrument as a vibration part, which is located on the left side of the detection channel.

[0020] Without local vibration, a standard rice sample with a cadmium content of 0.074 mg / kg was pretreated to prepare a test solution. The sample was loaded according to the standard detection procedure of the heavy metal detector and analyzed by stripping voltammetry. Each test was repeated 10 times. Under these conditions, the average current response value was 1.22E-07A, and the standard deviation of the data was 0.88E-08A. With good instrument stability, it can be found that the current response value is at a low level without local vibration.

[0021] Similarly, a standard rice sample containing 0.074 mg / kg of cadmium was pretreated to prepare a test solution. When tested under localized vibration (11), the average current response value was 2.55E-07A, and the standard deviation of the measured data was 1.57E-08A. Specific test data are shown in Table 1. Figure 2 As shown, through data comparison, it can be found that the current response value measured by the vibration control group channel is significantly improved under vibration conditions. This indicates that the method of improving the detection performance of heavy metal ions by vibration is feasible, thereby avoiding the need for external stirring and meeting the actual heavy metal detection requirements.

[0022] Table 1. Peak values ​​of the 10-repetition curves obtained under no-vibration and vibration conditions, respectively.

[0023] Example 2: like Figure 1 As shown, this embodiment uses a technique to improve the detection performance of heavy metal ions through vibration. When the local area 11 is set to the vibration position, the effect of vibration on improving the detection sensitivity of heavy metal ions is investigated by detecting samples with different cadmium ion concentrations.

[0024] A standard rice sample containing 0.074 mg / kg of cadmium was used for pretreatment. The sample was then diluted with digestion buffer from a blank rice sample (cadmium content <0.02 mg / kg) to obtain rice dilutions of 0.037 mg / kg and 0.025 mg / kg, respectively. Samples were loaded according to the standard testing procedure of a heavy metal detector, and analysis was performed using the stripping voltammetry method. Each test was repeated 10 times. Under vibration-free conditions, the average current responses of the three samples (0.074 mg / kg, 0.037 mg / kg, and 0.025 mg / kg) were 1.18E-07A, 0.59E-07A, and 0.33E-07A, respectively, with standard deviations of 0.89E-08, 0.65E-08, and 0.35.5E-08, respectively. The average current responses of the three samples (0.074 mg / kg, 0.037 mg / kg, and 0.025 mg / kg) obtained under vibration conditions were 2.59E-07A, 1.69E-07A, and 0.88E-07A, respectively, and the standard deviations of the three sets of data were 1.09E-08, 0.75E-08, and 0.45E-08, respectively.

[0025] like Figure 3 As shown, linear fitting was performed based on the test current values ​​obtained under different concentrations under vibration and non-vibration conditions. It can be seen that the detection results are linear under both vibration and non-vibration conditions, but the slope (i.e., sensitivity) of the linear fitting curve obtained under vibration conditions (3.46e-6) is significantly greater than the slope under non-vibration conditions (1.72e-6), indicating that vibration can significantly improve the detection sensitivity.

[0026] Example 3: like Figure 1 As shown, this embodiment uses a technique to improve the detection performance of heavy metal ions through vibration. When the local part 11 is set to the vibration position, the influence of vibration power on the performance of the detector is investigated by setting different power (supply current) of the vibration motor.

[0027] A standard rice sample containing 0.074 mg / kg of cadmium was used for pretreatment. The sample was loaded according to the standard detection procedure of the heavy metal detector, and analysis was performed using the stripping voltammetry method. Each test was repeated 12 times. The average current responses obtained under the conditions of vibration motor power supply current of 80mA (rated power), 70mA, 65mA, and 60mA were 2.62E-07A, 2.56E-07A, 1.89E-07A, and 1.28E-07A, respectively. The standard deviations of the four sets of data were 1.65E-08, 1.59E-08, 1.11E-08, and 0.93E-08, respectively.

[0028] like Figure 4As shown, as the vibration power (supply current) increases, the detection current also increases accordingly. To ensure that the vibration motor can work stably for a long time, the rated power is selected as the maximum power.

[0029] The application of a local vibration device in a heavy metal detector demonstrates that the technique of improving heavy metal ion detection performance through vibration can be used not only in single-channel heavy metal detection but also in multi-channel detection. This method significantly simplifies the instrument structure, making it lighter and more portable, and correspondingly simplifies the operation steps, reducing operational difficulty and instrument costs.

[0030] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for improving the detection performance of heavy metal ions through vibration, characterized in that, include: By adding a vibration generator to the heavy metal detector, the electrode interface of the heavy metal detector can be locally vibrated. The detection liquid on the electrode inserted at the electrode interface can also vibrate in the dripping area on the electrode to promote the liquid phase diffusion and mass transfer process, so as to achieve the purpose of continuous mixing of the detection liquid. This increases the dissolution peak current of the analyte and enhances the intensity of the detection signal.

2. The method for improving the detection performance of heavy metal ions by vibration as described in claim 1, characterized in that: The vibration generator is a miniature DC vibration motor or an AC vibration motor.

3. The method for improving the detection performance of heavy metal ions by vibration as described in claim 1, characterized in that: The position of the vibration generator is adjustable to ensure that the solution in the electrode droplet area vibrates.

4. The technical method for improving the detection performance of heavy metal ions by vibration as described in claim 1, characterized in that: The vibration frequency of the vibration generator is controllable and can be selected based on the detection limit and stability, achieving the lowest possible metal ion detection limit while ensuring stable detection results.

5. The technical method for improving the detection performance of heavy metal ions by vibration as described in claim 3, characterized in that: The electrode is a screen-printed electrode.

6. The technical method for improving the detection performance of heavy metal ions by vibration as described in claim 4, characterized in that: The intensity of the vibration can be adjusted by changing the input current or voltage of the vibration generator.

7. The technical method for improving the detection performance of heavy metal ions by vibration as described in claim 4, characterized in that: The vibration generator is positioned at least one of the following locations on the detection host: the left side, the right side, or the port position of the electrode interface.

8. An electrochemical detection system for heavy metal ion detection, characterized in that, include: Detection host; Electrodes are used to hold the detection solution and carry out electrochemical reactions. A vibration generator is disposed within the detection host and / or integrated with the electrodes; The control unit is configured to control the vibration generator to apply localized mechanical vibration to the electrode during the enrichment and / or dissolution of heavy metal ions through the electrode.

9. The detection system as described in claim 8, characterized in that: The control unit is also configured to adjust the vibration frequency and / or intensity of the vibration generator.

10. The detection system as described in claim 8, characterized in that: The vibration generator is positioned at least one location on the detection host, corresponding to the left, right, or port position of the electrode interface.

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