Electrochemical molecular imprinting sensor as well as preparation method and application thereof

Abstract

The invention relates to an electrochemical molecular imprinting sensor as well as a preparation method and application thereof. The electrochemical molecular imprinting sensor is used for high-selectivity recognition of perfluorooctane sulfonate. The electrochemical molecular imprinting sensor comprises a base electrode, and gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles, gold nanoparticles and gold nanoparticles, which are laid on the surface of the base electrode in sequence, a probe having a multiple fluorophilic effect; the functional monomer of the molecularly imprinted membrane is o-phenylenediamine. The electrochemical molecular imprinting sensor provided by the invention has the characteristics of high selectivity, high response speed and good sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of pollutant detection, and in particular to an electrochemical molecular imprinting sensor and a preparation method and application thereof. Background Art

[0002] Perfluorooctane sulfonate (PFOS) has become an important new pollutant for water monitoring due to its bioaccumulation, neurotoxicity, reproductive and developmental toxicity and endocrine disruption. Currently, the detection of PFOS in water mainly relies on liquid chromatography-mass spectrometry technology. Although these methods have high sensitivity, they rely on expensive detection equipment and take a long time for sample pretreatment, which makes it difficult to meet the requirements of on-site detection of PFOS in environmental samples. Summary of the invention

[0003] In view of the above analysis, the embodiments of the present invention aim to provide an electrochemical molecular imprinting sensor and a preparation method and application thereof, so as to solve at least one of the above problems.

[0004] In one aspect, the present invention provides an electrochemical molecular imprinting sensor, comprising a base electrode and: Gold nanoparticles, with a particle size range of 35-40 nm; Probes with multiple fluorine-affinity effects; Molecular imprinting membrane, whose functional monomer is o-phenylenediamine.

[0005] Furthermore, the base electrode is a glassy carbon electrode, a gold electrode or a screen-printed electrode.

[0006] Furthermore, the probe having multiple fluorine-affinity effects is 1H,1H,2H,2H-perfluorodecylthiol.

[0007] On the other hand, the present invention provides a method for preparing an electrochemical molecular imprinting sensor, which can at least be used to prepare the above-mentioned electrochemical molecular imprinting sensor, and the preparation method comprises the following steps: S100: providing basic electrodes; S200: modifying the base electrode with gold nanoparticles to obtain a gold nanoparticle / base electrode; S300: modifying the gold nanoparticles / basic electrode with the F17 probe to obtain the F17 / gold nanoparticles / basic electrode; S400: immersing F17 / gold nanoparticles / base electrode in PFOS solution, utilizing the FF bond interaction between F17 and PFOS to obtain PFOS / F17 / gold nanoparticles / base electrode; S500: PFOS / F17 / gold nanoparticles / base electrode are placed in an o-phenylenediamine solution, and o-phenylenediamine is electrochemically polymerized on the surface of PFOS / F17 / gold nanoparticles / base electrode using cyclic voltammetry. PFOS is then eluted in a methanol-water mixed solution, and an electrochemical molecular imprinting sensor is finally obtained.

[0008] Furthermore, the base electrode needs to be polished first, and then placed in ethanol and ultrapure water in sequence for step-by-step ultrasonic treatment for 5 to 10 minutes.

[0009] Further, in step S200, the base electrode is immersed in a 0.5 mM HAuCl4 solution, and the gold nanoparticles / base electrode is prepared by chronoamperometry and cyclic voltammetry; The test conditions of the chronoamperometry were as follows: initial potential of 0.8 V and pulse width of 15 s; The test conditions of cyclic voltammetry were as follows: potential range was -0.4 V to 0.3 V, scanning speed was 50 mV / s, and the number of cycles was 50.

[0010] Furthermore, in step S300, the gold nanoparticles / basic electrode is immersed in a F17 probe solution and incubated at room temperature to obtain a F17 / gold nanoparticles / basic electrode.

[0011] Furthermore, in step S400, the concentration of the PFOS solution is 1 mM to 5 mM, and the F17 / gold nanoparticles / base electrode are immersed in the PFOS solution and incubated for 20 to 180 min.

[0012] Furthermore, in step S500, the methanol-water mixture is a mixture of methanol and water in a volume ratio of 0:1 to 7:1.

[0013] The present invention also provides an application of an electrochemical molecular imprinting sensor. The electrochemical molecular imprinting sensor prepared based on the preparation method can be used for the detection of perfluorooctane sulfonic acid.

[0014] Compared with the prior art, the present invention can achieve at least one of the beneficial effects. Based on the basic electrode, the present invention utilizes the multiple fluorine-affinity effects of perfluorinated substances and combines molecular imprinting recognition technology to prepare a highly selective electrochemical molecular imprinting sensor capable of detecting perfluorooctane sulfonic acid in water environment.

[0015] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0017] Figure 1 DPV graphs of AuNPs / GCE, F17 / AuNPs / GCE, PFOS / F17 / AuNPs / GCE, and o-PDMIP / PFOS / F17 / AuNPs / GCE (before and after PFOS elution) in a specific embodiment; Figure 2 is the FESEM of o-PD MIP / F17 / AuNPs / GCE in a specific embodiment; Figure 3 The DPV curve in the concentration range of 0-1 mM PFOS in a specific embodiment (left figure) and the established standard curve (right figure); Figure 4 It is a comparison chart of the recognition performance of the electrochemical molecular imprinting sensor for PFOS and perfluorinated analogues (PFOA, PFNA, PFHPA and PFDA) in a specific implementation manner. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral connection, which can be a mechanical connection, or an electrical connection, which can be a direct connection, or can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] The terms "top", "bottom", "above", "lower", and "on" used throughout the description are relative to the relative positions of components of a device, such as the relative positions of the top and bottom substrates within a device. It is understood that devices are multifunctional regardless of their orientation in space.

[0021] The common working surface of the present invention can be a plane or a curved surface, can be inclined, or can be horizontal. For the convenience of description, the embodiment of the present invention is placed on a horizontal plane and used on the horizontal plane, and "high and low" and "up and down" are defined in this way.

[0022] A specific embodiment of the present invention discloses an electrochemical molecular imprinting sensor, comprising a base electrode and: Gold nanoparticles (AuNPs), with a particle size range of 35-40 nm; Probes with multiple fluorine-affinity effects; Molecularly imprinted polymer (MIP), whose functional monomer is o-Phenylenediamine (o-PD).

[0023] The electrochemical molecular imprinting sensor (hereinafter referred to as the sensor) of the present invention can be used to quickly detect PFOS in environmental samples, and has the characteristics of high selectivity, high sensitivity and strong stability.

[0024] The basic electrode is a glassy carbon electrode, a gold electrode or a screen-printed electrode. Preferably, the glassy carbon electrode (GCE) has the advantages of good conductivity, high chemical stability, wide application range, and easy processing.

[0025] By modifying the glassy carbon electrode with gold nanoparticles, the active area of ​​the electrode surface was increased, which promoted the Fe 2+ Fe 3+ The conversion process can improve the electrochemical response signal of the prepared sensor to potassium ferrocyanide.

[0026] The probe with multiple fluorine-affinity is 1H, 1H, 2H, 2H-perfluorodecylthiol (chemical formula: C 10 H5F 17 S, referred to as F17). F17 can be used for the selective recognition of PFOS due to its multiple fluorine-affinity effects. The FF bond between F17 and PFOS can prevent the attachment of other organic matter and ions in water.

[0027] The molecular imprinting membrane is electrochemically polymerized in an o-phenylenediamine solution using cyclic voltammetry on the surface of the F17 / gold nanoparticles / base electrode, and then perfluorooctane sulfonic acid is eluted in a methanol / water mixed solution to finally obtain the electrochemical molecular imprinting sensor of perfluorooctane sulfonic acid.

[0028] The present invention also provides a method for preparing the electrochemical molecular imprinting sensor, comprising the following steps: S100: providing basic electrodes; S200: modifying the base electrode with gold nanoparticles to obtain a gold nanoparticle / base electrode; S300: modifying the gold nanoparticles / basic electrode with the F17 probe to obtain the F17 / gold nanoparticles / basic electrode; S400: immersing F17 / gold nanoparticles / base electrode in PFOS solution, utilizing the FF bond interaction between F17 and PFOS to obtain PFOS / F17 / gold nanoparticles / base electrode; S500: PFOS / F17 / gold nanoparticles / base electrode are placed in an o-phenylenediamine solution, and o-phenylenediamine is electrochemically polymerized on the surface of PFOS / F17 / gold nanoparticles / base electrode using cyclic voltammetry. PFOS is then eluted in a methanol-water mixed solution, and an electrochemical molecular imprinting sensor is finally obtained.

[0029] In step S100, the base electrode needs to be polished (for example, the glassy carbon electrode is polished with 0.03 μm alumina powder on the skin), and then placed in ethanol and ultrapure water in turn for 5 to 10 minutes of step-by-step ultrasonic treatment.

[0030] In step S200, the base electrode is immersed in a 0.5 mM HAuCl4 solution, and the gold nanoparticles / base electrode are prepared by chronoamperometry and cyclic voltammetry. The test conditions of the chronoamperometry are: the initial potential is 0.8 V, the pulse width is 15 s; the test conditions of the cyclic voltammetry are: the potential range is -0.4 V to 0.3 V, the scanning speed is 50 mV / s, and the number of cycles is 50.

[0031] In step S300, the gold nanoparticles / base electrode are immersed in a F17 probe solution and incubated at room temperature (20-30°C) to obtain a F17 / gold nanoparticle / base electrode, wherein the F17 is mainly connected to the surface of the gold nanoparticles through Au-S bonds. The concentration of the F17 probe solution is 80-110 mM (preferably 100 mM), and the incubation is carried out at room temperature for 20-120 min. For example, the incubation time is 20, 40, 60, 90, 120 min, etc. The F17 probe solution is prepared using ultrapure water.

[0032] In step S400, the concentration of the PFOS solution is 1 mM to 5 mM, and the F17 / gold nanoparticles / base electrode are immersed in the PFOS solution and incubated for 20 to 180 min. For example, the incubation time is 20, 40, 60, 120, and 180 min. PFOS mainly interacts with the F17 probe through the FF bond.

[0033] In step S500, the methanol-water mixture is a mixture of methanol and water in a volume ratio of 0:1 to 7:1 (exemplarily, the ratio is 0:1, 3:1, 7:1, 1:0, etc.; preferably 5:1). The methanol-water mixture can elute the PFOS molecules embedded in the imprinting membrane.

[0034] After elution, the sensor is air-dried and stored, preferably under a nitrogen atmosphere and stored in a refrigerator at 4°C.

[0035] The electrochemical molecular imprinting sensor of the present invention can be used for the detection of perfluorooctane sulfonic acid (PFOS), at least for detecting whether an environmental sample contains perfluorooctane sulfonic acid, and further for detecting the content of PFOS in the environmental sample by differential pulse voltammetry.

[0036] During field use, the prepared o-PD MIP / F17 / AuNPs / GCE electrode (prepared in the laboratory and brought to the site) was first tested for a blank background value in 5 mL of 5 mM ferric / potassium ferroferrocyanide solution to obtain a current value (I0). Subsequently, the electrode was immersed in the water sample to be tested for 60 minutes, and a subsequent differential pulsed voltammetry (DPV) test was performed using the same process. After the test, the concentration of PFOS in the water was calculated based on the calibration curve.

[0037] The DPV test was performed in 5 mL of 5 mM iron / potassium ferrocyanide solution (Fe 3+ with Fe 2+ The test was carried out in a three-electrode system, in which the prepared electrode was the working electrode, the platinum wire was the counter electrode, and the silver / silver chloride was the reference electrode. The potential range of the parameters was -0.1~0.6 V (vs Ag / AgCl), and the scanning speed was 50 mV / s.

[0038] By constructing a PFOS calibration curve within a standard concentration range, fluorooctane sulfonic acid in environmental samples can be quantified. For example, a standard curve with a PFOS concentration range of 0 to 1 mM is constructed, and the concentration of PFOS within this range can be measured.

[0039] The electrochemical molecular imprinting sensor of the present invention uses iron / potassium ferrocyanide as an external standard probe. When PFOS is present, the Fe in the potassium ferrocyanide solution near the electrode interface 2+ Fe 3+ The conversion of PFOS is inhibited, resulting in a lower signal response. When PFOS is eluted, a higher current value is generated. The sensor before and after elution is measured using differential pulse voltammetry to obtain the signal changes of the probes before and after elution, thereby quantitatively analyzing the PFOS concentration in the water sample.

[0040] The electrochemical molecular imprinting sensor of the present invention can be used to detect PFOS in water environment and has the characteristics of high selectivity, high sensitivity and strong stability.

[0041] [Example] An electrochemical molecular imprinting sensor is provided, and the preparation method thereof comprises the following steps: S100: Provide a glassy carbon electrode (GCE), polish the GCE, and then perform step-by-step ultrasonic treatment in ethanol and ultrapure water for 5 min. S200: The glassy carbon electrode was immersed in a 0.5 mM HAuCl4 solution, and the gold nanoparticles / glassy carbon electrode (denoted as AuNPs / GCE) was prepared by chronoamperometry and cyclic voltammetry; S300: immerse AuNPs / GCE in 100 mM F17 solution and incubate at room temperature for 90 min to obtain F17 / gold nanoparticles / glassy carbon electrode (denoted as F17 / AuNPs / GCE); S400: immersing the above F17 / AuNPs / GCE in a 2 mM perfluorooctane sulfonic acid solution and incubating at room temperature for 60 min to obtain a PFOS / F17 / gold nanoparticle / glassy carbon electrode (referred to as PFOS / F17 / AuNPs / GCE); S500: PFOS / F17 / AuNPs / GCE was placed in 5 mL of 10 mM o-phenylenediamine solution, and o-phenylenediamine was electrochemically polymerized on the surface of PFOS / F17 / gold nanoparticles / glassy carbon electrode by cyclic voltammetry. Specifically, cyclic voltammetry CV was performed in the potential range of 0-1 V at a scan rate of 50 mV / s for 8 cycles to obtain o-PD MIP / PFOS / F17 / gold nanoparticles / glassy carbon electrode (referred to as o-PD MIP / PFOS / F17 / AuNPs / GCE); The o-PD MIP / PFOS / F17 / AuNPs / GCE was placed in a mixed solution of methanol and water in a volume ratio of 5:1 to remove PFOS, and finally an electrochemical molecular imprinting sensor (denoted as o-PD MIP / F17 / AuNPs / GCE) was obtained.

[0042] In 5 mM [Fe(CN)6] 3- / 4- Differential pulse voltammetry was used in the solution to characterize the electrochemical behaviors of the o-PD MIP / PFOS / F17 / AuNPs / GCE electrode before and after PFOS removal, AuNPs / GCE, F17 / AuNPs / GCE, and PFOS / F17 / AuNPs / GCE. The characterization results are shown in Figure 2. Figure 1As shown, it can be seen from the DPV graph that after F17 modification, its current value is significantly reduced. After further assembly of PFOS, the current value is further reduced. After subsequent polymerization of o-phenylenediamine, the current value of DPV also decreases. After PFOS is eluted, the current value increases significantly, indicating that PFOS is successfully removed from the molecular imprinting membrane.

[0043] Figure 2 This is the field emission scanning electron microscopy (FESEM) of o-PD MIP / F17 / AuNPs / GCE. It can be seen from the figure that the electrode surface has a film-like structure, indicating the successful preparation of the sensor interface.

[0044] o-PD MIP / F17K / AuNPs / GCE was used for PFOS detection in water environment by incubation in real water samples. The DPV curves in the concentration range of 0~1 mM PFOS and the established standard curve were carried out with the same process. The potential range of DPV test was -0.1 V~0.6 V (vs Ag / AgCl), and the scanning speed was 50 mV / s. The experimental results are shown in Figure 3 As shown in the figure, it can be seen that the electrochemical molecular imprinting sensor of the present invention has the characteristics of high sensitive response (R 2 =0.9903).

[0045] The prepared sensor was used to study the selectivity of the sensor of the present invention with the same concentration of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), tridecafluoroheptanoic acid (PFHPA), and nonadecafluorodecanoic acid (PFDA). The results are shown in Figure 4 As shown, since PFOS was selected as the template molecule for polymerization during the preparation of o-PDMIP / F17 / AuNPs / GCE, the prepared sensor had no obvious recognition ability for other perfluorinated analogs, which also shows that the sensor prepared by the present invention has the characteristic of high selectivity.

[0046] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An electrochemical molecular imprinting sensor, characterized in that: It includes a basic electrode and the following components sequentially laid on the surface of the basic electrode: Gold nanoparticles, with a particle size range of 35-40 nm; Probes with multiple fluorine-affinity effects; Molecular imprinting membrane, whose functional monomer is o-phenylenediamine.

2. The electrochemical molecular imprinting sensor according to claim 1, characterized in that: The basic electrode is a glassy carbon electrode, a gold electrode or a screen-printed electrode.

3. The electrochemical molecular imprinting sensor according to claim 1, characterized in that: The probe with multiple fluorine-affinity effects is 1H, 1H, 2H, 2H-perfluorodecyl mercaptan.

4. A method for preparing an electrochemical molecular imprinting sensor, characterized in that: At least it can be used to prepare the electrochemical molecular imprinting sensor according to any one of claims 1 to 3, and the preparation method comprises the following steps: S100: providing basic electrodes; S200: modifying the base electrode with gold nanoparticles to obtain a gold nanoparticle / base electrode; S300: modifying the gold nanoparticles / basic electrode with the F17 probe to obtain the F17 / gold nanoparticles / basic electrode; S400: immersing F17 / gold nanoparticles / base electrode in PFOS solution, utilizing the FF bond interaction between F17 and PFOS to obtain PFOS / F17 / gold nanoparticles / base electrode; S500: PFOS / F17 / gold nanoparticles / base electrode are placed in an o-phenylenediamine solution, and o-phenylenediamine is electrochemically polymerized on the surface of PFOS / F17 / gold nanoparticles / base electrode using cyclic voltammetry. PFOS is then eluted in a methanol-water mixed solution, and an electrochemical molecular imprinting sensor is finally obtained.

5. The electrochemical molecular imprinting sensor according to claim 4, characterized in that: The base electrode needs to be polished first, and then placed in ethanol and ultrapure water in turn for 5 to 10 minutes of step-by-step ultrasonic treatment.

6. The electrochemical molecular imprinting sensor according to claim 4, characterized in that: In step S200, the base electrode is immersed in a 0.5 mM HAuCl4 solution, and the gold nanoparticle / base electrode is prepared by chronoamperometry and cyclic voltammetry; The test conditions of the chronoamperometry were as follows: initial potential of 0.8 V and pulse width of 15 s; The test conditions of cyclic voltammetry were as follows: potential range was -0.4 V to 0.3 V, scanning speed was 50 mV / s, and the number of cycles was 50.

7. The electrochemical molecular imprinting sensor according to claim 4, characterized in that: In step S300, the gold nanoparticles / basic electrode is immersed in a F17 probe solution and incubated at room temperature to obtain a F17 / gold nanoparticles / basic electrode.

8. The electrochemical molecular imprinting sensor according to claim 7, characterized in that: In step S400, the concentration of the PFOS solution is 1 mM to 5 mM, and the F17 / gold nanoparticles / base electrode are immersed in the PFOS solution and incubated for 20 to 180 min.

9. The electrochemical molecular imprinting sensor according to claim 4, characterized in that: In step S500, the methanol-water mixture is a mixture of methanol and water in a volume ratio of 0:1 to 7:

1.

10. An application of an electrochemical molecular imprinting sensor, characterized in that: The electrochemical molecular imprinting sensor according to any one of claims 1 to 3, or / and the electrochemical molecular imprinting sensor prepared according to the preparation method according to any one of claims 4 to 9, can be used for the detection of perfluorooctane sulfonic acid.

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