阅读说明：本技术 一种生物质衍生多孔碳表面负载聚苯胺用于吡虫啉的电化学检测方法 (Electrochemical detection method for imidacloprid by loading polyaniline on surface of biomass-derived porous carbon ) 是由 丁龙华 于欣 刘宏 甘宜梧 于 2020-05-26 设计创作，主要内容包括：本发明涉及一种生物质衍生多孔碳表面负载聚苯胺用于吡虫啉的电化学检测方法。通过惰性氛围中高温碳化和氢氧化钾处理制备拉菲草衍生多孔碳材料,以过硫酸铵为氧化剂、高氯酸为掺杂剂,在多孔碳表面负载聚苯胺纳米材料,超声分散与nafion溶液中滴涂于电极表面,采用差分脉冲伏安法对吡虫啉进行检测。本发明得到的比表面积大、传质速度快的多孔碳聚苯胺复合材料,用于吡虫啉的检测,本方法操作简单、灵敏度高。(The invention relates to an electrochemical detection method for imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon. The preparation method comprises the steps of preparing a porous carbon material derived from the Laphyra, loading a polyaniline nano material on the surface of the porous carbon by using ammonium persulfate as an oxidant and perchloric acid as a dopant through high-temperature carbonization and potassium hydroxide treatment in an inert atmosphere, carrying out ultrasonic dispersion and dripping the polyaniline nano material on the surface of an electrode in nafion solution, and detecting imidacloprid by adopting a differential pulse voltammetry. The porous carbon polyaniline composite material with large specific surface area and high mass transfer speed is used for detecting imidacloprid, and the method is simple to operate and high in sensitivity.)

1. An electrochemical detection method for imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon is characterized by comprising the following steps:

(1) cutting the Laffera, and processing in a tube furnace to obtain a carbon material;

(2) treating the carbon material in the step (1) with KOH, and then treating the carbon material in a tubular furnace at high temperature to obtain a porous carbon material (PC);

(3) uniformly mixing aniline, an oxidant and acid by taking the PC obtained in the step (2) as a support to prepare a porous carbon surface loaded polyaniline nanowire (PC @ PANI) composite material;

(4) taking a certain amount of PC @ PANI obtained in the step (3) to be placed in nafion solution, ultrasonically dispersing, and dropwise coating on the surface of an electrode;

(5) the electrode is placed in a buffer solution containing imidacloprid and detected by adopting differential pulse voltammetry.

2. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (1), the preparation of the Laphyra-derived carbon material comprises the following steps: taking 5.0 g of Laphyra, cutting into pieces, placing the pieces into an alumina crucible, and roasting in a tubular furnace, wherein the roasting conditions are as follows: in an argon atmosphere, 800^oC treatment for 2 hours, with a heating rate of 10^oC/min。

3. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (2), the preparation of the porous carbon comprises the following steps: taking 0.5 g of the material obtained in the step (1), adding the material into 20 mL of KOH aqueous solution containing 1.5 g of KOH, stirring and mixing for 2 hours, and drying in an oven at 100 ℃ overnight; the resultant was put into an alumina corundum crucible and fired at 800 ℃ for 2 hours (10 ℃/min) in an argon atmosphere to obtain a porous carbon material (PC).

4. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (3), the oxidant is ammonium persulfate, and the acid is perchloric acid.

5. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (4), preparing the PC @ PANI composite material: firstly, preparing a solution A: 50 mL of 1.0M perchloric acid was added to 18 mL of an ethanol solution, and after stirring for 10 minutes, 0.05M aniline, -5^oC, stirring in an ice bath for 30 minutes, and then adding 16 mg of PC; preparing a solution B: 0.03M ammonium persulfate was added to 20 mL of 1.0M perchloric acid, and the vessel was placed in-5^oC, cooling in ice bath; subsequently, the solution B is added to the solution A, -5^oC, continuously stirring and reacting for 1.0 h; centrifuging, filtering, washing and drying the reacted solution to obtain a final product, thus obtaining the PC @ PANI compositeA material.

6. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (5), 0.01 g of PC @ PANI is placed in 1 mL of 0.5wt% nafion solution, ultrasonically dispersed and dropwise coated on the surface of a glassy carbon electrode.

7. The method for electrochemically detecting imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon according to claim 1, which is characterized in that: in the step (6), the electrode is placed in phosphate buffer solution with pH 7.0 and containing imidacloprid with different concentrations, and the voltage level (-0.6) - (-1.4) V is scanned by adopting differential pulse voltammetry for detection.

Technical Field

The invention relates to a method for detecting imidacloprid which is a pesticide residue, in particular to a method for detecting imidacloprid by using polyaniline loaded on the surface of biomass-derived porous carbon through an electrochemical method.

Background

Imidacloprid (IMD), known as 1- (6-chloropyridine-3-pyridylmethyl) -N-nitroimidazolidine-2-ylamine, is a novel super-efficient systemic insecticide containing pyridine rings. As a systemic insecticide with remarkable low-dose insecticidal effect, imidacloprid is the most widely applied neonicotinoid insecticide. After spraying, the imidacloprid pesticide does not decompose or degrade very quickly and inevitably remains in the environment, agricultural products or organisms. People can cause the pesticide residue to be enriched in human bodies after drinking water containing the pesticide residue for a long time or eating grains, vegetables, fruits and the like containing the pesticide residue. The imidacloprid pesticide can inhibit the combination of acetylcholine and acetylcholine receptors, act on nervous system and seriously harm human health. Therefore, it is necessary to establish a method for accurately and rapidly detecting imidacloprid.

At present, the main methods for detecting imidacloprid are as follows: gas chromatography, high performance liquid chromatography, liquid-mass spectrometry, enzyme-linked immunosorbent assay. These methods require expensive equipment, require experienced personnel, and are complicated in processing. The imidacloprid is a substance with electrochemical activity, and the electrochemical method has the advantages of simple operation, high sensitivity, quick response and the like, and can be used as a better detection means.

The conductive polymer in an intrinsic state is usually an insulator, but can be converted into a semiconductor or a conductor by oxidation or proton doping, and thus can be used as a better electrode modification material. Polyaniline is one of conductive polymers, has the advantages of high specific surface area, good conductivity and the like, and is more suitable for constructing electrochemical sensors. However, the mechanical properties of conductive polymers are generally poor, which limits the development of practical applications. One of the more desirable improvement methods is to compound a conductive polymer with an inorganic material having better mechanical properties. A carbon polyaniline composite material modified electrode grows on the surface of porous carbon in situ and is used for constructing an imidacloprid electrochemical sensor.

Disclosure of Invention

The invention aims to establish an electrochemical detection method for imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon.

The process of the electrochemical detection method for imidacloprid by loading polyaniline on the surface of the biomass-derived porous carbon comprises the following steps:

(1) cutting the Laffera, and processing in a tube furnace to obtain a carbon material;

(2) treating the carbon material in the step (1) with KOH, and then treating the carbon material in a tubular furnace at high temperature to obtain a porous carbon material (PC);

(3) uniformly mixing aniline, an oxidant and acid by taking the PC obtained in the step (2) as a support to prepare a porous carbon surface loaded polyaniline nanowire (PC @ PANI) composite material;

(4) taking a certain amount of PC @ PANI obtained in the step (3) to be placed in nafion solution, ultrasonically dispersing, and dropwise coating on the surface of an electrode;

(5) the electrode is placed in a buffer solution containing imidacloprid and detected by adopting differential pulse voltammetry.

The method for electrochemical detection of imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon comprises the following specific steps:

(1) preparing a Laphyra derivative carbon material: taking 5.0 g of Laphyra, shearing the Laphyra, putting the Laphyra into an alumina crucible, and roasting in a tubular furnace. The roasting conditions are as follows: in an argon atmosphere, 800^oC treatment for 2 hours, with a heating rate of 10^oC/min。

(2) Preparation of porous carbon: taking 0.5 g of the material obtained in the step (1), adding the material into 20 mL of KOH aqueous solution containing 1.5 g of KOH, stirring and mixing for 2 hours, and drying in an oven at 100 ℃ overnight; the resultant was put into an alumina corundum crucible and fired at 800 ℃ for 2 hours (10 ℃/min) in an argon atmosphere to obtain a porous carbon material (PC).

(3) The oxidant is ammonium persulfate, and the acid is perchloric acid.

(4) Preparing the PC @ PANI composite material. Firstly, preparing a solution A: 50 mL of 1.0M perchloric acid was added to 18 mL of an ethanol solution, and after stirring for 10 minutes, 0.05M aniline, -5^oC, stirring in an ice bath for 30 minutes, and then adding 16 mg of PC; preparing a solution B: 0.03M ammonium persulfate was addedTo 20 mL of 1.0M perchloric acid, the container was placed in-5^oC, cooling in ice bath; subsequently, the solution B is added to the solution A, -5^oC, continuously stirring and reacting for 1.0 h; and centrifuging, filtering, washing and drying the reacted solution to obtain a final product, thus obtaining the PC @ PANI composite material.

(5) 0.01 g of PC @ PANI is put into 1 mL of 0.5wt% nafion solution, ultrasonically dispersed and dropwise coated on the surface of a glassy carbon electrode.

(6) And (3) placing the electrode prepared in the step (5) in phosphate buffer solution with different concentrations of imidacloprid and pH 7.0, and scanning the voltage level (-0.6) - (-1.4) V by adopting differential pulse voltammetry for detection.

The invention has the beneficial effects that:

(1) the invention takes the Laphyra as the biomass, and prepares the derived porous carbon material through high-temperature treatment.

(2) The porous carbon material is used as a support body to synthesize the porous carbon polyaniline composite material with good conductivity and high mass transfer speed.

(3) The invention is used for detecting imidacloprid, and has good stability and high sensitivity.

Detailed Description

The following is a description of detailed embodiments of the present invention: an electrochemical detection method for imidacloprid by loading polyaniline on the surface of biomass-derived porous carbon.