【摘要】：作為農(nóng)業(yè)大國,農(nóng)業(yè)發(fā)展中作物病蟲害防治是保證農(nóng)產(chǎn)品穩(wěn)產(chǎn)增收的關(guān)鍵環(huán)節(jié)。噴灑化學(xué)藥劑是應(yīng)用最為普遍的防治措施,然而噴灑農(nóng)藥量不足不能有效殺死病蟲害,噴灑農(nóng)藥量過大不僅造成資源浪費、環(huán)境污染,甚至威脅人類健康。目前噴霧沉積量檢測大多采用水敏紙和實驗室的光度法,然而這兩種方法在一定程度上均存在一定的弊端。因此開發(fā)一種操作簡便、價格低廉的便攜式現(xiàn)場噴霧沉積量檢測系統(tǒng)尤為重要。本文旨在電分析化學(xué)的基礎(chǔ)上,研發(fā)出靈敏度高,選擇性好,性能穩(wěn)定的直接電化學(xué)傳感器,通過設(shè)計信號處理電路硬件處理單元、信號顯示軟件處理單元、以及系統(tǒng)中電源電路關(guān)鍵,實現(xiàn)整體系統(tǒng)的構(gòu)建,并對系統(tǒng)進行了性能分析實驗。主要完成工作包括以下幾個方面:(1)有機磷農(nóng)藥電化學(xué)傳感器的構(gòu)建及其性能研究。將氮摻雜石墨烯納米材料修飾到絲網(wǎng)印刷電極表面,制備成對農(nóng)藥快速響應(yīng)的敏感元件,構(gòu)建了一種簡單靈敏的無酶電化學(xué)傳感器,用于農(nóng)藥甲基對硫磷的檢測。采用掃描電子顯微鏡對敏感部位結(jié)構(gòu)進行表征。通過利用循環(huán)伏安技術(shù)(CV)、差分脈沖伏安技術(shù)(DPV)、線性掃描伏安技術(shù)(LSV)來研究甲基對硫磷的電化學(xué)行為。由于氮摻雜結(jié)構(gòu)和性質(zhì)的獨特性,氮摻雜石墨烯對PBS溶液中的甲基對硫磷產(chǎn)生較高的電催化活性。在信噪比為3的情況下,此傳感器對甲基對硫磷的最高靈敏度為15.32μA/μmol。在優(yōu)化條件下,制備的傳感器具有較好的穩(wěn)定性和選擇性。(2)系統(tǒng)中信號檢測關(guān)鍵單元的分析與設(shè)計。系統(tǒng)調(diào)理電路的硬件單元設(shè)計,包括恒電位電路設(shè)計、I/V轉(zhuǎn)換放大電路、濾波電路以及電源電路設(shè)計.在12V直流電源能量供應(yīng)下,將微安級電流信號轉(zhuǎn)成0-2.5V范圍內(nèi)的模擬電壓信號;對信號轉(zhuǎn)換部分電路完成測試,確保得到預(yù)期功能效果,并得到輸出電壓與藥液濃度之間的數(shù)量關(guān)系用于軟件編程,檢測靈敏度0.6V/μmol。完成信號顯示單元的軟件設(shè)計,選擇控制芯片STC89C52、A/D轉(zhuǎn)換芯片PCF8591以及1602液晶完成噴霧沉積質(zhì)量濃度的數(shù)據(jù)顯示,將模擬電壓信號轉(zhuǎn)成數(shù)字信號由單片機程序處理實現(xiàn)液晶顯示。(3)系統(tǒng)整體結(jié)構(gòu)性能測試與應(yīng)用。完成檢測系統(tǒng)整體結(jié)構(gòu)的構(gòu)建,并通過實際噴霧檢測試驗與電化學(xué)工作站檢測結(jié)果相對比,對系統(tǒng)實際應(yīng)用性能作數(shù)據(jù)分析,完成對系統(tǒng)準確度和穩(wěn)定性的性能測試。系統(tǒng)應(yīng)用于葉面噴霧沉積均勻性和整株噴霧沉積量分布的噴霧沉積量檢測。該檢測系統(tǒng)方法簡單,較好的準確度和穩(wěn)定性,且實現(xiàn)了小型便攜化。確定了系統(tǒng)的穩(wěn)定檢出時間240s以及實際應(yīng)用系統(tǒng)檢測誤差小于5%?在實際噴霧作業(yè)環(huán)境下,農(nóng)藥噴霧沉積量檢測電化學(xué)傳感系統(tǒng)表現(xiàn)出穩(wěn)定好、便攜式的優(yōu)點,在現(xiàn)場噴霧沉積量監(jiān)測中具有較好的應(yīng)用前景。
[Abstract]:As a large agricultural country, the control of crop pests and diseases in agricultural development is the key link to ensure the stable yield and income of agricultural products. Spraying chemical agents is the most common control measure, however, the lack of spraying agricultural drugs can not effectively kill diseases and insect pests, spraying too much pesticides not only cause waste of resources, environmental pollution, and even threaten human health. At present, most of the spray deposition detection adopts water-sensitive paper and laboratory photometric method, however, to a certain extent, these two methods have some disadvantages. Therefore, it is very important to develop a portable field spray deposition detection system with simple operation and low price. The purpose of this paper is to develop a direct electrochemical sensor with high sensitivity, good selectivity and stable performance on the basis of electroanalytical chemistry. The hardware processing unit of signal processing circuit, the signal display software processing unit and the key of power supply circuit in the system are designed to realize the construction of the whole system, and the performance analysis experiment of the system is carried out. The main work includes the following aspects: (1) Construction and performance of organophosphorus pesticide electrochemical sensor. Nitrogen-doped graphene nanomaterials were modified on the surface of screen printing electrode to prepare sensitive elements for rapid response to pesticides. A simple and sensitive enzyme-free electrochemical sensor was constructed for the detection of pesticide methyl parathion. The structure of the sensitive part was characterized by scanning electron microscope (SEM). The electrochemical behavior of methyl parathion was studied by using cyclic volt-ampere technique (CV), differential pulse volt-ampere technique (DPV), linear scanning volt-ampere technique (LSV). Because of the unique structure and properties of nitrogen doping, nitrogen-doped graphene has high electrocatalytic activity for methyl parathion in PBS solution. When the signal-to-noise ratio (SNR) is 3, the maximum sensitivity of the sensor to methyl parathion is 15.32 渭 A / 渭 mol. Under the optimized conditions, the sensor has good stability and selectivity. (2) the analysis and design of the key units of signal detection in the system. The hardware unit design of the system conditioning circuit, including potentiostatic circuit design, I V conversion amplifier circuit, filter circuit and power supply circuit design. Under the energy supply of 12V DC power supply, the microampere current signal is converted into an analog voltage signal in the range of 0 鈮，

本文編號：2507789