农药残留快速检测技术综述 下载本文

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is responsible for Organization training, and implementation, and check; 12, master workshops annual economic indicators of implementation, reporting to financial health on a regular basis; 13, is responsible for the daily oversight in the allocation and use of funds; 14, responsible for all Department statistics, collecting, sorting, reporting of accounting reports; 15, the company responsible for the supervision of the Treasury, including the \d grade\y, a library of materials, products for regular inventory handling, sampling, storage monitoring, the picking work, and provide the inventory report, and make the appropriate accounting treatment; 16, responsible for waste and recycling, transportation and settlement; 17, is responsible for all product sales accounting functions; 18, responsible for the company's raw materials, auxiliary materials, account management; 19, is responsible for the flow of control of all assets of the company, according to the changes in accounting treatment offixed assets and assets to the departments responsible for clearing, settlement and asset monthly report submitted to the asset management section of the Finance Department of the company organized on a company-wide special inspection of asset management; 20, according to the company's business activities, monthly projects involved in the business activities of the company (including expenses, business management, cost control, cash flow, revenue, etc) financial analysis, provide a basis for decisions for the company, the business of the company responsible for monitoring, forecasting and risk analysis; 21, responsible for the settlement of transactions with the Bank; 22, is农药残留快速检测技术研究进展

邓敏姬 邓敏航 郑琪 黄卿仪 易蜀婷

摘要:主要综述了农药残留检测技术中目前广泛应用的酶抑制检测法、酶联免疫检测法、活体生物测定法、生物传感器法和仪器分析法等快速测定方法的原理、优缺点及其进展,指出了农药残留快速检测技术中存在的问题和发展方向。

关键词:农药残留;酶抑制;酶联免疫;活体生物测定;生物传感器;速测

Abstract:Summary of the pesticide residues in the main detection technique is currently widely used in the enzyme inhibition assay, enzyme-linked immunosorbent assay, in vivo bioassay, biological sensors and analysis equipment, such as the rapid determination of the principles, strengths and weaknesses and progress. Pointed out the technology for rapid detection of pesticide residue problems and development direction.

Keywords: pesticide residues; enzyme inhibitor; enzyme-linked immunosorbent assay; vivo bioassay; biological sensors; speed test

正文:长期以来,由于人们在防治农作物病虫害过程中不合理和超剂量使用化学农药,导致农产品中的农药残留量越来越高,影响了农产品的出口和人民的健康,也破坏了农业生态环境。当前世界各国政府正在不断加强农药残留的监测工作,对农药残留检测灵敏度和效率的要求逐步提高,对快速检测分析新技术的开发也日益重视。常规的农药残留分析方法如液相色谱法(HPLC)、气相色谱法(GC)、质谱(MS)法等,均存在着样品前处理复杂、仪器设备昂贵、分析费时长、要求熟练的技术人员才能完成等问题。由于这些方法不能满足样品现场快速检测的要求,迫使人们运用新的原理和方法去开发特异性强、灵敏度高、方便快捷、准确安全的快速检测新技术。本文主要综述了目前广泛应用的酶抑制法、酶联免疫分析方法、活体生物测定方法和生物传感器法等快速测定方法的研究进展。 1.酶抑制法

1.1酶抑制法是一种简便、灵敏、经济的快速检测方法,是相对成熟的一种对部分农药进行残留速测技术。它基于有机磷农药对酶活性的抑制作用,适用于有机磷和氨基甲酸酪类农药。[1,2]

在目前条件下,酶抑制法是净化蔬菜市场的一种有效可行的方法,其优点是能对抑制胆碱酯酶的农药品种进行快速灵敏的检测、样品前处理简单、检测时间短、所需仪器设备简单、

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适用于现场测定。缺点是使用的酶基质和显色剂有一定的特异性,需控制的条件比较多。

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1.2影响因素:1)温度和PH对酶促反应的影响: 酶的活性都随着温度的升高先升高后降低;2)时间对酶促反应的影响;3)温度和农药品种对农药抑制作用的影响:在一定的温度范围内(25-45 ℃)植物酯酶和乙酰胆碱酯酶受到农药的抑制作用都是随着温度的升高而增强;4)时间对农药抑制作用的影响:抑制时间越长,农药的抑制作用越强。

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1.3酶抑制法根据所使用的酶的种类不同可大致分为两类:胆碱酯酶法和植物酯酶法。 1.3.1胆碱酯酶法

原理:乙酰胆碱酯酶(AChE)抑制法的检测原理以乙酰胆碱为底物,在AChE的作用下,乙酰胆碱水解成胆碱和乙酸,胆碱和二硫对硝基苯甲酸(DTNB)产生显色反应,使反应液呈黄色。

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特点:操作简单测定所需的时间短不需要贵重的仪器费用较低适合于现场的快速检测,AChE抑制法虽然在回收率和精密度上较经典方法差一些,但可以满足半定量的要求适合于我国的

is responsible for Organization training, and implementation, and check; 12, master workshops annual economic indicators of implementation, reporting to financial health on a regular basis; 13, is responsible for the daily oversight in the allocation and use of funds; 14, responsible for all Department statistics, collecting, sorting, reporting of accounting reports; 15, the company responsible for the supervision of the Treasury, including the \d grade\y, a library of materials, products for regular inventory handling, sampling, storage monitoring, the picking work, and provide the inventory report, and make the appropriate accounting treatment; 16, responsible for waste and recycling, transportation and settlement; 17, is responsible for all product sales accounting functions; 18, responsible for the company's raw materials, auxiliary materials, account management; 19, is responsible for the flow of control of all assets of the company, according to the changes in accounting treatment offixed assets and assets to the departments responsible for clearing, settlement and asset monthly report submitted to the asset management section of the Finance Department of the company organized on a company-wide special inspection of asset management; 20, according to the company's business activities, monthly projects involved in the business activities of the company (including expenses, business management, cost control, cash flow, revenue, etc) financial analysis, provide a basis for decisions for the company, the business of the company responsible for monitoring, forecasting and risk analysis; 21, responsible for the settlement of transactions with the Bank; 22, is小规模分散式的农产品生产与经销体系。另外,各种农药因其化学结构和作用机理不同对AChE的抑制能力也不相同,氧化型有机磷的抑制能力较强,AChE抑制法对其的灵敏度较高最小检出浓度较低;而硫代型有机磷的抑制能力较差,最小检出浓度较高;但辛硫磷因为含有肟基选择毒力大大增强最小,检出浓度较低;对氨基甲酸酯类农药的检测灵敏度相对都比较高。

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1.3.1.1比色法

比色法是酶抑制法农药残留快速检测测定技术中最常采用的一种方法,也是最简单的一种测定技术。

原理:它通过酶水解底物碘化硫代乙酰胆碱,生成的碘化硫代胆碱,能与5,5’一二硫代一2,2’二硝基苯甲酸(DTNB)作用,生成5一琉基一2一硝基苯甲酸(黄色)。于特征波长(410.nom)下进行比色,测定吸光值,根据吸光值的大小,计算乙酰胆碱酯酶被抑制的程度,并通过与农药浓度进行回归分析,建立回归方程,从而通过测定未知样品对酶活性的抑制率求出样品中残留农药的量的一种方法。

特点:利用此方法对蔬菜、果品及农产品中农药残留量进行测定,灵敏度高、操作简便、检验速度快,可检测多种农药的综合残留量。但由于酶易失活,不易保存,检测时受温度影响,需要控制的条件较多。

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1.3.1.3速测卡法

原理:速测是根据有机磷农药能够强烈抑制小麦酯酶的活性这一特性研制而成,农药残留速

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测卡法是应用农药对乙酰胆碱酯酶抑制原理设计的一种根据颜色变化的直观检测方法。其中红色药片为有2,6一二氯靛酚乙酸酯的经真空干燥后的滤纸片,白色药片含有小麦酯酶。 方法:在使用时将1一2滴样品液滴到白色药片上,对折速测卡使两药片重叠。如果样品中不含有机农药,那么2,6一二氯靛酚乙酸酯在小麦酯酶的作用下迅速发生水解反应,生成蓝色靛酚和乙酸,因而白色药片会显蓝色;如果样品中含有少量有机磷农药,则有机磷农强烈抑制小麦酯酶的活性,使得2,6一二氯靛酚乙酸酯的水解反应不能进行,白色药仍然保持白色或呈浅蓝色。 1.3.2植物酶抑制法

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原理:利用植物酯酶水解2,6-二氯乙酰靛酚,水解产物靛酚为蓝色,最大吸收波长为605 nm,根据反应溶液在水解前后颜色的变化,用目测或仪器来判定农药对酶的抑制程度,从而判断有机磷或氨基甲酸酯类农药的残留量。

特点:在利用酶抑制原理测定农药残留的方法中,植物酯酶与动物酯酶相比,抑制程度的各项指标均不逊色很多,同时又具有酶源方便易得,提取、保存方便,成本低等优势。但是目前的研究表明植物酷酶方法的精确度和灵敏度不及乙酰胆碱酯酶法,乙酰胆碱酯酶法的检出限数量级在0.001 mg/kg附近,而植物酯酶法只能在0. l mg/kg附近,灵敏度较低。 2.酶联免疫分析法(ELISA)

2.1原理:EllSA的核心技术是抗原抗体的特异性反应。ELISA的基本原理是将抗原抗体之间的特异性免疫反应和酶对底物的高度催化效应结合起来,以酶促反应的放大作用来显示

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初级免疫反应。它既可测抗原也可测抗体。

2.2方法:EUSA需要固相载体作为吸附剂,用固相载体吸附抗体(抗原),加待测抗原(抗体),再与相应酶标记抗体(抗原)进行抗原抗体特异免疫反应,生成抗体(抗原)一待测抗原(抗体)一酶标记抗体(抗原)复合物,最后再与该酶底物发生反应生成有色产物。待测抗原(抗体)定量与有色产物量成正比,因此可借吸光度值计算抗原(抗体)量。ELISA法既可进行定性测定,又可进行定量测定。在上述反应中,酶促反应只进行一次,而抗原一抗体免疫反应

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可进行一次或数次。

2.3应用:ELISA技术还可应用于食品中其它成分的测定,⑴抗营养素因子如大豆及其制

is responsible for Organization training, and implementation, and check; 12, master workshops annual economic indicators of implementation, reporting to financial health on a regular basis; 13, is responsible for the daily oversight in the allocation and use of funds; 14, responsible for all Deparment statistics, collecting, sorting, reporting of accounting reports; 15, the company responsible for the supervision of the Treasury, including the \d grade\y, a library of materials, products for regular inventory handling, sampling, storage monitoring, the picking work, and provide the inventory report, and make the appropriate accounting treatment; 16, responsible for waste and recycling, transportation and settlement; 17, is responsible for all product sales accounting functions; 18, responsible for the company's raw materials, auxiliary materials, account management; 19, is responsible for the flow of control of all assets of the company, according to the changes in accounting treatment offixed assets and assets to the departments responsible for clearing, settlement and asset monthly report submitted to the asset management section of the Finance Department of the company organized on a company-wide special inspection of asset management; 20, according to the company's business activities, monthly projects involved in the business activities of the company (including expenses, business management, cost control, cash flow, revenue, etc) financial analysis, provide a basis for decisions for the company, the business of the company responsible for monitoring, forecasting and risk analysis; 21, responsible for the settlement of transactions with the Bank; 22, is品中的胰蛋白酶抑制因子;⑵食品营养成分如牛初乳中乳铁蛋白含量等;⑶食品加工过程中的酶的含量的变化;⑷检测某些特定的转基因表达蛋白,以分析食品是否来自转基因生物或

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者含有转基因成分。

2.4影响因素:影响因素一般涉及到样本的收集保存、试剂准备、加样、温育、洗板、

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显色、比色、结果判断和结果报告及解释等方面。

2.5前景:免疫分析法以其固有的优势,在农药残留分析中日益显示出强大的应用前景。其中以EUSA技术最活跃,EHSA具有特异性强、灵敏度高、快速、简便、痕量检测,以及可大批量样本检测的优点,其检测限可达到纳克甚至更低浓度降24〕。到现在为止,国际上已有上百种农药可用免疫分析法检测,且已制成商品化快速检测试剂盒或试剂条。目前我国已研制出6种农药残留酶联免疫检测试剂盒(甲霜灵、甲胺磷、毒死蟀、对硫磷、2,4一D、百菌清),胶体金免疫快速检测试纸16种(3,5,6一三氯二毗吮醇、、苯菌灵、除草定、丁草胺、毒死蟀、禾草灵、甲草胺、甲蔡威、甲霜灵、霜霉威、西玛津、嗅苯睛、乙草胺、异丙草胺、异丙甲草胺、芬去津);另外研制出高效快速地检测生物毒素的免疫检测试剂盒13种和免疫胶体金纸条5种;研制出兽药残留酶联免疫检测试剂盒11种,其中有些试剂盒已实现产业化,取得了显著的经济效益和社会效益固。与国外相比,国内在这方面的研究相对较少,但正越来越受到研究检测工作者的高度重视,目前研发各种农药残留检测试剂盒的步伐

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日益加快,所以EllSA法在农药残留检测中将有广阔的应用前景。

抗体特异性及灵敏性虽有较大程度提高;但仍不能同时检测数十种甚至更多农药残留。用于食品农药残留检测,在检测单个农药时具有快速、方便等优点;但由于农药品种繁多及混

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配使用等原因,在检测大批样品时,仍显得无能为力。 3.活体生物测定

3.1原理:活体检测法是使用活的生物体直接测定。如农药与细菌作用后可影响细菌的发光强度,以检测农药残留量。 3.2方法

3.2.1用发光细菌检测农药残留

发光细菌体内的荧光素在有氧时经荧光酶的作用会产生荧光,但当受到某些有毒化合物的作用时发光会减弱,其减弱的程度与有毒物的浓度呈一定的线性关系,利用这一特点对农药残

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留试样进行测定。

该方法的特点是快速、简便、灵敏、价廉,适合于现场,缺点是农药浓度与发光强度的线性亲系不够准确,只能用于半定量测定。 3.2.2用家蝇检测蔬菜中的残留农药

以采收前1~2天的蔬菜为检测对象,随机抽取检测样品,将饲料放于菜汁中,接触后3~4h观察死亡率,并且需要用无农药污染的蔬菜作为对照。死亡率在4%以下为安全或较安全;死

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亡率在5%~10%蔬菜中农药残留量超标;死亡率大于11%表示污染严重或极严重。

该方法的优点是无需仪器,无需前处理,过程简单。缺点是无法定量,检测时间比较长,敏感性家蝇饲养比较困难。 4生物传感器法

生物传感器是将传感技术与农药免疫技术相结合而建立起来的,可以说它是免疫分析技术的一种延伸或分支。根据生物功能不同主要分为不同类型传感器,利用农药对靶酶活性的抑制作用研制传感器时,应选择活性高而其活性对农药敏感的酶作为生物传感器称为酶传感;利用农药与特异性抗体结合特性研制免疫传感器;另外还微生物传感器和组织传感器等等[11]

4.1原理:生物敏感膜内含有能与目标物进行选择性作用的生物活性组分;换能器则能敏感捕捉生物活性组分与目标物之间的作用过程,并将其表达为可检测的物理信号。当待测物与