Residue of Organphosphorus Pesticides in Chewing Cane Juices Detected by QuEChERS and GC-NPD Method
quarantine pest 名词解释
quarantine pest 名词解释Quarantine pest is a noun phrase that refers to a type of organism that is harmful to plants and can cause significant damage to agricultural crops. These organisms are typically regulated and subjected to strict quarantine measures to prevent their entry or spread to new areas.1. The agricultural inspector identified a quarantine pest in the shipment of imported fruits.农业检查员在进口水果的货物中发现了一种检疫害虫。
2. The presence of a quarantine pest on the farm has led to a decrease in crop yields.农场上的一种检疫害虫的存在导致了作物产量的下降。
3. The authorities have imposed a ban on the movement of plants and plant products to control the spread of quarantine pests.当局已经禁止植物和植物产品的流动，以控制检疫害虫的传播。
4. Farmers must regularly monitor their crops for any signs of quarantine pests and report them immediately.农民们必须定期监测作物，以发现任何检疫害虫的迹象并立即报告。
蔬菜中有机磷农药残留检测方法及其应用研究
摘要论文建立了蔬菜中11 种农药多残留的气相色谱分析方法。
对NY/T761-2008《蔬菜和水果中有机磷、有机氮、拟除虫菊酯和氨基甲酸酯类农药多残留的测定》标准的蔬菜前处理方法进行了改进，探讨了蔬菜基质对检测的影响。
使用DB-17 毛细管柱分离，FPD 检测器进行检测。
结果显示：11 种有机磷农药分离效果好，在黄瓜、西红柿、生姜中的3 个浓度添加水平，回收率为71.2%-117.9%，相对标准偏差（RSD）为2.1%-11.2%，最低检出限为0.005mg/kg-0.06mg/kg，保留时间为6.396min-19.400min。
在各自限性范围内线性关系好（r>0.999）；使用40℃加热氮吹浓缩，可分别提高敌敌畏、甲拌磷回收率至95.00%和103.3%；在被测得13 种蔬菜中，甘蓝、娃娃菜、上海青有少量杂峰影响农药检出；韭菜有大量的基质峰干扰农药检出。
为了有效控制蔬菜农药残留提供科学依据，2009 年9 月至12 月对天河区4 家超市及1 处农贸市场进行随机抽样检测，用气相色谱法测定其中的有机磷农药。
共检测蔬菜样品64 份，其中农药残留阳性的有10 份，超标率为15.63%。
叶菜类蔬菜合格率为71.43%，而瓜菜类、根茎类和茄果类全部合格。
在11 种标的农药中，检测出5 种，其中 3 种为国家禁用农药。
论文还研究了不同清洗方法对去除蔬菜中有机磷农药残留的影响。
采用气相色谱法（GC）对经过不同方法浸泡处理的娃娃菜中敌敌畏和乐果的残留量进行分析，结果显示：除了超声波清洗之外，清水、洗涤剂以及食用碱均能不同程度的去除娃娃菜中残留的农药。
其中斧牌洗洁精对敌敌畏和乐果两种农药残留的去除效果最佳，斧牌洗洁精对两种农药的去除率为分别为84.38%和76.11%。
关键词：气相色谱（GC）；有机磷农药残留；蔬菜ABSTRACTMethods were set up for determination of 11 organ phosphorus pesticides multi-residuein vegetables by gas chromatography and define the scope of application of this method by analysis of vegetable matrix. Vegetable pretreatment method in standard of NY/T 761-2008 was modified in this paper, and DB-17 capillary column and flame photometric detector (FPD) were used. The result showed that 11 organ phosphorus pesticides were separated from each other. The fortified recovery of 11 pesticides gained from cucumber, tomato, and ginger with three spiked levels ranged from71.2% to 117.9%. The Relative standard deviation (RSD) was 2.1% to 11.2%, the Minimum detection limit of the method was 0.005~0.06 mg/kg for DB-17 column, and the Retention time was 6.396 to 19.400 minutes. The calibration curves showed good linearity with correlative coefficient of more than 0.999. Sample was heated up to 40℃ when blew by nitrogen (N2), the recoveries of Dichlorovos and Phorate would enhance to95.00% and 103.3% respectively. Among 13 vegetables detected, green pepper, baby cabbage and shanghai green have several peaks of matrix to impact detection of pesticide residues while garlic chive was found a large number of peaks interfere with the detection of pesticides.A survey of organ phosphorus pesticide in sixty four vegetable samples collected randomly from four supermarkets and one vegetable wholesale market of Guangzhou city was carried out from September to December in 2009. Gas chromatography analysis for 11 organ phosphorus pesticide residues in the samples showed that the qualification rate of leaf vegetables was 71.43%, and no investigated pesticide residue was detected in the all examined the raw melons vegetables, the root vegetables, and the solanaceous fruit vegetables. Five kinds of organ phosphorus pesticides were detected in 10 kinds of samples (64 samples) with the disqualification rate being of 15.63%, among which three prohibited pesticides for planting vegetables according to relevant laws were detected. Forbidden pesticide residue was detected with relatively high frequency in the vegetable samples.The effects of different rinsing methods on the removal ratio of organ phosphorus pesticide residues from Baby cabbage were investigated. The gas chromatography (GC) was used to analyze the pesticide residues in baby cabbage rinsed by different method. The results showed that clear water rinsing, detergent and edible alkali can remove the residual pesticide in baby cabbage at different level，except for treatment with ultrasonic. Among all these methods，d etergent with brand of Axe can remove residual pesticide effectively. The removalratio of Dichlorovos and Dimethoate was 84.38%, 76.11% by detergent with brand of Axe. Keyword：Gas chromatography; organic phosphorus pesticide residue; vegetable目录摘要 (I)Abstract ...................................................................................................................................... I I 第一章：绪论.. (1)1.1有机磷农药 (1)1.2蔬菜中有机磷农药残留现状 (2)1.3农药残留危害 (4)1.3.1农药残留对人体健康的危害 (4)1.3.2农药残留对生态系统的危害 (5)1.3.3农药对害虫天敌的危害 (5)1.3.4农药对土壤微生物的危害 (5)1.3.5农药对水环境的影响 (5)1.4蔬菜中有机磷农药的前处理方法与分析方法 (6)1.4.1农药残留的前处理技术 (6)1.4.2农药残留的分析检测技术 (7)1.5蔬菜表面有机磷农药的去除方法 (8)1.5.1物理方法81.5.2化学方法101.5.3生物方法111.6本研究的目的与意义 (11)1.7研究内容 (12)第二章蔬菜中11 种有机磷农药残留的气相色谱检测及蔬菜基质影响的研究 (14)2.1 引言 (14)2.2实验材料与仪器设备 (14)2.3实验方法 (15)2.3.1气相色谱分析条件 (15)2.3.2GC-MS 分析条件 (16)2.3.3样品提取162.3.4 净化 (16)2.4结果与讨论 (16)2.4.1种有机磷农药混合标准液色谱分离效果图 (16)2.4.2氮吹温度对敌敌畏、甲拌磷回收率的影响 (18)2.4.3不同基质对检测效果的影响 (19)2.4.4线性范围、标准曲线、检出限和保留时间 (23)2.4.5回收率和精密度实验 (24)2.5本章小节 (26)第三章广州市售蔬菜有机磷农药残留情况调查分析 (27)3.1 引言 (27)3.2实验材料与仪器设备 (27)3.3实验方法 (27)3.3.1测定方法273.3.2评定标准283.4结果与讨论 (28)3.4.1总体检测情况 (28)3.4.2不同种类农药检出率 (28)3.4.3不同类别蔬菜中农药残留情况 (29)3.4.4不同品种蔬菜中农药残留情况 (30)3.4.5不同来源蔬菜的农药残留检测情况 (31)3.5本章小节 (31)第四章：清洗方法对蔬菜中有机磷农药残留去除效果的研究 (33)4.1 引言 (33)4.2实验材料与仪器设备 (33)4.3实验方法 (34)4.3.1样品处理方法 (34)4.3.2样品前处理方法 (34)4.3.3GC 检测条件344.3.4清洗方法344.3.5农药残留率的计算 (35)4.4结果与讨论 (35)4.4.1清水浸泡时间对农药去除的效果 (35)4.4.2超声波清洗对农药去除的效果 (36)4.4.3洗涤剂浸泡对农药去除的效果 (37)4.4.4食用碱浸泡对农药去除的效果 (39)4.5本章小节 (40)结论与展望 (41)参考文献 (43)第一章绪论第一章绪论1.1有机磷农药二十世纪末，在我国农药生产种类中，杀虫剂占了农药总产量的近70%，而在杀虫剂总量中，有机磷农药又占了近70%[1]，有机磷农药在我国农药生产和使用中有着特殊的地位。
乙酰胆碱酯酶和发光菌检测有机磷农药毒性研究
第32卷第6期2011年6月环境科学ENVIRONMENTAL SCIENCEVol．32，No．6Jun．，2011乙酰胆碱酯酶和发光菌检测有机磷农药毒性研究贾玉玲1，蔡强1，彭惠民2，钟平方4，何苗3，施汉昌3（1.浙江清华长三角研究院生态环境研究所，嘉兴314000；2.重庆医科大学基础医学院，重庆400016；3.清华大学环境科学与工程系，北京100084；4.重庆三大伟业制药有限公司，重庆402460）摘要：有机磷农药（organophosphorus pesticides ，OPs ）污染形势严峻．研究采用乙酰胆碱酯酶（acetylcholinesterase ，AChE ）和T 3发光菌2种生物检测法，在急性毒性实验基础上，研究了几种有机磷农药的联合毒性，为今后OPs 检测标准的制定提供参考．实验结果表明，在最佳反应条件下，AChE 对不同OPs 的敏感性不同，敌敌畏﹥敌百虫﹥乙酰甲胺磷﹥氧乐果﹥三唑磷，对5种OPs 的检出浓度分别为1.69、3.78、4.03、7.32和8.03μg /mL ；利用T 3发光菌检测有机磷农药的单一毒性，表明发光菌相对发光率与OPs 浓度呈负相关，相关系数在0.93 0.98，OPs 对T 3发光菌的半数效应浓度（EC 50）分别为0.398、0.712、0.152、0.094、0.140mg /mL ，毒性大小顺序为：乙酰甲胺磷＞三唑磷＞氧乐果＞敌敌畏＞敌百虫；利用2种方法评价5种OPs 的联合作用，表明OPs 二元混合物联合作用方式为协同作用和部分相加作用．关键词：有机磷农药；乙酰胆碱酯酶；发光菌；急性毒性；联合毒性中图分类号：X502文献标识码：A文章编号：0250-3301（2011）06-1820-05收稿日期：2010-07-13；修订日期：2010-10-11基金项目：国家高技术研究发展计划（863）项目（2007AA062419）；浙江省重点科技计划项目（2006C23069）；浙江省自然基金项目（Y507081）；浙江省重大科技项目（2007C13010）作者简介：贾玉玲（1984 ），女，硕士研究生，主要研究方向为环境监测，E-mail ：archer200224@163．com Detection of the Toxicity of Organophosphorus Pesticide withAcetylcholinesterase and Luminescent BacteriumJIA Yu-ling 1，CAI Qiang 1，PENG Hui-min 2，ZHONG Ping-fang 4，HE Miao 3，SHI Han-chang 3（1.Department of Environmental Technology and Ecology ，Yangtze Delta Region Institute of Tsinghua University ，Zhejiang Jiaxing 314000，China ；2.Faculty of Basic Medical Sciences ，Chongqing Medical University ，Chongqing 400016，China ；3.Department of Environmental Science and Engineering ，Tsinghua University ，Beijing 100084，China ； 4.Chongqing SAN-DA Pharmaceutical Company ，Chongqing 402460，China ）Abstract ：Organphosphorus pesticides （OPs ）can lead to serious environmental pollution problems．Whose bioeffect of multi-OPs is still lack of consideration although single component has been studied．To evaluate joint acute toxicity of OPs ，two bioassay ，AchE and T 3luminous bacterium ，were studied ，The result shows that ：The sensitivity of AChE to different OPs are different ：dichlorvos ＞trichlotfon ＞acephate ＞omethoate ＞triazophos ，the detection limit of five kinds of OPs are 1.69，3.78，4.03，7.32and 8.03μg /mL．Detecting the single toxicity of OPs with method of T 3luminous bacterium ，the relationship between luminous efficiency of luminous bacterium and the concentration of OPs is negatively correlated ，and the correlation coefficient is between 0.93and 0.98，the EC 50value of OPs to T 3luminescent bacterium are 0.398，0.712，0.152，0.094，0.140mg /mL ，the toxicity order of OPs to T 3luminous bacterium is ：acephate ＞triazophos ＞omethoate ＞dichlorvos ＞trichlorfon ；Using such two kinds of methods to evaluate the joint toxicity of OPs showed that the joint mode action of binary mixtures of OPs includes the synergy effect and partial additive effect．Key words ：organophosphorus pesticides （OPs ）；acetylcholinesterase ；luminescent bacteria ；acute toxicity ；joint toxicity农药是用于预防、消灭或控制病、虫、草和其他有害生物以及调节植物、昆虫生长的一种物质或几种物质的混合物［1］．有机磷农药因相对于有机氯农药容易降解，在环境中残留时间较短，20世纪80年代后被大量用于病虫害的防治．有机磷农药（organophosphorus pesticides ，OPs ）是一类含有C —P 键或C —O —P 、C —S —P 、C —N —P 键的磷酸酯类或硫代磷酸酯类，是一类神经性毒物［2］．各种OPs 毒性不同，但大多属剧毒和高毒类．常见的仪器检测方法可精确定量样品中污染物的种类和含量，如气相色谱法、高效液相色谱法等［3］，但这些方法检测成本较高，样品前处理复杂，不能直接判断环境中污染物毒性大小，在毒性快速预警方面的应用受到限制．酶抑制法是目前最为常用的快速检测有机磷农药含量及毒性的方法之一，目前在国内外已被广泛应用，例如试纸条、酶生物传感器等，但其检测灵敏度略低于仪器检测法．常用于检测环境中OPs 的酶主要为乙酰胆碱酯酶6期贾玉玲等：乙酰胆碱酯酶和发光菌检测有机磷农药毒性研究（acetylcholinesterase，AChE），其检测原理是有机磷农药的抑制作用［4，5］．发光菌毒性检测法的检测原理是根据反应前后发光菌发光强度的变化率确定有毒物毒性大小，具有成本低、操作简单、反应灵敏等优点，因此被广泛应用于各种工业废水［6，7］和地表水［8］的毒性监测．为了能够准确及时反映水体中有机磷农药的污染状况，实现在线预警监测，需要将确证性检测与毒性检测方法结合起来．酶检测方法一方面具有检测成本低、易于操作等优点，另外还可实现半定量分析，因此满足在线预警监测需求；发光菌检测法是目前应用最广泛的毒性评价检测方法，也满足在线预警监测需要．本研究利用自制的AChE首先测定了5种OPs 的急性毒性，之后测定其联合毒性，并与发光菌毒性检测结果做比较，以期为今后OPs检测方法的选择及运用提供研究基础，也为今后饮用水在线监测预警体系的建立提供基础．1材料与方法1.1仪器与试剂高速冷冻离心机（湘仪，TGL-20M），紫外可见分光光度计（岛津，UV-Probe2450），AL204-IC电子天平（Mettler-Toledo）；6173酸碱度/氧化还原/温度-台式测试仪（Jenco）；Milli-Q Academic超纯水器（Millipore）；88-Ⅰ型定时恒温磁力搅拌器（上海司乐仪器有限公司）；水质毒性快速检测仪（BHP9511，北京滨松光子技术股份有限公司）；电热恒温培养箱（SHP-150）；立式压力蒸汽灭菌器（LDZX-50FA）；净化工作台（SW-CJ-1D）；微量振荡器（MH2）．实验所用试剂：自制AChE［酶比活为458.43μmol/（min·mg），实验每次用20μL］；明亮发光杆菌（photobacterium phosphoreum）T3变种，中国科学院南京土壤研究所；胰蛋白胨，琼脂粉，酵母提取物，均购自国药集团．牛血清白蛋白（BSA），考马斯亮蓝G-250，二硫代二硝基苯甲酸（DTNB），硫代乙酰胆碱（ATCh），硫代丁酰胆碱（BTCh），均购自SIGMA公司．80%敌敌畏（dichlorvos）（湖北沙隆达），30%乙酰甲胺磷（acephate）（湖北沙隆达），40%氧乐果（omethoate）（沙隆达郑州农药），90%敌百虫（trichlorfon）（南通江山农药化工），30%三唑磷（triazophos）（湖北沙隆达）．数据分析采用Origin8.0．1.2实验方法1.2.1乙酰胆碱酯酶毒性实验将5种农药稀释为不同浓度梯度（8000 0.1μg/mL）溶液，按酶活测定方法［9］，加入底物后迅速加入20μL不同浓度农药和显色剂混匀，412nm处测定吸光度值的变化．以农药浓度对数值为X轴，抑制率为Y轴作图．I为抑制率（%）；E1为无农药抑制时的酶液活性［μmol/（min·mg）］；E2为某一浓度农药抑制时酶液的活性［μmol/（min·mg）］．抑制率I（%）=E1－E2E1ˑ100%实验采用Mansour等［10］提出的等毒法评价5种OPs二元混合物的联合抑制效应，通过共毒系数的计算，评价混合物的联合作用．计算5种OPs对AChE的半数抑制浓度值IC50，将5种OPs按照其IC50值一半的浓度两两混合，则预期抑制率应该是50%，那可由实际测得抑制率和预期抑制率计算共毒系数．共毒系数=实测抑制率－预期抑制率预期抑制率ˑ100如果共毒系数在10 20之间，表示有弱的协同作用，当其＞20时，表示有协同作用；共毒系数在－20 －10之间时，说明2种有毒物有弱的拮抗作用，而当其＜－20时，表示为拮抗作用；当共毒系数值在－10 10之间时，表示为简单的相加作用［11］．1.2.2T3发光菌毒性试验T3发光菌培养基和培养方法参照文献［12，13］．利用3%NaCl配制系列浓度的有机磷农药，各吸取2mL于比色管中，用2mL3%的NaCl溶液作空白对照，每个浓度做3个平行，然后迅速吸取50μL T3发光菌液［14］，比色管中摇匀，采用已经改进的毒性检测方法［15］，15min后用生物毒性测试仪测定发光强度，计算相对发光率［16］．相对发光率=样品发光强度对照发光强度ˑ100%根据预实验，找出抑制率为50%时的浓度，再按照等对数间距设置5 8个浓度梯度，计算发光菌发光抑制率为50%时的农药浓度，然后对农药浓度和相对发光率进行回归分析，计算半数效应浓度EC［17］．关于联合毒性评价，采用毒性单位法（由Sprague和Ramsay提出）、相加指数（1977年由Marking提出）和混合毒性指数法（1981年由1281环境科学32卷Kobnemann 提出）［18］．将5种OPs 按照等浓度（mg /mL ）混合，测定各混合物对发光菌的毒性，回归分析求得EC 50（方法同发光菌单一毒性测定），根据上述联合毒性评价方法评价OPs 的联合毒性．2结果与讨论2.1乙酰胆碱酯酶毒性试验根据分析结果可知，5种OPs 对鱼脑AChE 的毒性不同．敌敌畏对AChE 活性的抑制作用最大（图1）．据报道［19］，以酶活性抑制率16%为标准，AChE 对敌敌畏最敏感，检出浓度为1.69μg /mL ，敌百虫检出浓度为3.78μg /mL ，2种OPs 的检出浓度均低于已有研究结果．AChE 对乙酰甲胺磷、氧乐果及三唑磷的检出浓度分别为4.03、7.32和8.03μg /mL．不同OPs 对鱼脑AChE 的毒性作用和敏感性不同：敌敌畏﹥敌百虫﹥乙酰甲胺磷﹥氧乐果﹥三唑磷．图15种有机磷农药对乙酰胆碱酯酶的抑制曲线Fig．1Inhibition curve of five kinds of OPs to AChEAChE 对不同OPs 的敏感性存在差异，可能是由于AChE 对不同种类的OPs 化学结合力不同，即分子结构不同造成的．敌敌畏是5种农药中毒性极高、残留时间长的高毒物质，并且在我国已经被明令禁止使用．据研究一般含有手性原子的OPs 比不含手性原子的农药毒性强，且对AChE 的抑制力也强，而含有手性磷原子的农药又比含有手性碳原子的毒性强，分别含有一个手性碳原子和手性磷原子的OPs 毒性最强．敌百虫和氧乐果只含有一个手性碳原子，乙酰甲胺磷分别含有一个手性碳原子和手性磷原子，三唑磷均没有2种手性原子，所以毒性乙酰甲胺磷﹥氧乐果﹥三唑磷，敌百虫毒性之所以大于乙酰甲胺磷，可能是由于敌百虫在PBS 缓冲液中（pH =8.0）反应时，部分转化为毒性更强的敌敌畏［20］．在上述实验结果基础上，通过计算IC 50，求共毒系数，结果如表1．根据表1可知，5种有机磷农药两两组合，10种二元混合物的共毒系数均在37 45之间，表现为协同作用．表1有机磷农药混合物联合作用结果Table 1Results of the joint effects of the mixture混合物组成预期抑制率实测抑制率共毒系数/μg ·mL －1作用结果敌敌畏+敌百虫0.50.69739.4协同作用敌敌畏+氧乐果0.50.72144.2协同作用敌敌畏+乙酰甲胺磷0.50.68637.2协同作用敌敌畏+三唑磷0.50.69939.8协同作用敌百虫+氧乐果0.50.71643.2协同作用敌百虫+乙酰甲胺磷0.50.69539.1协同作用敌百虫+三唑磷0.50.69739.5协同作用氧乐果+乙酰甲胺磷0.50.72444.9协同作用氧乐果+三唑磷0.50.70941.9协同作用乙酰甲胺磷+三唑磷0.50.68637.2协同作用根据上述结果可知：①5种有机磷农药的10种二元混合物，联合作用方式表现为协同作用，且共毒系数越大（37 45之间），协同作用也越大．②根据实验结果可知，原本毒性弱于敌敌畏的4种OPs ，其二元混合物的共毒系数都大于敌敌畏与它们之间的共毒系数，表明即使毒性较低的有机磷农药混合后，其联合毒性也会高于2种农药毒性之和，对环境威胁更大．OPs 抑制AChE ，主要在于它与AChE 的酯解部位丝氨酸共价结合，改变了其周围电子效应，而电子效应又通常与化学反应关系密切，所以OPs 的电性结构对AChE 的抑制作用也有影响［21］．分子最低未占轨道能E lumo 可以衡量分子对电子亲和力的大小，一般负值越大，该分子接受电子的能力越强［22］．敌百虫的E lumo 为－0.150cV ，氧乐果的E lumo为－0.065cV ，三唑磷的E lumo 为－1.968cV ，当其两两混合，其E lumo 的绝对值都增大，即亲电能力得到了增强，所以混合后更容易与AChE 反应，即毒性越大，联合作用形式为协同作用．2.2T 3发光菌毒性实验通过农药对发光菌发光的抑制实验，得到不同浓度敌敌畏、敌百虫、氧乐果、乙酰甲胺磷和三唑磷对发光菌的相对发光率，然后将二者进行线性回归，通过SPSS 软件求得EC 50值．5种OPs 对发光菌发光率均有不同程度的抑制，并且随着作用时间的延长，其对发光强度的抑制率增加，实验选择15min 为测定时间，结果如表2所示．通过上述实验结果可知，发光菌的相对发光率22816期贾玉玲等：乙酰胆碱酯酶和发光菌检测有机磷农药毒性研究与有机磷农药的浓度呈负相关，相关系数在0.930.98之间，确定了敌敌畏、敌百虫、氧乐果、乙酰甲胺磷、三唑磷对发光菌的半数效应浓度分别为：0.398、0.712、0.152、0.094、0.140mg/mL，5种OPs对T3发光菌毒性大小顺序为：乙酰甲胺磷＞三唑磷＞氧乐果＞敌敌畏＞敌百虫．表2有机磷农药对T3发光菌的毒性作用Table2Toxicity of five kinds of OPs on T3bacterium农药名称时间/min线性方程1）相关系数（R2）EC50/mg·mL－1敌敌畏15Y=－0.0022X+1.38480.9530.398敌百虫15Y=－0.0080X+1.06100.9720.712乙酰甲胺磷15Y=－0.0040X+0.91890.9390.094氧乐果15Y=－0.0019X+0.85470.9800.152三唑磷15Y=－0.0050X+1.24620.9550.1401）Y：发光强度抑制率，%，X：有机磷农药浓度，mg·mL－1根据发光菌实验结果EC50值看出，发光菌对5种有机磷农药的敏感性次于AChE，说明与OPs的特异性反应不如AChE．发光菌对5种OPs的敏感性顺序为乙酰甲胺磷＞三唑磷＞氧乐果＞敌敌畏＞敌百虫，说明发光菌对乙酰甲胺磷的毒性最为敏感，此结果与AChE检测结果不同，一方面由于2种检测方法的基本原理不同，其反应会存在差异；另外实验过程中使用了甲醇作为助溶剂，其本身对发光菌的发光强度有一定的抑制作用［23］．实验测定了5种OPs的二元混合物在等浓度配比下的联合毒性，采用毒性单位法、相加指数法及混合毒性指数法对联合毒性作用评价，结果如表3．利用3种方法对有机磷联合毒性进行评价，10种二元混合物联合毒性作用具有不同的表现方式．结果表明，只有敌敌畏/乙酰甲胺磷组M＞M，AI ＜0，MTI＜0，3种评价方法均为拮抗作用；其余各组M＜1，M＞M＞1，表现为协同作用、部分相加作用；AI＞0，表现为协同作用；敌敌畏/氧乐果的0＜MTI＜1，表现为部分相加作用；其余组合MTI ＞1，表现为协同作用．虽然3种评价方法在结果上略有差异，但总体上表明OPs混合物的联合毒性表现为协同作用或部分相加作用．3结论（1）2种方法检测OPs二元混合物的联合作用，结果表明联合作用方式基本为协同作用和部分相加作用，OPs混合物毒性不是简单相加作用，其联合毒性大于两者单一毒性之和．（2）联合毒性试验结果表明，在制定毒性评价表3有机磷农药混合物对发光菌的联合毒性Table3Joint toxicity of mixture on T3luminescent bacterium有机磷农药EC50/mg·mL－1TUi1）M2）M3）AI4）MTI5）敌敌畏0.1080.271 1.3810.981 1.0590.890氧乐果0.710敌敌畏0.1010.253 1.5610.395 1.532 3.085敌百虫0.142敌敌畏0.685 1.721 1.2369.008－8.008－9.37乙酰甲胺磷7.287氧乐果0.0750.493 1.2130.5980.672 3.662敌百虫0.105氧乐果0.0540.355 1.6170.930.075 1.151乙酰甲胺磷0.575敌百虫0.0630.088 1.1310.7580.319 3.250乙酰甲胺磷0.670敌敌畏0.0540.136 1.3520.5220.915 3.155三唑磷0.386乙酰甲胺磷0.0370.394 1.6700.6580.519 1.816三唑磷0.264氧乐果0.0430.283 1.9210.590.6950.680三唑磷0.307敌百虫0.0370.052 1.1970.316 2.1647.406三唑磷0.2641）TUi为混合物第i组分毒性单位，TUi=ci/EC50，i，ci是混合物在半数效应第i组分浓度；2）M表示混合物毒性单位，M=ΣTU i；3）M=M/TUi max（TUi max指混合物中毒性单位的最大值）；4）相加指数法AI：当M≤1时，AI=1/M－1；当M＞1时，AI=1－M；5）混合毒性指数法MTI，MTI=1－lg M/lg 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andToxicology，2001，66（2）：135-154．［18］林春，康立娟，苏丽敏．2，4-二硝基甲苯与硝基苯衍生物对发光菌的联合毒性［J］．吉林大学学报（理学版），2002，40（4）：98-101．［19］刘世文，侯云修，陈佳荣，等．纯化乙酰胆碱酯酶抑制法测定游离有机磷［J］．现代检验医学杂志，2005，20（2）：7-9．［20］周润福．有机磷旋光异构体与生物活性的关系［J］．农药，1983，（3）：42-45．［21］Becerro M A，Thacker R W，Turon X，et al．Biogeography of sponge chemical ecology：comparisons of tropical and temperatedefenses［J］．Oecologia，2003，135（1）：91-101．［22］颜冬云，蒋新，余贵芬，等．有机磷农药对乙酰胆碱酯酶的抑制作用及其机理分析［A］．见：第三届全国环境化学学术大会论文集［C］．2005．573-574．［23］董玉瑛，雷炳莉，马静，等．助溶剂对发光菌生物毒性测试的影响［J］．化工学报，2006，15（3）：170-173．4281。
食品分析方法（Foodanalysismethods）
食品分析方法（Food analysis methods）The content of food inspection and analysis is very rich, and the range is very extensive, in many kinds of food, there are many components are the same, there are some group provisions are not the same. In particular, different kinds of food have different characteristics. Let's start with food analysisI. range of food analysis Analgtical range1. analysis of nutritional components of food (analysis of general components)Nutrients including: 1 the water activity water water water and ash ash the moderate fat fat the acidity acidity, carbohydrate, Protein, protein, carbohydrate, amino acid Amino chloride chloride that vitamin Vitamin, trace elements trace elementAccording to the analysis above, we know that these nutrients, from water to water test activity, from protein to Amino acids test and multi vitamin test are illustrated by analysis of food inspection object material, from the macro micro direction gradually.The inspection of trace elements includes the examination of essential elements of human body and the examination of harmful elements to human body.2. analysis of contaminants in foodFood contaminants are classified into two categories according to their natureBiological pollution refers to the growth and reproduction of microorganisms, resulting in toxins affecting healthSuch as: Aspergillus, in peanut rot produced; corn, milk and dairy products and meat products produced dichlorvos.Chemical pollutionA pesticides (organic chlorine, organic phosphorus, etc.)B heavy metal poisoning (Hg, Pb, As, Cd)C packaging materials (polycyclic compounds)D produced during machining. Smoke and smoke food may produce carcinogens 3-4 benzopyreneAccording to the metal source can be divided into:(1) natural environment, air and water(2) production, processing, machinery, ordinary containers(3) pollution of three wastes treated by agricultureChemical pollution is mostly pesticide metal. Generally, the organochlorine pesticides in fruits and vegetables can be divided into two categories: chlorinated benzenes and their derivatives. Such as: DDT, 666, etc.. The other is potassium chloride supporting agents such as naphthalene Di's agent, thiskind of parenchymal organs such as liver and kidney damage caused by pesticide poisoning, finally liver malnutrition, resulting in degeneration, necrosis. There are 1059 common organic phosphorus, 1605, dichlorvos, trichlorfon, 4049, which is oily liquid, a solid, before both on human lethal dose of 0.1g. The residues of these pesticides were longer in soil.For the above two pesticides, the former is more toxic than the latter, and organochlorine pesticide residues are common in our food. Especially in animal food, most of them are vegetables 0.02mg/kg, carnivorous animals are 1mg/kg, sea cucumber fish 0.5mg/kg, freshwater fish 2mg/kg. According to these figures, the human diet also contains DDT and its metabolites, but with reduced usage and limit the scope of use of organochlorine pesticide residues in the diet can also be reduced year by year, such as the United States in 1965 for 0.9ug/kg/day, 67 for 0.8 years, 69 years and 70 years was 0.5, 0.4, 72 for 0.3 years.In the process of food processing, this pesticide cannot be removed by simple washing of fruits, carrots, potatoes, etc. if peeled, the residue decreased significantly; on baking bread and cakes, the pesticide volatilization temperature can also make residues decreased, but DDT in the central part of content is high. The bread.3. analysis of food auxiliary materials and additivesUsed in food processing, auxiliary materials and additives are generally industrial products, the use of dose varieties have strict rules, especially the additive is to improve the color, flavor and taste of the bread or prevent food spoilage and add.If used improperly, the consequences will be unimaginable.Inspection of food additives,Including preservatives, antioxidants, coloring agent, bleaching agent, acidity agent, coagulant, bulking agent, thickening agent, sweetening agent, coloring agent, quality improver, flavor monomer 14.With the development of food industry and chemical industry, food additives and the number increasing, so their impact on human health should pay special attention to, especially with the continuous improvement and development of research methods of food poison mechanics, previously thought harmless food additives, in recent years, and found that there may be chronic toxicity, carcinogenic effects. Teratogenicity, mutagenicity or other hazards, so it must be controlled within the allowable limit.4. sensory evaluation of Sense organ appraisalA. olfactory identification Scent appraisal (sense of smell)B. visual identification of Vision appraisalC. taste identification Sense of tasteD. tactile identification of tactile sensationSensory evaluation is to examine the shape, color, taste, and consistency of food based on human sensory organs. Thisidentification is an indispensable part of any test method, and is carried out before various analytical methods, so sensory evaluation is also very important.A) olfactory identification Scent appraisal (sense of smell)A person's sense of smell is quite sensitive. Of course, the most sensitive smell is the police dog, sometimes with the general methods and instruments can not be analyzed, and can be found by smell test. Such as: pork, fish protein in the initial stage of decomposition, with the general method is not measured out, but with our nose, can smell an odor of ammonia (as the basic unit of protein in food is further decomposed into ammonia amino acid, and alpha keto acid); and if not, a variety of indicators changes in Lipid Rancidity, but can smell rancid taste.We say whether or Kazakhstan oil ammonia smell taste, they are volatile food smell, the volatile matter is highly affected by the temperature, the temperature low volatile odor is slow, light, generally in the determination of odor, can be heated slightly. For example: We measured in liquid samples, take a few drops of on a clean hand rub, and then see whether there is abnormal smell smell the determination of solid deep odor samples, with cut bamboo into the depths of the food, and then pull out immediately sniffing.In addition, the general inspection in order from the smell of light to strong, otherwise inaccurate.B) visual inspection Vision appraisalThe so-called visual inspection is to use your eyes to judge the nature of food, on many occasions, it is a very important means of food, the shape and color of evaluation of food quality, fresh degree, there is no contaminated Great relationship. For example, according to the color of fruits and vegetables, we can judge the maturity of fruits and vegetables. Another example: according to the color of the wine, you can judge what wine is.Visual inspection is usually done during the day, because the lights at night can make the appearance of food artifacts. And at the time of the inspection, check the appearance, such as check cans, its appearance has no drum tank, concave tank phenomenon; for fish, meat inspection, can see its color is normal; the bottled liquid should put the bottle upside down to see if there are impurities and sediment; 4. For the inspection of bottled liquid, first remove the part into the transparent glass tube through the light observation there is no abnormal phenomenon.C) taste examination (20 to 40 degrees, low concentration to high concentration)Taste should pay attention to the temperature of the food, because the sensitivity of the taste organ is closely related to the temperature of the food. The best temperature for food tasting is between 20 and 40 degrees, and when you check two kinds of food, you should first check the food with low taste, and then check the high concentration of food, because the two kinds of taste food will affect each other. For example: checkthe sugar and apples, if you check the sugar first, then check the apple, then feel the taste of apple is lighter than before eating. This is because sugar absorbs volatile aromatic compounds in apples,At the same time, the sweetness of sugar also conceals the taste of apples, so when we evaluate the flavor of food, we should first check the low concentration, then check the high concentration of food.In addition to the examination of a large number of food, such as the evaluation of a taste of wine, we will be evaluated in each wine after the mouthwash, for each of two mug, and not smoke. In order to reduce the influence of smoking on wine. When you check the food, for some spoilage food, do not taste test, if you want to, after the examination to gargle with water.D) tactile examination tactile sensationThe tactile examination mainly examines the elasticity and consistency of the food and the quality of the food. We can grab a handful of water, it is the evaluation of the particles as full as check cereal and so on; inspection of meat and meat products, to touch its elasticity, determine whether meat fresh; check honey to touch its consistency, usually at a temperature of 20 DEG C, the temperature is too high or too low to have impact on the analysis results.According to the above four aspects of sensory identification, indicating that all kinds of food have certain sensory characteristics, consumers generally rely on sensory todetermine the choice of food. Of course, good sensory examination, not necessarily high nutritional value.Two. Methods of food analysis methodThe main application of chemical analysis by 1. volumetric method is thatVolumetric method, gravimetric method, colorimetric methodThree. Development and progress of food physical and chemical inspection at home and abroadThe progress of physical and chemical inspection of food at home and abroad can be roughly divided into four aspects:First, the basic theoryThe sample separation pretreatment extraction, purification and concentration (enrichment) theory and technologyThis part is the main basic theory of food theory inspection. It is also an indispensable part of the discipline itself. Therefore, in recent years, domestic and foreign research on it is more and more in-depth.The samples were separated and extracted in addition to the original heat digestion method, cold digestion method, dry ashing method, solvent extraction method, volatilization and distillation method, and the digestion tank method andion-exchange resin exchange method were developed. Recentreports on the use of digestive decomposition reagent HCLO4 have increased. At the same time, the sample separation and extraction of the interfering substances (such as interfering elements of trypsin interferon) removal and masking theory has made a lot of research, it is to eliminate the theory basis and the method of interference generated in the sample pretreatment. In addition, the application of masking agent in the digestion process of sample is gradually widespread, and the theoretical discussion is made.Study on the application of statistical processing and analysis of the error theory of foodThe study of quality controlIn recent years, domestic food quality control has only been reported, starting later than abroad.Two analysis method1. new detection methods2. new project analysis method researchImprovement of 3. classical methods4. a simple and rapid method5. multi discipline infiltration and related researchThree application of analytical instruments:In recent years, the use of food analysis instruments has gradually increased. For example, fluorine electrode and chlorine electrode in electrochemistry. Thin layer chromatography with thin layer scanner gradually makes quantitative hope.Four scientific researchDomestic and foreign researches mainly focus on production and development, and exploit protein resources on the basis of physical and chemical basis. For example, the extraction of albumin from blood, separation of amino acids and so on; for example, in order to improve the palatability and water retention properties of processed foods, the application of food additives (such as water retaining agent) is increasing, and its detection is also adapted. In addition, there is a big demand for rapid and simple methods of food inspection, especially for the detection of fresh milk. Many schools have done a lot of research achievements.。
pesticides analysis
Pesticides AnalysisIntroductionPesticides are chemical substances used to control pests, such as insects, weeds, and fungi, that can damage crops or cause harm to humans. Pesticides play a crucial role in modern agriculture, ensuring food security and increasing crop yields. However, the potential negative impact of pesticides on human health and the environment has raised concerns. Therefore, the analysis of pesticides is essential to assess their presence, concentration, and potential risks.Importance of Pesticides AnalysisPesticides analysis is necessary for several reasons:1.Safety of Food and Water: Pesticides can contaminate food andwater sources through agricultural practices. Analyzing thepresence and levels of pesticides in these resources helps inensuring food safety and preventing potential health risks.2.Environmental Monitoring: Pesticides can have detrimental effectson ecosystems and non-target organisms. Analyzing their occurrence and distribution in soil, air, and water bodies helps in assessing their environmental impact and designing appropriate mitigationstrategies.3.Regulatory Compliance: Governments and regulatory agenciesestablish maximum residue limits (MRLs) for pesticides to protectconsumers and the environment. Pesticides analysis is necessaryfor regulatory compliance and to enforce these limits.4.Product Development and Improvement: Pesticide manufacturersanalyze their products to determine their effectiveness, stability, and potential environmental risks. This analysis drives productimprovement and ensures their proper usage.Methods of Pesticides AnalysisDifferent methods are employed for the analysis of pesticides, depending on the sample type and the desired information. Below are some commonly used methods:1. Chromatographic TechniquesChromatographic techniques, such as gas chromatography (GC) and liquid chromatography (LC), are widely used for pesticides analysis. These techniques separate the individual pesticide compounds from a complex mixture and allow for their identification and quantification.2. Mass SpectrometryMass spectrometry (MS) is often coupled with chromatographic techniques to enhance the sensitivity and specificity of pesticide analysis. MS provides information about the molecular weight and structure of pesticide compounds, facilitating their identification and characterization.3. ImmunoassaysImmunoassays, such as enzyme-linked immunosorbent assays (ELISA), are rapid and cost-effective methods for screening pesticides. These assays utilize specific antibodies that bind to pesticide molecules, producing a detectable signal in the presence of the pesticide.4. Sample Preparation TechniquesSample preparation is a crucial step in pesticides analysis, as it concentrates and purifies the target compounds. Common sample preparation techniques include solvent extraction, solid-phase extraction, and QuEChERS (quick, easy, cheap, effective, rugged, and safe) method.Applications of Pesticides Analysis1. Agricultural MonitoringPesticides analysis plays a vital role in monitoring the use of pesticides in agriculture. By analyzing soil, water, and crop samples, scientists can assess the effectiveness of pesticide application, adherence to safety regulations, and potential risks to the environment.2. Food Safety AssessmentFood safety authorities and regulatory agencies analyze food samples to ensure compliance with pesticide residue limits. Pesticides analysis helps identify potential sources of contamination and contributes to the overall assessment of the safety of the food supply chain.3. Environmental Impact EvaluationPesticides can have unintended consequences on non-target organisms, such as birds, bees, and aquatic life. Pesticides analysis helps in evaluating their ecological impact and determining ways to minimize or mitigate the risks.4. Forensic InvestigationsIn cases of suspected pesticide poisoning or illegal use of pesticides, analysis of biological samples, such as blood or urine, can provide evidence for forensic investigations. Pesticides analysis helps in identifying the presence of specific pesticides and linking them to potential sources.ConclusionPesticides analysis is crucial for ensuring the safety of food, water, and the environment. Through the use of various analytical techniques, scientists can identify and quantify pesticide residues, evaluate their potential risks, and enforce regulatory compliance. Continued advancements in pesticides analysis will further contribute tosustainable agricultural practices and the protection of human health and the environment.。
气相色谱法测定蔬菜中7 种残留有机磷农药
0引言农药残留污染一直影响着人们的生活质量和食品贸易的顺利进行。
随着人们生活水平的日益提高，对食品安全意识的不断增强，蔬菜中农药残留问题也得到了更大的关注[1-2]。
有机磷农药作为一种高效、广谱的杀虫剂，在蔬菜、水果杀虫剂中占据了重要的地位，至今仍是世界上生产和使用最多的农药品种[3]。
但因其极性毒性强，在蔬菜、水果中的残留易引起食物中毒，因此，加强有机磷农药残留检测，是保障蔬菜安全的重要措施。
而高效、快捷、准确是农药残留检测发展的必然趋势。
此文在充分调查惠州地区有机磷农药使用情况后，确定七种有机磷农药作为待检农药，以进一步检测惠州蔬菜基地使用的农药中是否含有高毒、禁用农药成分，同时使用气相色谱建立一种适合蔬菜使用的快速、准确的检测方法。
1材料与方法1.1仪器与试剂1.1.1仪器岛津GC-2010气相色谱仪，配火焰光度检测器（FPD ），GC solution 色谱工作站，RTX-1701毛细管柱，漩涡混合器，旋转蒸发仪，循环水式真空泵，智能恒温槽，移液器，电子天平等。
1.1.2试剂乙酸乙酯，无水硫酸钠，均为分析纯；乙酸乙酯，为色谱纯；7种有机磷农药标准品：敌百虫、敌敌畏、甲胺磷、基金项目：惠州市科技局资助项目“惠州蔬菜害虫控制与应用研究”（2008P07）。
第一作者简介：吴福中，男，1979年出生，硕士，安徽庐江人，从事蔬菜害虫防治和有害生物研究，主持和参与科研课题3项，发表学术论文十余篇。
通信地址：516006惠州市仲恺大道口岸新区，E-mail ：zhongwfu@ 。
收稿日期：2009-05-06，修回日期：2009-06-09。
气相色谱法测定蔬菜中7种残留有机磷农药吴福中1，王锦海2，刘志红2，洪桂德2(1惠州出入境检验检疫局，广东惠州516006；2勇记农业开发（惠州）有限公司，广东惠州516229)摘要：采用岛津GC2010气相色谱仪，火焰光度检测器（FPD ），毛细管气相色谱法测定蔬菜中7种有机磷农药的残留量，7种有机磷农药都能得到较好的分离，分离效果好。
豇豆农药残留检测 的措施和建议
豇豆农药残留检测的措施和建议英文回答：Pesticide Residue Detection in Cowpea: Measures and Recommendations.Introduction.Cowpea (Vigna unguiculata) is a widely cultivated legume crop in tropical and subtropical regions, prized for its nutritional value and versatile uses. However, the application of pesticides to control pests and diseases can leave behind chemical residues on the crop, posingpotential health risks to consumers. To ensure food safety and consumer protection, effective measures are necessary to detect and monitor pesticide residues in cowpea.Detection Methods.Various analytical techniques are employed to detectpesticide residues in cowpea. These methods include:Chromatography (e.g., GC-MS, LC-MS/MS): Thesetechniques separate and identify individual pesticide compounds based on their physical and chemical properties.Immunoassay (e.g., ELISA): This method uses antibodies specific to target pesticides to bind and quantify residues.Biosensors: These devices utilize biological components to detect and measure pesticide residues.Regulatory Measures.Regulatory authorities worldwide have established maximum residue limits (MRLs) for pesticides in food crops, including cowpea. These limits are based on extensivesafety assessments and are designed to protect consumers from harmful effects. Monitoring programs are implementedto enforce compliance with MRLs and ensure consumer safety.Good Agricultural Practices (GAPs)。
(完整版)托福TPOextra答案解析和原文翻译
TPO 34阅读解析第一篇Population and Climate【P1】地球人口的增长已经对大气和生态环境产生了影响。
化石燃料的燃烧，毁林，城市化，种植大米，养殖家畜，生产作为助推燃料和制冷剂的CFC增加了空气中CO2，甲烷，二氧化氮，二氧化硫灰尘和CFOs 的含量。
约70%的太阳能量穿过大气直射地球表面。
太阳射线提高了土地和海洋表面的温度，随后土地和海洋表面将红外射线反射会太空中。
这能使地球避免温度过高。
但是并不是所有的红外射线被返回会太空中，一些被大气中的气体吸收，然后再次反射回地球表面。
温室气体就是其中吸收了红外射线的一种气体，然后再次反射一些红外线到地球。
二氧化碳，CFC，甲烷和二氧化氮都是温室气体。
大气中温室效应形成和建立的很自然。
事实上，大气中如果没有温室气体，科学家预测地球温度比当前的能够低33度。
【P2】大气中当前二氧化碳浓度是360ppm。
人类活动正在对大气中二氧化碳浓度的增加有着重要的影响，二氧化碳浓度正在快速增长，目前预估在未来50-100年内，浓度将是目前的一倍。
IPCC在1992中做出一份报告，在该份报告中大多数大气科学家中观点一致，预测二氧化碳浓度翻倍可能会将全球气温提高1.4-4.5度。
IPCC在2001年的报告中做出的预测是气温几乎将会提高2倍。
可能发生的气温升高比在冰河时期发生的变化要大很多。
这种温度的升高也不会是一直的，在赤道周围变化最小，而在极点周围的变化则是2-3倍。
这些全球变化的本地化影响很难预测，但是大家一致认为可能会影响洋流的改变，在北半球的一些区域可能增加在冬天发洪水的可能性，在一些区域夏天发生干旱的概率提高，还有海平面的升高也可能会淹没位置较低的国家。
【P3】科学家积极参与地球气候系统中物理，化学和生物成分的调查，为了对温室气体的增加对未来全球气候的影响做出准确预测。
全球环流模型在这个过程中是重要的工具。
这些模型体现包含了当前对大气环流模式，洋流，大陆影响和类似东西所掌握的知识，在变化的环境下预测气候。
气相色谱法测定根茎类蔬菜中有机磷农药残留的基质效应研究
气相色谱法测定根茎类蔬菜中有机磷农药残留的基质效应研究张 阳1，张志红2*（1.资阳市农产品质量监测检验中心，四川资阳 641300；2.四川水井坊股份有限公司，四川成都 610000)摘 要：参照《蔬菜和水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯类农药多残留的测定》（NY/T 761—2008），研究了气相色谱法测定根茎类蔬菜中有机磷农药残留的基质效应。
结果表明，相同根茎类蔬菜基质中，有机磷农药添加量不同，产生的基质效应不同，且低浓度的有机磷农药产生的基质效应明显强于高浓度的有机磷农药；不同的有机磷农药在相同基质中表现出的基质效应具有明显差异，如氧乐果在根茎类蔬菜基质中均表现出很强的基质效应，最高达298%，而敌敌畏则表现为弱基质效应或不存在基质效应。
建议对根茎类蔬菜进行有机磷农药残留检测时，先采用科学合理的方法消除或减少基质效应，如通过预实验确定最佳的基质加标浓度进行结果校正，从而保证检测结果的准确性与可靠性。
关键词：根茎类蔬菜；有机磷农药；基质效应；气相色谱法Study on Matrix Effect of Determination of Organophosphorus Pesticide Residue in Root and Tuber Vegetables by GasChromatographyZHANG Yang1, ZHANG Zhihong2*(1.Ziyang Agricultural Product Quality Monitoring and Testing Center, Ziyang 641300, China;2.Sichuan Swellfun Co., Ltd., Chengdu 610000, China)Abstract: Referring to agricultural industry standard NY/T 761—2008, the matrix effect determination of organophosphorus pesticide residue in root and tuber vegetables by gas chromatography was studied in present work. The results showed that different amount of organophosphorus pesticides in same root and tuber vegetables produced different matrix effects. The matrix effects of low concentration organophosphorus pesticides were significantly stronger than that of high concentration organophosphorus pesticides. The matrix effects of different organophosphorus pesticides in the same matrix were obviously different. For example, omethoate exhibited strong matrix effects in root and tuber vegetables, with a maximum of 298%, while dichlorvos exhibited weak matrix effects or no matrix effects. It is recommended that when conducting organophosphorus pesticide residue testing on root and tuber vegetables, scientific and reasonable methods should be used to eliminate or reduce matrix effects, such as using pre-experiments to determine the optimal matrix spiking concentration for result correction, in order to ensure the accuracy and reliability of the test results.Keywords: root and tuber vegetables; organophosphorus pesticide; m atrix effect; gas chromatography基质效应（Matrix Effects，ME）是指样品中除目标化合物以外的其他成分对待测物测定结果的影响，即造成的定性定量误差，根据实际情况又可分为基质增强效应和减弱效应[1-5]。
SPE_GC在水果和蔬菜有机磷农药残留分析中的应用
μｇ／ｍｌ、乙酰甲胺磷 ７７２μｇ／ｍｌ、毒死蜱 ６００μｇ／ｍｌ、氧 乐果 ２０００μｇ／ｍｌ、马拉硫磷 ０．７０４ｍｇ／ｍｌ、对硫磷 ０．９６０ｍｇ／ ｍｌ、甲基对硫磷 ０．５４０ｍｇ／ｍｌ、ＤＤＶＰ０．９２０ｍｇ／ｍｌ 的标准 母液。
随着农药的大量使用，水果和蔬菜中农药残留问题 日益严重，引起了人们的高度重视。水果和蔬菜中的 农药残留分析是目前食品安全的一个重点，特别是在目 前世界贸易的进一步加大的背景下，成为贸易中关注的 一个焦点。因此，建立高效、高灵敏度和高准确度的 检测方法尤为重要。
农药残留分析普遍采用的是液 － 液萃取分离法，基 于组分在互不相溶两相中分配系数的差异萃取欲测组 分，方法选择性较高，处理复杂样品效果佳，并且操 作简单、易掌握，使用所需玻璃器皿简单，故而一直 盛行不衰，但也明显存在一些缺点：（１）萃取操作过程冗 长，并有乳化、毒性、易燃、环境污染等问题；（ ２ ） 提取液体积较大，在加热浓缩中可能引起欲测组分的分 解变化；（３）有机溶剂中多含有某些微量杂质，随着萃取 蒸发被浓缩后会影响色谱分离；（４）不适于具有生物活性 组分的分离。
※分析检验
食品科学
2004, Vol. 25, No. 10 235
ＳＰＥ－ＧＣ 在水果和蔬菜有机磷 农药残留分析中的应用
陈 浩 １，王 豹 １，韦明元 １，徐 娟 １，李 庆 １，陈智东 ２ （１．华中农业大学理学院，湖北 武汉 ４３００７０；２．湖北省农科院测试中心，湖北 武汉 ４３００６４）
甲胺磷、乐果、甲拌磷、乙酰甲胺磷、马拉硫 磷、对硫磷、甲基对硫磷、氧乐果、毒死蜱标样 国 家标准物质中心提供；溶剂：高纯水，甲醇、乙氰、色谱条件