吡虫啉在小麦中吸收、易位和分布的测定
Summary
这里介绍的是使用液相色谱-串联质谱（LC-MS-MS）测定水培条件下小麦中吡虫啉的吸收，易位和分布的方案。结果表明：吡虫啉可被小麦吸收，在小麦根系和叶片均检测到吡虫啉。
Abstract
新烟碱类杀虫剂是一类杀虫剂，因其新颖的作用方式、高杀虫活性和强大的根系吸收而被广泛使用。吡虫啉是全球使用最广泛的杀虫剂，是具有代表性的第一代新烟碱类杀虫剂，用于农作物、蔬菜和果树的害虫防治。随着吡虫啉的广泛应用，其在作物中的残留物引起了越来越多的关注。本研究将15株小麦幼苗置于含有0.5 mg/L或5 mg/L吡虫啉的培养基中水生培养。在水培1 d、2 d和3 d后测定小麦根叶中吡虫啉的含量，探讨吡虫啉在小麦中的迁移和分布。结果表明：小麦植株根叶均检出吡虫啉，根系吡虫啉含量高于叶片;此外，小麦中吡虫啉浓度随着暴露时间的增加而增加。暴露3 d后，0.5 mg/L处理组小麦根叶分别含有4.55 mg/kg±1.45 mg/kg和1.30 mg/kg±0.08 mg/kg吡虫啉，5 mg/L处理组根叶分别含有42.5 mg/kg±0.62 mg/kg和8.71 mg/kg±0.14 mg/kg吡虫啉， 分别。本研究结果有助于更好地了解作物中的农药残留情况，为农药环境风险评估提供数据参考。
Introduction
在当今的农学中，使用杀虫剂对于提高作物产量至关重要。新烟碱类杀虫剂通过控制昆虫神经系统中的烟碱乙酰胆碱受体来改变膜电位平衡，从而抑制昆虫中枢神经系统的正常传导，导致昆虫瘫痪和死亡1。与传统杀虫剂相比，新烟碱类具有作用方式新颖、杀虫活性高、根系吸收强等优点，使其在农药市场上大获成功2，3。据报道，2014年新烟碱类药物的销量占世界农药市场的27%。2005—2010年，新烟碱类的年均增长率为11.4%，其中约7%在中国注册4，5，6。2016年底至2017年上半年，我国农药销量在回落后开始反弹，农药价格持续上涨，其中新烟碱类杀虫剂价格呈现大幅涨幅7。到目前为止，已经开发了三代新烟碱类杀虫剂，每代含有吡啶氯、噻唑基和四氢呋喃基团的尼古丁，分别为8.
吡虫啉是第一代新烟碱类杀虫剂，分子式为C9H10ClN5O2，为无色结晶。吡虫啉主要用于防治害虫，如蚜虫、飞虱、黄粉虫和蓟马9 ，可应用于水稻、小麦、玉米、棉花等作物和马铃薯等蔬菜以及果树。由于农药的长期、大量、持续施用，既有益虫，也有害虫的天敌迅速减少，一些农业害虫对农药产生抗药性，造成农药持续施用量不断增加的恶性循环10.此外，农药的广泛使用导致土壤质量恶化，农产品中农药残留持久性等生态问题，不仅对农业生态环境造成重大破坏11 ，而且对人类健康构成严重威胁12。农药喷洒严重影响土壤微生物和土壤动物的生长和质量13.农药的不合理或过量使用，给水土环境、动植物甚至人类生命造成了重大安全隐患14。近年来，随着农药的广泛应用，农作物农药残留超标问题愈发严重。当吡虫啉用于提高蔬菜产量时，吡虫啉在蔬菜中的吸收率随着吡虫啉的量和残留量的增加而增加15。作为主要粮食作物，小麦的生产和安全都至关重要。因此，小麦用农药的残留和分配政策需要明确。
近年来，已经开发出许多从水、土壤和植物中提取吡虫啉残留物的方法。QuEChERS方法（快速、简单、廉价、有效、坚固、安全）是一种结合了固相微萃取技术和分散固相萃取技术的新方法，涉及使用乙腈作为萃取溶剂，分别使用NaCl和无水MgSO4去除样品中的混合杂质和水16.QuEChERS方法需要最少的玻璃器皿，并且具有简单的实验步骤，使其成为最受欢迎的农药提取方法之一17。对于吡虫啉的检测，液相色谱（LC）的检测限低至1×10−9 g18，气相色谱（GC）的检测限低至1 × 10−11 g 19。由于其高分辨率和灵敏度，LC-MS和GC-MS显示出更低的吡虫啉检测限，为1×10-13至1×10-14g 20，21;因此，这些技术非常适合分析痕量吡虫啉残留物。
本研究以吡虫啉为目标污染物，以小麦为试验作物，研究吡虫啉残留在小麦中的分布情况。该协议详细介绍了一种通过探索吡虫啉在水培条件下生长的小麦植物不同部分的吸收和储存来全面分析小麦中农药吡虫啉富集和转移的方法。本研究旨在为小麦农药残留风险评估提供理论依据，指导农业生产活动中合理施用农药，减少农药残留，提高作物生产安全性。
Protocol
Representative Results
Discussion
近年来，农药吡虫啉残留的预处理和检测方法经常被报道。Badawy等人23使用高效液相色谱法测定了在温室条件下生长的番茄果实中吡虫啉的含量，并报告吡虫啉的线性良好，范围为0.0125-0.15μg/mL。Zhai等24使用LC-MS-MS研究了中国细香葱中吡虫啉的残留。本研究采用QuEChERS方法从小麦根叶中提取吡虫啉。作为一种快速有效的方法，QuEChERS方法非常适合并广泛用于从土壤…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项工作得到了国家自然科学基金（第42277039号）的支持。
Materials
| Acetonitrile | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | 01-06-1995 | Suitable for HPLC, gradient grade, >99.9% |
| Analytical balance | Sartorius Lab Instruments Co.Ltd. | GL124-1SCN | |
| Artificial climate incubator | Shanghai Badian Instrument Equipment Co. Ltd. | HK320 | |
| Centrifuge | Eppendorf China Co. Ltd. | Centrifuge5804 | |
| Disposable syringe | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | Z116866 | Capacity 5 mL, graduated 0.2 mL, non-sterile |
| Formic acid | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | Y0001970 | European pharmacopoeia reference standard |
| Graphitized carbon black (GCB) | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | V900058 | 45 μm |
| H2O2 | Sigma-Aldrich (Shanghai) Trading Co.Ltd. | 31642 | 30% (w/w) |
| Hoagland’s Basal Salt Mixture | Shanghai Yu Bo Biotech Co. Ltd. | NS1011 | Anhydrous, reagent grade |
| Hydroponic equipment | Jiangsu Rongcheng Agricultural Science and Technology Development Co.Ltd. | SDZ04BD | |
| Hypersil BDS C18 column | Thermo Fisher Scientific (China) Co. Ltd. | 28103-102130 | |
| Imidacloprid | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | Y0002028 | European pharmacopoeia reference standard |
| MgSO4 | Sigma-Aldrich (Shanghai) Trading Co. Ltd. | 208094 | Anhydrous, reagent grade, >97% |
| NaCl | Sigma-Aldrich (Shanghai) Trading Co.Ltd. | S9888 | Reagent grade, 99% |
| pH meter | Shanghai Thunder Magnetic Instrument Factory | PHSJ-3F | |
| Phytotron box | Harbin Donglian Electronic Technology Co. Ltd. | HPG-280B | |
| Pipettes | Eppendorf China Co. Ltd. | Research plus | |
| Syringe filter | Sigma-Aldrich (Shanghai) Trading Co.Ltd. | SLGV033N | Nylon, 0.22 µm pore size, 33 mm, non-sterile |
| Ultra performance liquid chromatography tandem triple quadrupole mass spectrometry | Thermo Fisher Scientific (China) Co. Ltd. | UltiMate 3000 | |
| TSQ Quantum Access MAX | |||
| Vortex mixer | Shanghai Yetuo Technology Co. Ltd. | Vortex-2 | |
| Wheat seed | LuKe seed industry | Jimai 20 |
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