Summary

QuEChERS法-气相色谱-串联质谱法测定牛油果品种中45种农药

Published: December 08, 2023
doi:

Summary

本方案描述了使用Qu ick-Easy-Ch eap-E ffective-R ugged-S afe(QuEChERS)方法与甲酸铵,然后使用气相色谱-串联质谱法分析鳄梨品种中的多类农药残留。

Abstract

气相色谱 (GC) 串联质谱 (MS/MS) 是一种卓越的分析仪器,广泛用于监测食品中的农药残留。然而,这些方法容易受到基质效应 (ME) 的影响,这可能会影响准确的定量,具体取决于分析物和基质的特定组合。在缓解 ME 的各种策略中,基质匹配校准是农药残留应用中的主流方法,因为它具有成本效益和直接实施。本研究采用Qu ick-Easy-Ch eap-E ffective-R ugged-S afe(QuEChERS)方法,结合甲酸铵和GC-MS/MS分析了3种不同品种的鳄梨(Criollo、Hass和Lorena)中的45种代表性农药。

为此,用 10 mL 乙腈提取 5 g 鳄梨样品,然后加入 2.5 g 甲酸铵以诱导相分离。随后,使用 150 mg 无水 MgSO4、50 mg 伯-仲胺、50 mg 十八烷基硅烷、10 mg 石墨化炭黑和 60 mg 氧化锆基吸附剂 (Z-Sep+) 通过分散固相萃取进行纯化过程。GC-MS/MS分析在不到25分钟的时间内成功进行。进行了严格的验证实验,以评估该方法的性能。对每个品种鳄梨的基质匹配校准曲线的检查表明,大多数农药/品种组合的 ME 保持相对一致,低于 20%(被认为是软 ME)。此外,该方法对所有三个品种的定量限均低于5 μg/kg。最后,大多数农药的回收率在70-120%的可接受范围内,相对标准差值低于20%。

Introduction

在化学分析中,基质效应 (ME) 可以通过多种方式定义,但广泛接受的一般定义如下:它是指信号的变化,特别是当样品基质或其部分存在时校准曲线斜率的变化,在分析特定分析物期间。作为一个关键方面,ME必须在任何分析方法的验证过程中进行彻底的调查,因为它直接影响目标分析物1定量测量的准确性。理想情况下,样品预处理程序应具有足够的选择性,以避免从样品基质中提取任何成分。然而,尽管付出了巨大的努力,但在大多数情况下,这些基质成分中的许多最终仍然会进入最终测定系统。因此,此类基质组件通常会影响恢复率和精度值,引入额外的噪声,并增加方法中涉及的总体成本和劳动力。

在气相色谱 (GC) 中,ME 是由于 GC 系统中存在活性位点而产生的,这些活性位点通过各种机制与目标分析物相互作用。一方面,基质成分阻断或掩盖了这些活性位点,否则这些活性位点会与目标分析物相互作用,从而导致频繁的信号增强2。另一方面,保持畅通无阻的活性位点可能会由于强烈的相互作用而引起峰拖尾或分析物分解,从而导致阴性 ME。但是,在某些情况下,这可以提供潜在的好处2.需要强调的是,尽管使用高惰性组件并进行适当的维护,但在气相色谱系统中实现完全惰性是极具挑战性的。随着连续使用,GC系统中基质组分的积累变得更加明显,导致ME增加。如今,人们普遍认为,含有氧、氮、磷、硫和类似元素的分析物表现出更大的 ME,因为它们很容易与这些活性位点相互作用。相反,高度稳定的化合物(如碳氢化合物或有机卤素)不会发生这种相互作用,并且在分析过程中不会显示可观察到的 ME 2,3

总体而言,ME无法完全消除,因此在完全消除基质成分不可行时,需要制定几种补偿或校正策略。在这些策略中,氘代内标 (IS)、分析物保护剂、基质匹配校准、标准品添加方法或进样技术的改进已在科学文献中记录 1,2,4,5。SANTE/11312/2021 指南还推荐了这些策略6.

关于基质匹配校准在补偿ME方面的应用,实际情况下的样本序列包括不同类型的食品或来自同一商品的各种样本。在这种情况下,假设使用来自同一商品的任何样本将有效地补偿所有样本中的 ME。然而,在现有文献中,缺乏足够的研究来专门调查这个问题7.

在含有相当比例的脂肪和色素的基质中测定农药的多残留量是一项具有挑战性的任务。大量共萃取的材料会显著影响萃取效率,并干扰随后的色谱测定,可能会损坏色谱柱、离子源和检测器,并导致显著的MEs8,9,10。因此,在分析此类基质中痕量农药时,需要在分析前大幅减少基质成分,同时确保高回收率值7。获得高回收率值对于确保农药分析保持可靠、准确并符合监管标准至关重要。这对于确保食品安全、环境保护以及农业及相关领域的知情决策至关重要。

鳄梨是一种具有高商业价值的水果,在世界各地的热带和地中海气候中种植,在其原产地和众多出口市场都广泛消费。从分析的角度来看,鳄梨是一种复杂的基质,含有大量脂肪酸(即油酸、棕榈酸和亚油酸),类似于坚果,具有重要的色素含量,如绿叶,以及糖和有机酸,类似于其他水果中的含量11.由于其脂肪性质,在采用任何分析方法进行分析时必须特别注意。虽然在某些情况下使用GC-MS对鳄梨进行了农药残留分析8,12,13,14,15,16,17,18,19,20,但与其他基质相比,其频率相对较低。在大多数情况下,应用了 Qu ick-Easy-Ch eap-E ffective-R ugged-S afe (QuEChERS) 方法的一个版本 8,12,13,14,15,16,17,18。这些研究都没有调查不同鳄梨品种之间MEs的一致性。

因此,本工作的目的是使用 QuEChERS 方法与甲酸铵和 GC-MS/MS 研究 45 种代表性农药在不同品种鳄梨(即 Criollo、Hass 和 Lorena)中的 ME 一致性和回收值。据我们所知,这是首次对此类脂肪基质样品进行此类研究。

Protocol

1. 储备液和工作溶液的制备 注意:出于安全原因,建议在整个协议中佩戴丁腈手套、实验室外套和安全眼镜。 在 10 mL 容量瓶中以约 1,000 mg/L 的浓度在乙腈中制备 45 种商业农药标准品(见 材料表)的单独储备溶液。 合并上述单独的储备溶液,在 25 mL 容量瓶中制备 400 mg/L 乙腈储备溶液。注意:该混合溶液将用于制备用于回收和校准…

Representative Results

根据 SANTE/11312/2021 准则6 对分析方法进行了全面验证,包括线性、ME、恢复率和可重复性的评估。 对于线性评估,使用多个浓度水平(范围为5至600 μg/kg)的加标空白样品构建基质匹配的校准曲线。大多数选定农药的决定系数(R2)均大于或等于0.99,表明浓度与响应之间存在高度线性关系。选择的最低校准水平(LCL)为5 μg/kg,遵守为食品监测目的而?…

Discussion

与基质匹配校准相关的主要限制源于使用空白样品作为校准标准品。这导致要处理用于分析的样品数量增加,并且每个分析序列中基质组分的进样量增加,从而可能导致更高的仪器维护需求。尽管如此,这种策略比标准添加更合适,因为标准添加会产生更多的进样样品,因为需要为每个样品执行校准曲线。因此,在这两种情况下,都需要使用样品制备技术来最大限度地减少这种共萃取,同时保持?…

Disclosures

The authors have nothing to disclose.

Acknowledgements

我们要感谢EAN大学和拉古纳大学。

Materials

3-Ethoxy-1,2-propanediol Sigma Aldrich 260428-1G
Acetonitrile Merk 1006652500
Ammonium formate Sigma Aldrich 156264-1KG
AOAC 20i/s autosampler Shimadzu 221-723115-58
Automatic shaker MX-T6-PRO SCILOGEX 8.23222E+11
Balance OHAUS PA224
Centrifuge tubes, 15 mL Nest 601002
Centrifuge tubes, 2 mL Eppendorf 4610-1815
Centrifuge tubes, 50 mL Nest 602002
Centrifuge Z206A MERMLE 6019500118
Choper 2L Oster 2114111
Column SH-Rxi-5sil MS, 30 m x 0.25 mm, 0.25 µm Shimadzu 221-75954-30 MS GC column 
Dispensette 5-50 mL BRAND 4600361
DSC-18 Sigma Aldrich 52600-U
D-Sorbitol Sigma Aldrich 240850-5G
Ethyl acetate Merk 1313181212
GCMS-TQ8040  Shimadzu 211552
Graphitized carbon black Sigma Aldrich 57210-U
Injection syringe Shimadzu LC2213461800
L-Gulonic acid γ-lactone Sigma Aldrich 310301-5G
Linner splitless Shimadzu 221-4887-02
Magnesium sulfate anhydrus Sigma Aldrich M7506-2KG
Methanol Panreac 131091.12.12
Milli-Q ultrapure (type 1) water Millipore F4H4783518
Pipette tips 10 – 100 µL Biologix 200010
Pipette tips 100 – 1000 µL Brand 541287
Pipette tips 20 – 200 µL Brand 732028
Pipettes Pasteur NORMAX 5426023
Pippette Transferpette S variabel 10 – 100 µL BRAND 704774
Pippette Transferpette S variabel 100 – 1000 µL BRAND 704780
Pippette Transferpette S variabel 20 – 200 µL SCILOGEX 7.12111E+11
Primary-secondary amine Sigma Aldrich 52738-U
Shikimic acid Sigma Aldrich S5375-1G
Syringe Filter PTFE/L 25 mm, 0.45 µm NORMAX FE2545I
Triphenyl phosphate (QC) Sigma Aldrich 241288-50G
Vials with fused-in insert Sigma Aldrich 29398-U
Z-SEP+ Sigma Aldrich 55299-U zirconium oxide-based sorbent
Pesticides CAS registry number
4,4´-DDD Sigma Aldrich 35486-250MG 72-54-8
4,4´-DDE Sigma Aldrich 35487-100MG 72-55-9
4,4´-DDT Sigma Aldrich 31041-100MG 50-29-3
Alachlor Sigma Aldrich 45316-250MG 15972-60-8
Aldrin Sigma Aldrich 36666-25MG 309-00-2
Atrazine Sigma Aldrich 45330-250MG-R 1912-24-9
Atrazine-d5 (IS) Sigma Aldrich 34053-10MG-R 163165-75-1
Buprofezin Sigma Aldrich 37886-100MG 69327-76-0
Carbofuran Sigma Aldrich 32056-250-MG 1563-66-2
Chlorpropham Sigma Aldrich 45393-250MG 101-21-3
Chlorpyrifos Sigma Aldrich 45395-100MG 2921-88-2
Chlorpyrifos-methyl Sigma Aldrich 45396-250MG 5598-13-0
Deltamethrin Sigma Aldrich 45423-250MG 52918-63-5
Dichloran Sigma Aldrich 45435-250MG 99-30-9
Dichlorvos Sigma Aldrich 45441-250MG 62-73-7
Dieldrin Sigma Aldrich 33491-100MG-R 60-57-1
Diphenylamine Sigma Aldrich 45456-250MG 122-39–4
Endosulfan A Sigma Aldrich 32015-250MG 115-29-7
Endrin Sigma Aldrich 32014-250MG 72-20-8
EPN Sigma Aldrich 36503-100MG 2104-64-5
Esfenvalerate Sigma Aldrich 46277-100MG 66230-04-4
Ethion Sigma Aldrich 45477-250MG 563-12-2
Fenamiphos Sigma Aldrich 45483-250MG 22224-92-6
Fenitrothion Sigma Aldrich 45487-250MG 122-14-5
Fenthion Sigma Aldrich 36552-250MG 55-38-9
Fenvalerate Sigma Aldrich 45495-250MG 51630-58-1
HCB Sigma Aldrich 45522-250MG 118-74-1
Iprodione Sigma Aldrich 36132-100MG 36734-19-7
Lindane Sigma Aldrich 45548-250MG 58-89-9
Malathion Sigma Aldrich 36143-100MG 121-75-5
Metalaxyl Sigma Aldrich 32012-100MG 57837-19-1
Methidathion Sigma Aldrich 36158-100MG 950-37-8
Myclobutanil Sigma Aldrich 34360-100MG 88671-89-0
Oxyfluorfen Sigma Aldrich 35031-100MG 42874-03-3
Parathion-methyl Sigma Aldrich 36187-100MG 298-00-0
Penconazol Sigma Aldrich 36189-100MG 66246-88-6
Pirimiphos-methyl Sigma Aldrich 32058-250MG 29232-93-7
Propiconazole Sigma Aldrich 45642-250MG 60207-90-1
Propoxur Sigma Aldrich 45644-250MG 114-26-1
Propyzamide Sigma Aldrich 45645-250MG 23850-58-5
Pyriproxifen Sigma Aldrich 34174-100MG 95737-68-1
Tolclofos-methyl Sigma Aldrich 31209-250MG 5701804-9
Triadimefon Sigma Aldrich 45693-250MG 43121-43-3
Triflumizole Sigma Aldrich 32611-100MG 68694-11-1
α-HCH Sigma Aldrich 33377-50MG 319-86-8
β-HCH Sigma Aldrich 33376-100MG 319-85-7

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Cite This Article
Varela-Martínez, D. A., González-Curbelo, M. Á., González-Sálamo, J., Hernández-Borges, J. Determination of 45 Pesticides in Avocado Varieties by the QuEChERS Method and Gas Chromatography-Tandem Mass Spectrometry. J. Vis. Exp. (202), e66082, doi:10.3791/66082 (2023).

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