Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, Campus Dom Bosco, Praça Dom Helvécio 74, Fábricas, São João del-Rei, Minas Gerais, 36301-160, Brazil.
Anal Bioanal Chem. 2018 May;410(14):3361-3374. doi: 10.1007/s00216-018-1031-9. Epub 2018 Apr 2.
In this work, we developed a HPLC method for the multidetermination of avermectins (AVM) (abamectin-ABA 1b and ABA 1a, eprinomectin-EPR, and ivermectin-IVM) and milbemycins (moxidectin-MOX) in milk samples using polypyrrole (PPy) as adsorbent material in pipette-tip solid-phase extraction (PT-PPy-SPE). PPy was characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray diffraction and the data agreed with the literature. The sample preparation included the clean-up of the milk by protein precipitation (PP) with acetonitrile and extraction of the analytes by PT-PPy-SPE. The chromatographic method was developed in reverse phase and isocratic mode with flow rate at 1.2 mL min and ultraviolet detection at 250 nm. The mobile phase composition was acetonitrile:methanol:water (55:25:20, v/v/v). The studied parameters and the optimized conditions for the sample preparation were washing solvent (300 μL water), volume and type of eluent (500 μL methanol), volume and pH of sample (1 mL and pH 10), amount of adsorbent material (50 mg PPy), and without addition of salt (NaCl). The method was linear over the concentration range from 20 to 3000 ng mL with coefficients of correlation (r) ≥ 0.99 for all analytes and recoveries around 100%. The method developed and validated was used for the analyses of real milk samples from cow treated with Ivomec (IVM 3.5%), in which were found 21.51 ± 2.94 ng mL of IVM. Finally, the results proved that PT-PPy-SPE coupled to HPLC-UV was economical, simple, and easy-to-perform technique. Graphical abstract Pipette-tip solid phase extraction using polypirrole as adsorbent material for determination of avermectins and milbemycins in milk.
在这项工作中，我们开发了一种 HPLC 方法，用于在牛奶样品中多测定阿维菌素（AVM）（阿维菌素-ABA 1b 和 ABA 1a、依普菌素-EPR 和伊维菌素-IVM）和米尔贝肟（莫昔克丁-MOX），使用聚吡咯（PPy）作为吸附材料在微量固相萃取（PT-PPy-SPE）中。PPy 通过扫描电子显微镜、热重分析、傅里叶变换红外光谱和 X 射线衍射进行了表征，数据与文献一致。样品制备包括用乙腈进行蛋白质沉淀（PP）对牛奶进行净化，并用 PT-PPy-SPE 提取分析物。色谱方法在反相和等度模式下开发，流速为 1.2 mL min，紫外检测波长为 250nm。流动相组成为乙腈:甲醇:水（55:25:20，v/v/v）。研究了参数并优化了样品制备的条件，包括洗涤溶剂（300 μL 水）、洗脱剂的体积和类型（500 μL 甲醇）、样品的体积和 pH 值（1 mL 和 pH 10）、吸附材料的量（50 mg PPy）和不添加盐（NaCl）。该方法在 20 至 3000 ng mL 的浓度范围内呈线性，所有分析物的相关系数（r）均≥0.99，回收率约为 100%。开发和验证的方法用于分析用 Ivomec（IVM 3.5%）处理的奶牛的实际牛奶样品，其中发现 IVM 的含量为 21.51±2.94ng mL。最后，结果证明，PT-PPy-SPE 与 HPLC-UV 结合是一种经济、简单、易于操作的技术。
