Wei Dan, Guo Ming
College of Bioscience and Engineering, Hebei University of Economics and Business。。。 Shijiazhuang 050061, China.
Zhejiang Chemical Production Quality Inspection Co., Ltd, Hangzhou 310023, China.
Se Pu. 2022 Apr;40(4):313-322. doi: 10.3724/SP.J.1123.2021.08014.
Traditional Chinese medicine (TCM) is gaining popularity worldwide, but its quality is often affected by excessive pesticide residues during cultivation and production. A sensitive and reliable method for the simultaneous determination of multi-residue pesticides in TCMs is the key to guarantee the quality and safety of TCMs. In this study, broad-spectrum hydrophilic-lipophilic balanced magnetic adsorbents were prepared for the magnetic matrix solid phase dispersion (MMSPD) extraction of 76 pesticides from three different TCMs before their detection by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Unlike the traditional matrix solid phase dispersion (MSPD), which required tedious SPE column packing, an external magnetic field was employed in our method for magnetic isolation and extraction from TCM samples, followed by grounding adsorption. First, broad-spectrum hydrophilic-lipophilic balanced magnetic adsorbents, FeO@PLS, were successfully fabricated by the swelling polymerization of divinyl benzene (DVB) and -vinyl pyrrolidone (NVP) on the surface of FeO magnetic particles. The prepared materials were systematically characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) for their morphologies, chemical structure, and crystalline structure. Then, the obtained magnetic particles (FeO@PLS) were applied to MMSPD for the simultaneous extraction and analysis of the 76 pesticides in honeysuckle, chrysanthemum, and pseudo-ginseng root (dry) prior to detection by HPLC-MS/MS. In order to establish the optimal extraction conditions, the key parameters affecting the MMSPD extraction efficiency were optimized, including the amount of magnetic materials FeO@PLS (5, 10, 12, 15, 20 mg), volume fractions of methanol in water for matrix purification (0%, 5%, 10%, 20%, 25%), grinding adsorption time for dispersion (2, 3, 4, 5, 6 min), type (methanol, methanol containing 0.1% (v/v) formic acid, acetonitrile, acetonitrile containing 0.1% (v/v) formic acid) and volume (0.5, 1, 2, 2.5, 5 mL) of elution solvent, and vortex time for desorption (1, 2, 3, 4, 5 min). Finally, the optimal conditions were set as follows: 10 mg of the magnetic adsorbent FeO@PLS, 10 mL 20% (v/v) of methanol in water with a vortex time of 1 min for matrix purification, grinding time of 5 min for dispersion and adsorption, 0.5 mL acetonitrile containing 0.1% (v/v) formic acid as the elution solvent, and vortex time of 1 min for desorption. Then, the 76 pesticides were separated on an Agilent ZORBAX Eclipse Plus C18 column (100 mm×3.0 mm, 1.8 μm) with gradient elution and analyzed in multiple reaction monitoring (MRM) mode by positive electrospray ionization (ESI). Under the optimal conditions, good linearities were obtained for the 76 pesticides in the concentration ranges of 10 to 200 μg/kg, with correlation coefficients ( )≥0.9965. The limits of detection (LODs, =3) were in the range of 0.6-3.0 μg/kg, and the limits of quantification (LOQs, =10) ranged from 2.0 to 10.0 μg/kg. The proposed method was successfully applied to 76 pesticide residue analysis in honeysuckle, chrysanthemum, and pseudo-ginseng root (dry). At three spiked levels, the recoveries were 69.1%-112.2%, 67.1%-102.8% and 70.1%-105.1%, with RSDs of 2.0%-12.4%, 2.1%-13.2% and 2.0%-13.5% for honeysuckle, chrysanthemum, and pseudo-ginseng root(dry), respectively. The prepared magnetic material FeO@PLS has the characteristics of both strong magnetic responsibility and high broad-spectrum adsorption property for hydrophilic (e. g., carbendazim) and lipophilic (e. g., edifenphos) pesticides. The implementation of the MMSPD method before the analysis of the 76 pesticides by HPLC-MS/MS has the following advantages: less consumption of the magnetic materials, sample, and organic solvent; simple operation; high sensitivity; and satisfactory accuracy and precision. Hence, this is a potential method for the simultaneous determination of multiple pesticide residues in complex non-liquid TCM samples.
中药在全球范围内越来越受欢迎，但其质量在种植和生产过程中常受到过量农药残留的影响。建立一种灵敏可靠的同时测定中药中多种农药残留的方法是保证中药质量和安全的关键。本研究制备了广谱亲水亲脂平衡磁性吸附剂，用于在高效液相色谱 - 串联质谱（HPLC - MS/MS）检测前，对三种不同中药中的76种农药进行磁性基质固相分散（MMSPD）萃取。与传统的基质固相分散（MSPD）不同，传统方法需要繁琐的固相萃取柱装填，而本方法采用外部磁场从中药样品中进行磁性分离和萃取，随后进行研磨吸附。首先，通过在Fe₃O₄磁性颗粒表面进行二乙烯基苯（DVB）和N - 乙烯基吡咯烷酮（NVP）的溶胀聚合，成功制备了广谱亲水亲脂平衡磁性吸附剂Fe₃O₄@PLS。通过扫描电子显微镜（SEM）、傅里叶变换红外光谱（FT - IR）和X射线衍射仪（XRD）对制备的材料进行了系统表征，以研究其形态、化学结构和晶体结构。然后，将得到的磁性颗粒（Fe₃O₄@PLS）应用于MMSPD，用于在HPLC - MS/MS检测前同时萃取和分析金银花、菊花和三七（干品）中的76种农药。为了确定最佳萃取条件，对影响MMSPD萃取效率的关键参数进行了优化，包括磁性材料Fe₃O₄@PLS的用量（5、10、12、15、20 mg）、用于基质净化的水中甲醇体积分数（零、5%、10%、20%、25%）、分散研磨吸附时间（2、3、4、5、6 min）、洗脱溶剂的类型（甲醇、含0.1%（v/v）甲酸的甲醇、乙腈、含0.1%（v/v）甲酸的乙腈）和体积（0.5、1、2、2.5、5 mL）以及解吸涡旋时间（1、2、3、4、5 min）。最后，确定最佳条件如下：10 mg磁性吸附剂Fe₃O₄@PLS，10 mL 20%（v/v）甲醇水溶液用于基质净化，涡旋时间1 min，分散研磨吸附时间5 min，0.5 mL含0.1%（v/v）甲酸的乙腈作为洗脱溶剂，解吸涡旋时间1 min。然后，76种农药在Agilent ZORBAX Eclipse Plus C18柱（100 mm×3.0 mm，1.8 μm）上进行梯度洗脱分离，并采用正离子电喷雾电离（ESI）在多反应监测（MRM）模式下进行分析。在最佳条件下，76种农药在10至200 μg/kg浓度范围内具有良好的线性关系，相关系数（r）≥0.9965。检测限（LODs，S/N = 3）在0.6 - 3.0 μg/kg范围内，定量限（LOQs，S/N = 10）在2.0至10.0 μg/kg范围内。所提出的方法成功应用于金银花、菊花和三七（干品）中76种农药残留的分析。在三个加标水平下,金银花、菊花和三七（干品）的回收率分别为69.1% - 112.2%、67.1% - 102.8%和70.1% - 105.1%，相对标准偏差（RSDs）分别为2.0% - 12.4%、2.1% - 13.2%和2.0% - 13.5%。制备的磁性材料Fe₃O₄@PLS对亲水性（如多菌灵）和亲脂性（如乙嘧酚磺酸酯）农药具有强磁响应性和高广谱吸附性的特点。在通过HPLC - MS/MS分析76种农药之前实施MMSPD方法具有以下优点：磁性材料、样品和有机溶剂消耗少；操作简单；灵敏度高；准确度和精密度令人满意。因此，这是一种用于同时测定复杂非液体中药样品中多种农药残留的潜在方法。
