新烟碱类农药是一类相对较新的农药,由于其对非目标生物的潜在生态风险而引起了广泛关注。建立了一种固相萃取与液相色谱-串联质谱(SPE-LC-MS/MS)相结合的方法,用于快速,准确地检测八种新烟碱类农药(dinotfuran,e-nitenpyra,噻虫嗪,clothianidin,吡虫啉,吡虫啉,啶虫脒,和噻虫啉)在废水中。选择色谱流动相和MS参数,并采用单因素法确定最优柱型,提取量,样品加载速度,和SPE的pH值。最优参数如下:柱型,HLB柱(500mg/6mL);样品提取体积,500mL;样品加载速度,10mL/min;和样品pH,6-8.通过优化色谱梯度洗脱程序,降低了废水样品的基体效应,检查样品的稀释系数,并使用同位素内标校准方法。在分析之前,废水样品用超纯水稀释5倍进行预处理。随后,使用含有0.1%(v/v)甲酸和甲醇的2mmol/L乙酸铵水溶液作为流动相,在ZORBAXEclipsePlusC18色谱柱(100mm×2.1mm,1.8μm)。使用阳离子多反应监测(MRM)模式定量样品10分钟。吡虫啉-d4用作同位素内标。通过应用响应面方法选择冲洗和洗脱溶剂的类型和质量,进一步优化了SPE过程。SPE柱的最佳预处理包括用10%甲醇水溶液冲洗和用甲醇-乙腈(1∶1,v/v)混合物(7mL)洗脱。8种新烟碱类农药在相关范围内呈良好的线性关系,线性相关系数(r)均大于0.9990。方法检出限(MDL)范围为0.2至1.2ng/L,方法定量限(MQLs)范围为0.8至4.8ng/L。8种新烟碱类农药在3个加标水平下的平均回收率在82.6%-94.2%之间,相对标准偏差(RSD)范围为3.9%至9.4%。最后,优化后的方法成功地应用于分析四个污水处理厂的废水样品。结果表明,八种新烟碱类农药在未检测到(ND)至256ng/L的浓度范围内可以普遍检测到。该方法MDL低,准确度高,与其他类似方法相比,它是痕量检测废水中八种新烟碱类农药的合适选择。所提出的方法可用于监测环境影响和评估废水中新烟碱类农药的潜在风险。从而促进非目标生物的保护和这些农药在农业中的可持续使用。
Neonicotinoid pesticides are a relatively new class of pesticides that have garnered significant attention owing to their potential ecological risks to nontarget organisms. A method combining solid phase extraction with liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) was developed for the rapid and accurate detection of eight neonicotinoid pesticides (dinotefuran, E-nitenpyram, thiamethoxam, clothianidin, imidacloprid, imidaclothiz, acetamiprid, and thiacloprid) in wastewater. The chromatographic mobile phase and MS parameters were selected, and a single-factor method was used to determine the optimal column type, extraction volume, sample loading speed, and pH for SPE. The optimal parameters were as follows: column type, HLB column (500 mg/6 mL); sample extraction volume, 500 mL; sample loading speed, 10 mL/min; and sample pH, 6-8. The matrix effects of the wastewater samples were reduced by optimizing the chromatographic gradient-elution program, examining the dilution factor of the samples, and using the isotope internal standard calibration method. Prior to analysis, the wastewater samples were diluted 5-fold with ultrapure water for pretreatment. Subsequently, 2 mmol/L ammonium acetate aqueous solution containing 0.1% (v/v) formic acid and methanol was used as mobile phases for gradient elution on a ZORBAX Eclipse Plus C18 column (100 mm×2.1 mm, 1.8 μm). The samples were quantified using positive-ion multiple reaction monitoring (MRM) mode for 10 min. Imidacloprid-d4 was used as the isotope internal standard. The SPE process was further optimized by applying response surface methodology to select the type and mass of rinsing and elution solvents. The optimal pretreatment of the SPE column included rinsing with 10% methanol aqueous solution and elution with methanol-acetonitrile (1∶1, v/v) mixture (7 mL). The eight neonicotinoid pesticides showed satisfactory linearity within the relevant range, with linear correlation coefficients (r) all greater than 0.9990. The method detection limits (MDLs) ranged from 0.2 to 1.2 ng/L, and the method quantification limits (MQLs) ranged from 0.8 to 4.8 ng/L. The average recoveries of the eight neonicotinoid pesticides were in the range of 82.6%-94.2% at three spiked levels, with relative standard deviations (RSDs) ranging from 3.9% to 9.4%. Finally, the optimized method was successfully applied to analyze wastewater samples collected from four sewage treatment plants. The results indicated that the eight neonicotinoid pesticides could be generally detected at concentrations ranging from not detected (ND) to 256 ng/L. The developed method has a low MDL and high accuracy, rendering it a suitable choice for the trace detection of the eight neonicotinoid pesticides in wastewater when compared with other similar methods. The proposed method can be utilized to monitor the environmental impact and assess the potential risks of neonicotinoid pesticides in wastewater, thus promoting the protection of nontarget organisms and the sustainable use of these pesticides in agriculture.