A green, sensitive and accurate dispersive liquid–liquid microextraction (DLLME) method was used to preconcentrate four selected pesticides in dam lake water samples for determination by gas chromatography–mass spectrometry (GC–MS). Conditions of the DLLME method were comprehensively investigated and optimized according to type/volume of extraction solvent, type/volume of dispersive solvent, and type/period of mixing. The developed method was validated according to the limits of detection and quantitation, accuracy, precision and linearity. Under the optimum conditions, limit of detection values calculated for alachlor, acetochlor, metolachlor and fenthion were 1.7, 1.7, 0.2 and 7.8 µg/kg (mass based), respectively. The method recorded 202, 104, 275 and 165 folds improvement in detection power values for acetochlor, alachlor, metolachlor and fenthion, respectively, when compared with direct GC–MS measurements. In order to evaluate the accuracy of the developed method, real sample application with spiking experiments was performed on dam lake water samples, and satisfactory percent recovery results in the range of 81%–120% were obtained.

采用绿色，灵敏，准确的分散液-液微萃取（DLLME）方法对坝湖水样中的四种选定农药进行预浓缩，以通过气相色谱-质谱法（GC-MS）测定。根据萃取溶剂的类型/体积，分散溶剂的类型/体积以及混合的类型/时间，对DLLME方法的条件进行了全面研究和优化。根据检测和定量，准确度，精密度和线性度的限制，对开发的方法进行了验证。在最佳条件下，对甲草胺，乙草胺，异丙甲草胺和二硫磷的检测极限分别为1.7、1.7、0.2和7.8 µg / kg（以质量计）。该方法记录了乙草胺，乙草胺，与直接GC-MS测量相比，分别使用甲草胺和倍硫磷。为了评估所开发方法的准确性，对坝湖水样品进行了加标实验的实际样品应用，回收率在81％–120％范围内令人满意。