Two miniaturized sample preparation techniques, ultrasound-assisted emulsification microextraction (USAEME) and micro-solid-phase extraction (μ-SPE) have been integrated for the pre-concentration of four polar chlorophenoxy acid (CPA) herbicides from environmental aqueous samples. An metal-organic framework, MIL-101(Cr), characterized by its high porosity and large surface area, was explored as a sorbent. Despite the simplicity and convenience of μ-SPE, its use can potentially be limited by a long equilibration time, especially when applied to polar analytes. However, as demonstrated in this work, this drawback can be overcome by employing 1-octanol as a medium during the USAEME step to concentrate, and transport the polar herbicides through the polypropylene membrane of the μ-SPE device, onto the MIL-101(Cr). After μ-SPE, the herbicides were desorbed using 125 μL of organic solvent, and analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Under the most favorable conditions, wide calibration ranges with good linearity (r² ≥ 0.995) are attained for all the herbicides. The limits of detection of the method range between 7.20 and 58.1 ng L⁻¹ while the limits of quantification (LOQs) range between 24.0 and 194 ng L⁻¹. The LOQs determined are lower than the guidelines set by the World Health Organization for the respective herbicides. USAEME-μ-SPE-UHPLC-MS/MS also shows good repeatability, with relative standard deviations ≤15.2%. Enrichment factors are between 21 and 70. The method was applied to the analysis of tap and reservoir waters, in which satisfactory relative recoveries ranging between 64.4% and 106% were obtained. The MIL-101(Cr) exhibited superior extraction capability in comparison to activated carbon and multi-walled carbon nanotubes.

集成了两种小型化的样品制备技术，即超声辅助乳化微萃取（USAEME）和微固相萃取（μ-SPE），用于从环境水性样品中预富集四种极性氯苯氧酸（CPA）除草剂。探索了一种金属有机骨架MIL-101（Cr），它具有高孔隙率和大表面积的特点，可作为一种吸附剂。尽管μ-SPE既简单又方便，但其使用可能会受到平衡时间长的限制，尤其是应用于极性分析物时。但是，如本工作所示，可以通过在USAEME步骤中使用1-辛醇作为介质来浓缩该极性除草剂，并将极性除草剂通过μ-SPE装置的聚丙烯膜运输到MIL-101（铬）。在μ-SPE之后，使用125μL有机溶剂解吸除草剂，并通过超高效液相色谱-串联质谱（UHPLC-MS / MS）进行分析。在最有利的条件下，宽校准范围具有良好的线性度（r²  ≥0.995）被实现为所有的除草剂。该方法的检测限在7.20至58.1 ng L ^-1之间，而定量限（LOQ）在24.0至194 ng L ^-1之间。确定的最低限量低于世界卫生组织为相应除草剂设定的指导原则。USAEME-μ-SPE-UHPLC-MS/ MS还显示出良好的重复性，相对标准偏差≤15.2％。富集系数在21到70之间。该方法用于自来水和水库水的分析，获得了令人满意的相对回收率，介于64.4％和106％之间。与活性炭和多壁碳纳米管相比，MIL-101（Cr）表现出优异的提取能力。