Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2#, Haidian District, Beijing 100194, China.
J Chromatogr A. 2012 Sep 7;1254:23-9. doi: 10.1016/j.chroma.2012.07.051. Epub 2012 Jul 24.
A novel, rapid ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) technique combined with magnetic retrieval (MR-IL-DLLME) has been developed and used to analyze five benzoylurea insecticides (BUs) in environmental water samples. This procedure was based on the magnetic retrieval of the ionic liquid using unmodified magnetic nanoparticles (MNPs). In this experiment, the fine ionic liquid droplets formed in aqueous samples functioned as an extractant for the extraction of BUs; after the extraction process was completed, Fe₃O₄ MNPs were added as a carrier to retrieve and separate the ionic liquid from the sample solution. After the supernatant was removed, the ionic liquid was desorbed using acetonitrile and subsequently injected directly into an HPLC system for analysis. The optimum experimental parameters are as follows: 20 mg of Fe₃O₄ (20 nm) as magnetic sorbents; 70 μL of [C₆MIM][PF₆] as the extraction solvent; 300 μL of acetonitrile as the disperser solvent; a vortex extraction time of 90 s with the vortex agitator set at 2800 rpm and no ionic strength. Under the optimized conditions, good linearity was obtained with correlation coefficients (r) greater than 0.9981. The repeatability and reproducibility of the proposed method were found to be good, and the limits of detection ranged from 0.05 μg L⁻¹ to 0.15 μg L⁻¹. The proposed method was then successfully used for the rapid determination of BUs in real water samples. The recoveries of five BUs at two spiked levels ranged from 79.8 to 91.7% with RSDs less than 6.0%.
一种新型的、快速的离子液体分散液液微萃取（IL-DLLME）技术与磁性回收（MR-IL-DLLME）相结合，已被开发并用于分析环境水样中的五种苯甲酰脲类杀虫剂（BUs）。该方法基于未修饰的磁性纳米颗粒（MNPs）对离子液体的磁性回收。在该实验中，形成于水相样品中的细小离子液体液滴作为萃取剂用于萃取 BUs；萃取过程完成后，加入 Fe₃O₄ MNPs 作为载体，从样品溶液中回收和分离离子液体。去除上清液后，用乙腈解吸离子液体，然后直接注入 HPLC 系统进行分析。最佳实验参数如下：20 mg Fe₃O₄（20nm）作为磁性吸附剂；70 μL [C₆MIM][PF₆]作为萃取溶剂；300 μL 乙腈作为分散溶剂；涡旋提取时间为 90s，涡旋搅拌器转速设置为 2800rpm，无需离子强度。在优化条件下，得到了良好的线性关系，相关系数（r）大于 0.9981。所提出方法的重复性和重现性良好，检出限范围为 0.05 μg L⁻¹ 至 0.15 μg L⁻¹。该方法随后成功用于实际水样中 BUs 的快速测定。五种 BUs 在两个加标水平下的回收率在 79.8%至 91.7%之间，相对标准偏差（RSD）小于 6.0%。
