School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China.
J Chromatogr A. 2012 Jun 8;1241:13-20. doi: 10.1016/j.chroma.2012.04.017. Epub 2012 Apr 12.
A novel sample preparation technique termed dynamic liquid-liquid-solid microextraction (DLLSME) was developed and on-line coupled to high performance liquid chromatography (HPLC) for direct extraction, desorption, and analysis of trace estrogens in complex samples. The DLLSME consists of the aqueous donor phase, the organic medium phase and the molecularly imprinted polymer filaments (MIPFs) as solid acceptor phase. The organic solvent with lesser density was directly added on top of the aqueous sample, and the dynamic extraction was performed by circulating the organic solvent through the MIPFs inserted into a PEEK tube which served as an extraction and desorption chamber. Afterwards, the extracted analytes on the MIPFs were on-line desorbed and then introduced into the HPLC for analysis. To evaluate the feasibility of the on-line system, a new DLLSME-HPLC method was developed for the analysis of five estrogens in aqueous samples by using 17β-estradiol MIPFs as the solid phase. Under the optimized conditions, the enrichment factors of 51-70, limits of detection of 0.08-0.25 μg/L and precision within 4.5-6.9% were achieved. Furthermore, the proposed method was applied to the analysis of real samples including urine, milk and skin toner, satisfactory recovery (81.9-99.8%) and reproducibility (4.1-7.9%) were obtained. Especially, 0.59 μg/L of 17β-estradiol was determined in female urine sample. The DLLSME offers an attractive alternative for direct analysis of trace analytes in aqueous samples and could potentially be extended to other adsorptive materials.
一种新型的样品制备技术，称为动态液-液-固微萃取（DLLSME），已被开发出来，并与高效液相色谱（HPLC）在线耦合，用于直接萃取、解吸和分析复杂样品中的痕量雌激素。DLLSME 由水相供体相、有机介质相和分子印迹聚合物纤维（MIPFs）作为固相接受相组成。密度较小的有机溶剂直接添加到水样顶部，通过将有机溶剂循环通过插入聚醚醚酮（PEEK）管中的 MIPFs 进行动态萃取，PEEK 管用作萃取和解吸室。之后，将 MIPFs 上提取的分析物在线解吸，然后引入 HPLC 进行分析。为了评估在线系统的可行性，使用 17β-雌二醇 MIPFs 作为固相，开发了一种用于水样中五种雌激素分析的新型 DLLSME-HPLC 方法。在优化条件下，实现了 51-70 的富集因子、0.08-0.25μg/L 的检测限和 4.5-6.9%的精密度。此外，该方法还应用于实际样品的分析，包括尿液、牛奶和爽肤水，获得了令人满意的回收率（81.9-99.8%）和重现性（4.1-7.9%）。特别是，在女性尿液样品中检测到 0.59μg/L 的 17β-雌二醇。DLLSME 为直接分析水样中的痕量分析物提供了一种有吸引力的替代方法，并可能扩展到其他吸附材料。
