Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, Sao Paulo, Brazil.
J Sep Sci. 2011 Jun;34(11):1317-25. doi: 10.1002/jssc.201100096. Epub 2011 May 5.
In this article, a novel polydimethylsiloxane/activated carbon (PDMS-ACB) material is proposed as a new polymeric phase for stir bar sorptive extraction (SBSE). The PDMS-ACB stir bar, assembled using a simple Teflon(®)/glass capillary mold, demonstrated remarkable stability and resistance to organic solvents for more than 150 extractions. The SBSE bar has a diameter of 2.36 mm and a length of 2.2 cm and is prepared to contain 92 μL of polymer coating. This new PDMS-ACB bar was evaluated for its ability to determine the quantity of pesticides in sugarcane juice samples by performing liquid desorption (LD) in 200 μL of ethyl acetate and analyzing the solvent through gas chromatography coupled with mass spectrometry (GC-MS). A fractional factorial design was used to evaluate the main parameters involved in the extraction procedure. Then, a central composite design with a star configuration was used to optimize the significant extraction parameters. The method used demonstrated a limit of quantification (LOQ) of 0.5-40 μg/L, depending on the analyte detected; the amount of recovery varied from 0.18 to 49.50%, and the intraday precision ranged from 0.072 to 8.40%. The method was used in the analysis of real sugarcane juice samples commercially available in local markets.
本文提出了一种新型的聚二甲基硅氧烷/活性炭（PDMS-ACB）材料，作为搅拌棒吸附萃取（SBSE）的新型聚合物相。采用简单的聚四氟乙烯/玻璃毛细管模具组装的 PDMS-ACB 搅拌棒，经过超过 150 次萃取，表现出了优异的稳定性和耐有机溶剂性。SBSE 棒的直径为 2.36 毫米，长度为 2.2 厘米，内置 92 μL 聚合物涂层。通过在 200 μL 乙酸乙酯中进行液解吸（LD），并通过气相色谱-质谱联用（GC-MS）分析溶剂，评估了这种新型 PDMS-ACB 棒测定甘蔗汁样品中农药含量的能力。采用部分因子设计评估了萃取过程中涉及的主要参数。然后，采用星型配置的中心组合设计对显著的萃取参数进行了优化。所采用的方法显示出了 0.5-40 μg/L 的定量限（LOQ），具体取决于检测到的分析物；回收率在 0.18-49.50%之间变化，日内精密度在 0.072-8.40%之间。该方法用于分析当地市场上商业销售的真实甘蔗汁样品。
