Department of Environmental Engineering, Technical University of Crete, Polytechneioupolis, GR-73100 Chania, Greece.
Talanta. 2010 Mar 15;80(5):2057-62. doi: 10.1016/j.talanta.2009.11.005. Epub 2009 Nov 12.
A new and fast equilibrium-based solvent microextraction technique termed vortex-assisted liquid-liquid microextraction (VALLME) has been developed and used for the trace analysis of octylphenol, nonylphenol and bisphenol-A in water and wastewater samples. According to VALLME, dispersion of microvolumes of a low density extractant organic solvent into the aqueous sample is achieved by using for the first time vortex mixing, a mild emulsification procedure. The fine droplets formed could extract target analytes towards equilibrium faster because of the shorter diffusion distance and larger specific surface area. Upon centrifugation the floating extractant acceptor phase restored its initial single microdrop shape and was used for high-performance liquid chromatographic analysis. Different experimental parameters were controlled and the optimum conditions found were: 50 microl of octanol as the extractant phase; 20 ml aqueous donor samples; a 2 min vortex extraction time with the vortex agitator set at a 2500 rpm rotational speed; centrifugation for 2 min at 3500 rpm; no ionic strength or pH adjustment. The calculated calibration curves gave high levels of linearity yielding correlation coefficients (r(2)) greater than 0.9935. The repeatability and reproducibility of the proposed method were found to be good and the limits of the detection were calculated in the low microg l(-1) level ranging between 0.01 and 0.07 microg l(-1). Matrix effects were determined by applying the proposed method to spiked tap, river water and treated municipal wastewater samples. The proposed method was finally applied to the determination of target pollutants in real wastewater effluent samples using the standard addition method.
一种新的、快速的基于平衡的溶剂微萃取技术，称为涡旋辅助液-液微萃取（VALLME），已被开发并用于痕量分析水中的辛基酚、壬基酚和双酚 A 以及废水样品。根据 VALLME，通过首次使用涡旋混合，一种温和的乳化程序，将微体积的低比重萃取有机溶剂分散到水样中。由于扩散距离较短和比表面积较大，形成的细小液滴可以更快地达到平衡，从而萃取目标分析物。离心后，浮起的萃取剂接受相恢复到初始的单个微滴形状，并用于高效液相色谱分析。控制了不同的实验参数，找到了最佳条件：50 微升辛醇作为萃取相；20 毫升水相供试品；涡旋搅拌器转速为 2500rpm 的 2 分钟涡旋萃取时间；以 3500rpm 的转速离心 2 分钟；不进行离子强度或 pH 值调节。计算得到的校准曲线具有较高的线性度，相关系数（r(2)）大于 0.9935。所提出方法的重复性和再现性良好，检测限计算值在低微克每升水平，范围在 0.01 至 0.07 微克每升之间。通过将该方法应用于加标自来水、河水和处理后的城市废水样品，确定了基质效应。最后，使用标准添加法将该方法应用于实际废水排放样品中目标污染物的测定。
