Microextraction Tech

Carbon nanotubes reinforced hollow fiber microextraction (HF-SLPM) was proposed for the first time by Es´haghi et al. in 2010 (1). The original technique consisted of a multi-phase system where the aqueous donor and acceptor phases were separated by a polymeric membrane with a dispersion of carbon nanotubes in 1-octanol immobilized in its pores. The pH gradient established at both sides of the reinforced hollow membrane allowed the extraction of the target analytes. Due to its multiphase nature,  HF-SLPM  involves a selectivity enhancement compared to traditional hollow fiber liquid phase microextraction. Diethylstilbestrol The direct immobilization of carbon nanotubes (CNTs) in the pores of a polypropylene hollow fiber have been recently proposed by researchers from the Chinese Academy of Sciences of Beijing at China (2), for the isolation and preconcentration of diethylstilbestrol from milk. Diethylstilbestrol is a steroid hormone used for animal growth and it pre...

Electromembrane extraction (EME), which was firstly proposed in 2006 by Pedersen-Bjergaard and Rasmussen, is based on the voltage-assisted migration of the target analytes from two aqueous solutions: the sample and the acceptor phase. Both phases are separated by a polymeric membrane where an organic solvent is immobilized in the form of a supported liquid membrane (SLM). EME shares some of the principles and a similar manifold that this employed for hollow fiber-liquid phase microextraction (HF-LPME). As it is schematized in the Figure, the sample is located in an appropriate vessel where a polypropylene hollow fiber (HF) is introduced. The HF contains the acceptor phase in the lumen and an organic solvent in the internal pores acting as a physical barrier between the two aqueous solutions. Moreover, the EME manifold involves two electrodes which are located in the sample and the HF lumen, respectively. The voltage applied between both electrodes is the driving force of this ext...