Magnetic nanoparticles coated with non-ionic surfactants as restricted access material for solid phase extraction
Restricted access materials (RAMs) are sorbents with enhanced selectivity due to their inherent structure since their extractive groups are protected by external functional groups that exclude macromolecules by a size exclusion and/or an electrostatic repulsion mechanism. Thus, only the small target analytes are able to reach the extracting phase avoiding the clogging of the sorbent by the sample matrix. In a recent article accepted for publication in Journal of Chromatography A (1), researchers from Wuhan at China have proposed a new RAM based on the combination of magnetic nanoparticles and non-ionic surfactants. Magnetite nanoparticles (Fe304), which are synthesized by an oxidative-coprecipitation method, are the core of these RAMs providing them with a paramagnetic behavior which is essential for their easy isolation after the extraction process. The magnetite particles, with sizes in the low nm range, are subsequently derivatized with dodecyltriethoxisilane anchoring C12 ext...