Solid-phase extraction (SPE) is one of the most commonly used
sample pretreatment techniques due to its simplicity, high enrichment
factor and low consumption of organic solvent. The selection
of appropriate adsorbents will greatly benefit the analytical performance
(such as analytical sensitivity, selectivity and precision)
improvement in SPE techniques and the quest for new SPE adsorbents
has never ceased. To date, many novel adsorbents, such as
nanometer-sized materials [9,10], carbon nanotubes [11], mesoporous
materials [12], magnetic nanoparticles [13,14] have been
employed in SPE. Magnetic nanoparticles are superparamagnetic,which means that they are attracted to a magnetic field, but retain
no residual magnetism after the field is removed. Target analytes
adsorbed by the suspended superparamagnetic particles can be
removed very quickly from a matrix using a magnetic field, and the
particles will not agglomerate after removal of the field. Therefore,
magnetic solid phase extraction (MSPE) with magnetic nanoparticles
as the adsorbents has aroused greatest interest in analytical
community in recent years [15].