Triacontyl modified silica gel as a sorbent for the preconcentration of polycyclic aromatic hydrocarbons in aqueous samples prior to gas chromatographic-mass spectrometry determination

Triacontyl modified silica gel as a sorbent coupled with gas chromatography-mass spectrometry(GC-MS) was developed to determine EPA prior 16 polycyclic aromatic hydrocarbons(PAHs) in water samples.Various parameters of solid-phase extraction such as organic modifier solvent,eluent,sample flow rate and volume were optimized.The developed method was found to yield a linear calibration curve in the concentration range of 0.05-8μg/L with respect to naphthalene,acenaphthylene,acenaphthene and 0.01-8μg/L for dibenz[a,h]anthracene and 0.05-14μg/L for fluorene,phenanthrene,anthracene and 0.01-14μg/L for the rest of analytes.Furthermore,the good accuracy and repeatability of the method made sure the requirements for achieving reliable analysis of PAHs in the environmental water samples,and the recoveries of optimal method were in the range of 80-120%except to higher volatility PAHs.C_(30)-bonded silica was proved to be an efficient sorbent for extraction of high molecular weight PAHs.

A nanocomposite consisting of silica-coated magnetite and phenyl-functionalized graphene oxide for extraction of polycyclic aromatic hydrocarbon from aqueous matrices

In this study,graphene oxide was covalently immobilized on silica-coated magnetite and then modified with 2-phenylethylamine to give a nanocomposite of type Fe3O4@SiO2@GO-PEA that can be applied to the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons（PAHs） from water samples.The resulting microspheres（Fe3O4@SiO2@GO-PEA） were characterized by Fourier transform-infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）,CHNS elemental analysis,and vibrating sample magnetometry（VSM） techniques.The adsorbent possesses the magnetic properties of Fe3O4 nanoparticles that allow them easily to be separated by an external magnetic field.They also have the high specific surface area of graphene oxide which improves adsorption capacity.Desorption conditions,extraction time,amount of adsorbent,salt concentration,and pH were investigated and optimized.Following desorption,the PAHs were quantified by gas chromatography with flame ionization detection（GC-FID）.The limits of detection（at an S/N ratio of 3） were achieved from 0.005 to0.1 μg/L with regression coefficients（R2） higher than 0.9954.The relative standard deviations（RSDs） were below 5.8%（intraday） and 6.2%（inter-day）,respectively.The method was successfully applied to the analysis of PAHs in environmental water samples where it showed recoveries in the range between 71.7%and 106.7%（with RSDs of 1.6%to 8.4%,for n = 3）.The results indicated that the Fe3O4@SiO2@GO-PEA microspheres had a great promise to extraction of PAHs from different water samples.