A novel needle trap sorbent based on carbon nanotube-sol-gel for microextraction of polycyclic aromatic hydrocarbons from aquatic media.

A new type of composite material based on carbon nanotubes (CNTs) and sol-gel chemistry was prepared and used as sorbent for needle trap device (NTD). The synthesized composite was prepared in a way to disperse CNTs molecules in a sol-gel polymeric network. CNT/silica composites with different CNT doping levels were successfully prepared, and the extraction capability of each composite was evaluated. Effects of surfactant and the oxidation duration of CNTs on the extraction efficiency of synthesized composites were also investigated. The applicability of the synthesized sorbent was examined by developing a method based on needle trap extraction (NTE) and gas chromatography mass spectrometry detection (GC-MS) for the determination of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Important parameters influencing the extraction process were optimized and an extraction time of 30 min at 50 °C and sampling flow rate of 2.5 mL min(-1) gave maximum peak area, when NaCl (15%, w/v) was added to the aqueous sample. The linearity for acenaphthene, acenaphthylene and fluorene was in the concentration range of 0.01-20 ng mL(-1) and for naphthalene and anthracene was in the range of 0.1-50 ng mL(-1). Limits of detection was 0.001 ng mL(-1), for acenaphthene, acenaphthylene and fluorene, and 0.01 ng mL(-1), for naphthalene and anthracene using time-scheduled selected ion monitoring (SIM) mode, and the RSD% values (n=3) were all below 11.2% at the 1 ng mL(-1) level. The developed method was successfully applied to real water samples while the relative recovery percentages obtained for the spiked water samples were from 73.8 to 113.8%.