Evaluation of carbon nanocones/disks as sorbent material for solid-phase extraction

The potential of carbon nanocones/disks as sorbent material in solid-phase extraction (SPE) procedures has been evaluated. For this aim,a model analytical problem, the determination of chlorophenols in water samples, was selected. An accurately weighed amount of 20 mg of purified carbon nanocones/disks was packed in 3 mL commercial SPE cartridges. Once conditioned, up to 8 mL. of water samples can be pre-concentrated without analyte losses. The chlorophenols were eluted by using 200 mu L of hexane. Aliquots of 2 mu L. of the organic extract were injected in the gas chromatograph-mass spectrometer for separation and quantification. The purification of the commercial nanocones/disks to reduce the presence of amorphous carbon has been successfully achieved by heating the carbon nanocones/disks at 450 degrees C for 20 min. Detection limits of chlorophenols were in the range 0.3-8 ng mL(-1) by using 2 mL of sample. Moreover, excellent average recovery values (98.8-100.9%) have been obtained after the analysis of water samples from different nature. Finally, the performance of the carbon nanocones/disks as sorbent material has been compared with that of multiwalled carbon nanotubes, providing the former better results under the experimental conditions assayed. (C) 2009 Elsevier B.V. All rights reserved.