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 20mg of purified carbon nanocones/disks was packed in 3 mL commercial SPE cartridges. Once conditioned, up to 8 mL of water samples can be preconcentrated without analyte losses. The chlorophenols were eluted by using 200 microL of hexane. Aliquots of 2 microL 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.