The adsorptive properties of powdered carbon materials with a strongly differentiated porosity and their applications in electroanalysis and solid phase microextraction.

The adsorption of 4-chlorophenol from an aqueous solution on carbonaceous materials (one carbon black and two powdered activated carbons) with a strongly differentiated porosity was investigated. The kinetic data were fitted well to the pseudo-second order model. The amount of 4-chlorophenol adsorbed at equilibrium was increased with an increase in the specific surface area of the tested materials. The adsorption isotherms were analyzed using the Langmuir and Freundlich models. The Langmuir isotherm was slightly favorable (R(2)>0.99) rather than the Freundlich isotherm (R(2)>0.98). Carbon materials were also used for the modification of carbon paste electrodes as well as for the preparation of novel solid phase microextraction fibers. The peak current of the differential pulse voltammetry curves was increased along with the amount of added carbon paste electrode modifier. The signal response was closely related to the porosity of the materials used, and increased with the increase in the specific surface area. The amount of 4-chlorophenol extracted from the samples by the solid phase microextraction fiber's surface was also correlated with the specific surface area of the tested materials. All the novel fibers were better than the commercially available fibers prepared from polidimethylosiloxane.