Evaluation of carbon nanotubes as a solid-phase extraction adsorbent for the extraction of cephalosporins antibiotics, sulfonamides and phenolic compounds from aqueous solution

Abstract

The adsorptive potential of carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes) for solid-phase extraction of three groups of highly polar compounds (namely cephalosporins antibiotics, sulfonamides and phenolic compounds) was tested in this article. The analytes were strongly retained by the carbon nanotubes. And acceptable recoveries were obtained with the addition of ammonium acetate into eluents. The effects of solution pH on the recoveries of the antibiotics and phenolic compounds were examined. To check the retention abilities of three groups of compounds on carbon nanotubes, fixed amount of each analyte was added to different volumes (up to 500 mL) of aqueous solution, and then extracted by the sorbents. Comparative studies showed that the carbon nanotubes were much superior to C 18 for the extraction of the highly polar analytes. For the cephalosporins antibiotics and sulfonamides, the carbon nanotubes showed stronger retention capability than graphitized carbon blacks, but for some of the phenolic compounds graphitized carbon blacks seemed to be more suitable, indicating different retention mechanisms of these analytes. To further assess the enrichment ability of carbon nanotubes for highly polar compounds, the solid-phase extraction method of multi-walled carbon nanotubes packed cartridge was well developed, and the sulfonamides were used as model compounds. Under the optimal procedures, the detection limits of sulfonamides were in the range of 27-38 ng L −1 . The spiked recoveries from several real water samples obtained for sulfathiazole and sulfadiazine ranged from 55% to 79% and 72% to 92%, respectively, while the recoveries of sulfapyridine and sulfamethazine were in the range of 85-102%.

Photodegradation of sulfapyridine under simulated sunlight irradiation: Kinetics, mechanism and toxicity evolvement

“…The difference of SPY degradation rates was likely related to the SPY speciation under different pH values. SPY has pK a1 and pK a2 values of 2.74 and 8.29 (Niu et al, 2007). Under acidic and alkaline environment different SPY speciation might affect the absorption of light wavelength (Fig.…”

Determination of 16 polycyclic aromatic hydrocarbons in environmental water samples by solid-phase extraction using multi-walled carbon nanotubes as adsorbent coupled with gas chromatography–mass spectrometry

“…Carbon nanotubes (CNTs) have attracted much interest that was directed toward exploiting their unique thermal, mechanical, electronic and chemical properties [25] since discovered. The multi-walled CNTs (MWCNTs) composed of several rolled-up graphite sheets [26] displayed large specific surface areas [27] and high adsorption capacity [28], which was primarily owe to their dramatically hydrophobic surface and unique structure with internal tube cavity [29].…”

Carbon Nanotubes as a New Solid Phase Extraction Sorbent for Analysis of Environmental Pollutants

“…Limit of quantification was 0.5 μg/ kg for three barbiturates. The adsorptive potential of SWCNTs and MWCNTs for SPE of three groups of highly polar compounds (namely cefalosporin antibiotics, sulfonamides and phenolic compounds) was tested (Niu et al, 2007). It was found that the analytes were strongly retained by carbon nanotubes.Acceptable recoveries were obtained by adding ammonium acetate into the eluents.…”