A simple strategy based on fibers coated with surfactant-functionalized multiwalled carbon nanotubes to improve the properties of solid-phase microextraction of phenols in aqueous solution

Abstract

Methods and experiments In this study, a functionalized multiwalled carbon nanotube (MWCNT)-coated solid-phase microextraction (SPME) fiber was developed for concentrating analytes in aqueous samples. Sodium deoxycholate (NaDC) was used as a dispersing agent for non-covalent modification of MWCNTs. The coating showed porous structure and large adsorption capacity. To investigate the capability of this MWCNTs/NaDC SPME fiber, it was applied to the analysis of phenols in aqueous solution. After extraction, the analytes were desorbed in an acetonitrile–water solution and analyzed using high-performance liquid chromatography. Results The MWCNTs/NaDC fiber exhibited good analytical performance, and fine preparation reproducibility was obtained with the relative standard deviations (RSDs) ranging from 4.9% to 10.2% (n = 6) in one batch, from 5.7% to 11.9% (n = 3) among different batches. Under the optimum extraction conditions, the detection limits were 0.15–0.30 ng/mL(S/N = 3), the linear detection ranges were 1–100 ng/mL (R2 ≥ 0.9997) for these analytes, and good recoveries (80.3–95.4%) were obtained for the spiked samples. Conclusion This is a simple and accurate pretreatment method for the analysis of phenols in aqueous samples.

Selectivity of PEG/Salt Aqueous Two-Phase System Enhanced by Surfactant@MWCNT Composites

“…The contents of PEG were 25 or 20 wt %. The salts used include (NH 4 ) 2 SO 4 (23,18, or 10 wt %) and Na 2 SO 4 (10 wt %). The adjuvants include MWCNTs (0.2−1.0 mg/mL), surfactants (0.5−4.0 wt %, including TX-100, Tween 80, SDS, SDBS, and AOT), and MWCNT (0.2−1.0 mg/mL)/surfactant (0.5−4.0 wt %) mixtures.…”

“…19−21 Multiwalled carbon nanotubes (MWCNTs) have a hollow tubular structure with a large specific surface area, and hence, they exhibit strong surface adsorption ability. 22,23 MWCNTs have high chemical stability and good biocompatibility and are easy to functionalize. 24,25 The surface properties of MWCNTs and the structures and properties of adsorbates together determine the behavior of MWCNTs.…”

“…Multiwalled carbon nanotubes (MWCNTs) have a hollow tubular structure with a large specific surface area, and hence, they exhibit strong surface adsorption ability. , MWCNTs have high chemical stability and good biocompatibility and are easy to functionalize. , The surface properties of MWCNTs and the structures and properties of adsorbates together determine the behavior of MWCNTs. For example, surfactants can adsorb on the surface of MWCNTs through noncovalent interactions, which improves the stability and dispersibility of MWCNTs in water, and also changes the absorption behavior of MWCNTs. ,, …”

“…For example, surfactants can adsorb on the surface of MWCNTs through noncovalent interactions, which improves the stability and dispersibility of MWCNTs in water, and also changes the absorption behavior of MWCNTs. 23,26,27 In this study, we used surfactant@MWCNT as an adjuvant to improve the selectivity of PEG/salt ATPS. The surfactants used include Triton X-100 (TX-100), Tween 80, sodium dodecyl sulfate (SDS), sodium dodecyl benzenesulfonate (SDBS), and bis (2-ethylhexyl) phenylalanine (Phe), L-tyrosine (Tyr), S-mandelic acid (Maa), theophylline (Thp), theobromine (Thb), and cephalexin (Cep), were selected as model extracts.…”

Aramid-wrapped CNT hybrid sol–gel sorbent for polycyclic aromatic hydrocarbons

“…For example, Sarafraz-Yazdi's group investigated the functionalization of CNTs with polyethylene glycol (PEG) polymeric tails to enhance their dispersion and compatibility in sol–gel matrices. 25 Additionally, many modified CNTs with surfactants, 26 amino acids, 27 cyclodextrins, 28,29 polythiophene, 30 and polyaniline–polypyrrole 31 have been prepared and their utility as microextraction sorbents has been evaluated. Moreover, nitrogen-doped CNTs with excellent analytical performance for the extraction of polychlorinated biphenyls (PCBs) have been described.…”