Synthesis of layered zinc hydroxide intercalated with dodecyl sulfate organic-inorganic hybrid nanocomposite as a fiber coating for the headspace solid-phase microextraction of aromatic hydrocarbons from water.

We describe the synthesis of a layered zinc hydroxide-dodecyl sulfate organic-inorganic hybrid nanocomposite as a new solid-phase microextraction fiber. The fiber coating can be prepared easily in a short time and the reaction is at room temperature; it is mechanically stable and exhibits relatively high thermal stability. The synthesized layered zinc hydroxide-dodecyl sulfate nanocomposite was successfully prepared and immobilized on a stainless steel wire and evaluated for the extraction of aromatic compounds from aqueous sample solutions in combination with gas chromatography and mass spectrometry. The method yields good results for some validation parameters. Under optimum conditions (extraction time: 15 min, extraction temperature: 50°C, desorption time: 1 min, desorption temperature: 250°C, salt concentration: 0.5 g/mL), the limit of detection and dynamic linear range were 0.69-3.2 ng/L and 10-500 ng/L, respectively. The method was applied to the analyses of benzene, toluene, ethylbenzene, and o-, p-, and m-xylenes in two real water samples collected from the Aji river and Mehran river, Tabriz, Iran. Under optimum conditions, the repeatability and reproducibility for one fiber (n = 3), expressed as the relative standard deviation, was 3.2-7.3% and 4.2-11.2% respectively. The fibers are thermally stable and yield better recoveries than conventional methods of analysis.

Polypyrrole-montmorillonite nanocomposite as sorbent for solid-phase microextraction of phenolic compounds in water.

A fiber-coated polypyrrole-montmorillonite nanocomposite was prepared for solid-phase microextraction. The fiber coating can be prepared easily; it is mechanically stable and exhibits relatively high thermal stability. The prepared fiber was evaluated for the extraction of some phenolic compounds from aqueous sample solutions by gas chromatography-mass spectrometry. The effects of the extraction and desorption parameters including extraction time, extraction temperature, stirring rate, ionic strength, pH and desorption temperature and time have been studied. At optimum conditions, the repeatability for one fiber (n = 5), expressed as % relative standard deviation was between 6.5 and 7.8% for the phenolic compounds. The detection limits for the studied phenolic compounds were between 0.05-1.3 ng/mL. The developed method offers the advantage of being simple to use, with shorter analysis time, lower cost, thermal stability of the fibers, and high relative recovery in comparison to conventional methods of analysis.