No abstract

In this study, an acid-treated-activated carbon was prepared from chestnut oak shell carbonization followed by modification with hydrochloric acid/nitric acid and then used as a new sorbent for headspace needle-trap extraction of chlorophenol compounds from aqueous solutions. Different techniques, including scanning electron microscopy, nitrogen adsorption-desorption analysis, and Fourier transform-infrared spectroscopy were used for the characterization of the sorbents. The effects of some experimental parameters, including the temperature, pH, sorbent amount, and time of extraction were optimized. The developed method is fast and sensitive, providing low and sub ng/L detection limits. The limits of detection and quantification were in the range of 0.75-5 and 5-15 ng/ml, respectively, and the equilibrium time was 20 min. Wide linearity in the range of 15-2000 ng/L with R 2 > 0.9993 was obtained. Repeatability of the method was accessed at 50, 100, and 200 ng/L concentration levels and RSD% of 5%-12% was achieved. The introduced method was applied for analyzing real water samples containing spiked chlorophenols, and the relative recovery values were found to be in the range of 84%-99% at the concentration levels of 50, 100 and 200 ng/L.

In current work, aniline-naphthylamine copolymers were prepared using electrochemical technique and then applied as a new sorbent for needle trap extraction of some volatile organic compounds from aqueous solution in headspace mode. The scanning electron microscopy and infrared spectrometry techniques were used to characterization of synthesized aniline-naphthylamine copolymers of aniline and naphthylamine. The results showed that aniline-naphthylamine copolymer compared to unmodified polymer, has higher porosity and non-uniform structures. The significant parameters of the sorbent preparation and extraction process such as the type and concentration of polymer, time and voltage of electrochemical deposition, the extraction time and temperatures and salt content were studied and optimized. The modified device is sensitive and fast providing good analytical parameters so that the detection limit of 0.9-2 ng L− 1 and the quantification limit of 3–7 ng L− 1 along with equilibrium time of 20 minutes were obtained. The linearity of method was obtained in the range of 15-1500 ng L− 1 with R2 > 0.9996. The method repeatability was considered at 50 ng L− 1 and relative standard deviations of 3–5% were obtained. To finish, the performance of proposed device was studied via the extraction of selected analytes in real water samples and the relative recovery values were found to be in the range of 94–102%, showing no matrix effect.