A sensitive and simple method using magnetic multi-walled carbon nanotube (MWCNTs-FeO MNP), as the adsorbent, has been successfully developed for extraction and pre-concentration of arsenic, lead and cadmium with detection by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The nanosorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). The key factors affecting the signal intensity such as pH, adsorbent amount, etc. were investigated. Under optimal conditions, the limits of detection (three-time of signal to noise ratio, S/N 3) were 0.3, 0.6, 0.3 ng/mL for arsenic, lead and cadmium, respectively. Application of the adsorbent was investigated by the analysis of water, milk, Indian rice and red tea. The experimental data was analyzed and obeyed Langmuir and Freundlich adsorption models. The kinetic data was fitted to the pseudo-second-order model. Thermodynamic studies revealed the feasibility and exothermic nature of the system.

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The inclusion of a polyamidoamine dendrimer in a silica sol-gel yielded a solid nanosorbent that was used for the preconcentration, extraction, and determination of citalopram in hospital waste water, hemodialysis solution, and some drinking water. The method was developed by applying a novel nanosorbent for the solid-phase microextraction of citalopram, containing a silica sol-gel reinforced by polyamidoamine second-generation dendrimer, which was protected by a polypropylene hollow fiber. Plackett-Burman design and central composite design were utilized to evaluate the significance of several factors on the extraction efficiency. The adsorption mechanism and thermodynamic and kinetic aspects were studied. The adsorption process was exothermic and well fitted to the Bangham equation kinetic model. Under optimal conditions, the presented method was liner in the range of 0.05-100 μg/mL. The limits of detection of quantification of citalopram were 0.0095 and 0.031 μg m/L, respectively.

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The study presents the synthesis of nano-thiamine hydrochloride structure (NTH) using sol-gel method by hydrolysis of tetraethyl orthosilicate with ethanol and water mixture as silica source and nitric acid as catalyst support in which thiamine hydrochloride nanocrystals were dispersed in the silica glassy matrix. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The morphological observation of the SEM results reveals that the nano-thiamine hydrochloride composites are in the range of 5–15 nm in size.