Fabrication and implementation of bimetallic Fe/Zn nanoparticles (mole ratio 1:1) loading on hydroxyethylcellulose - Graphene oxide for removal of tetracycline antibiotic from aqueous solution.

Tetracycline (TC) as an antibiotic with high consumption causes the spread of contamination in an aqueous solution. In recent decades, antibiotics are the main cause of hindering the growth of microorganisms. Also, they are one of the important groups of pharmaceuticals with extensive usage in human and veterinary medicine. In the first work of its kind, we used a suitable adsorbent of biodegradable hydroxyethylcellulose (HEC) with graphene oxide (GO) by crosslinking ethylene glycol dimethacrylate (EGDMA) and the Fe/Zn with mole ratio 1:1 bimetallic nanoparticles with HEC-GO support. The materials were identified using FTIR, FE-SEM, EDX, TEM, and TG- DSC analyses. The factors affecting the adsorption process (contact time, initial concentration of TC, solution pH, adsorbent dosage, and reaction temperature) were evaluated in a series of batch systems. The adsorption data showed that the high adsorption capacity was obtained on the HEC-GO and HEC-GO/Fe-Zn (mole ratio 1:1) nanocomposites at pH 3. Also, the contact time as the main factor affecting the adsorption process by adsorbents was investigated and the best contact time was 100 and 20 min. The TC removal percentages of both adsorbents were 85% and 95% for HEC-GO and HEC-GO/Fe-Zn, respectively. The maximum adsorption capacity for TC was evaluated by the isotherm models. The experimental data fitted well with the Langmuir model. In addition, pseudo-first-order, pseudo-second-order, intraparticle diffusion, and the Elovich models were applied to kinetic data. The data indicated that TC adsorption on HEC-GO and HEC-GO/Fe-Zn (mole ratio 1:1) followed the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and exothermic. Nano-biocomposite (HEC-GO/Fe-Zn) can be used as an adsorbent to remove water pollutants.

A DNA Based Biosensor Amplified With ZIF-8/Ionic Liquid Composite for Determination of Mitoxantrone Anticancer Drug: An Experimental/Docking Investigation.

An ultrasensitive DNA electrochemical biosensor based on the carbon paste electrode (CPE) amplified with ZIF-8 and 1-butyl-3-methylimidazolium methanesulfonate (BMIMS) was fabricated in this research. The DNA/BMIMS/ZIF-8/CPE was used for the selective determination of a mitoxantrone anticancer drug in aqueous solution, resulting in a good catalytic effect and a powerful ability for determining mitoxantrone. Also, the interaction of the mitoxantrone anticancer drug with guanine bases of ds-DNA was used as a powerful strategy in the suggested biosensor, which was confirmed with docking investigation. Docking study of mitoxantrone into the ds-DNA sequence showed the intercalative binding mode of mitoxantrone into the nitrogenous-based pairs of ds-DNA. The effective factors such as ds-DNA concentration, temperature, buffer types, and incubation time were also optimized for the fabricated mitoxantrone biosensor. The results showed that, under optimum conditions (T = 25°C; incubation time=12 min; pH= 4.8 acetate buffer solution and [DNA] = 50 mg/L), the DNA/BMIMS/ZIF-8/CPE could be used in mitoxantrone assay in a concentration ranging from 8.0 nM to 110 µM with a detection limit of 3.0 nM. In addition, recovery data between 99.18 and 102.08% were obtained for the determination of mitoxantrone in the injection samples using DNA/ZIF-8/BMIMF/CPE as powerful biosensors.

Evaluation of Pt,Pd-Doped, NiO-Decorated, Single-Wall Carbon Nanotube-Ionic Liquid Carbon Paste Chemically Modified Electrode: An Ultrasensitive Anticancer Drug Sensor for the Determination of Daunorubicin in the Presence of Tamoxifen.

Measuring the concentration of anticancer drugs in pharmacological and biological samples is a very useful solution to investigate the effectiveness of these drugs in the chemotherapy process. A Pt,Pd-doped, NiO-decorated SWCNTs (Pt,Pd-NiO/SWCNTs) nanocomposite was synthesized using a one-pot procedure and combining chemical precipitation and ultrasonic sonochemical methods and subsequently characterized by TEM and EDS analysis methods. The analyses results showed the high purity and good distribution of elements and the ~10-nm diameter of the Pt,Pd-NiO nanoparticle decorated on the surface of the SWCNTs with a diameter of about 20-30 nm. Using a combination of Pt,Pd-NiO/SWCNTs and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (1B23DTFB) in a carbon paste (CP) matrix, Pt,Pd-NiO/SWCNTs/1B23DTFB/CP was fabricated as a highly sensitive analytical tool for the electrochemical determination of daunorubicin in the concentration range of 0.008-350 µM with a detection limit of 3.0 nM. Compared to unmodified CP electrodes, the electro-oxidation process of daunorubicin has undergone significant improvements in current (about 9.8 times increasing in current) and potential (about 110 mV) decreasing in potential). It is noteworthy that the designed sensor can well measure daunorubicin in the presence of tamoxifen (two breast anticancer drugs with a ΔE = 315 mV. According to the real sample analysis data, the Pt,Pd-NiO/SWCNTs/1B23DTFB/CP has proved to be a promising methodology for the analysis and measuring of daunorubicin and tamoxifen in real (e.g., pharmaceutical) samples.

Synthesis of N-doped TiO2/SiO2/Fe3O4 magnetic nanocomposites as a novel purple LED illumination-driven photocatalyst for photocatalytic and photoelectrocatalytic degradation of naproxen: optimization and different scavenger agents study.

N-doped TiO2/SiO2/Fe3O4 as a new magnetic photocatalyst that is active in visible light has been prepared by simple sol-gel method. The prepared samples were characterized by XRD, FESEM, EDX, TEM, BET, BJH, VSM, XPS, FT-IR, and DRS-UV/Vis analysis. The photocatalytic effect of synthesized samples on naproxen degradation was studied. The operational parameters were optimized through central composite design to achieve maximum efficiency. The optimum values for maximum efficiency were obtained at pH of 4.29, catalyst mass of 0.06 g, naproxen concentration of 9.33 mg L-1, and irradiation time of 217.06 min. At these optimum conditions, the maximum photocatalytic degradation percentages of naproxen were found to be 96.32% at desirability function value of 1.0. Coupling the electrical current with the photocatalytic process proved that the electrical current was considerably efficient in decreasing the degradation time of removing the naproxen from aqueous solutions. The photocatalytic activity of the nanoparticles was also studied under sunlight. Considering the results provided by UV-Vis spectrophotometry and total organic carbon, it was found that the prepared samples are extraordinarily efficient to degrade naproxen under both purple LED and solar lights. Furthermore, the effect of different scavenger agents on naproxen degradation has been studied.

Erratum to "Comparison between Different Extraction Methods for Determination of Primary Aromatic Amines in Food Simulant".

[This corrects the article DOI: 10.1155/2018/1651629.].

Facile preparation of multifunctional carbon nanotube/magnetite/polyaniline nanocomposite offering a strong option for efficient solid-phase microextraction coupled with GC-MS for the analysis of phenolic compounds.

The aim of this study was to synthesize a highly efficient organic-inorganic nanocomposite. In this research, the carbon nanotube/magnetite/polyaniline nanocomposite was successfully prepared through a facile route. Monodisperse magnetite nanospheres were prepared through the coprecipitation route, and polyaniline nanolayer as a modified shell with a high surface area was synthesized by an in situ growth route and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The prepared nanocomposite was immobilized on a stainless-steel wire for the fabrication of the solid-phase microextraction fiber. The combination of headspace solid-phase microextraction using carbon nanotube/magnetite/polyaniline nanocomposite fiber with gas chromatography and mass spectrometry can achieve a low limit of detection and can be applied to determine phenolic compounds in water samples. The effects of the extraction and desorption parameters including extraction temperature and time, ionic strength, stirring rate, pH, and desorption temperature and time have been studied. Under the optimum conditions, the dynamic linear range was 0.01-500 ng/mL and the limits of detection of phenol, 4-chlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol were the lowest (0.008 ng/mL) for three times. The coefficient of determination of all calibration curves was more than 0.990.

A novel strategy to increase performance of solid-phase microextraction fibers: electrodeposition of sol-gel films on highly porous substrate.

In the present work, the effect of substrate porosity for preparation of solid-phase microextraction (SPME) fibers was investigated. The fibers were prepared by electrodeposition of sol-gel coatings using negative potentials on porous Cu wire and compared with previous reported technique for preparation of SPME fibers using positive potentials on smooth gold wire. Porous substrate was prepared by electrodeposition of a thin layer of Cu on a Cu wire. The extraction capability of prepared fibers was evaluated through extraction of some aromatic hydrocarbons from the headspace of aqueous samples. The effect of substrate porosity and some operating parameters on extraction efficiency was optimized. The results showed that extraction efficiency of SPME fibers highly depends on porosity of the substrate. The LOD ranged from 0.005 to 0.010 ng/mL and repeatability at the 1 ng/mL was below 12%. Electrodeposited films were characterized for their surface morphology and thermal stability using SEM and thermogravimetric analysis, respectively. SEM analysis revealed formation of porous substrate and subsequently porous coating on the wire surface and thermogravimetric analysis showed high thermal stability of the prepared fiber.

Antibacterial diterpenoids from Astragalus brachystachys.

Antibacterial bioassay guided fractionation of acetone extracts of Astragalus brachystachys resulted in isolation of sclareol and two related labdane-type diterpenoids, 14R-epoxysclareol and 6beta-hydroxysclareol. The antibacterial activity of the isolated compounds was measured and it was deduced that the epoxidation at the double bond of sclareol or hydroxylation at C-6 decreased the activity of the resulting compounds. Salvigenin (5-hydroxy-4',6,7-trimethoxyflavone) was also separated from this plant for the first time.