Determination of Residual Nonsteroidal Anti-Inflammatory Drugs in Aqueous Sample Using Magnetic Nanoparticles Modified with Cetyltrimethylammonium Bromide by High Performance Liquid Chromatography

A simple and sensitive solid-phase extraction method for separation and preconcentration of trace amount of four nonsteroidal anti-inflammatory drugs (naproxen, indomethacin, diclofenac, and ibuprofen) using Fe3O4 magnetic nanoparticles modified with cetyltrimethylammonium bromide has been developed. For this purpose, the surface of MNPs was modified with cetyltrimethylammonium bromide (CTAB) as a cationic surfactant. Effects of different parameters influencing the extraction efficiency of drugs including the pH, amount of salt, shaking time, eluent type, the volume of solvent, amount of adsorbent, sample volume, and the time of desorption were investigated and optimized. Methanol has been used as desorption solvent and the extracts were analysed on a reversed-phase octadecyl silica column using 0.02 M phosphate-buffer (pH = 6.02) acetonitrile (65 : 35 v/v) as the mobile phase and the effluents were measured at 202 nm with ultraviolet detector. The relative standard deviation (RSD%) of the method was investigated at three concentrations (25, 50, and 200 ng/mL) and was in the range of 3.98–9.83% (n=6) for 50 ng/mL. The calibration curves obtained for studied drugs show reasonable linearity (R2>0.99) and the limit of detection (LODs) ranged between 2 and 7 ng/mL. Finally, the proposed method has been effectively employed in extraction and determination of the drugs in biological and environmental samples

Use of nanomaterials in the pretreatment of water samples for environmental analysis

The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water sup-plies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of in-terferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that renders sample preparation a relevant part of environmental monitoring strategies. The discovery and ap-plication of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.publishe

Preconcentration and Determination of Organochlorine Pesticides in Seawater Samples Using Polyaniline/Polypyrrole-Cellulose Nanocomposite-Based Solid Phase Extraction and Gas Chromatography-Electron Capture Detection

In this work, the chemically modified filter paper with polyaniline/polypyrrole (PANI/PPY), denoted as PANI/PPY/cellulose nanocomposite, was prepared and used as the solid phase extraction (SPE) sorbent for preconcentration and extraction of some organochlorine pesticides (OCPs) in natural water samples. The proposed sorbent was also characterized with scanning electron microscopy (SEM) and exhibited that globular polymers could incorporate into the cellulose fibers of the paper sheet. Several experimental parameters related to the preconcentration of OCPs on the coated filter paper were also examined. The experimental results showed that the PANI/PPY coated filter paper could extract OCPs with relatively high enrichment factors. The evaluation also exhibited a dynamic range of 5-250 µg L-1 for OCPs with proper correlation coefficient (R²). The limit of detections of heptachlor, aldrin, dieldrin, endrin and 4-dichlorodiphenyltrichloroethane (4-DDT) were found to be 0.39, 0.28, 0.47, 0.51 and 0.31 µg L-1, respectively. The proposed method was also applied for analysis of OCPs in seawater sample and the recoveries of analytes were in the range of 77.4 to 102.7 %

Determination of biphenyl and biphenyl oxide in aqueous samples by headspace single drop microextraction coupled to gas chromatography

In this work, biphenyl and biphenyl oxide were extracted by headspace single drop microextraction (HS-SDME) and analyzed by gas chromatography-flame ionization detection (GC-FID). The extraction occurred from the tip of a microsyringe by suspending a 3.5 µL drop of toluene, as extracting solvent, containing acetonaphton, as internal standard. The effect of different parameters such as the nature of extraction solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, ionic strength and extracting time on the extraction efficiency of the analytes were investigated and optimized. Under optimized conditions the limits of detection (S/N = 3) of biphenyl and biphenyl oxide were 0.40 ± 0.03 and 0.30 ± 0.06 µg mL‑1, respectively. Good linearities were obtained for both analytes with the correlation coefficients higher than 0.997 and the relative standard deviations (R.S.D.) were in the range of 1-3%. The recoveries of analytes from spiked water samples were near to 100%

Cation Exchange Superparamagnetic Al-Based Metal Organic Framework (Fe₃O₄/MIL-96(Al)) for High Efficient Removal of Pb(II) from Aqueous Solutions

A cation-exchange metal–organic framework sorbent with high adsorption capacity, active anionic surface, available adsorptive sites, good response in magnetic field and also available enclosed space between the particles for encapsulation of the analyte was in situ prepared by magnetization of a metal organic framework structure of aluminum named as MIL-96­(Al). The units of magnetic MIL-96­(Al) was synthesized by embedding method under hydrothermal condition and well characterized. The mechanism of sorption can be the electrostatic interaction between the anionic structures of the adsorbent with hydrated Pb²⁺ ions. The high percent of OH groups on the surface of Fe₃O₄/MIL-96­(Al) led to high adsorption capacity (>301.5 mg g^–1) of the sorbent for Pb²⁺ ions in aqueous media. The thermodynamic study of Pb²⁺ adsorption onto the sorbent surface demonstrated that the process was spontaneous, exothermic and physical. The face-centered central composite design was applied for optimizing the adsorption conditions, and the effective parameters were obtained as pH of 6.92, amount of sorbent of 32.4 mg and adsorption time of 25 min

Cation Exchange Superparamagnetic Al-Based Metal Organic Framework (Fe₃O₄/MIL-96(Al)) for High Efficient Removal of Pb(II) from Aqueous Solutions

A cation-exchange metal–organic framework sorbent with high adsorption capacity, active anionic surface, available adsorptive sites, good response in magnetic field and also available enclosed space between the particles for encapsulation of the analyte was in situ prepared by magnetization of a metal organic framework structure of aluminum named as MIL-96­(Al). The units of magnetic MIL-96­(Al) was synthesized by embedding method under hydrothermal condition and well characterized. The mechanism of sorption can be the electrostatic interaction between the anionic structures of the adsorbent with hydrated Pb²⁺ ions. The high percent of OH groups on the surface of Fe₃O₄/MIL-96­(Al) led to high adsorption capacity (>301.5 mg g^–1) of the sorbent for Pb²⁺ ions in aqueous media. The thermodynamic study of Pb²⁺ adsorption onto the sorbent surface demonstrated that the process was spontaneous, exothermic and physical. The face-centered central composite design was applied for optimizing the adsorption conditions, and the effective parameters were obtained as pH of 6.92, amount of sorbent of 32.4 mg and adsorption time of 25 min

Photosynthetic response of Persian Gulf acroporid corals to summer versus winter temperature deviations

With on-going climate change, coral susceptibility to thermal stress constitutes a central concern in reefconservation. In the Persian Gulf, coral reefs are confronted with a high seasonal variability in water temperature, and both hot and cold extremes have been associated with episodes of coral bleaching and mortality. Using physiological performance as a measure of coral health, we investigated the thermal susceptibility of the common acroporid, Acropora downingi, near Hengam Island where the temperature oscillates seasonally in the range 20.2–34.2 °C. In a series of two short-term experiments comparing coral response in summer versus winter conditions, we exposed corals during each season (1) to the corresponding seasonal average and extreme temperature levels in a static thermal environment, and (2) to a progressive temperature deviation from the annual mean toward the corresponding extreme seasonal value and beyond in a dynamic thermal environment. We monitored four indictors of coral physiological performance: net photosynthesis (Pn), dark respiration (R), autotrophic capability (Pn/R), and survival. Corals exposed to warming during summer showed a decrease in net photosynthesis and ultimately died, while corals exposed to cooling during winter were not affected in their photosynthetic performance and survival. Coral autotrophic capability Pn/R was lower at the warmer thermal level within eachseason, and during summer compared to winter. Corals exposed to the maximum temperature of summer displayed Pn/R < 1, inferring that photosynthetic performance could not support basal metabolic needs under this environment. Our results suggest that the autotrophic performance of the Persian Gulf A. downingi is sensitive to the extreme temperatures endured in summer, and therefore its populations may be impacted by future increases in water temperature

Measurment and assessment of concentration of heavy metal (Hg, Cd, Pb) in canned tuna fish distributed in Mazandaran province of Iran in 2014-2015

&nbsp;&nbsp;&nbsp;&nbsp; Introduction: Heavy metals are one of the pollutants which are found in minor amounts in natural water and high concentration in industry waste water. Heavy metals poisoning effects are increasing in marine organisms especially fishes due to disposal of industrial wastes to marine environment and their bio accumulation. The aim of this study is to determine of mercury, cadmium and lead levels in canned fish sold in Mazandaran province of Iran. &nbsp;&nbsp;&nbsp;&nbsp; Materials and Methods: This descriptive-cross sectional study was done on 12 types of canned tuna distributed, 3 numbers of each type and overall 36 sample. The concentration of 3 type heavy metals assessed with standard method by Atomic Absorption and then expressed based on &micro;g/g of wet weight. The results were compared with WHO and Iran National Standard Organization. &nbsp;&nbsp;&nbsp;&nbsp; Results: The results show that, minimum and maximum of mercury level in 36 samples of canned tuna fish was 0.01 and 0.5 &micro;g/g, cadmium 0.001 and 0.05 and lead 0.001 and 0.3 respectively. According to replicates experiments, the mean concentration of mercury in 12 such samples of canned tuna fish was from 0.106 to 0.31, cadmium from 0.006 to 0.022 and lead from 0.03 to 0.15&micro;g/g.&nbsp; that there was a significant difference in samples(p<0.001). &nbsp;&nbsp;&nbsp;&nbsp; Conclusion: This research determined that the rate of mercury, cadmium and lead in canned tuna fish distributed in Mazandaran province were less than 0.5, 0.05 and 0.3&micro;g/g and below the WHO/FAO- recommended levels