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BACKGROUND: This study aimed to investigate the asthma profile among children/adolescents and the relationship of the prevalence of air pollution profiles using latent class analysis (LCA). OBJECTIVES: In this cross-sectional study, a case rural community was selected in an industrial area, and two rural control communities were selected in unexposed areas. METHODS: Hourly concentrations of PM10, SO2, NO2, and total volatile organic compounds were obtained from the records of a fixed air quality monitoring station, and the concentrations of benzene, toluene, xylenes styrene were measured during six campaigns. Asthma data was collected using the International Study of Asthma and Allergies in Childhood in 7-18 years old children/adolescents. The modeling was conducted using LCA. RESULTS: A higher amount of air pollution indices were observed in the case than both control communities. LCA divided the participants into three clusters; "healthy" (92.8%), "moderate" (2.8%), and "severe" (4.4%). A higher probability of severe asthma (6.8%) was observed in the case than control communities (2.6% and 1.8%). Additionally, after adjusting for possible confounders, the odds of asthma was lower in the control communities than the case in both moderate and sever classes (Odds Ratios in the range of 0.135-0.697). CONCLUSIONS: This study indicates asthma profiles of children/adolescents and the higher prevalence of severe class in the area, explaining the possible effect of air pollution.

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In this investigation, an efficient sorbent based on Fe3O4@polyphenols magnetic nanoparticles has been prepared using the extract of Mentha piperita leaves for the first time. The main purposes of this study were synthesis of economically affordable and environmentally friendly sorbent using the extract of Mentha piperita leaves and evaluating its application as a sorbent in magnetic solid phase extraction. The functional groups, magnetic property, size, and shape of the synthesized sorbent were characterized. The sorbent was utilized for the extraction and preconcentration of various pesticides (chlorpyrifos, fenazaquin, penconazole, diniconazole, oxadiazon, haloxyfop-methyl, hexaconazole, clodinafop-propargyl, tebuconazole, and fenoxaprop-p-ethyl) from vegetable, fruit, and water samples. After magnetic solid phase extraction, a dispersive liquid-liquid microextraction method was done to achieve low detection limits. The enriched pesticides were monitored by gas chromatography-tandem mass spectrometry. The synthesized sorbent was characterized by Fourier transform infrared, scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction, and vibrating sample magnetometer techniques, which confirmed the successful synthesis of the magnetic nanoparticles. The effective parameters such as the sorbent weight, ionic strength, pH, vortex time, and kind and volume of elution and extraction solvents were studied. Under optimum extraction conditions, the method showed broad linear ranges (0.05-1000 µg L-1) with low limits of detection (0.27-4.13 ng L-1) and quantification (0.91-13.8 ng L-1). Extraction recoveries and enrichment factors were in the ranges of 54-89 % and 491-811, respectively.

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A new version of magnetic solid-phase extraction performed in a narrow-bore tube has been proposed for the extraction and preconcentration of different pesticides from various vegetable and fruit juices followed by gas chromatography. A few milligrams of C8 @SiO2 @Fe3 O4 nanoparticles are added into an aqueous sample solution placed in a narrow-bore tube. The sorbent particles move down through the tube under gravity and are collected at the end of the tube by applying an external magnetic field. The end of the tube is narrower and it is connected to a stopcock. After a predetermined time, the stopcock is opened and the solution is passed through the bed of the sorbent maintained by the magnet. Then the adsorbed analytes are desorbed using an elution solvent. To achieve high enrichment factors, a dispersive liquid-liquid microextraction method is carried out. The nanoparticles were characterized by scanning electron microscopy, X-ray diffraction, and FTIR spectroscopy. Under the optimum extraction conditions, limits of detection and quantification were in the ranges of 0.1-0.3 and 0.3-0.9 µg/L, respectively. High enrichment factors (1166-1605) and good extraction recoveries (58-80%) were obtained.

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Coarse particles are primarily deposited via sedimentation, commonly referred as dust fall (DF). This study presented the monthly and spatial variations of atmospheric DF and their elemental components (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr, Ti, V, Si, and Hg). Dust samples were collected from four urban and suburban sampling sites around Tabriz, Iran, by using the ASTM method D-1739 during April to September 2017. Moreover, the ICP-OES was used to determine metal components of the DF. The obtained results showed that the DF amount ranged between 1.8-27.6 (7.4 ± 5.6) g/m2.month. The elements of Fe (11863-13,906 mg/Kg and 85%-89%), Al (858-1205 mg/Kg and 4%-8%), and Si (274-386 mg/Kg) were the dominant elemental concentrations of the DF. The average value of enrichment factor (EF) for Hg, Pb, Cu, Sr, Co, Ni, Mn, and V was greater than 10 in all the samples, showing that anthropogenic sources emit a considerable amount of elements in DF rather than the soil or Urmia lake bed. The result of correlations between the concentration of dust fall with humidity, temperature, wind speed, and precipitation showed that there was a direct relationship between the amount of dust fall and wind speed while humidity, precipitation, and temperature were inversely proportional to the amount of dust fall. This study revealed that earth crust and anthropogenic activities such as vehicle traffic, combustion of fossil fuel, and different industrial activities were the main sources of the DF in the studied areas.

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Purpose: In this investigation, a new version of magnetic solid phase extraction (MSPE) performed in a narrow-bore tube has been proposed. In this study, hydrophobic octyl (C8) functionalized Fe3O4 magnetic nanoparticles (MNPs) stabilized by SiOH groups (Fe3O4@SiO2@C8) are used as magnetic nano-sorbents for the extraction of cardiovascular drugs from human plasma prior to their determination by high performance liquid chromatography-photodiode array detection. Methods: After precipitation of the plasma proteins, the supernatant is diluted with deionized water and filled into the narrow-bore tube. Then mg-level of the sorbent is added into the tube. The sorbent is dispersed and moved down through the solution instead of passing the solution from the cartridge. Using an external magnet, the collected nano-sorbents at the bottom of the tube are transferred on top of the solution and released to move down through the solution for three times to increase the extraction efficiency. Results: The linearity of the assay was ranging from 0.4-500 mg mL-1. The limits of detection and quantification of the method were obtained in the ranges of 0.05-0.07 and 0.16-0.24 mg L-1, respectively. The extraction recoveries were obtained in the range of 31-49%. Intra- and inter-day precisions were calculated and obtained in the ranges of 5-8 and 7%-9% for 0.5 mg L-1 of each analyte, and 5-6 and 6%-8% for 2 mg L-1 of each analyte, respectively. Conclusion: The proposed method was successfully used in determination of the studied drugs in patient's plasmas.

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In this study, a gas-assisted dispersive liquid-phase microextraction method using a deep eutectic solvent as the extraction solvent combined with gas chromatography and flame ionization detection was developed for the extraction and determination of some pesticide residues in vegetable and fruit juice samples. In this method, choline chloride and 4-chlorophenol at a molar ratio of 1:2 were mixed. By heating and vortexing, a clear, water-immiscible, and homogeneous liquid was formed. The obtained deep eutectic solvent was added to an aqueous solution of the analytes in a conical test tube. Air was bubbled into the aqueous solution and a cloudy solution was obtained. During this step, the analytes were extracted into the fine droplets of the extraction solvent. After centrifugation, an aliquot of the settled phase was injected into the separation system. Under the optimum extraction conditions, enrichment factors, and extraction recoveries were obtained in the ranges of 247-355 and 49-71%, respectively. The obtained values for the limits of detection and quantification were in the ranges of 0.24-1.4 and 0.71-4.2 µg/L, respectively. The proposed method is simple, fast, efficient, and inexpensive.

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The present study describes a microextraction and determination method for analyzing residual solvents in pharmaceutical products using dynamic headspace-liquid phase microextraction technique followed by gas chromatography-flame ionization detection. In this method dimethyl sulfoxide (µL level) placed into a GC liner-shaped extraction vessel is used as a collection/extraction solvent. Then the liner is exposed to the headspace of a vial containing the sample solution. The effect of different parameters influencing the microextraction procedure including collection/extraction solvent type and its volume, ionic strength, extraction time, extraction temperature and concentration of NaOH solution used in dissolving the studied pharmaceuticals are investigated and optimized. Under the optimum extraction conditions, the method showed wide linear ranges between 0.5 and 5000 mg L-1 . The other analytical parameters were obtained in the following ranges: enrichment factors 240-327, extraction recoveries 72-98% and limits of detection 0.1-0.8 mg L-1 in solution and 0.6-3.2 µg g-1 in solid. Relative standard deviations for the extraction of 100 mg L-1 of each analyte were obtained in the ranges of 4-7 and 5-8% for intra-day (n = 6) and inter-day (n = 4) respectively. Finally the target analytes were determined in different samples such as erythromycin, azithromycin, cefalexin, amoxicillin and co-amoxiclav by the proposed method.

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In this study, a simultaneous derivatization/air-assisted liquid-liquid microextraction method has been developed for sample preparation of some phenolic compounds in fuels and engine oil. Analytes are transferred by back liquid-liquid extraction into NaOH solution and then are derivatized with butyl chloroformate and extracted simultaneously into carbon tetrachloride. The extracted derivatized analytes are analyzed using gas chromatography with flame ionization detection. The effect of extracting solvent type, derivatization agent and extraction solvent volumes, ionic strength of the aqueous solution, number of extraction cycles, etc., on the extraction efficiency is investigated. The calibration graphs are linear in the range of 3-10,000 µg/L. Enhancement factors, enrichment factors, and extraction recoveries are in the ranges of 497 to 1471, 571 to 991, and 60 to 109%, respectively. Detection limits are obtained in the range of 0.8 to 2.0 µg/L. Relative standard deviations for the extraction of each selected phenols are in the ranges of 2-4% for intraday (n = 6) and 3-6% (n = 5) for interday precisions for 200 µg/L. This technique is successfully applied for the extraction, preconcentration, and determination of the selected phenols in gasoline, kerosene, gas oil, and engine oil.

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