Publications by authors named "Sirwan Mohammadiazar"

6 Publications

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Electroless deposition of silver nanofractals on copper wire by galvanic displacement as a simple technique for preparation of porous solid-phase microextraction fibers.

J Sep Sci 2019 Oct;42(19):3110-3118

Department of Chemistry, Tehran North Branch, Islamic Azad University, Tehran, Iran.

A novel and porous solid-phase microextraction fiber was prepared by quick and simple galvanic displacement reaction and applied to the determination of some polycyclic aromatic hydrocarbons in sunflower oil. The parameters affecting the porosity and thickness of the fiber, and parameters affecting the extraction efficiency, including the extraction time, temperature, and ionic strength, were investigated and optimized. The morphology of prepared fiber was characterized by optical and scanning electron microscopy and thermal and chemical stabilities of the fiber were studied. Under the optimum conditions, the limits of detection ranged between 0.1 ng/mL for pyrene to 1.2 ng/mL for anthracene, and LOQ ranged between 0.3 ng/mL for pyrene to 3.6 ng/mL for anthracene. The relative standard deviations, including repeatability (within fibers) and reproducibility (between fibers), varied between 3.2-8.9 and 5.6-9.8%, respectively.
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http://dx.doi.org/10.1002/jssc.201900351DOI Listing
October 2019

Improvement of solid-phase microextraction efficiency by the application of a carbon-nanotubes-based ternary microextraction fiber composite.

J Sep Sci 2017 Sep 14;40(18):3682-3689. Epub 2017 Aug 14.

Department of Chemistry, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran.

In this study, a novel technique is proposed for preparation of an efficient and unbreakable metal-wire-supported solid-phase microextraction fiber. A sol-gel film was deposited on electrophoretically deposited carbon nanotubes on a stainless-steel wire. The applicability of the fiber was evaluated through the extraction of some aromatic pollutants as model compounds from the headspace of aqueous samples in combination with gas chromatography and mass spectrometry. The parameters affecting the structure and extraction efficiency of the fiber (including the type of solvent, time, and potential for electrophoretic deposition) and the parameters affecting the extraction efficiency (such as coating type, salt content, extraction temperature, and time) were investigated. The results showed that the film thickness will be increased by increasing the potential and time duration. Finally, the characterization of the deposited film was accomplished by scanning electron microscopy and thermogravimetric analysis. After the optimization of the extraction parameters, the limit of detection of less than 20 pg/mL was achieved, and the calibration curves were all linear (r  ≥ 0.9737), in the range from 50 to 500 pg/mL. The solid-phase microextraction fiber has a high mechanical strength; good stability and long service life, making it potentially applicable in the extraction of trace polycyclic aromatic hydrocarbons from aqueous samples.
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http://dx.doi.org/10.1002/jssc.201700055DOI Listing
September 2017

Solid-phase microextraction of methadone in urine samples by electrochemically co-deposited sol-gel/Cu nanocomposite fiber.

Biomed Chromatogr 2017 Aug 30;31(8). Epub 2017 Jan 30.

Department of Chemistry, Islamic Azad University, Tehran North Branch, Tehran, Iran.

Electrochemically co-deposited sol-gel/Cu nanocomposites have been introduced as a novel, simple and single-step technique for preparation of solid-phase microextraction (SPME) coating to extract methadone (MDN) (a synthetic opioid) in urine samples. The porous surface structure of the sol-gel/Cu nanocomposite coating was revealed by scanning electron microscopy. Direct immersion SPME followed by HPLC-UV determination was employed. The factors influencing the SPME procedure, such as the salt content, desorption solvent type, pH and equilibration time, were optimized. The best conditions were obtained with no salt content, acetonitrile as desorption solvent type, pH 9 and 10 min equilibration time. The calibration graphs for urine samples showed good linearity. The detection limit was about 0.2 ng mL . Also, the novel method for preparation of nanocomposite fiber was compared with previously reported techniques for MDN determination. The results show that the novel nanocomposite fiber has relatively high extraction efficiency.
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http://dx.doi.org/10.1002/bmc.3926DOI Listing
August 2017

Solid-phase nanoextraction of polychlorinated biphenyls in water and their determination by gas chromatography with electron capture detector.

J Sep Sci 2017 01 13;40(2):449-457. Epub 2016 Dec 13.

Veterinary Organization, Tehran, Iran.

A solid-phase nanoextraction method has been developed for the extraction and preconcentration of polychlorinated biphenyls using carboxyl multiwalled carbon nanotubes as a solid nano-sorbent. Parameters affecting extraction efficiency such as sorbent amount, desorption solvent type and volume, extraction time, pH, and salt content have been studied. Under optimized conditions, the correlation coefficient was up to 0.9989, the limits of detection was in the range of 1.4-3.5 ng/L, and limits of quantification was between 4.8 and 11.6 ng/L. The recoveries were in the range of 99-106% for different spiked analytes. The relative standard deviation for water samples spiked with two different spiking levels has been between 4 and 10%. The proposed sustainable method is rapid, easy to use, and small consumption of organic solvent for the detection and determination of trace levels of polychlorinated biphenyls in environmental waters.
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http://dx.doi.org/10.1002/jssc.201600720DOI Listing
January 2017

A single step technique for preparation of porous solid phase microextraction fibers by electrochemically co-deposited silica based sol-gel/Cu nanocomposite.

J Chromatogr A 2013 Feb 21;1278:1-7. Epub 2012 Nov 21.

Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14515-775, Tehran, Iran.

In this study, electrochemically co-deposited 3-trimethoxysilyl propyl methacrylate (3TMSPMA)/Cu nanocomposite is introduced as a novel and single-step technique for preparation of efficient and unbreakable solid phase microextraction (SPME) fibers; having strong interaction between the substrate and the coating. The applicability of prepared nanocomposite films was evaluated through extraction of some aromatic pollutants as model compounds from the headspace of aqueous samples in combination with gas chromatography-mass spectrometry (GC-MS). Different parameters affecting the structure and composition of the deposited films including applied potential, electrodeposition time, and precursor concentration; and the parameters affecting extraction efficiency such as extraction temperature, extraction time, and salt content were investigated. The results showed that morphology and grain size of the films are strongly affected by the ratio between the sol-gel precursor and Cu(2+) ions. Furthermore, potential of deposition influences the composition of films as it controls the kinetics of sol-gel/Cu co-deposition. Finally, characterization of the deposited films was accomplished by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).
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http://dx.doi.org/10.1016/j.chroma.2012.11.035DOI Listing
February 2013

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

J Sep Sci 2012 Dec 29;35(23):3354-60. Epub 2012 Oct 29.

Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.

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.
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http://dx.doi.org/10.1002/jssc.201200580DOI Listing
December 2012
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