Alireza Mohadesi; Somayeh Parvaresh; Zarrin Eshaghi; Mohammad Ali Karimi
Abstract
A chemically modified glassy carbon electrode was developed using multi-walled carbon nanotubes covalently immobilized with 2,6-dichlorophenolindophenol. The immobilization of 2,6-dichlorophenolindophenol with multi-walled carbon nanotubes was characterized by UV–visible absorption spectroscopy ...
Read More
A chemically modified glassy carbon electrode was developed using multi-walled carbon nanotubes covalently immobilized with 2,6-dichlorophenolindophenol. The immobilization of 2,6-dichlorophenolindophenol with multi-walled carbon nanotubes was characterized by UV–visible absorption spectroscopy and Fourier transform infrared spectroscopy, and was determined using cyclic voltammetry. The cyclic voltammetric response of 2,6-dichlorophenolindophenol grafted onto multi-walled carbon nanotubes indicated that it promoted the electrocatalytic, sensitive and stable determination of sulfide ions. Meanwhile, the dependence of response currents on the concentration of sulfide was also examined and was linear in the range of 1.8 µM – 2.5 mM. The detection limit of sulfide was 1.1 µM, and RSD for 10 and 1000 µM sulfide was 1.8 and 1.3 %, respectively. Many interfering species had little or no effect on the determination of sulfide. This procedure was applied for determination of sulfide in water samples.
Sayyed Hossein Hashemi; Massoud Kaykhaii; Ahmad Jamali Keikha; Enayat Saberi
Abstract
This paper describes trace determination of malachite green (MG) as a water pollutant dye by convenient spectrophotometry. A water-soluble hyper-branched polyamine was first prepared using the nuclophilic ring opening reaction of diepoxy and diamine monomer, which was then used for functionalization ...
Read More
This paper describes trace determination of malachite green (MG) as a water pollutant dye by convenient spectrophotometry. A water-soluble hyper-branched polyamine was first prepared using the nuclophilic ring opening reaction of diepoxy and diamine monomer, which was then used for functionalization of multiwalled carbon nanotubes. This compound (named WHPA-OMCNT) was applied as a highly efficient adsorbent for the extraction of MG from seawater samples of Chabahar Bay (located in the southern east of Iran). WHPA-OMCNT was used in a pipette-tip solid phase extraction process; and for this extraction, different parameters affecting the extraction efficiency, including type and volume of eluent solvent, sample of volume, number of cycles of extraction and elution, pH of sample solution, type and amount of salt, and concentration of surfactant (triton X-114) were optimized using both one-variable-at-a-time and Box-Behnken response surface methodology techniques employing seven factors in three-levels. Under optimum conditions, the linear range of proposed method for MG was 4-250 µg L-1 with a detection limit of 0.80 µg L-1 and RSDs better than 6.4%.
Mohammad Mazloum-Ardakani; Zahra Alizadeh; Laleh Hosseinzadeh; Bibifatemeh Mirjalili; Naeimeh Salehi
Abstract
In this work, we synthesis and application of functionalized carbon nanotubes (CNTs) In this work, we synthesis and application of functionalized carbon nanotubes (CNTs) with6-amino-4-(3,4-dihydroxyphenyl)-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5 carbonitrile (pyrazole derivative (APC)) as sensing ...
Read More
In this work, we synthesis and application of functionalized carbon nanotubes (CNTs) In this work, we synthesis and application of functionalized carbon nanotubes (CNTs) with6-amino-4-(3,4-dihydroxyphenyl)-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5 carbonitrile (pyrazole derivative (APC)) as sensing platform toward hydrazine (HZ). Electrochemical properties of functionalized carbon nanotubes composite (APC-CNT) were investigated by cyclic voltammetry, chronoamperometry and differential pulse voltammetry techniques. It was found that the APC-CNT composite exhibited a pair of redox peaks, which is due to the electron transfer between the APC and the glassy carbon electrode. The electrocatalytic properties of the APC-CNT composite for HZ oxidation was remarkably increased as compared to only CNTs. The kinetic parameters of the APC-CNT composite in the presence and absence of HZ was studied by electrochemical methods. The APC-CNT modified electrode revealed an excellent voltammetric response to oxidation of HZ with a wide linear range from 0.01 μM to 120.0 µM and limit of detection of 8.6 nM. Also, APC-CNT modified electrode shows high selectivity, good stability, reproducibility with a RSD less than 2.11%.
Mohammad Reza Rezaei Kahkha; Massoud Kaykhaii; Mahdi Shafee-Afarani; Batool Rezaei Kahkha
Volume 4, Issue 2 , September 2017, , Pages 10-16
Abstract
In this work, a microextraction technique based on pipette tip solid-phase extraction was used for preconcentration and determination of diazinon. Carbon nanotube functionalized by zinc sulfide and ethylene glycol was used as sorbent. Determination of diazinon was performed using high performance liquid ...
Read More
In this work, a microextraction technique based on pipette tip solid-phase extraction was used for preconcentration and determination of diazinon. Carbon nanotube functionalized by zinc sulfide and ethylene glycol was used as sorbent. Determination of diazinon was performed using high performance liquid chromatography and UV detection. Important parameters that influence the extraction efficiency (i.e. pH, amount of adsorbent, extraction time, salt addition, volumes of sample and eluting solvent and number of aspirating/dispensing cycles for both solvent and sample) were investigated and optimized. Results were showed that method was validated over the range of 0.50 - 100.0 µg L-1. Repeatability was satisfactory, bellow 3.78% for 5 replicate measurements of 20 µg L-1 of diazinon. The limit of detection of this method is 0.03 µg L-1 with an enrichment factor of 100 and short extraction time of 8.5 min, which confirmed suggested method is a reliable and accurate for extraction and preconcentration of diazinon.
Tahereh Rohani; Moghadase Yahyapoor
Volume 4, Issue 1 , March 2017, , Pages 34-39
Abstract
In this work, a new method was developed for the catalytic reduction of hydrogen peroxide at glassy carbon electrode modified with silver nanoparticles and multi-wall carbon nanotubes. Silver incorporated in this modified electrode acted as catalyst to reduce hydrogen peroxide. First, the electrochemical ...
Read More
In this work, a new method was developed for the catalytic reduction of hydrogen peroxide at glassy carbon electrode modified with silver nanoparticles and multi-wall carbon nanotubes. Silver incorporated in this modified electrode acted as catalyst to reduce hydrogen peroxide. First, the electrochemical behavior of silver, incorporated in modified electrode, was studied. The results illustrated the adsorption-controlled reaction at the modified electrode. Then, the behavior of catalytic reduction of hydrogen peroxide at the modified electrode was investigated. A linear calibration graph was obtained for hydrogen peroxide over the concentration range of 4.04×10−3 – 1.5×10−6 molL-1. The detection limit for hydrogen peroxide was estimated 1.42×10−7 molL-1. The relative standard deviation of ten replicate measurements (performed on a single electrode at hydrogen peroxide concentration of 1.5×10-4 molL−1) was 2.36%. The proposed electrode was used for the determination of hydrogen peroxide in real samples which led to satisfactory results.
