GYAH Corporation

Tehrān, Iran

GYAH Corporation

Tehrān, Iran
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Khadem A.,GYAH Corporation | Khadem A.,Shahrekord University | Raiesi F.,Shahrekord University
Applied Soil Ecology | Year: 2017

Biochar can be used as an organic amendment to improve soil physical and chemical attributes, with a potentially significant influence on soil microbial performance. However, this effect of biochar is poorly understood for arid soils with low organic matter content. The main objective of this study was to quantify the response of microbial attributes to corn biochar in two calcareous soils with different texture. Three slow pyrolysis biochars were prepared at 200, 400 and 600 °C from corn feedstocks. The biochars were added to sandy and clayey soils at 0.5 and 1% (w/w) and the mixtures were incubated for 90 days under standard laboratory conditions (25 ± 1 °C and 70% of soil field capacity). Soils amended with raw (uncharred) feedstock and unamended (without biochar and raw residue) as the control were also considered in the experiment. The soil properties measured included microbial respiration during 60 days, microbial biomass carbon (C), substrate-induced respiration (SIR), fungal (FR) and (BR) bacterial respiration at the end of the incubation. Compared with the unamended control, the addition of corn raw feedstock or its biochar significantly increased cumulative microbial respiration (62–462%), MBC (66–169%), SIR (50–216%), BR (129–308%) and FR (42–200%), but tended to decrease FR/BR ratio (5–90%), depending largely upon its production temperature and application rate as well as soil texture. The positive effects of biochar addition on increasing microbial properties were more pronounced at 1% than 0.5% application rates for all the attributes and in sandy than clayey soils for MBC, SIR and FR attributes. Overall, the measured microbial attributes were all greater in uncharred than charred feedstock treatments and tended to decline with increasing pyrolysis temperature. The relative abundance of soil bacteria increased with biochar addition and pyrolysis temperature, while that of soil fungi decreased. Biochar addition increased microbial performance potentially due to an increase in soil C content while increasing pyrolysis temperature altered biochar chemistry and properties which may have contributed to the decreased microbial performance. It is concluded that although biochar application may improve microbial processes and attributes in calcareous soils with low organic matter content, its effects on microbiological properties are mainly meditated by soil texture, pyrolysis temperature for biochar production and application rate. The greatest response by the microbial indicators can occur when corn biochars produced at low temperatures were added to less fertile sandy soils at 1% addition rate. The study provided clear evidence that application of low temperature corn biochars at 45–50 t ha−1 to calcareous soils may have a great potential for improvements in the microbial indicators of soil quality. © 2017 Elsevier B.V.

Farajzadeh M.A.,University of Tabriz | Bahram M.,Urmia University | Vardast M.R.,Urmia University | Vardast M.R.,Islamic Azad University | Bamorowat M.,GYAH Corporation
Microchimica Acta | Year: 2011

A method was developed for analyzing the organophosphorus pesticides Fenitrothion, Diazinon and Ethion in water samples via dispersive liquid-liquid microextraction and high-performance liquid chromatography. Chloroform and methanol were selected as extraction and dispersive solvents, respectively. Extraction and dispersive solvents (and their volumes), the pH of the sample, and salting out effect were optimized to give a calibration plot that is linear in the range from 10 to 4000 ng. mL-1. Detection limits are 2 ng. mL-1 for Fenitrothion and 3 ng. mL-1 for Diazinon and Ethion. The relative standard deviations for six replicate measurements of 500 ng. mL-1 of the three pesticides are 3.3, 2.2 and 4.1%, respectively. © 2010 Springer-Verlag.

Abolghasemi M.M.,Islamic Azad University at Maragheh | Hassani S.,Islamic Azad University at Maragheh | Bamorowat M.,GYAH Corporation
Microchimica Acta | Year: 2016

A mesoporous silica surface of type SBA-15 was made more hydrophobic by modification with ethoxytrimethylsilane to obtain a hybrid organic–inorganic mesoporous nanocomposite, which then was impregnated with Nafion. The resulting nanocomposite was used as a fiber coating for solid-phase microextraction (SPME). The trimethylsilyl-modified Nafion/SBA-15 nanocomposite with high surface area was characterized by SEM and FTIR. It was immobilized on a stainless steel wire in order to fabricate a fiber for SPME. This fiber was evaluated for its suitability for extracting triazolic agrochemicals from water samples before their quantification through a combination of gas chromatography and mass spectrometry. Experimental conditions for fiber coating, extraction time, stirring rate, ionic strength, pH value, desorption temperature and desorption time were optimized. Under optimum conditions, the repeatability for one fiber (for n = 3) ranges from 4.3 to 5.6 % (relative standard deviation). The detection limits are between 50 and 90 pg⋅mL−1. The method is simple, fast, low-cost (in terms of equipment), and the fiber used for SPME has high thermal stability and good recovery. © 2015, Springer-Verlag Wien.

Asadpour-Zeynali K.,University of Tabriz | Saeb E.,University of Tabriz | Vallipour J.,University of Tabriz | Bamorowat M.,GYAH Corporation
Journal of AOAC International | Year: 2014

Simultaneous spectrophotometric determination of three neonicotinoid insecticides (acetamiprid, imidacloprid, and thiamethoxam) by a novel method named generalized net analyte signal standard addition method (GNASSAM) in some binary and ternary synthetic mixtures was investigated. For this purpose, standard addition was performed using a single standard solution consisting of a mixture of standards of all analytes. Savings in time and amount of used materials are some of the advantages of this method. All determinations showed appropriate applicability of this method with less than 5% error. This method may be applied for linearly dependent data in the presence of known interferents. The GNASSAM combines the advantages of both the generalized standard addition method and net analyte signal; therefore, it may be a proper alternative for some other multivariate methods.

This study describes an extraction method based on silylated extraction vessel-dispersive liquid-liquid microextraction (SEV-DLLME) for preconcentration of some triazole pesticides (penconazole, hexaconazole, tebuconazole, diniconazole, triticonazole, and difenconazole) from aqueous samples. For this purpose, the interior surface of funnel-shaped extraction vessel is activated by concentrated NaOH and HCl solutions, silylated by trimethylchlorosilane (TMCS) and used in extraction of the analytes from a relatively high volume of aqueous sample. The adsorbed analytes are desorbed by methanol, which acts as a dispersive solvent in the following DLLME method. In the first step, the effects of different factors i.e., concentrations of NaOH, HCl, and silylated agent and their contact times were studied using central composite design (CCD) and response surface method. Extraction time, extraction solvent (chloroform) volume, dispersive solvent (methanol) volume, centrifugation rate and time, and salting-out effect in DLLME procedure were optimized in the same way using CCD, in the second step. High enrichment factors (EFs) (more than 1,000 in most cases) and low detection limits (at sub μg L-1 level) are attainable by using gas chromatography-flame ionization detection. The repeatability and reproducibility of the proposed method are good and the relative standard deviations (RSD %) for six repeated experiments (C = 100 μg L-1 of each pesticide) are less than 7.25%. Finally, the method was successfully applied in determination of analytes in some aqueous samples such as wastewater, well water, and some fruit juice samples. © 2011 Springer-Verlag.

Majidi M.R.,University of Tabriz | Fadakar Bajeh Baj R.,University of Tabriz | Bamorowat M.,GYAH Corporation
Measurement: Journal of the International Measurement Confederation | Year: 2016

1-Allyl-3-methylimidazolium tetraflouroborate ([AMIM][BF4]) ionic liquid modified carbon-ceramic electrode was applied for Imidacloprid electrochemical determination. Surface of the modified electrode was characterized using scanning electron microscopy (SEM), and Energy Dispersive X-ray Analysis (EDX). These analyses showed the deposition of ionic liquid on the surface of carbon-ceramic electrode caused formation of graphene-like nanoplatelets. Based on high surface area and rich edge defects which resulting from graphene-like nanoplatelets and high ionic conductivity of ionic liquid (IL), the modified electrode exhibited electro-catalytic activity for Imidacloprid reduction. Operational parameters including IL volume, solution pH; which affect the analytical performance of modified electrode were optimized. The calibration curve for Imidaclopride was linear in the range of 5 × 10−8–7 × 10−6 M with the detection limit (S/N = 3) of 31 nM (3.1 × 10−8 M). This modified electrode was applied for imidacloprid determination in some commercial formulation and agricultural products and the results were in good agreement with standard high-performance liquid chromatography method. © 2016 Elsevier Ltd

Farajzadeh M.A.,University of Tabriz | Djozan D.,University of Tabriz | Nouri N.,University of Tabriz | Bamorowat M.,GYAH Corporation | Shalamzari M.S.,University of Tabriz
Journal of Separation Science | Year: 2010

Stir bar sorptive extraction (SBSE) combined with dispersive liquid-liquid microextraction (DLLME) has been developed as a new approach for the extraction of six triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole, triticonazole and difenconazole) in aqueous samples prior to GC-flame ionization detection (GC-FID). A series of parameters that affect the performance of both steps were thoroughly investigated. Under optimized conditions, aqueous sample was stirred using a stir bar coated with octadecylsilane (ODS) and then target compounds on the sorbent (stir bar) were desorbed with methanol. The extract was mixed with 25 μL of 1,1,2,2-tetrachloroethane and the mixture was rapidly injected into sodium chloride solution 30% w/v. After centrifugation, an aliquot of the settled organic phase was analyzed by GC-FID. The methodology showed broad linear ranges for the six triazole pesticides studied, with correlation coefficients higher than 0.993, lower LODs and LOQs between 0.53-24.0 and 1.08-80.0 ng/mL, respectively, and suitable precision (RSD < 5.2%). Moreover, the developed methodology was applied for the determination of target analytes in several samples, including tap, river and well waters, wastewater (before and after purification), and grape and apple juices. Also, the presented SBSE-DLLME procedure followed by GC-MS determination was performed on purified wastewater. Penconazole, hexaconazole and diniconazole were detected in the purified wastewater that confirmed the obtained results by GC-FID determination. In short, by coupling SBSE with DLLME, advantages of two methods are combined to enhance the selectivity and sensitivity of the method. This method showed higher enrichment factors (282-1792) when compared with conventional methods of sample preparation to screen pesticides in aqueous samples. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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