Development and Validation of a Method for the Simultaneous Determination of 20 Organophosphorus Pesticide Residues in Corn by Accelerated Solvent Extraction and Gas Chromatography with Nitrogen Phosphorus Detection
Vesna Kostik,
Biljana Gjorgeska,
Bistra Angelovska
Issue:
Volume 2, Issue 4, August 2014
Pages:
46-54
Received:
17 July 2014
Accepted:
5 August 2014
Published:
10 August 2014
Abstract: The method for simultaneous determination of 20 organophosphorus pesticide residues in corn samples has been developed and validated. For the extraction of organophosporus pesticide residues from the samples, the accelerated solvent technique with the mixture of dichloromethane: acetone (1:1, V/V) was used. Clean up was done using liquid – liquid extraction with n – hexane, followed by solid phase extraction on primary secondary amine adsorbent, and elution with the mixture of acetone: toluene (65:35). The determination of the pesticides was carried out by gas chromatography with nitrogen phosphorus detection. Separation and quantitative determination of the analytes were performed on a fused silica capillary ZB-35 column (30 m x 0.25 mm i.d. x 0.25 µm, Phenomenex). The recovery was investigated in blank corn samples fortified with mevinphos, diazinon, dimethoate, bromofos-methyl, chlorfenvinphos, fenamiphos, ethion and phosalone at 5 ng/g, 10 ng/g, 15 ng/g , 20 ng/g and 25 ng/g, respectively and with methacrifos, phorate, etrimfos, parathion-methyl, pirimiphos - methyl, fenitrothion, chlorpyrifos, malathion, parathion, bromofos-ethyl, phosmet and azinphos-methyl at 10 ng/g, 20 ng/g, 30 ng/g, 40 ng/g and 50 ng/g, respectively. The recovery ranged from 76.0% to 112.0%. Repeatability expressed as relative standard deviation (RSD) was less than 8.2%. Linearity expressed as correlation coefficient (R2) ranged from 0.9935 to 0.9996. Measurement uncertainty (Ux) was lower than 14.2% for all tested pesticides. The limits of quantification (LOQ) were bellow 5 ng/g for all tested pesticides. The satisfactory Z-score results of international proficiency tests confirm good analytical performances of the developed method.
Abstract: The method for simultaneous determination of 20 organophosphorus pesticide residues in corn samples has been developed and validated. For the extraction of organophosporus pesticide residues from the samples, the accelerated solvent technique with the mixture of dichloromethane: acetone (1:1, V/V) was used. Clean up was done using liquid – liquid e...
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Anaerobic Co-Digestion of Biodegradable Municipal Solid Waste with Human Excreta for Biogas Production: A Review
Issue:
Volume 2, Issue 4, August 2014
Pages:
55-62
Received:
8 August 2014
Accepted:
16 August 2014
Published:
30 August 2014
Abstract: Biogas, which is principally composed of methane and carbon dioxide, can be obtained by anaerobic fermentation of biomass like: manure, sewage sludge, municipal solid waste. Biogas production represents a very promising way to overcome the problem of waste treatment. Furthermore, the solid residuals of fermentation might be reused as fertilizers. This review clearly indicates that co-digestion of organic waste is one of the most effective biological processes to treat a wide variety of solid organic waste products and sludge as well as biogas production. The prime advantages of this technology include (i) organic wastes with a low nutrient content can be degraded by co-digesting with different substrates in the anaerobic bioreactors, and (ii) the process simultaneously leads to low cost production of biogas, which could be vital for meeting future energy-needs.
Abstract: Biogas, which is principally composed of methane and carbon dioxide, can be obtained by anaerobic fermentation of biomass like: manure, sewage sludge, municipal solid waste. Biogas production represents a very promising way to overcome the problem of waste treatment. Furthermore, the solid residuals of fermentation might be reused as fertilizers. T...
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