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Hachami F.,University Ibn Zohr | Salghi R.,Laboratoire Dingenieries Des Procedes Of Lenergie Et Of Lenvironnement | Errami M.,Laboratoire Dingenieries Des Procedes Of Lenergie Et Of Lenvironnement | Bazzi L.,University Ibn Zohr | And 3 more authors.
Physical and Chemical News

The aim of this study is to investigate the possibilities and ways of reducing the negative effects of pesticides on the environment. The obsolete methidathion organophosphorous pesticide stock is treated by electrolysis system. The results obtained show that the application of electrolysis in pesticide allows to reduce the Chemical Oxygen Demand (COD). For 2% NaCl and 3% NaCl the achieved reduction was 75 and 70%, respectively, while for 4% NaCl was 48%. In all cases, the pH of electrolysis was significantly reduced after 45 min. The COD of methidathion solution was observed to fall with pseudo first-order kinetics. An increasing of applied current leads an increase of the rate of electrochemical oxidation process. The effect of temperature shows that for 25 and 65oC the achieved reduction was 75 and 50%, respectively. The rate constant kI obtained exhibits a negative temperature coefficient which confirms that the electrochemical degradation proceeds via a complex mechanism. Source

Zougagh M.,Regional Institute for Applied Science Research | Salghi R.,Laboratoire Dingenieries Des Procedes Of Lenergie Et Of Lenvironnement | Dhair S.,Laboratoire Dingenieries Des Procedes Of Lenergie Et Of Lenvironnement | Rios A.,Regional Institute for Applied Science Research | Rios A.,University of Castilla - La Mancha
Analytical and Bioanalytical Chemistry

A new method, based on the formation of gold nanoparticles (AuNPs) and spectrophotometric analysis, is proposed to determine total phenolic acids in virgin argan oil samples. These compounds have reducibility due to the presence of the phenol group in their molecular structure, and a redox reaction occurs in the presence of HAuCl 4. The formation of AuNPs as a result of the redox reaction leading to colour changes can be visually observed, resulting in strong light signals that show absorption at 555 nm. As ferulic acid represents more than 95% of the total phenolic acid content of virgin argan oil, this compound was used as an adulteration marker to carry out the screening of samples for the evaluation of the authenticity of virgin argan oils. The analytical features of this screening method also allowed a low precision quantization of the quality of the product. Then, a reference HPLC-DAD/FD method was used to confirm the potential adulterated samples, as well as to provide a detailed quantitative analysis of the most representative phenolic compounds in the samples. The overall screening-confirmation strategy was validated by analysing pure virgin argan oil samples and argan oil samples adulterated with other commercial vegetable oils, demonstrating the reliability of the results. This approach is characterised by its simplicity, low cost, rapid information and responded to practical laboratories needs. [Figure not available: see fulltext.] © 2011 Springer-Verlag. Source

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