DLLME-GC/ECD Method for the Residual Analysis of Parathion-Methyl and its Application in the Study of the UV-Photodegradation Process

Abstract

A new method has been developed to determine trace levels of organophosphorus pesticide parathion-methyl in water samples by using dispersive liquid-liquid microextraction (DLLME), followed by gas chromatograph coupled with electron capture detector (GC/ECD) analysis. The optimized and validated method showed high extraction recovery (101.1%), high enrichment factor (57.3), low limits of detection and quantification, 0.083 and 0.250 μg L -1 , respectively. The established DLLME-GC/ECD method has been successfully applied for the evaluation of the photodegradation of the parathion-methyl by UV 254nm radiation in different conditions of pH and temperature. The parathion-methyl photodegradation at pH 3 and 35 °C achieved > 99.5% after 120 min of exposition. For this condition, it was observed the kinetic rate of 0.0515 min -1 , the quantum yield of 1.22 × 10 -5 mol Einstein -1 and a half-life time of 13.46 min. All experimental conditions tested proved to be strongly influenced by pH and temperature. The application of the optimized process in distilled and drinking water spiked with parathion-methyl provided residues of this pesticide at levels below the maximum permitted by Brazilian legislation, which is 9.0 μg L -1 .

Metal oxide-based electrochemical sensors for pesticide detection in water and food samples: a review

“…143 This insecticide, mainly sprayed on beans, wheat, cotton and fruits, can affect the neurological systems of all living things, including watersheds, humans, and animals. 144 Gopi et al 145 constructed an effective electrochemical sensor based on BiVO 4 as an electrocatalyst for detecting hazardous paraoxon pesticide. The material characterization revealed that the synthesized BiVO 4 had superior conductivity, sufficient oxygen vacancies, and good chemical stability.…”