Detection of malathion, fenthion and methidathion by using heparin-reduced gold nanoparticles

Green-synthesized gold nanoparticles were utilized for the detection of organophosphorous pesticides. Heparin, one of glycosaminoglycans, was used as a reducing and stabilizing agent. The reaction conditions were optimized, and high resolution-transmission electron microscopic images revealed gold nanoparticles of various shapes. Organophosphorous pesticides in water were detected by simply mixing them with gold nanoparticles. NaCl induced a color change in the mixed solution from wine-red to purple-blue that was dependent on the pesticide concentration in the range of 10-1,000 ppb. Gold nanoparticles were immobilized on a silica gel matrix in order to prepare solid supports for removing pesticides. The incorporation of atomic gold and heparin bound to 2 g of silica gel was determined 4,058 ppm and 33 microg as measured by inductively coupled plasma-atomic emission spectrophotometry and carbazole assay, respectively. AuNPs-immobilized silica gel columns were successfully applied for removing fenthion in water confirmed by RP-HPLC and FT-IR analyses.