Abstract
Neonicotinoid insecticides (neonics) are referred to as nicotine-like active organic ingredients that are employed in agriculture to eliminate insects. However, societal concerns have been raised since these compounds can affect humans, aquatic organisms and environmentally beneficial organisms like bees. In this study, the magnetic poly (3-aminobenzoic acid) based activated carbon (Fe3O4@PABA/AC) nanocomposite was successfully synthesized using co-precipitation and in-situ polymerization procedures. The nanocomposite and the synthesized intermediate materials were characterized and confirmed by FTIR, TEM, SEM/EDS, BET and XRD. The results from FTIR confirmed the C-N weak band stretching at 2066 cm-1 and the intense peak around 566 cm-1 for functional group analysis, confirming the presence of PABA and Fe3O4 in the nanocomposite, respectively. The morphological structures were determined by SEM and TEM. SEM results showed PABA covering AC surface with pores observed. Furthermore, the smooth surface was observed after magnetic nanoparticles doping. Additionally, TEM results indicated mesoporous activated carbon with PABA on its surface. Magnetic nanoparticles distributed heterogeneously on the PABA/AC surface. The EDS confirmed the existence of all atoms that were proposed to be present in the nanocomposite with no impurities. The nanoadsorbent was employed as a solid phase in preconcentration of the selected neonicotinoids (acetamiprid, imidacloprid, thiacloprid and clothianidin) via magnetic dispersive solid-phase nanoextraction (d-DMSPNE). The neonicotinoids preconcentrated were analysed using HPLC-DAD. The d-DMSPNE methodology was optimized using 25-1 fractional factorial statistical design. Under optimum conditions, the LODs and LOQs ranged from 0.77-1.4 μg L1 and 2.5-4.8 μg L1, respectively. The intra and inter days studies were conducted ten times at a concentration level of 100 μg L1 within the same day and five consecutive days, respectively. The RSD% that estimates the precision of the developed d-DMSPNE procedure ranged from 0.35-0.75% and 1.68-5.47%, respectively. The d-DMSPNE method was then applied in the preconcentration of the selected neonicotinoid from the influent, effluent and river water samples and the extraction recoveries that are comparable to the ones obtained using synthetic water samples were obtained...
M.Sc. (Nanoscience)