چكيده لاتين
Pesticides are a group of chemical compounds that are used to eliminate plant pests and control their diseases, and thus play an important role in reducing the loss of agricultural products and increasing their quality. Neonicotinoid insecticides are a group of pesticides that have received much attention in recent years due to their high efficiency and selective activity. Among the neonicotinoid insecticides, acetamiprid is widely used due to its systemic nature, high permeability and low hydrophobicity. Due to excessive use of these insecticides, they are found in the environment and food, and their residues have harmful effects on human health and the environment. Therefore, it is necessary to develop fast and reliable methods to extract and measure the residues of these emerging pollutants in food and environmental samples. The aim of this research is to develop a magnetic solid phase extraction (MSPE) method for easy and quick sample preparation followed by high performance liquid chromatography analysis to determine the residues of acetamiprid in a real sample. In this research, iron oxide magnetic nanoparticles were first synthesized by co-precipitation method and in order to prevent their rapid accumulation and oxidation, the nanoparticles were modified with silica. Then, in order to improve the adsorption properties of the adsorbent, its surface was modified using a Metal-organic framework. Metal- Organic frameworks have been widely used to modify the surface of magnetic nanoparticles due to their unique properties such as high specific surface area, large pore volume, high thermal stability, adjustable pore size, and multiple functions. In this research, metal- organic framework MIL-68-Al was used to modify the surface of silica-coated iron oxide magnetic nanoparticles. To characterize the synthesized adsorbent, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), elemental analysis by energy dispersive spectroscopy (EDS) and Nitrogen gas adsorption-desorption isotherm (BET) was used. Then, in order to improve the extraction efficiency, the effective factors were optimized in concentration of 300.0 ng.mL-1 of acetamiprid. under optimal conditions including the amount of adsorbent: 0.3 mg, adsorption time: 10 minutes, pH = 7, salt concentration: 0 ⁒ w/v, desorption time: 2 minutes, desorption solvent: acetonitrile and volume of desorption solvent: 1 mL, extraction efficiency of 93.19 ⁒ was obtained. As a result, the linear concentration range of the method was 10-300 ng.mL-1 with R2= 0.9998. The limit of detection (LOD) and quantification (LOQ) were 3.99 and 13.30 ng.mL-1,respectively. Relative standard deviation (RSD) was in the range of 0.26-1.42 ⁒. This MSPE method was successfully applied for determination of acetamiprid in apple juice sample.
