A novel approach based on capillary liquid chromatography for the simultaneous determination of neonicotinoid residues in cereal samples

A simple and effective method using solid-liquid extraction followed by capillary liquid chromatography with diode array detection (CLC-DAD) has been established for the extraction and determination of seven neonicotinoid insecticides commercially available (imidacloprid, thiacloprid, clothianidin, thiamethoxam, acetamiprid, nitenpyram and dinotefuran) in cereal samples. The separation was achieved in less than 19 min using a Zorbax XDB-C18 column (150 mm x 0.5 mm i.d, 5 mu m) at a 25 degrees C, with a mobile phase consisting of ultrapure water and acetonitrile at a flow rate of 10 mu L/min. Detection wavelengths of 254 or 270 nm were used, depending on the analyte. Variables affecting the extraction efficiency were optimized, such as type and volume of extraction solvent, and extraction and centrifugation time. Under the optimal conditions, the proposed method was characterized according to SANTE/12682/2019 guideline, in terms of linearity (R-2 >= 0.9901), repeatability (RSD <= 7.6%), reproducibility (RSD <= 10%) and trueness (recoveries >= 80%). The limits of detection and quantification were in the ranges of 3-5 and 9-18 mu g/kg, respectively, being adequate for the determination of these compounds in cereal samples at levels below its maximum residue limits (MRLs) established by the European legislation. The advantages of a miniaturized technique such as CLC in terms of high mass sensitivity and reduced solvent consumption, combined with the simplicity of the solid-liquid extraction procedure, make this method a useful alternative for the monitoring of these residues at trace level in cereal samples.