Magnetic dispersive solid-phase extraction of organochlorine pesticides from honey samples in a narrow-bore tube prior to HPLC analysis

Abstract

The evaluation of pollutant residues, particularly pesticides, in honey samples is of utmost importance to maintain human safety. In this study, a magnetic dispersive solid-phase extraction method within a narrow-bore tube was introduced for the extraction and preconcentration of four organochlorine pesticides (OCPs) from honey samples. For this purpose, 40 mg of the synthesized magnetic Ni-MOF-I sorbent dispersed into 1 mL of acetonitrile was injected into the sample solution filled in a narrow-bore tube. An external magnet was placed near the end of the tube to collect the sorbent. After 5 min, the stopcock connected to the tube was opened, allowing the sample solution to pass through the sorbent held by the magnet at a flow rate of 5 mL min⁻¹. The sorbent was then eluted using 250 μL of acetonitrile following the evaporation of the eluent. The analytes were redissolved in the mobile phase and analyzed by an analytical system. Under the optimized conditions, the analytes exhibited acceptable extraction recoveries ranging from 56% to 76% and a wide linear range of 1–1000 ng g⁻¹ with an r² value of ≥0.993. The limits of detection and quantification were found to be in the range of 0.11–0.25 ng g⁻¹ and 0.37–0.84 ng g⁻¹, respectively. Moreover, the proposed method demonstrated high precision with relative standard deviation values of ≤4.3% and 4.9% for intra- and inter-day precisions, respectively. Eventually, the desired approach was successfully carried out to monitor OCP residues in 30 honey samples, revealing no sign of the studied pesticides in any of the analyzed samples.