Development of multiresidue DLLME and QuEChERS based LC–MS/MS method for determination of selected neonicotinoid insecticides in honey liqueur

Abstract

Honey liqueur is an alcoholic drink derived from honey and strong fruit brandy of suitable type, traditionally made in Serbia and other Balkan countries. Although European Union has regulated the levels of neonicotinoid insecticides in honey and pollen, there is an increased risk of the presence of these compounds in traditional products made from honey. The objective of this study was to develop an optimized LC–MS/MS analytical method with dispersive liquid–liquid microextraction (DLLME) and QuEChERS sample preparation procedures for analysis of seven neonicotinoids (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid and thiacloprid) in honey liqueur. The LC–MS/MS conditions were optimized to unequivocally provide good chromatographic separation, selectivity and specificity of developed method. The method was validated to fulfill the requirements of SANCO/12495/2011 for both sample pretreatment procedures providing results for accuracy (R, 69.2–113.4% for DLLME; 71.8–94.9% for QuEChERS), precision (RSD expressed in terms of repeatability (3.21–10.20% for DLLME; 4.19–12.81% for QuEChERS) and within-laboratory reproducibility (9.11–16.63% for DLLME; 11.32–16.40% for QuEChERS)), limits of detection (LOD, 0.5–1.5μgL−1 for DLLME; 1.0–2.5μgL−1 for QuEChERS) and quantification (LOQ, 1.0–5.0μgL−1 for DLLME; 2.5–10.0μgL−1 for QuEChERS). Matrix effects were compensated by the use of matrix-matched calibration. Analysis of real honey liqueur samples obtained from local markets showed the presence of clothianidin or thiacloprid in four of the analyzed samples, therefore implicating the necessity of ongoing control of this type of traditional product.