Liquid chromatography with diode array detection and tandem mass spectrometry for the determination of neonicotinoid...

The combination of solid-phase extraction with dispersive liquid-liquid microextraction (SPE-DLLME) is proposed for the determination of five neonicotinoid insecticides in honey. After a cleanup stage, the analytes were eluted using acetonitrile. DLLME was performed by injecting rapidly the acetonitrile extract into 10 mL of water containing a 10% (w/v) NaCl and 100 μL of CHCl3. The settled organic phase obtained after centrifugation was evaporated, reconstituted in acetonitrile (ACN), and submitted to liquid chromatography (LC) with photodiode array detection (DAD) and atmospheric pressure chemical ionization-ion trap-tandem mass spectrometry (APCI-IT-MS/MS). The matrix effect was evaluated, and quantification was carried out using external aqueous calibrations when using DAD, the matrix-matched calibration method was applied for MS/MS. Detection limits in the 0.2-1.0 and 0.02-0.13 ng/g ranges were obtained when using DAD and MS/MS, respectively. The SPE-DLLME-LC-APCI-IT-MS/MS method was applied for the analysis of different honey samples, and none was found to contain residues.