LC-MS/MS method for simultaneous determination of myclobutanil, hexaconazole, diniconazole, epoxiconazole and tetraconazole enantiomers in soil and earthworms

A new method using gel permeation chromatography (GPC) clean-up followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of myclobutanil, hexaconazole, diniconazole, epoxiconazole and tetraconazole enantiomers in soil and earthworms. The soil and earthworm samples were extracted with acetonitrile and then purified with a GPC procedure conducted on a CO785 column with cyclohexane and ethyl acetate (50:50, V/V) as the mobile phase at a flow rate of 4.7 mL/min. The eluent between 7.5 min and 15 min was collected for LC-MS/MS analysis. The LC mobile phase and MS/MS conditions were optimised. Formic acid (0.1%, V/V) was added to the water phase to enhance MS responses. The LODs of the enantiomers were between 0.001–0.003 mg/kg. At three fortification levels of 0.01–1.00 mg/kg, recoveries were between 81.2% and 100.2% in soil and earthworms. The relative standard deviation was below 14%. The results of earthworm experiment showed that hexaconzole and diniconazole...