Abstract
Imazalil is a widely used systemic chiral fungicide that is still being employed
as a racemic mixture without distinguishing the difference between enantiomers,
which often leads to its inaccurate risk assessment. In this study, a robust and
highly sensitive chiral separation method was developed for imazalil enantiomers
by ultrahigh-performance liquid chromatography?tandem mass spectrometry and was
further applied to study the degradation dynamics of imazalil enantiomers in
apples and field soils at three sites in China. The baseline enantioseparation
for imazalil was achieved within 3.5 min on a Lux Cellulose-2 (CCMPC) column
with acetonitrile (ACN)/water (65:35, v/v) with a mobile phase at 0.5 mL/min
flow rate and a column temperature of 20 °C. The limit of quantitation (LOQ) for
each enantiomer was <0.60 μg/kg, with a baseline resolution of approximately
1.75. The research showed that (S)-(+)-imazalil degraded more rapidly than
(R)-(?)-imazalil in Gala apples, whereas (R)-(?)-imazalil preferentially
degraded in Golden Delicious apples. No significant enantioselectivity was
observed in OBIR-2T-47 apples and field soils from the three sites. Results of
this study provide useful references for risk assessment and the rational use of
imazalil in further agricultural produce practice.