Purpose: To extract and analyze the volatile components of Chrysanthemum morifolium Ramat. 'huaiju' by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Methods: Volatile components were extracted by HS-SPME and identified by GC-MS. The relative contents of the components were determined by area normalization. Results:The enhanced SPME conditions of C. morifolium involved sample extraction using a 65 µm polydimethylsiloxane/divinylbenzene extraction fiber after balancing for 40 min at 80 °C. A total of 48 components of the essential oil were identified. The major constituents

ABSTRACT:The analytical technique for the determination of azoxystrobin in tomato and soil was obtained by gas chromatography with tandem mass spectrometry (GC-MS/ MS), and its dissipation fate was also investigated under field conditions. Azoxystrobin residues in tomato and soil were extracted with ethylacetate+cyclohexane extraction and followed by the dispersive-SPE purification. The average recoveries in tomatoes and soils at different spiked concentrations (0.1, 0.5 and 1.0 mg/kg) ranged from 86.16% to 105.47% with RSDs from 6.8% to 12.3%. The LOD ranged from 0.003 µg/kg to 0.004 µg/kg, and LOQ ranged from 0.009 µg/kg to 0.012 µg/kg. This developed methodology was also used to investigate the residues and dissipation of azoxystrobin in tomatoes and soil under the field conditions. The initial azoxystrobin concentrations in tomato fruits in Henan province and in Zhejiang province were 0.494 mg/kg and 0.638 mg/kg with half-lives of 9.9 days and 11.5 days, respectively. Concentrations were reduced by more than 50% at 10 days after application for both sample sets. Initial azoxystrobin concentrations in soil were 1.747 mg/kg and 1.845 mg/kg in Henan province and in Zhejiang province with half-lives of 8.6 days and 7.7 days, respectively.