Identification of Sex Pheromone of Miltochrista striata (Lepidoptera: Arctiidae).

A species of lichen moth, Miltochrista striata (Bremer & Grey, 1852), feeds on lichens in Chinese tea plantations (Camellia sinensis (L.) O. Kuntze (Ericales:Theaceae)). A previous sex attractant screening test showed that male moths of M. striata were attracted by a mixture of (Z,Z,Z)-3,6,9-octadecatriene (Z3,Z6,Z9-18:H), (Z,Z,Z)-3,6,9-nonadecatriene (Z3,Z6,Z9-19:H), and their monoepoxy derivatives. To determine which of the component is an effective sex attractant for M. striata, the sex pheromone glands of female moths were excised and extracted with n-hexane. By comparison with the retention time and mass spectra of synthetic chemicals, two compounds in the crude extracts were identified as Z3,Z6,Z9-18:H and (Z,Z)-3,6-cis-9,10-epoxy-octadecadiene (Z3,Z6,epo9-18:H) using gas chromatography-mass spectrometry. The results of electroantennographic tests showed that the electrophysiological activities of Z3,Z6,Z9-18:H and Z3,Z6,epo9-18:H were distinctly higher than those of (Z,Z)-6,9-cis-3,4-epoxy-octadecadiene, (Z,Z)-3,9-cis-6,7-epoxy-octadecadiene, (Z,Z,Z)-3,6,9-nonadecatriene, (Z,Z)-6,9-cis-3,4-epoxy-nonadecatriene, (Z,Z)-3,9-cis-6,7-epoxy-nonadecatriene, and (Z,Z)-3,6-cis-9,10-epoxy-nonadecatriene. Field trapping showed that only a mixture of Z3,Z6,Z9-18:H and Z3,Z6,epo9-18:H attracted male moths, and the optimal mixture of these compounds was the ratio of 4:6 at 1.0-mg dosage. The results represent the first determination of the sex pheromone of a lichen moth in a tea plantation and provide a scientific basis to develop an effective protocol using sex pheromone to monitor populations of M. striata.

Residue Determination of cis-Epoxiconazole Enantiomers in Fruit and Tea by Ultra Performance Convergence Chromatography Combined with Quadrupole Time-of-Flight Mass Spectrometry / 分析化学

Abstract A chiral separation and residue determination method for cis-epoxiconazole enantiomers in apple, grape and tea samples was developed and validated by ultra performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry ( UPC2-QTOF/MS) . The Chrial CCA column was used to separate cis-epoxiconazole enantiomers and the chromatography conditions ( mobile phase modifier and proportion, column temperature, automated backpressure regulator, and auxiliary solvent ) were optimized. Samples were extracted by acetonitrile, and respectively purified by Cleanert TPT or Pesti-Carb solid phase extraction ( SPE ) columns, then analyzed by UPC2-QTOF/MS. The optimum conditions were as follows:mobile phase was CO2/isopropanol (95: 5, V/V), flow-rate was 2. 0 mL/min, automated backpressure regulator (ABPR) was 13. 79 MPa, column temperature was 30℃, with a post-column mauxiliary solvent of methanol/water (1:1, V/V) containing 2 mmol/L ammonium formate. The analyte was quantified by matrix external standard method. The results showed that linear range of this method was 0. 01-1. 00 mg/L, and the correlation coefficients were above 0 . 99 . The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 005, 0. 025 and 0. 25 mg/kg) in fruit matrix were 67. 9%-92. 8% with relative standard deviations (RSDs, n=6) less than 10%, and the limit of quantification (LOQ) of enantiomers was 0. 005 mg/kg. The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 01, 0. 05 and 0. 5 mg/kg) in black tea were 74 . 1% -84 . 0% with RSDs ( n=6 ) less than 8%, and the LOQ for these two enantiomers was 0. 01 mg/kg. This method is rapid, convenient and reliable, and could meet the requirement of residue analysis.