Liquid chromatography–electrospray ionization–timeof-
flight mass spectrometry (LC–ESI–TOF-MS), in positive
ionization was used to detect the pesticides. The separation
of the selected pesticides was carried out using an HPLC
system (consisting of vacuum degasser, autosampler and a
binary pump) (Agilent Series 1100, Agilent Technologies,
Palo Alto, CA, USA) equipped with a reversed-phase C8
analytical column of 150mm×4.6mm and 5m particle
size (Zorbax Eclipse XDB-C8). Column temperature was
maintained at 25 ◦C. The injected sample volume was 50 l.
Mobile phasesAandBwere acetonitrile andwater with 0.1%
formic acid, respectively. The optimized chromatographic
method held the initial mobile phase composition (10% A)
constant for 5 min, followed by a linear gradient to 100% A
in 25 min. The flow-rate usedwas 0.6 ml/min.A12-min postrun
time back to the initial mobile phase composition was
used after each analysis. This HPLC system was connected
to a time-of-flight mass spectrometer Agilent MSD TOF
(Agilent Technologies) with an electrospray interface, using
the operational parameters included in Table 1. LC–TOF-MS
Liquid chromatography–electrospray ionization–timeof-flight mass spectrometry (LC–ESI–TOF-MS), in positiveionization was used to detect the pesticides. The separationof the selected pesticides was carried out using an HPLCsystem (consisting of vacuum degasser, autosampler and abinary pump) (Agilent Series 1100, Agilent Technologies,Palo Alto, CA, USA) equipped with a reversed-phase C8analytical column of 150mm×4.6mm and 5m particlesize (Zorbax Eclipse XDB-C8). Column temperature wasmaintained at 25 ◦C. The injected sample volume was 50 l.Mobile phasesAandBwere acetonitrile andwater with 0.1%formic acid, respectively. The optimized chromatographicmethod held the initial mobile phase composition (10% A)constant for 5 min, followed by a linear gradient to 100% Ain 25 min. The flow-rate usedwas 0.6 ml/min.A12-min postruntime back to the initial mobile phase composition wasused after each analysis. This HPLC system was connectedto a time-of-flight mass spectrometer Agilent MSD TOF(Agilent Technologies) with an electrospray interface, usingthe operational parameters included in Table 1. LC–TOF-MS
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