6890n 5975 gc ms system

Chemical quantification was monitored with a Waters 2690 HPLC system equipped with a ternary gradient pump, programmable variable-wavelength UV detector, column oven, electric sample valve, and C₁₈ reversed-phase column (Phenomenex Lunar 5 μm C₁₈ 250 × 4.6 mm) with array detection from 190 to 400 nm (total scan) based on retention time and peak area of the pure standard. The samples were determined using a mobile phase of 70:30 acetonitrile/water at a flow rate of 1.0 mL·min⁻¹. The injection volume was 10 μL (Chen et al., 2015 (link)).
The metabolites of permethrin were analyzed and identified with an Agilent 6890N/5975 GC-MS system equipped with an autosampler and OnColumn, split/splitless capillary injection system, with an HP-5MS capillary column (30.0 m × 250 μm × 0.25 μm) with array detection from 30 to 500 nm (total scan). The operating conditions were following the method of our previous study (Chen et al., 2014 (link)). The ionization energy was 70 eV, and the temperatures of the transfer line and the ion trap were 280 and 230°C, respectively. The injection volume was 1.0 μL with splitless sampling at 250°C. High purity helium gas was used as a carrier gas at a flow rate of 1.5 mL min⁻¹.

Fenvalerate metabolites were identified using a Shimadzu GC2010 Plus gas chromatograph coupled to a Shimadzu MS2010 Plus mass spectrometer in electron ionization mode (70 eV) with a DB-5 column (30.0 m × 0.25 mm × 0.25 mm). The samples (extracts of fenvalerate, phenol, and catechol) were filtered through a 0.45 µm organic phase membrane filter and analyzed on an Agilent 6890N/5975 GC-MS system. Helium (99.999%) was used as GC carrier gas at a constant flow rate of 1.5 mL/min. The injection volume was l µL. Injection mode was splitless at 250 °C. The temperature of the transmission line and the ion source are 250 °C and 280 °C, respectively. GC oven was programed with the initial temperature of 60 °C for 2 min, followed increase to 190 °C at 8 °C min^− 1 ramp, holding for 1 min, then increased to 230 °C at 10 °C min^− 1 ramp, holding for 4 min, and finally increased to 270 °C at 10 °C min^− 1 ramp, holding for 25 min. Metabolites identified by GC-MS analysis were matched to real-world standard compounds from the National Institute of Standards and Technology (NIST, USA) library database (Chen et al. 2013 (link)).

Azoxystrobin concentration was monitored by HPLC equipped with a C₁₈ reversed-phase column (Phenomenex, 250 nm × 4.60 mm, 5 μm, Alliance e2695, Waters Corporation, Milford, MA, USA) and a PAD detector at a column temperature of 28 ± 1 °C. Then, 10 μL of each sample was injected and azoxystrobin concentration was determined at 230 nm wavelengths. A mobile phase of 70:30 acetonitrile/water (v/v) was used at a flow rate of 1.0 mL·min⁻¹ [48 (link)].
To identify the azoxystrobin degradation metabolites, extracts were analyzed by GC-MS on a DB-5MS capillary column (30.0 m × 250 μm × 0.25 μm) with an Agilent 6890N/5975 GC-MS system equipped with an auto-sampler and on-column, split/splitless capillary injection system, and an array detection from 40–430 nm (total scan). Operating conditions were as follows: injection volume was 1.0 μL with splitless sampling at 260 °C and helium (>99.999% purity) was used as a carrier gas at a flow rate of 1.0 mL∙min⁻¹. Temperatures corresponding to the transfer line and ion trap were 280 °C and 230 °C, respectively, at ionization energy of 70 eV. The column was initially held at 200 °C for 3 min and then raised at 25 °C·min⁻¹ to 280 °C for 20 min.