Hplc series200

AEA, PEA, OEA, 1AG, and 2AG plasma levels were measured by a validated in-house assay [7 (link)]. Briefly, 0.5 mL of plasma underwent liquid–liquid extraction with 2 mL toluene after the addition of isotopic internal standards. Extracts were injected into the LC–MS/MS platform (HPLC Series200, PerkinElmer, Waltham, Massachusetts; API4000 QTrap, Sciex, Toronto, ON, Canada), separated on a Discovery HS C18 column (7.5 cm × 4.6 mm; particle size: 3 µm), ionized in positive mode by atmospheric pressure chemical ionization and detected by multiple reaction monitoring of both quantitative and confirmation transitions. Baseline separation between 2AG and 1AG isomers was achieved. Functional sensitivities were 0.02 for AEA, 0.20 for PEA and OEA, 0.16 for 2AG, and 0.08 pmol/mL for 1AG.

The extracts were analysed by means of a HPLC series 200 binary pump equipped with an autosampler (Perkin Elmer, Norwalk, CT, USA). The column was an X-Terra C18 (2.1 × 150 mm; 3.5 µm), protected by a guard column (Waters, Milford, MA, USA). The mobile phase was composed of water (phase A) and acetonitrile (phase B), both being 5 mM in formic acid. The analyte separation was carried out by applying a flow rate of 0.200 mL min⁻¹ and eluting in linear gradient: phase B was increased from 35% to 100% in 16 min, and then held at 100% for 4 min, for a total run time of 20 min. The autosampler needle device was washed with the phase B after each injection. The detection was performed with an API 4000 Qtrap mass spectrometer (AB SCIEX, Foster City, CA, USA) equipped with an electrospray source using the following settings: capillary voltage +5000 V, air nebulizer gas 2 L min⁻¹, air-drying gas at 350 °C and 20 L min⁻¹, nitrogen curtain gas 5 L min⁻¹, nitrogen collision gas 4 mTorr. The full width at half maximum (FWHM) was set at m/z 0.7 ± 0.1 in each mass-resolving quadrupole to operate with a unit resolution. Chromatograms were acquired using the multiple-reaction monitoring (MRM) scan mode. Recovery capacity (R%) was expressed in percentages and determined considering the peak area of the extracted pesticide with respect to the peak area of the initial amount.

The content of PAHs in the extracts was assayed using the HPLC Series 200 equipped with the DAD (absorption) that was provided by PerkinElmer and an FL (fluorescence) detector. The analytical column to separate PAHs provided by Waters was used (250 × 4.6 mm, 5 μm). The mobile phase was composed of eluent A: H₂O and eluent B: ACN. A gradient separation program of a varied flow rate was used. The initial composition of the mobile phase was 70 % of eluent B, and its concentration was increased linearly throughout the analysis. The gradient was completed after 34 min when the content of eluent B reached 100 %.
The extracts of the unpolluted (initial) soil samples were analyzed using a fluorescence detector at an excitation wavelength of λ_ex = 250 nm and emissions of λ_em = 405 nm. The injection was 10 μL.
The extracts of the samples of soils that had been polluted with PAHs and incubated for 10, 30, 60, 120, 180, and 360 days were analyzed using an absorption detector. The detection was done at λ = 254 nm. The injection was 100 μL.
The qualitative analysis of respective hydrocarbons was performed by comparing the soil extract chromatograms with the chromatograms of the model mixtures.
The quantitative assays of fluorene, anthracene, pyrene, and chrysene were done based on their model curves.