The analytical reference standards of 8-oxoGua. 8-oxodGuo and 8-oxoGuo were purchased by Spectra 2000 s.r.l (Rome, Italy). The isotope labeled internal standards (13C15N2) 8-oxodGuo and (13C15N2) 8-oxoGuo were obtained from CDN Isotopes Inc. (Pointe-Claire, QC, Canada). (13C15N) 8-oxoGua (98%) was obtained from Cambridge Isotope Laboratories Inc. (Tewksbury, MA, USA).
Glacial acetic acid 30% NH3. Dimethyl sulfoxide. Sodium hydroxide solution (50%–52% in water) and CHROMASOLV® gradient grade ≥99.9% Methanol and Acetonitrile for HPLC/MS ≥99.9% carbon disulfide low benzene content were obtained from Sigma Aldrich (Saint Louis, MO, USA). Purified water was obtained from a Milli-Q Plus system (Millipore Milford, MA, USA). Anotop 10LC syringe filter device (0.2 µm pore size, 10 mm diameter) were purchased from Whatman Inc. (Maidstone, UK). A Kinetex Polar C18 column 100 A. (150 × 4.6 mm, 2.6 µm) supplied by Phenomenex (Torrance, CA, USA) were used throughout the study.
The urine samples were analyzed on a Series 200 LC quaternary pump (PerkinElmer, Norwalk, CT, USA) coupled with an AB/Sciex API 4000 triple-quadrupole mass spectrometry detector equipped with a Turbo Ion Spray (TIS) probe.
Glacial acetic acid 30% NH3. Dimethyl sulfoxide. Sodium hydroxide solution (50%–52% in water) and CHROMASOLV® gradient grade ≥99.9% Methanol and Acetonitrile for HPLC/MS ≥99.9% carbon disulfide low benzene content were obtained from Sigma Aldrich (Saint Louis, MO, USA). Purified water was obtained from a Milli-Q Plus system (Millipore Milford, MA, USA). Anotop 10LC syringe filter device (0.2 µm pore size, 10 mm diameter) were purchased from Whatman Inc. (Maidstone, UK). A Kinetex Polar C18 column 100 A. (150 × 4.6 mm, 2.6 µm) supplied by Phenomenex (Torrance, CA, USA) were used throughout the study.
The urine samples were analyzed on a Series 200 LC quaternary pump (PerkinElmer, Norwalk, CT, USA) coupled with an AB/Sciex API 4000 triple-quadrupole mass spectrometry detector equipped with a Turbo Ion Spray (TIS) probe.