Sciex 5500 triple quadrupole mass spectrometer

UPLC-MS/MS analysis was performed on Sciex 5500+ triple quadrupole mass spectrometer equipped with an ESI source and an Exionlc ad system ultra-high performance liquid chromatography (AB SCIEX, USA). The system was controlled and the data were collected using the SCIEX Analyst OS software package (version 1.7.1). The data were analyzed using the SCIEX OS software package (version 2.0.0.45330).
Chromatographic separation of naringenin was performed on six chiral analytical columns. Cellulose tris (3,5-dimethylphenylcarbamate) (Lux Cellulose-1), cellulose tris (3-chloro-4-methylphenylcarbamate) (Lux Cellulose-2), cellulose tris (4-methylbenzoate) (Lux Cellulose-3), and cellulose tris (4-chloro-3-methylphenylcarbamate) (Lux Cellulose-4) were purchased from Phenomenex (Torrance, USA). Amylose-tris (3-chloro-5-methylphenyl carbamate) (Chiralpak IG-3) was purchased from Daicel (Tokyo, Japan). All five columns were sized 150 mm × 2.0 mm i.d. packed with 3-μm particles. Hydroxypropyl-β-cyclodextrin (InfinityLab Poroshell 120 Chiral-CD) was purchased from Agilent (CA, USA), and the column was sized 150 mm × 2.1 mm i. d. packed with 2.7-μm particles.

Drug was extracted by protein precipitation [in acetonitrile/water (5:1, v/v)]. Prior to extraction, tissues were homogenized using a MINILYS homogenizer and Precellys–Keramik kit (Bertin Technologies, Bordeaux). Calibration curves ranged between 5–5000 ng/mL (plasma) and 0.35–1000 ng/mL (tissue).
Lamivudine triphosphate (lamivudine-TP) tissue concentrations were determined using weak anion exchange chromatography. Biopsies were homogenized in a solution of methanol and 20 mM EDTA/EGTA (70:30, v/v). A biobasic AX column with a pH gradient mobile phase was used to elute lamivudine-TP and detection was performed on an SCIEX 5500 triple quadrupole mass spectrometer. The assay was validated over the concentration range of 0.075–213 pmol.

5-methyl-2’-deoxycytidine genomic content was measured using LC-MS as described previously [31 (link)]. Briefly, genomic DNA was extracted and digested into single nucleosides. Chromatographic separation was achieved with a Thermo Hypercarb porous graphite column (100 mm × 2.1 mm, 5 μm) and isocratic elution with a 10 mM ammonium acetate:acetonitrile with 0.1% formic acid (70:30, v/v) mobile phase over a 5 min total analytical run time. An AB Sciex 5500 triple quadrupole mass spectrometer operated in positive electrospray ionization mode was used for the detection of 5-methyl-2′-deoxycytidine.