6410b triple quad mass spectrometer

10 μl of investigated solution was diluted with methanol to 1 mL, then 20 μl of the above dilution was further diluted with methanol to 1 mL. The mixture was injected onto MS system. LC-MS measurements were performed on a 1200 series liquid chromatograph coupled with a 6410B Triple Quad mass spectrometer (Agilent, USA). Separation was performed at 40 °C with a Poroshell 120 EC-18 column (3.0 × 75 mm, 2.7 µm, Agilent, USA). Mobile phases were: 0.1% formate buffer pH 3.2 [A] and 0.1% formic acid in acetonitrile [B]. Gradient elution was programmed as follows: 95% [A] and 5% [B] for 5 min., followed by a linear change of 80% [A] and 20% [B] in 3 min., then linear change to 5% [A] and 95% [B] in 5 min. and was held for 7 min., then by a linear change of 95% [A] and 5% [B] for 2 min. Post time was 2 min. and total chromatographic cycle was 24 min. The flow rate was 0.5 mL/min. The instrument was operated with electrospray ionization (ESI) source in the positive mode. MS conditions were: drying gas temperature (nitrogen), 300 °C; nebulizing gas flow, 8 L/min; nebulizing gas pressure, 40 psi; capillary voltage, 4 kV; fragmentor voltage, 50–250 V. The acquisition was carried out in the scan mode (m/z 50–650).

The amount of Rb₁, Rg₁ and R₁ was analyzed by an HPLC system. A Shimadzu shim-pack C₁₈ column (250 mm × 4.6 mm, 5 μm) was used as the stationary phase. The mobile phase consisted of ultra-water (A) and acetonitrile (B) and was run in an isocratic mode at a flow rate of 1.0 mL·min⁻¹. The following gradient was performed: 0–23 min, 23% B; 23–40 min, 35% B. The column temperature was maintained at 35 °C. Aliquots of 20 μL were injected. Monitoring and quantitation of Rb₁, Rg₁ and R₁ were performed at 204 nm.
Agilent 1200 liquid chromatograph combined with an Agilent 6410B Triple Quad mass spectrometer was used to identify Rb₁, Rg₁ and R₁ in biological samples. An Agilent zorbax eclipse plus C₁₈ column (150 mm × 2.1 mm, 5 μm) was used as the stationary phase. The mobile phase for LC-MS analysis consisted of acetonitrile-water (5:5, v/v) at a flow rate of 0.5 mL·min⁻¹.