Api 4000 triple quadrupole linear ion trap qtrap mass spectrometer

The concentrations of Gem, dFdU, and V-Gem were determined in mouse plasma samples using a novel LC-MS/MS method utilizing a Shimadzu HPLC system (Shimazu, Kyoto, Japan) coupled with an Applied Biosystems API 4000 triple quadrupole/linear ion trap (QTRAP) mass spectrometer (Foster City, CA). Following plasma sample collection and preparation (see above), 8 μL of supernatant was injected onto an Agilent Poroshell 120 EC-C18 column (2.7 μm, 2.1 × 50 mm, Santa Clara, CA). Analyte separation was achieved using a gradient elution method combining water (plus 0.1% formic acid) and acetonitrile (plus 0.1% formic acid) at a flow rate of 0.35 mL/min. The gradient was initiated and held at 1% acetonitrile for 0.5 min, increased to 90% acetonitrile linearly from 0.5 – 1.0 min, held at 90% acetonitrile from 1.0 – 3.0 min, decreased to 1% acetonitrile linearly from 3.0 – 3.1 min, and held at 1% acetonitrile until the end of the run (5.1 min). To minimize and monitor for carryover, injections of blank water were performed between all sample injections.
The MS was operated in a positive multiple reaction monitoring (MRM) mode using turbo electrospray ionization. The source-dependent parameters were set as follows: curtain gas 30 psi, ionspray voltage 5500 V, temperature 500 °C, gas1 50 psi and gas2 50 psi. The analyte-specific MS parameters are summarized in Table 1.

The LC–MS/MS analysis was performed on a Shimadzu HPLC system (Shimadzu, Tokyo, Japan) coupled with an Applied Biosystems API 4000 triple quadrupole/linear ion trap (QTRAP) mass spectrometer (Foster City, CA).
Ten microliters of sample solution were injected into LC-MS/MS. Analytes were separated on a Waters Atlantis T3 C18 column (5um, 150×2.1mm, Dublin, Ireland). The mobile phase consisted of water containing 2 mM ammonium acetate and 0.2% formic acid (v/v) (phase A) and acetonitrile containing 0.2% formic acid (v/v) (phase B), and was delivered at a flow rate of 0.2 ml/min. A gradient elution was applied for the separation with the time program set as follows: phase B was started at 2% for 2 min, then increased to 4% during the time period of 2 to 4 min, further increased to 50% during 4 to 6 min, then returned to 2% at 6.5 min, and maintained until the end of run (9 min).
MS was operated in a positive ion mode using turbo electrospray ionization. As shown in Figure 1, the following transitions were monitored on a positive multiple reaction monitoring (MRM) mode: VACV, 325.2 > 152.1; ACV, 226.2 > 152.1; VACV-d4 (IS), 329.2 > 152.1; ACV-d4 (IS), 230.2 > 152.1. The source-dependent parameters were set as follows: curtain gas 20, ionspray voltage 4800, temperature 500, gas 1 60 and gas 2 60. The analyte-specific MS parameters were summarized in Table 1.