Esquire lc quadrupole ion trap mass spectrometer

HPLC analysis was conducted on an Agilent 1290 Series HPLC System (Agilent, USA), and the mobile phases were as follows: 0.1% formic acid in ultrapure water as A, and chromatographically pure methanol as B. Elution conditions were as follows: 0–8 min, 50% B; 8–12 min, 50–98% B; 12–20 min, 98% B. The flow rate was 1 ml/min, column temperature was 30°C, and detection wavelengths were 270, 300, 330, and 360 nm.
LC–MS/MS spectra were determined in a Bruker Esquire-LC quadrupole ion trap mass spectrometer (Germany). HPLC conditions were the same as mentioned above with detection wavelength at 270 nm. The ESI source operated in both positive and negative modes; capillary voltage was set at 4500 V; end plate offset voltage was set at 500 V; nebulizer pressure was 20.0 psi; drying gas temperature was 200°C; drying gas (N₂) flow rate was 4.0 l/min; and the collision gas was ultrapure N₂. Samples were introduced into the electrospray source at a flow rate of 4 μl/min. Targeted MS/MS mode (m/z 250 ± 200) was used to analyze the top two ions. The scan rate was three spectra per second in the range of m/z 100–1000 for MS and m/z 100–1000 for MS/MS.

LC-ESI-IT-MS analysis of the olive oils was performed on a Hewlett-Packard Model 1100 Series liquid chromatograph coupled both to an Agilent 1100 Series DAD (Photo Diode-Array Detector) (Hewlett–Packard Development Company, L.P., Palo Alto, CA, USA), and to a Bruker Esquire-LC quadrupole ion-trap mass spectrometer equipped with atmospheric pressure ESI+ interface (ESI-IT-MS). Isocratic elution was applied with a flow of 0.3 mL/min by using a Kinetex C₁₈ column (2.6 μm 100A 100 × 2.1 mm) (Phenomenex, Sydney, Australia) as stationary phase, and isopropanol:methanol 10/90 (v/v), 10 mM in ammonium acetate, as mobile phase. Samples were prepared by diluting 1:200 (5 mM) each EVOO with a solution of MeOH:CHCl₃ 8/2 (v/v), and 4 μL were injected. Relative quantitation of TAG species was established by peak area integration of the MS extracted ion currents of the corresponding major ions produced by ESI ionization by assuming the same response time for all the TAGs species.