6120 quadrupole mass spectrometer

The UHPLC-DAD-MS data were obtained from an Agilent 1290 Infinity series UHPLC with a diode array detector and an Agilent 6120 quadrupole mass spectrometer. The mass spectrometer contained a dual APCI and ESI interface. The LC Column was a Waters Acquity UPLC BEH C₁₈ column (2.1 × 100 mm, 1.7 µm). The column temperature was 30 °C. The flow rate was 0.3 mL/minute. The mobile phase eluent consisted of acetonitrile and water both containing 0.05% formic acid. The gradient was 5% acetonitrile programmed to 80% acetonitrile in 15 minutes, and then 100% in 20 minutes. Ionization and detection of compounds were carried out on the mass spectrometer using the ESI positive mode over the mass range of m/z 100–1000. The fragmentor and capillary voltages were 120 V and 4000 V, respectively. The drying gas flow rate was 10.0 L/minute, the nebulizer pressure was 30 psi, and the drying gas temperature was 300 °C. The DAD was set to monitor 254 nm, 280 nm, and 325 nm.

LC-MS analyses were performed on an Agilent 1100 LC system with DAD
detector and 6120 quadrupole mass spectrometer, using an Eclipse Plus C18 column
(4.6 mm × 50 mm, 5 μm) for separation. The mobile phase was
acetonitrile:water 5 : 95% (v/v) containing 0.2% formic acid (A) and
acetonitrile:water 95 : 5 (v/v) containing 0.2% formic acid (B) with the
following gradient elution program: 5% B from 0–3 min, 75% B from
3–12 min, and 5% B at 12.01 min, with a total runtime of 15 min. The
mobile phase flow rate was 0.4 mL/min with injection volume of 15 μl. ESI
MS scans with capillary voltage of 4000V, nebulizer pressure at 45psig and gas
flow at 12 L/min were analyzed using ChemStation software (Agilent). The ApoE
peptide+ApoER2 LA1–2 peptide 4-ONE crosslink experiment was characterized
on a Triple TOF^™5600 + system with
Duo-Spray^™ion source (Sciex, Framingham, MA) in positive
(ESI) mode with the following settings: ion spray voltage, 5500 V; turbo spray
temperature, 550°C; declustering potential 60 V; collision energy 10 eV;
gas 1, gas 2, and curtain gas were 60, 60, and 20 psi, respectively. The sample,
dissolved in 10 mM ammonium acetate was directly infused using the on-board
syringe pump at a flow rate of 10 μL/min. MS scans were collected across
various mass ranges between m/z=500 to 3800 and analyzed with
Sciex OS and Analyst software (Sciex).