Cto 20ac

For measurements, a Shimadzu high-performance liquid chromatography (HPLC) apparatus (DGU-405, LC-20AB, SIL-20AC HT, CTO-20AC, CBM-20A, Duisburg, Germany) coupled to an API4000 triple quadrupole MS (Sciex, Darmstadt, Germany) was used. The following MS ion source parameters were applied for electrospray ionisation (ESI): ionisation voltage, 2500 V; nebuliser gas, 50 psi; heating gas, 50 psi; curtain gas, 30 psi; temperature, 600 °C; collision gas level, 7. Data acquisition and processing were carried out with Analyst (version 1.6.2, Sciex) and MultiQuant software (version 3.0.1, Sciex). Processed data were further analysed using Microsoft Excel (version 2019, Microsoft) and OriginPro (version 2020, Origin Lab). Chemical structures were drawn with ChemDraw software (version 20.1.1, PerkinElmer) and chromatograms were exported from Analyst software. Figures were labelled with PowerPoint (version 2019, Microsoft).

A Prominence UFLC system from Shimadzu (Duisburg, Germany), consisting of two low-pressure gradient pumps (LC-20 AD), an autosampler (SIL-20ACHT), a column oven (CTO-20 AC), and the controlling module (CMB-20A), coupled to a QTRAP LC-MS/MS 3200 from SCIEX (Framingham, MA, USA) was used. Analysis was performed with the security guard cartridge UHPLC Biphenyl RP-18e (3.0-mm ID columns) pre-column coupled to the analytical column Biphenyl RP-18e 100A 150 × 3.0 mm (2.6 μm), both obtained from Phenomenex (Aschaffenburg, Germany). The flow rate was 0.4 mL/min with solvent A, 0.1% formic acid in water; and solvent B, acetonitrile:methanol 1:1, v/v, with 0.1% formic acid. The isocratic gradient elution was as follows: 0–4.0 min from 0 to 70% B, 4.01–7.0 min 70% B, 7.01 0% B. During the first 1.0 min after sample injection, the eluent was switched to waste to avoid the ionization source from contamination due to aCSF matrix components. The column oven temperature was set to 30 °C. Positive electrospray ionization (ESI) mode was applied combined with multiple reaction monitoring (MRM) detection.
Quantitative analysis was carried out using the Analyst 1.5.1 software (SCIEX, Montreal, Canada).

The LC-MS/MS system consisted of an HPLC apparatus (Shimadzu LC-20AB, SIL-20AC HT, CTO-20AC, CBM-20A, Duisburg, Germany) and an API 4000 triple quadrupole mass spectrometer (Sciex, Darmstadt, Germany). The substance-specific parameters used for multiple-reaction-monitoring (MRM) measurement are listed in Online Resource 2. The following source parameters were applied: ion spray voltage (ESI+), 5500 V; temperature, 550 °C; nebulizer gas, 50 psi; heating gas, 60 psi; curtain gas, 30 psi; and collision gas (nitrogen), level 9. A Synergi™ Polar-RP (150 × 2 mm, 4 μm; Phenomenex, Aschaffenburg, Germany) was used as an analytical column protected by a guard column. The binary linear gradient consisted of eluent A (deionized water containing 5 mmol/L ammonium formate, 0.1% formic acid) and eluent B (LC-MS-grade methanol, 5 mmol/L ammonium formate, 0.1% formic acid) with a flow rate of 0.4 mL/min: 0 min 10% B, 10 min 40% B, and 26 min 100% B. The column was equilibrated at starting conditions for 6 min prior to each run. Analyst (Version 1.6.2) and MultiQuant software (Version 3.0.1), both provided by Sciex (Darmstadt, Germany), were used for data acquisition and processing.