Micromass q tof mass spectrometer

Chemical reactions were performed in over-dried glassware under nitrogen and anhydrous conditions, unless otherwise stated. Reactions were magnetically stirred using a Teflon-coated stir bar and monitored by pre-coated silica gel aluminum plates (0.25 mm thickness) with a fluorescent indicator (254 nm), using UV light as the visualizing agent. Alternatively, oxidative staining using an aqueous basic solution of KMnO₄ and heat was carried out for visualization. Silica gel (60 Å, 200–425 mesh) was used for flash column chromatography. Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker 400 MHz spectrometer (Bruker, Billerica, MA, USA) in acetone-d₆, CDCl₃, or DMSO-d₆ as the solvent. Chemical shifts are reported in parts per million (ppm) with reference to the hydrogenated residues of the deuterated solvent as the internal standard. Coupling constants (J values) are recorded in Hertz (Hz), and signal patterns are expressed as follows: singlet (s), doublet (d), dd (doublet of doublets), triplet (t), quintet (quint), and multiplet (m). Elemental analyses were performed on a 2400 Perkin Elmer Series II analyzer (PerkinElmer, Inc., Waltham, MA, USA). High-resolution mass spectrometry was conducted using a Micromass Q-ToF mass spectrometer (Waters Corporation, Milford, MA, USA).

Q-TOF MS/MS was performed with Micromass Q-TOF mass spectrometer (Waters Corp., Manchester, UK) using an electrospray ionization (ESI) interface. The MS data were collected in Centroid mode both in positive and negative ion mode. The analytical parameters of Q-TOF mass spectrometry were as follows: capillary voltage 3.0 kV (ESI⁺)/2.8 kV (ESI⁻); cone voltage 35 V; extraction cone voltage 3 V; ion source temperature 125 °C; desolvation gas temperature 320 °C; desolvation gas (N₂) flow rate, 700 L/h; cone gas (nitrogen) flow, 50 L/h; collision gas, argon; MCP detector voltage, 2350 V; collision energy, 6 V; scanning time, 0.4 s; and scanning time interval, 0.1 s. To ensure the accuracy and repeatability of the mass-to-charge ratio, a concentration of 200 pg/mL leucine-cerebral peptide solution (Waters) was used as the Lock-Spray calibration solution, and the exact mass-to-charge ratios in positive and negative ion modes were [M + H]⁺ = 556.2771 and [M + H]⁻ = 554.2615, respectively. The lock spray frequency was set at 10 s, and the lock mass data were averaged over 10 scans for correction. The data acquisition range was m/z 50–1000, and the acquisition time was 0–16 min.

NMR spectra were obtained using a Varian Unity Plus VXR (Varian Inc., Walnut Creek, CA, USA), 500 MHz instrument in CDCl₃ solutions. The chemical shifts were reported in units of d (ppm) downfield from tetramethylsilane, which was used as an internal standard; coupling constants (J) are reported in hertz and refer to apparent peak multiplicities. High-resolution mass spectra (HRMS) were recorded on a MICROMASS Q-TOF mass spectrometer (Waters, Milford, MA, USA).

Silibinin was identified in mice blood plasma using Liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI-MS). The High Pressure Liquid Chromatography (HPLC) separation was performed at 25°C using a Waters^® reversed phase C18 column (100 mm × 2.1 mm dimension; 5 μm particle size). ESI-MS was carried out using Waters^® micromass^® Q-TOF Mass Spectrometer at Regional Sophisticated Instrumentation Centre (RSIC), Panjab University, Chandigarh, India. For HPLC, the mobile phase consisted of acetonitrile and 10 mM ammonium acetate (pH 5.45) in the ratio of 50:50 (v/v). The detection of Silibinin was carried out at 288 nm and the flow rate was 100 μl/min with a total run time of 10 minutes. Mass spectrometric (MS) analysis was performed in negative ion mode under the following conditions: capillary voltage 2960 V, sample cone voltage 30 V, extraction cone voltage 1.0 V and desolvation temperature 350°C. The mass spectra were recorded in the m/z range of 100–700.