Solarix 9.4t

Reactions were monitored by TLC using silica gel-coated aluminum sheets (Qingdao Haiyang Chemical Co., Qingdao, China) and visualized in UV light (254 nm). ¹H-NMR and ¹³C-NMR assays were recorded on a Bruker AVANCE 500 NMR spectrometer (Fällanden, Switzerland), and chemical shifts are reported in form of δ (ppm). Deuterated chloroform, deuterated methanol, or deuterated DMSO served as the solvent (Beijing InnoChem Science and Technology Co., Ltd., Beijing, China). HR-MS spectra were performed on high-resolution ESI mass spectrum (Solarix 9.4T, Bruker, Germany). Melting points were measured at a rate of 5 °C/min using an X-5 micro melting point apparatus (Beijing Tech Instrument Co., Ltd., Beijing, China). The specific rotation of the synthesized compounds was measured using P-1020 polarimeter (Jasco, Tokyo, Japan). Cellular morphologies were observed using an inverted fluorescence microscope (Olympus IX71, Tokyo, Japan). Mechanisms of apoptosis were detected by flow cytometry (BD FACSCanto II, San Jose, CA, USA). Silica-gel column chromatography was performed using 200–300 mesh silica gel. The yields were calculated based on the last step reaction. All solvents and chemicals used were analytical or high-performance liquid chromatography grade. The abilities of ALT and AST in serum were measured with assay kit (Nanjing Jiancheng Biotechnology Co., Ltd., Nanjing, China).

The MALDI‐MS imaging method followed Yang W's description
²⁴ (link) with some modifications. The brain tissues of rats were isolated 1 h after treatment and frozen in liquid nitrogen immediately, then embedded in 2% CMC‐Na and frozen overnight at −80°C. Striatum sections (20 μm) were prepared by the cryostat microtome (Leica CM1950), then transferred onto conductive ITO glass slides (Bruker) and stored at −80°C until analysis. 2,4,6‐Trimethylpyrylium tetrafluoroborate (TMP‐TFB, Aladdin) was used as the derivatization reagent (7.6 mg/mL in methanol buffered with 3.5 μL of trimethylamine), and α‐cyano‐4‐hydroxycinnamic acid (CHCA, Aladdin; 10 mg/mL, prepared in 70% methanol solution containing 0.1% trifluoroacetic acid) was used as the MALDI matrix. MALDI‐MS imaging experiments were performed on the MALDI‐FT‐ICR mass spectrometer (Solarix 9.4 T, Bruker) in positive‐ion mode. Set the pixel size of the imaging resolution at 80 nm to obtain the optimal acquisition performance. MS imaging data were visualized using Fleximaging (Bruker). After the data were normalized by the total ion current, the DA mass spectrum peak (m/z 258.1502 ± 0.002) was determined. The colored spots in the image represent the location of the neurotransmitter, and the color of each spot is related to the signal intensity detected by the laser at each pixel.

A Bruker rapifleX MALDI Tissuetyper time-of-flight mass spectrometer (Bruker Daltonik, Bremen, Germany) was used. Images were generated with a 50 × 50 μm pixel size. The measurements were performed using reflectron mode with 200 shots per pixel at a laser frequency of 10 kHz. MSI data was acquired with a mass range of m/z 100–1000 for lipids in both positive and negative ion mode and m/z 40–1000 for metabolites in negative ion mode.
As the rapifleX offers high speed data acquisition but lacks sufficiently high mass resolution required to differentiate between specific amino acid masses, the measurements were complemented with matrix assisted laser desorption/ionization-Fourier transform-ion cyclotron resonance mass spectrometry imaging (MALDI-FTICR-MSI) (solariX 9.4 T, Bruker Daltonics, Bremen, Germany). High mass resolution data was acquired in a mass range of m/z 100–600 in positive ion mode with a 75 µm spatial raster width, 250 shots per pixel, and a laser frequency of 2 kHz. Pre-defined matrix peaks were selected as reference for online lock mass calibration.

The liquid products from the reaction of MB over [BMMIm]Br-Pd/C under the N₂ atmosphere were dissolved in methanol and analyzed by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS, Bruker FT-ICR-MS (Solarix 9.4T)). The ionization method and mode of detection employed were indicated for the corresponding experiment, and all masses were reported in atomic units per elementary charge (m/z) with an intensity normalized to the most intense peak.