Uvd170u detector

All chemicals were purchased from Sigma-Aldrich, Acros Chemicals, Fluorochem or Alfa Aesar and used without further purification unless otherwise stated. Anhydrous acetonitrile was obtained from a MBraun SPS800 solvent purification system unless otherwise stated. Flash column chromatography was performed using Biotage Flash Purification system. ¹H NMR and ¹³C NMR spectra were measured on a Bruker Avance 500 NMR spectrometer and Bruker Avance DPX400 spectrometer. ¹H NMR and ¹³C NMR spectra are reported as chemical shifts in ppm downfield from TMS and J values are given in Hertz. ³¹P NMR spectra were recorded on Bruker Avance DPX400 spectrometer or Bruker Avance 500 NMR spectrometer and are reported in chemical shifts downfield from 85% H₃PO₄. Reverse phase HPLC was performed on a system comprising of a Dionex P680 pump and a Dionex UVD170U detector unit.

¹D-and ²D-NMR experiments were recorded on Bruker AVANCE IIITM 600 MHz or Bruker AVIII 500 MHz spectrometers (Bruker, Bremen, Germany). Chemical shifts were referenced to the solvent residual peaks. The HRESIMS were acquired using an API Qstar Pulsar mass spectrometer (Bruker, Bremen, Germany). Optical rotations were recorded on an MCP 5100 polorimeter (Anton Paar, Graz, Austria). IR spectra were measured on a Nicolet 380 FT-IR spectrometer (Thermo, Pittsburgh, PA, America). HPLC analysis was performed on Agilent Technologies 1260 Infinity II (Agilent, Palo Alto, CA, USA) with a reversed-phased column (YMC-packed C18, 5 μm, 250 mm × 10 mm) using a Dionex P680 pump and detected with a Dionex UVD 170 U detector (λ = 254 nm). Silica gel (60–80, 200–300 mesh, Qingdao Marine Chemical Co. Ltd., Qingdao, China), ODS gel (20–45 μm, Fujian Silysia Chemical Co. Ltd., Fuzhou, China) and Sephadex LH-20 (40–70 μm, Merck, Darmstadt, Germany) were used for column chromatography. TLC was carried out on Silica gel G precoated plates (Qingdao Haiyang Chemical Co. Ltd., Qingdao, China), and the peaks on TLC were detected by a UV lamp at 254 nm and then sprayed with 5% H₂SO₄ in EtOH. The methanol used for HPLC analysis was of chromatographic grade (Concord Technology Co. Ltd., Tianjin, China). Tacrine hydrochloride hydrate (99%) and paclitaxel (99%) were purchased from Sigma Chemical.

The mixture of oligosaccharide alditols released from each sample was subjected to fractionation by HPLC (Dionex Chromeleon System, Sunnyvale, CA, USA) on a primary amino-bonded silica column (Supelcosyl, LC-NH₂, 4.6 × 250 mm, Supelco, Bellefonte, CA, USA). The column was equilibrated with the initial solvent using a mixture of acetonitrile/H₂O (80:20, v/v) with a flow rate of 1 ml/min. After the injection, a linear gradient to 40:60, v/v for 80 min was applied followed by isocratic conditions for 20 min. Oligosaccharides were eluted with H₂O. Oligosaccharides were detected by UV spectroscopy at 200 nm using an UVD 170 U detector (Dionex, Sunnyvale, CA, USA).