Unity 500 mhz spectrometer

The chemical structure of the HACA and the degree of substitution of the CA were assessed by using ¹H-NMR (Varian Unity 500MHz spectrometer, Palo Alto, CA, USA), in which CD₃OD and D₂O were used as the solvent. The hydrodynamic size and zeta potential of the HANPs and MPN-HANPs were observed by dynamic light scattering (DLS) using a Zetasizer Nano ZS90 (Malvern Ins. Worcestershire, UK) with a He-Ne 633nm laser at a 90° detection angle. The morphologies of the HANPs and MPN-HANPs were characterized by using HR-TEM (JEOL-2100F, Tokyo, Japan) operated at an accelerating voltage of 200 kV. For TEM images, the samples were dispersed in deionized water (DIW) and dropped onto a 300-mesh copper grid. The nanoparticles were then treated with 1% uranyl acetate for negative staining. The UV-visible (UV-Vis) absorption spectra were measured on a UV-vis spectrophotometer (Optizen 3220UV, Mecasys Co., Ltd., Daejeon, Korea). To investigate the stability of the nanoparticles, the changes in the scattering intensity of the HANPs and MPN-HANPs were assessed in the presence of sodium dodecyl sulfate (SDS) as a typical micelle-destabilizing agent. Briefly, the HANP and MPN-HANPs (1 mg/mL in DIW) were incubated with or without SDS (2.5 mg/mL). The resulting solutions were kept at room temperature and the scattering intensity of each solution was recorded using DLS as a function of time.

1D (¹H and ¹³C) and 2D (COSY, ROESY, HSQC, and HMBC) NMR spectra were acquired on a Varian Unity 500 MHz spectrometer (Varian Inc., Palo Alto, CA, USA). UV spectra were obtained on a Shimadzu UV-1650PC spectrophotometer (Shimadzu Corporation, Kyoto, Japan). IR spectra were recorded on a JASCO FT/IR-4100 spectrophotometer (JASCO Corporation, Tokyo, Japan). Optical rotations were measured on a Autopol III polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). High-resolution ESIMS was recorded on a hybrid ion-trap time-of-flight mass spectrometer (SYNAPT G2, Wasters Corporation, Milford, CT, USA). HPLC was performed on a PrimeLine pump (Analytical Scientific Instrument, Inc., El Sobrante, CA, USA) with RI-101 (Shodex, Munich, Germany). Semi-preparative HPLC was performed using an ODS column (YMC-Pack-ODS-A, 250 × 10 mm i.d, 5 µm) (YMC Corporation, Kyoto, Japan). Analytical HPLC was conducted on an ODS column (YMC-Pack-ODS-A, 250 × 4.6 mm i.d, 5 µm) (YMC Corporation, Kyoto, Japan).