Pl aquagel oh 40 column

The molecular weight distribution of the AG and micelles of Na₂GA was analyzed by gel permeation chromatography on the Agilent 1200 chromatograph with PL aquagel-OH 40 column at +30 °C with a refract- metric detector. The solvent were a 0.1 M aqueous solution of LiNO₃ or NaN₃, and the flow rate was 1 mL/min. The calibration was based on standard dextran with molecular weights of 1, 5, 12, 25, 80, 150, 270, and 410 kDa. The Agilent GPC Date Analysis software was used to process the results.

The ultraviolet–visible (UV–Vis) spectra and Fourier transform infrared (FTIR) spectra of LPs and MLPs were measured by the methods of Han et al. [4 (link)]; periodate oxidation analyses were performed with the method described by Hu et al. [15 (link)]; and atomic force microscope (AFM) images were observed according to our previous method [17 (link)].
The M_w distributions of LPs and MLPs were detected using a HPSEC system mainly composed of a model 510 pump (Waters, Milford, MA, USA), a PL aquagel-OH 40 column (8 μm, 7.5 × 300 mm, Agilent), a multi-angle laser light scattering (MALLS) detector (DAWN HELEOS-II 18, Wyatt Technology Co., Santa Barbara, CA, USA), and a differential refractive index (RI) detector (Optilab rEX, Wyatt Technology Co., Santa Barbara, CA, USA). Ammonium acetate solution (0.2 mol/L) was used as the mobile phase at a flow rate of 0.7 mL/min. Five milligrams of samples were dissolved in 2 mL ammonium acetate solution, followed by filtration through a 0.22 μm filter for injection. The injection volume was 20 μL and the column temperature was 30 °C.
After having been kept in a vacuum drier for a week, samples (30–40 mg) were put into a 5 mm NMR tube and dissolved in 1.0 mL dimethyl sulfoxide (DMSO). A Bruker AM 400 MHz spectrometer (Bruker, Rheinstetten, Germany) was used to record ¹H NMR spectrum with the operating frequency of 400.13 MHz at 30 °C.

The polysaccharide fraction of the extracts was analysed by performing a separation of the different molecules based on size exclusion liquid chromatography. An Agilent 1200 Series instrument equipped with a PL aquagel-OH 40 column (300 × 7.5 mm) with a particle size of 8 µm coupled to a refractive index detector (Agilent 1260 Infinity, Palo Alto, CA, USA) was used (Agilent Technologies, Palo Alto, CA, USA). The experimental conditions for elution are reported in a previous article [37 (link)].
Solutions submitted to analysis were obtained by dissolving the dried extracts in water at a concentration of 600 ppm. All solutions were then centrifuged and purified to remove possible interfering substances, such as polyphenols, by elution through a Dionex OnGuard II P cartridge. Prior to analysis, samples were filtered with nylon filters (0.2 micron). All analyses were performed in triplicate, by injecting a volume of 100 microliters.
Solutions of standard dextrans and of a molecular weight of 150, 50, and 12 kDa were used as references for building a calibration curve aimed at the determination of the molecular weight of the separated carbohydrates’ fractions.