Lc 2000plus series system

Preparative HPLC was conducted with a Jasco LC-2000 Plus Series system equipped with two PU 2,087 Plus pumps (flow up to 50 ml min⁻¹) and a diode array detector (MD-2010 Plus 195–650 nm). The purification of the compounds was performed in reverse phase mode with a 218TP Vydac C18 column (22 × 250 mm, Grace Davison Discovery Science).

¹H NMR spectra were measured using a JEOL JNM-ECX400 apparatus. The Fourier transform infrared spectrometry (FT-IR) spectra were measured using a Shimadzu IRAffinity-1S spectrometer. Size-exclusion chromatography (SEC) was performed using a JASCO LC-2000 Plus series system equipped with a PU-2080 Plus Intelligent HPLC pump, a RI-2031 Plus Intelligent RI detector, a CO-2065 Plus Intelligent column oven, an AS-2055 Plus Intelligent Sampler, and two linearly connected commercial column (TSKgel Super3000 and GMHXL, Tosoh Corporation) using THF as an eluent at 40 °C at a flow rate of 0.1 mL min⁻¹. The molecular weight calibration curve was calculated using polystyrene standard (Shodex). Differential Scanning Calorimetry (DSC) was performed using Hitachi DSC6200 at a rate of 2 °C min⁻¹ for polymer aqueous solution (1/1, w/w). UV-vis transmittance curves for polymer aqueous solution was obtained on UV-2600 (Shimadzu) system at 500 nm with heating and cooling from 10 to 80 °C at a rate of 1 °C min⁻¹. The cloud point temperature (T_cp) was defined as temperature at 50% UV-vis transmittance. Dynamic light scattering (DLS) measurements were performed on a Malvern ZEN 3600 Zetasizer Nano ZS equipped with a monochromatic coherent He–Ne laser with a fixed wavelength of 633 nm and 20 °C.

A Jasco^® LC-2000Plus Series System (Gross-Umstadt, Germany) was used for the HPLC-DAD analyses. LC-MS measurements were performed on an Agilent 1100 Series System, equipped with a binary high-pressure mixing pump, with a degasser module, an autosampler, an 1100 series photodiode array (PDA) detector (Agilent Technology, Germany), and an Esquire 3000 Plus ion-trap mass spectrometer with an electrospray ionization interface (Bruker Daltonics, Bremen, Germany). A Bruker Daltonics microTOF spectrometer focus was used for the high-resolution electrospray mass spectrometry. NMR analyses were acquired on AMX 400 and DMX 600 Bruker spectrometers. The offline ECD and ORD spectra were obtained on a Jasco J-715 spectropolarimeter. The data were evaluated using SpecDis_164^{17 (link)}. A Shimadzu UV-1800 spectrophotometer was used to perform in triplicate offline UV measurements. The Jasco P-1020-polarimeter operating with a sodium light source (λ = 589 nm) was used for the measurement of the optical rotation. The mechanical shaker operating at the frequency of 160 RPM (rotation per minutes) was from Bottmingen (Switzerland).