Luna omega polar c18 analytical column

Chromatographic analyses were performed with an Agilent Series 1100 HPLC system with a G1315B diode array detector (Agilent Technologies, Santa Clara, CA, USA) and an ion trap mass spectrometer (Esquire 6000, Bruker Daltonics, Madrid, Spain) with an electrospray interface operating in negative ion mode. Separation was performed in a Luna Omega Polar C₁₈ analytical column (150 × 3.0 mm; 5 µm particle size, Phenomenex, Madrid, Spain) with a Polar C₁₈ Security Guard cartridge (4 × 3.0 mm), both purchased from Phenomenex. Detailed chromatographic conditions are available in [96 ].

Chromatographic analyses were performed with an Agilent Series 1100 HPLC system with a G1315B diode array detector (Agilent Technologies) and an ion trap mass spectrometer (Esquire 6000, Bruker Daltonics) with an electrospray interface operating in negative ion mode. Separation was performed in a Luna Omega Polar C₁₈ analytical column (150 × 3.0 mm; 5 µm particle size) with a Polar C₁₈ Security Guard cartridge (4 × 3.0 mm), both purchased from Phenomenex. Detailed chromatographic conditions are available in [39 (link)].
The most abundant compounds (flavonoids) were quantified by UV signal at 350 nm and the following analytical standards: vicenin-2, kaempferol, luteolin, and quercetin. Calibration graphs were constructed in the 0.5–100 mg L⁻¹ range. Peak areas at 350 nm were plotted against analyte concentration. Each analytical standard was used to quantify the corresponding compound or compounds of the same chemical family. Detection limits (3σ criterion) were 0.1–0.2 mg L⁻¹. Repeatability (n = 10) and intermediate precision (n = 9, three consecutive days) were lower than 4 and 8%, respectively. The robustness of the chromatographic method was evaluated by recording analyte signals at ±2 nm of the optimum wavelength and by slightly varying the percentage of the mobile phase (2% changes), observing variations lower than 5% for all the analytes concerning the optimum conditions.

SMS was provided by Kangmei Pharmaceutical Co., Ltd. after adequate quality measurement. All the herbs were taken from the same batch. Decoctions were made at Guang’ anmen Hospital, China Academy of Chinese Medical Sciences, according to standard operating procedures. The major compounds in SMS were identified using high-performance liquid chromatography (HPLC; Waters 2695 HPLC system; Waters, CA, USA). A Luna® Omega Polar C18 analytical column (250 × 4.6 mm, 3.0 μm; Phenomenex, CA, USA) with a mobile phase that contained acetonitrile (A) and − 0.2% phosphoric acid acid in water (B) was used. The mobile phase gradient elution was programmed as follows: The mobile phase gradient elution was programmed as follows: 27% A (0–10 min), 27–38% A (10–12 min), 38% A (12–20 min), and 38–90% A (20–60 min); 73% B (0–10 min), 73–62% B (10–12 min), 62% B (12–20 min), and 62–10% B (20–60 min). The column temperature was maintained at 35 ∘C, the flow rate was set at 0.5 mL/min, and a detection wavelength of 203 nm was used. SMS was dissolved in double distilled water containing 0.05% dimethylsulfoxide (DMSO). The solution was centrifuged, filtered and disinfected using a syringe filter (specification: 13 mm nylon filter, 0.45 μm,100 pcs/pack), and preserved at − 20 ∘C for further experimentation [21 ].