Polar c18 security guard cartridge

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.

The phenolic fraction of the extracts was characterized by resorting to an HPLC Agilent 1100 Series with a G1315B diode array detector. A Luna Omega Polar C₁₈ analytical column of 150 × 3.0 mm and 5 µm particle size (Phenomenex), with a Polar C₁₈ Security Guard cartridge (Phenomenex) of 4 × 3.0 mm, was used. The HPLC system was connected to an ion trap mass spectrometer (Esquire 6000, Bruker Daltonics) equipped with an electrospray interface operating in negative mode. Detailed conditions are reported elsewhere [46 (link)]. Compounds identification was carried out based on analytical standards and mass spectra, whereasultra violet (UV) spectra were used for quantification purposes.