1290 infinity hplc apparatus

The phenolic acid content was determined by HPLC. The dry extracts were dissolved in 2 mL of methanol/water solution (4:1, v/v). The analysis itself was performed on Agilent Technologies 1290 Infinity HPLC apparatus (Santa Clara, CA, USA) with diode array detection (DAD) and an Eclipse XDB-C18 column (4.6 × 150 mm, 5 μm). The temperature was maintained at 35 °C, with a flow rate of 1.6 mL/min and an injection volume of 10 μL. The mobile phase consisted of acetonitrile as solvent A and water with 0.1% formic acid as solvent B. The elution profile was as follows: 0–5 min, 10% A and 90% B; 5–20 min, 18% A and 82% B; 20–25 min, 38% A and 62% B; 25–30 min, 100% A (isocratic elution). Compounds were detected at λ = 325 nm.
Authentic standards of caffeic acid (CA), rosmarinic acid (RA), and salvianolic acid B (SAB) (ChemFaces, Wuhan, China) were used for calibration. The following regression equations were obtained: for CA, y = 30.3230x − 20.3788 (R² = 0.9639); for RA, y = 12.1228x + 1281.4666 (R² = 0.9813); for SAB, y = 3.5352x − 3.3512 (R² = 0.9957). For the phenolic acids lacking a standard, quantification was based on the calibration curve of a similar compound: SAB for PLS, SAE, SAF I, and SAF II. The amounts of the analyzed compounds were expressed as mg/g DW.

For HPLC analysis, the samples (DM1–DM4) were dissolved in 10 mL of 80% (v/v) aqueous methanol and filtered through a PTFE syringe filter (25 mm, 0.22 µm). The phenolic acid contents were evaluated using an Agilent Technologies 1290 Infinity HPLC apparatus (Santa Clara, CA, USA) with a diode array detection (DAD) and Eclipse XDB-C₁₈ column (150 × 4.6 mm, 5 µm). The mobile phase (A) was acetonitrile, and the mobile phase (B) was 0.1% formic acid in water. The solvent system used for elution was: 0–5 min, 10% A and 90%; 5–20 min, 18% A and 82% B; 20–25 min, 38% A and 62% B; 25–30 min, 100% A. The flow rate was 1.6 mL/min, at a temperature of 35 °C. The detection wavelength was set at 325 nm. Individual calibration curves for the reference standards CA, RA and SAB (Sigma-Aldrich, Darmstadt, Germany) were constructed. The following regression equations were formulated based on the peak areas: CA y =23.75389x − 20.3788 (r² = 0.9639), RA y = 12.1228x + 1281.4666 (r² = 0.98129) and SAB y = 3.5352x − 20.3788 (r² = 0.99571). The amount of the compound in the plant material was expressed as mg/g DWE.

For HPLC analysis, the samples (DM1–DM4) were dissolved in 10 mL of 80% (v/v) aqueous methanol and filtered through a PTFE syringe filter (25 mm, 0.22 µm). The phenolic acid contents were evaluated using an Agilent Technologies 1290 Infinity HPLC apparatus (Santa Clara, CA, USA) with a diode array detection (DAD) and Eclipse XDB-C₁₈ column (150 × 4.6 mm, 5 µm). The mobile phase (A) was acetonitrile, and the mobile phase (B) was 0.1% formic acid in water. The solvent system used for elution was: 0–5 min, 10% A and 90%; 5–20 min, 18% A and 82% B; 20–25 min, 38% A and 62% B; 25–30 min, 100% A. The flow rate was 1.6 mL/min, at a temperature of 35 °C. The detection wavelength was set at 325 nm. Individual calibration curves for the reference standards CA, RA and SAB (Sigma-Aldrich, Darmstadt, Germany) were constructed. The following regression equations were formulated based on the peak areas: CA y =23.75389x − 20.3788 (r² = 0.9639), RA y = 12.1228x + 1281.4666 (r² = 0.98129) and SAB y = 3.5352x − 20.3788 (r² = 0.99571). The amount of the compound in the plant material was expressed as mg/g DWE.