Pack pro c18 column

The HPLC analysis was performed to determine the levels of oleanolic acid in D. moldavica with a Perkin Elmer Flexar QUATERNARY Pump (PerkinElmer, Inc., Shelton, CT, USA) and a PDA LC detector (PerkinElmer, Inc., Shelton, CT, USA). The samples were separated by a YMC Pack-Pro C18 column (25 cm × 4.6 mm) in gradient elution mode. Two mobile phases were obtained that comprised 0.2% acetic acid in H₂O (A) and acetonitrile (B); the overall flow rate was 0.8 mL/min. The column temperature was 30 °C and the injection volume was 5 μL. The gradient conditions of oleanolic acid were 10% (A) and 90% (B) for 0–45 min. The test solution (D. moldavica) was weighed (60 mg) and dissolved at 20 mg/mL in MeOH. Then, the solution was sonicated for 30 min and filtered using a 0.45 μm PVDF membrane filter. Similarly, the standard solution (oleanolic acid) was weighed (1 mg) and dissolved at a concentration of 1 mg/mL in MeOH. The standard solution was sonicated and filtered under the same conditions as the test solution. The analysis of oleanolic acid in DMEE was detected at a 210 nm wavelength. The oleanolic acid composites were calculated by applying the following calibration curve equation: oleanolic acid, y = 2567.7x + 23708, R² = 1. The average level of oleanolic acid in D. moldavica was approximately 4.32 ± 0.02 mg/g (Figure 1).

Folates in tissue samples and erythrocytes were determined by means of LC-MS/MS (Finnigan Surveyor Plus high performance liquid chromatography (HPLC) System, Thermo Electron Corporation, Waltham, MA, USA; triple quadrupole TSQ quantum discovery mass spectrometer, Thermo Electron Corporation, Waltham, MA, USA). The vitamers were separated on a YMC Pack Pro C₁₈ column (150 × 3 mm, 3 µm, YMC, Kyoto, Japan). The mobile phase for gradient elution consisted of 0.1% (v/v) aqueous formic acid (eluent A) and acetonitrile containing 0.1% (v/v) formic acid (eluent B) at a flow rate of 0.3 mL/min.
The system for Hcy, AdoMet, and AdoHcy measurement consisted of a Shimadzu Prominence LC-20A System (Shimadzu, Kyoto, Japan) and an API 4000 Q-Trap mass spectrometer (AB Sciex, Foster City, CA, USA). Analyte separation was carried out on a Phenomenex Gemini reversed phase column (110A 3u, 150 × 4.60 mm, Phenomenex, Aschaffenburg, Germany). The mobile phase for gradient elution consisted of 0.1% (v/v) aqueous formic acid (eluent A) and acetonitrile containing 0.1% (v/v) formic acid (eluent B) at a flow of 0.4 mL/min.
Gradients and source parameters of the LC-MS instrument for tissue, plasma samples [19 (link)], and erythrocytes [29 (link)] have been published earlier.

The quantitative analysis of the four P. japonicum samples was carried out by slightly modifying a previously reported method [57 ]. A YMC Pack-Pro C18 column (250 mm × 4.6 mm, 5 μm) maintained at a column temperature of 30 ℃ was equipped in the HPLC system. The method utilized a gradient elution with a mobile phase comprised of 0.1% TFA in water (A) and ACN (B). The gradient elution conditions were as follows: 90% A from 0 min to 10 min, 70% A at 30 min, 50% A at 40 min, and 0% A from 45 min to 55 min. The mobile phase flow rate was set to 1 mL/min, with an injection volume of 10 μL. Lastly, the detector wavelength was set at 330 nm.