G1315c dad detector

Qualitative analysis of KD was carried out by an Agilent 1260 high performance liquid chromatography with a G1315C DAD detector, a G1311B pump, a G1313A automatic sampler and a G1316A thermostatic column compartment (Agilent, California, United States). The working conditions were optimized and established as follows: column: ZORBAX SB-C18 (4.6 × 250 mm, 5 μm); mobile phase: water (A) and acetonitrile (B), a gradient mode (0–8 min, 95% A; 8–19 min, 95% A → 60% A; 19–25 min, 60% A → 24% A; 25–36 min, 24% A → 21% A); detection: UV, 220 nm; flow-rate: 0.8 ml/min. 0.3 g KD powder was dissolved in 25 ml of 10% acetonitrile (Merck, Germany) and was filtered with a 0.45 μm filter for high performance liquid chromatography analysis.

Samples were analyzed with an Agilent 1200 system with a reversed phase column Phenomenex Gemini NX C-18 (2 × 150 mm, 5 µm, 110 Å). Injection volume of samples was 20 µL. The flow rate was 0.3 mL/min with a binary gradient of A from 15% (ACN + 0.1% FA) to 95% in the time interval 2–31 min (Solvent B: MQ-H₂O + 0.1% FA). Rasfonin was detected with an Agilent G1315C DAD detector at 280 nm. Elution time of rasfonin was at around 21.1 min. For reference measurement and sample spiking, a 25 µg/mL rasfonin standard produced by our laboratory (see above) was used.