Qualitative and quantitative analysis of an alkaloid fraction from Piper longum L. using ultra-high performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry

- Comprehensive qualitative and quantitative analysis of an alkaloid fraction purified from Piper longum L.
- 18 standard compounds and 25 minor amide alkaloids were identified.
- A method based on relative response factor was used for quantitative analysis.
- The quality of alkaloid fraction was efficiently improved after appropriate purification.