extracts

[oj]

Hello,
I would like to determine flavonoide and ginsenoside in combination of two plants extracts by HPLC. The method must be selective for both extracts.

We have analysis method for each extract but not for combination of both.

1.)Analys method for first extract: column:Supelcosil LC-ABZ,250 mmx 4,6mm, 5um particles; mobile phase:gradient ;A=acetonitrile, B= water (0min=18%A;60min=42%A;61min=18%A;65min=18%A;)
UV, wavelength 200 nm.
Sample solution: dissolve sample in 80% methanol and water and heat in a water bath at 100°C for 8 hours.

2.)Analys method for second extract:
column:Kromasil 100 C18,250 mmx 4,6mm, 5um particles; mobile phase:gradient A=methanol, B= dilut phosphoric (V) acid (0min=30%A;50min=60%A);
UV, wavelength 370 nm.
Sample solution: dissolve sample in 80% methanol ,add hydrochloric acid and heat in a water bath at 85°C for 1 hours.

When we analyse the sample with both extracts with first method, the method is not selectiviti for second extract. The second extract has very good response on all wavelength from 200-370nm. The first extract has only at 200 nm good response.

Has anybody any idea how to determine combination of both extracts?
bye

[Rafael Chust]

Both methods seems quite alike, with the difference of wavelenght, which means both components are eluting at the same time.

Try to use method 2 at 200 nm with each extract and then a mix of two and give us your feedback.