Is there enyone who can help me with the separation of Streptomycine and DiHydroStreptomycine, because we have a limit of maximum 1% (w/w) Streptomycine in DHS, we can't find an accurate, reproducable method (%RSD lower than 2) because the area of the streptomycine peak is to small, the resolution is also poor, sometimes we have no separation because the DHS is to concentrated.
Every tip is welcome, every usefull tip is even better.

Have you tried LC/MS. The differences in mol. wt. would give you the selectivity and sensitivity that you would need.

Hello BJ,
LCMS is good, a good separation is more helpful. To get more resolution you can use a longer column or smaller particle size. To get sharp peaks you can run at higher flow rates at higher temperatures, and/or use smaller particle sizes. For higher mass sensitivity you should use a 2mmID or 1mmID column, but than you should optimize your HPLC instrument. With small ID capillaries and a small flow cell volume you can handle these 2mmID and 1mmID columns. With some optimization you should get sharp peaks and a much better resolution.
Good luck.
Gerhard