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- Posts: 15
- Joined: Wed Jul 09, 2014 6:27 pm
I’m not sure if this belongs in this section or even on this forum, but here goes!
I’m looking for some general lab technique tips on recovering the most possible mass from my fractions collected by preparative HPLC.
The solvent I’m collecting is 95:5 ethanol:water. Sample has low solubility in ethanol and is practically insoluble in water. Right now, I pool about 40mL of collected solution in 50mL plastic (PP) conical vials. I dry most of the solvent away under nitrogen blow. Next I wash with ~10mL ice cold water, centrifuge for 10 mins, collect supernatant. I add about 1mL of ice cold water again, then freeze and lyophilize.
A lot of the mass is stuck around the edges from the drying process and is difficult to collect. I painstakingly scrape away what I can and then redissolve the rest in ethanol to be added to the next run.
Just looking for any tips to improve this process. I’m thinking of centrifuging a couple times during the drying process (ex. Centrifuge at 40mL, 20 mL, 10mL solvent remaining)-- perhaps just vortexing would be enough. I’m sure there are obvious improvements I am overlooking.
Thanks!
I’m looking for some general lab technique tips on recovering the most possible mass from my fractions collected by preparative HPLC.
The solvent I’m collecting is 95:5 ethanol:water. Sample has low solubility in ethanol and is practically insoluble in water. Right now, I pool about 40mL of collected solution in 50mL plastic (PP) conical vials. I dry most of the solvent away under nitrogen blow. Next I wash with ~10mL ice cold water, centrifuge for 10 mins, collect supernatant. I add about 1mL of ice cold water again, then freeze and lyophilize.
A lot of the mass is stuck around the edges from the drying process and is difficult to collect. I painstakingly scrape away what I can and then redissolve the rest in ethanol to be added to the next run.
Just looking for any tips to improve this process. I’m thinking of centrifuging a couple times during the drying process (ex. Centrifuge at 40mL, 20 mL, 10mL solvent remaining)-- perhaps just vortexing would be enough. I’m sure there are obvious improvements I am overlooking.
Thanks!
