new lab setup help

[jiang295]

I am going to do natural product experiment. want to extract bitter compounds out of various food stuff.
i have some crude idea for the time being and need your advice.
obviously, successful isolation of individual bitter compound from complex food matrix need several step of purification. first step, fractionate food crude extract with GPC, second step, use 21mm RP-LC to further separate each fraction from GPC. then use 4.6mm RP-LC to polish final separation.
for GPC, i use sephadex G15 with exclusion limit down to 1.5kda, with which i hope to separate small molecules according to their hydrodynamic volume. of course, I will use very long GPC column up to 1m to achieve good peak capacity. I am not sure of first GPC step. any advice?is this strategy feasible?

[jiang295]

another thing i worry about is recovery of small molecules. I am afraid of adsorption of small molecules on sephadex materials.

[yangz00g]

I saw you have asked so many questions, why there was not even a single "thanks", are you coming from Mars?

[JGK]

you seem do be doing this in the wrong order.

I would think you need to define exactly what you want to extract before designing the entire extraction process.

initial Separation from crude extracts may be easier using column chromatography rather than HPLC.

Many different materials may cause "bitterness" and may not be extractable by a single method.

why worry about small molecules if your target molecule isn't one?

[sassman]

I agree. Depending on what compounds you want to isolate, there might be easier ways to extract and purify them rather than GPC/HPLC separation. You don't mention what the compounds will be used for or what purity you require. These considerations will also help to determine what procedure is most appropriate.

[jiang295]

thanks.

I agree. Depending on what compounds you want to isolate, there might be easier ways to extract and purify them rather than GPC/HPLC separation. You don't mention what the compounds will be used for or what purity you require. These considerations will also help to determine what procedure is most appropriate.