Chromatography Forum

What does SPE c18 do?
could you please give me a SPE C18 extraction protocol?

Thanks

In a nutshell, it is used to either extract moderately polar to non polar compounds from an aqueous matrix or it can be used as a filter to remove contaminants from an extract.

We have several applications on our website as do the other SPE manufacturers.

Don

thanks.

Could you please see whether this protocol makes senses?

I'm using SPE C18 (500 mg, 3 ml Column volumn).

1. Activate the column by using 2.5 ml 100% MeOH
2. Prewash the column with 8 ml 0.1% TFA pH 5.0
3. Load the sample (500 ml of serum + 1.5 ml of 0.1% TFA pH 5.0)
4. Wash the column with 2 ml of water
5. elute with 1.5 ml 25%MeOH in water

Can I increase the percentage of MeOH from 25% to 50%? Because I have to dry the samples after the elution step

thanks.

Could you please see whether this protocol makes senses?

I'm using SPE C18 (500 mg, 3 ml Column volumn).

1. Activate the column by using 2.5 ml 100% MeOH
2. Prewash the column with 8 ml 0.1% TFA pH 5.0
3. Load the sample (500 ml of serum + 1.5 ml of 0.1% TFA pH 5.0)
4. Wash the column with 2 ml of water
5. elute with 1.5 ml 25%MeOH in water

Can I increase the percentage of MeOH from 25% to 50%? Because I have to dry the samples after the elution step

I can't think of a good reason to use water in this elution solvent. Water will aid in the elution of polar compounds from a polar sorbent. It will interfere in the elution of non polar compounds from a non polar sorbent. I recommend elution with 100% MeOH. I'm saying this without knowledge of your analytes.

Don

Thanks.
So you think I should use 100%MeOH instead of 25% MeOH, don't you?

yes

It basically adsobs stuff (usually very nonpolar stuff like oils) that would otherwise adsorb to your column. Better to have a bunch of junk stuck to a disposible SPE column than your analytical column. Also the very polar compounds flow right through with a wash.