SPE C18

[panpicha]

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

Thanks

[Don Shelly]

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

[panpicha]

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

[Don Shelly]

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

[panpicha]

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

[Don Shelly]

yes

[MSCHemist]

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.