PAH/TPH Blank contamination- Tri-butyl phosphate

[semivoadude]

I am seeing a tri-butyl phosphate peak in my blanks. It is originating from the filter paper we use to filter the MeCL2 extract with sodium sulfate. Sometimes the levels are high enough to interfere. Does anyone know a way to reduce/eliminate this peak?
I ve found that rinsing the filter paper thouroughly w/ mecl2 reduces the concentration but I would like to eliminate it if possible. Im hoping to not have to use an alternate product

Thanks!

[Steve]

A phosphate free paper can be found at
https://www.macherey-nagel.ch/web/MN-WE ... amesE?Open

This will elimanate the problem

[Mark]

Another thought is to use a tapered glass tube with a small glass wool plug at the bottom to hold the sodium sulfate. You can buy very clean glass wool and the sodium sulfate can be heated in a muffle furnace to oxidixe any organics before use. (I used to work in an environmental lab and these were some of the precautions we took in preparing our extracts prior to concentration and analysis.

Regards,
Mark