Hello everyone,

I'm measuring total phosphorous in soil based on ISO 11263. When I digest sediment samples, I use mixture of concentrate H2SO4 and HClO4, slightly heating and then boiling for 20min until all organic matters are decomposed. I has check the recovery of method which was only ~20%. I am worry that H3PO4 released during digestion process by evaporation. So, is it possible to lost H3PO4 by evaporation?

Thank you and looking forward for your answers.