acetonitrile partitioning-Dimethoate
Posted: Mon Apr 28, 2014 3:01 pm
Dear Chromatographers.
I am performing an acetonitrile partitioning clean up for some organophosphorous pesticides following this procedure:
I´ve spiked 10mL of Hexane with the OP standard ( prepared in Hexane:Acetone 1:1), then it was extracted ( shaking 60seg each time) two times with 20mL portions of Hexane saturated Acetonitrile ( 200mL AcCN shaked with 80mL of Hexane for 2 min). After that the AcCN layers were transferred to a 1L funnel and 650mL of water plus 40mL of NaCl saturated water were added, this was mixed for 30 to 45 seconds, following that the sample was extracted with two portions of 100mL Hexane shaking vigorously 15seg each time. So, everything was fine except Dimethoate, it is missing, no recovery at all.
Maybe this compound is too polar to be back extracted in Hexane.....
Any suggestion?
Thank you.
I am performing an acetonitrile partitioning clean up for some organophosphorous pesticides following this procedure:
I´ve spiked 10mL of Hexane with the OP standard ( prepared in Hexane:Acetone 1:1), then it was extracted ( shaking 60seg each time) two times with 20mL portions of Hexane saturated Acetonitrile ( 200mL AcCN shaked with 80mL of Hexane for 2 min). After that the AcCN layers were transferred to a 1L funnel and 650mL of water plus 40mL of NaCl saturated water were added, this was mixed for 30 to 45 seconds, following that the sample was extracted with two portions of 100mL Hexane shaking vigorously 15seg each time. So, everything was fine except Dimethoate, it is missing, no recovery at all.
Maybe this compound is too polar to be back extracted in Hexane.....
Any suggestion?
Thank you.