EPA Method 548.1 Endothall

Method 548.1 is used to determine Endothall in drinking water sources and finished drinking water sources. The analytes are extracted from water using a 47mm Anion Exchange disk. The disk is extracted with the acidic methanol. After addition of a small volume of methylene chloride as a co-solvent, the dimethyl ester of endothall id formed within 30 minutes with modest heating (50°C). After addition of salted reagent water, the ester is partitioned into 8-10 ml of methylene chloride. The extract volume is reduced to 1 ml with nitrogen purge for a concentration factor of 100. The extract is analzyed by GC/MS or GC/FID with megabore capillary column.