ENVIRONMENTAL TESTING CATALOG 549.2

DCLS Method

Determination of Diquat in drinking water by liquid-solid extraction and HPLC with UV detection

Reference Method

EPA 549.2

Test Description

An aliquot of sample is filtered through a solid extraction disk. The analytes are removed from the disk using an acidic aqueous solvent. Ion pair solution is added to the final eluent volume and the extract is analyzed by High Performance Liquid Chromatography (HPLC). Diquat is quantified by measurement of ultraviolet (UV). A dissimilar mobile phase is used for analyte confirmation.

Sample Collection

Diquat is light-sensitive. Grab samples are collected in duplicate in 250mL amber PVC high density bottles which protect them from light and are preserved to a pH <2.

Storage Guidelines

The samples are stored in a refrigerator in the analytical lab area where they are kept between 0 to 6ºC until analysis.

Testing Group

Organics

Analyte

Diquat