The poster speaks about herbicides which are a specific group of plant protection products used to treat a variety of weeds such as crop rotation, tillage, and fallow systems. Acidic herbicides comprise families of compounds that include derivatives of benzoic acid (e.g. dicamba), acetic acid (e.g. 2,4-dichlorophenoxyacetic acid [2,4-D]), and other miscellaneous acids. Herbicides can enter surface water bodies either directly through spray or indirectly via surface water runoff. Herbicides can also reach water-bearing aquifers below ground (groundwater) from applications onto crop fields and seepage of contaminated surface water, Surface and ground water is pumped, piped, or diverted for use in the supply of drinking water.

The presence of pesticides in drinking water is monitored globally. The EU Drinking Water Directive sets a maximum limit of 0.1 μg/L for individual pesticide residues present in a sample (0.5 μg/L for total pesticides). In the USA, drinking water is regulated under the Safe Drinking Water Act, where there are varying maximum contaminant levels for each residue.

There is a need for reliable analytical methods for monitoring acidic herbicides in drinking water. Historically, methods have been based upon using liquid-liquid extraction or solid-phase extraction (SPE) as a concentration step. This poster will demonstrate a rapid method for the determination of a range of acidic herbicides in water samples using large volume direct injection on ACQUITY Premier HSS T3 column coupled with Waters ACQUITY Premier UPLC I-Class System and the Xevo TQ Absolute Mass Spectrometer to achieve best degree of performance and ultra-high sensitivity quantitative method. The calibration curves were run from 0.01 to 0.2 ug/L in drinking water. Data were acquired and processed using waters_connect software.