Thermo Fisher Scientific has developed a high-performance liquid chromatography (HPLC) method for a fast and sensitive determination of paraquat and diquat in tap and environmental water samples. This approach uses on-line solid phase extraction (SPE) and achieves method detection limits that meet the requirements of both U.S. Environmental Protection Agency Method 549.2 and European Union 98/83/EC. Application Note (AN) 1051: Sensitive and Rapid Determination of Paraquat and Diquat in Tap and Environmental Water demonstrates use of a mixed-mode column to provide sufficient retention, excellent resolution, and good peak shape for these herbicides.
Paraquat and diquat are widely used as agriculture herbicides to control crop and aquatic weeds. Contamination of drinking and environmental waters with paraquat and diquat is considered a risk factor for liver, heart, lung, and kidney illnesses. Therefore, regulatory agencies monitor the level of these compounds present in key water sources. The method described in AN 1051 demonstrates that use of on-line SPE-HPLC to determine paraquat and diquat in water samples offers the advantages of full automation, the absence of operator influence, time savings, and strict process control.