Paraquat and Diquat in food

Use of paraquat and diquat as herbicides

July 2023. The herbicides paraquat and diquat are among the most widely used crop protection products in the world. Chemically, they belong to the polar pesticides. As herbicides, they suppress photosynthesis in plants and thus weaken the growth of weeds. The Eurofins laboratories for food and feed analysis in Germany determine paraquat and diquat by individual methods with a low limit of quantification. 

Relevant legal bases and guidelines

Due to their adverse health effects, countries around the world have restricted the authorisation of both active ingredients in recent years. As a result, diquat has been banned for use as a plant protection product in the EU since 2019 and paraquat since 2007. Maximum levels for paraquat and diquat are set out in the annexes to Regulation (EU) No 396/2005. However, the use of paraquat and diquat is still allowed in many countries.  

Characteristics of paraquat and diquat

Over the last 50 years, paraquat and diquat have been used successfully as herbicides on many crops in the USA, Asia and Africa. Paraquat has many advantages as a herbicide over other active ingredients. It is fast acting, rainfast and effective against plants that have become resistant to other herbicides. Both are extremely toxic.

Due to its polar chemical properties, paraquat binds preferentially to glass surfaces and, similar to diquat, adheres strongly to mucopolysaccharides present in plants. These properties require special extraction procedures for the separation and measurement of both substances. In addition, a suitable analytical method for paraquat and diquat must allow successful analysis of highly swelling, high-fat foods such as chia seeds.  

Questions about our analyses or maximum levels?

If you have any questions about paraquat and diquat, or if you would like a consultation, please contact your personal account manager or our raw material and crop analysis expert Florian Heße.