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.
Analysis of paraquat and diquat in raw foods
The Eurofins laboratories for food and feed analysis in Germany offer LC-MS/MS analysis of all relevant foodstuffs. Due to their chemical properties, paraquat and diquat are not covered by pesticide screening. We determine paraquat and diquat by a single method with a low limit of quantification in food (LOQ of 0.01 - 0.02 mg/kg):
Raw food products and raw materials
- Fruit, vegetables
- Cereals
- Pseudocereals e.g. amaranth, buckwheat, quinoa, chia
- Oilseeds
- Pulses
- Soy
- Coffee, tea
- Cocoa
- Nuts
Processed food
- Wine
- Sugar
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Written by:
Katrin Rentsch
Eurofins SOFIA GmbH