UHPLC–MS/MS Tracks Flonicamid's Fate in Rice Paddies

Flonicamid is an insecticide that plants absorb and carry throughout their tissues, protecting crops from pests that feed by sucking plant sap. Researchers at China's Ningbo Academy of Agricultural Sciences developed a new testing method using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) that can measure flonicamid and three substances it breaks down into (known as TFNG, TFNA–AM, and TFNA) all at once. The method works on rice plants, brown rice, rice husks, and the soil and water of rice paddies. A paper based on the work was published in the journal Foods.¹

Why Has Flonicamid Become So Widely Used, and What Are Its Risks?

Rice is the main food for more than half the people in the world. Growing it depends more and more on heavy use of chemicals to fight pests and diseases, which means leftover pesticides in rice remain an ongoing health concern.²Many countries have limited the use of a group of insecticides called neonicotinoids because they harm helpful creatures they were not meant to target, such as bees.³This has pushed farmers and scientists to look for other insecticides. Flonicamid has become an important choice for farmers who combine several methods to control pests, because it works differently from other insecticides, is very effective against insects that pierce plants and suck their sap, and is relatively safe for the helpful insects that naturally prey on pests.^4,5In China, flonicamid is currently approved for use on 28 crops, including rice, apples, tea, and cucumbers, and it is sold in more than 300 different products.⁶ However, flonicamid is harmful to creatures that live in water, and studies have shown it can damage their nervous systems.^7,8

How Does Flonicamid Break Down in Rice Paddies, and Does It Pose a Health Risk?

The researchers first checked that their testing method was reliable. When they added known amounts of flonicamid to different kinds of samples, they recovered about 73% to 115% of it, and the results were consistent from test to test. They then ran experiments in rice fields and in the laboratory to see how flonicamid breaks down and changes in rice paddies, and whether eating the rice could pose a health risk. In the fields, the insecticide faded away at a steady rate: half of it was gone in about six days in the rice plants, three days in the soil, and seven days in the paddy water.¹

In the laboratory, flonicamid broke down much faster in soil with oxygen than in soil without it. Across five common types of Chinese soil, half of it disappeared within about 1–7 days when oxygen was present, compared with about 5–18 days when it was not.¹

Using ultrahigh-performance Liquid Chromatography–quadrupole time-0f-flight mass spectrometry (UHPLC–Q–TOF MS) allowed the team to identify six substances that flonicamid turns into as it broke down, including one that had never been reported before.¹

When the rice was harvested 7 to 21 days after spraying, the amount of insecticide left in the brown rice was always below China's legal safety limit. The researchers also estimated how much of the insecticide 12 different groups of people would consume by eating the rice. Even under the strictest European standards, people would take in less than 4% of the amount considered safe to eat every day, meaning the risk is very low.¹

“These results,” write the authors of the paper,¹ “indicate that flonicamid, when applied according to Good Agricultural Practice (GAP), poses a negligible dietary risk to consumers.”

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References

1. Fu, Y.; Wang, Q.; Zhang, L. et al. Residue Dissipation, Transformation Products, and Dietary Risk Assessment of Flonicamid in a Rice Paddy Ecosystem. Foods 2026, 15 (17), 3104. DOI: 10.3390/foods15173104
2. Pratap, V.; Ong, G. V.; Laudencia, I. L. et al. Multi-residue Pesticide Contamination in Marketed Rice and Recommended Mitigation Techniques by Household Washing and Cooking to Reduce Dietary Risks. Food Control 2026, 190, 112387. DOI: 10.1016/j.foodcont.2026.112387
3. Woodcock, B. A.; Isaac, N. J.; Bullock, J. M. et al. Impacts of Neonicotinoid Use on Long-term Population Changes in Wild Bees in England. Nat Commun. 2016, 7, 12459. DOI: 10.1038/ncomms12459
4. Ren, M.; Niu, J.; Hu, B. et al. Block of Kir Channels by Flonicamid Disrupts Salivary and Renal Excretion of Insect Pests. Insect Biochem Mol Biol. 2018, 99, 17-26. DOI: 10.1016/j.ibmb.2018.05.007
5. Zhang, X.; Duan, Y.; Liang, F. et al. Characteristics of Toxicokinetics and Metabolic Transformation of Flonicamid in Rats. Ecotoxicol Environ Saf. 2026, 309, 119511. DOI: 10.1016/j.ecoenv.2025.119511
6. Institute for the Control of Agrochemicals, Ministry of Agriculture and Rural Affairs. Pesticide Registration Data of China Pesticide Information Network. Available online: http://www.chinapesticide.org.cn/zgnyxxw/eng/aboutus (accessed 2026-07-05).
7. Taheri Mirghaed, A.; Baes, M.; Hoseini, S. M. Humoral Immune Responses and Gill Antioxidant-related Gene Expression of Common Carp (Cyprinus carpio) Exposed to Lufenuron and Flonicamide. Fish Physiol Biochem. 2020, 46 (2), 739-746. DOI: 10.1007/s10695-019-00747-x
8. Ghelichpour, M.; Taheri Mirghaed, A.; Zargar, A. The Response of Lufenuron- and Flonicamid-exposed Cyprinus carpio to Saltwater Challenge: Study on Ion-regulation and Stress Genes Expression and Plasma Antioxidant Characteristics. Aquac. Res. 2020, 51, 4829–4837. DOI: 10.1111/are.14773