RESEARCH ARTICLE Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil Suchi Chawla 1 & Hetal N. Gor 1 & Hemlatta K. Patel 1 & Kaushik D. Parmar 1 & Anil R. Patel 1 & Varsha Shukla 1 & Mohammad Ilyas 2 & Satish K. Parsai 3 & Somashekar 4 & Roop Singh Meena 5 & Paresh G. Shah 1 Received: 7 February 2018 /Accepted: 24 April 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70–120% with relative standard deviation ≤ 20% and HorRat values < 0.3–1.3. R 2 was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg -1 for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible. Keywords Cottonseed . Oilseed . Cottonseed meal . Fipronil . Flonicamid . Validation . QuEChERS . Multilocation . Liquid chromatography tandem mass spectrometry . Dissipation . Maximum residue limit . Risk assessment Introduction Cotton is known as white gold and is an important cash and oilseed crop in India. It occupies 5% of the total cultivated area distributed among three different agroclimatic zones in India (Vennila n.d.). The cotton plant has long been known as BNature’ s food and fiber plant.^ Cottonseed is a very valuable source of food for human consumption (as edible oil) and an excellent cattle, poultry, and fish feed (cottonseed meal). India shares 28% of total world’ s production of cotton- seed (www.abhaycotex.com/Investor_cottonseedoil.html, accessed on 11th April 2017). With cottonseed oil as the cheapest edible oil, the Indian population is now shifting its preferences for edible oil from groundnut oil to cottonseed oil (http://www.fnbnews.com/FB-Specials/Consumption-of- edible-oil-in-India—A-paradigm-shift, accessed on 11th April, 2017). India’ s per capita consumption for cottonseed Responsible editor: Philippe Garrigues Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-018-2126-8) contains supplementary material, which is available to authorized users. * Suchi Chawla suchisood10@yahoo.co.uk 1 Pesticide Residue Laboratory, AINP on Pesticide Residues, Anand Agricultural University, Anand, Gujarat 388110, India 2 Department of Entomology, VNMKV, Parbhani, Maharashtra 431401, India 3 BM College of Agriculture, RVS Krishi Vishwa Vidyalaya, Khandwa, Madhya Pradesh 450001, India 4 Main Agricultural Research Station Regional, University of Agricultural Sciences, Raichur, Karnataka 584101, India 5 All India Cotton Improvement Project, Agricultural Research Station, Sri Ganganagar, SKN University, Bikaner, Rajasthan 335001, India Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-2126-8