JCBPS; Section A; November 2015 – January 2016, Vol. 6, No. 1; 184-193. E- ISSN: 2249 –1929 Journal of Chemical, Biological and Physical Sciences An International Peer Review E-3 Journal of Sciences Available online atwww.jcbsc.org Section A: Chemical Sciences CODEN (USA): JCBPAT Research Article 184 J. Chem. Bio. Phy. Sci. Sec. A, November 2015 – January 2016; Vol.6 No.1; 184-193. Method validation and residues of fipronil and its metabolites in citrus fruit and soil on Gas Chromatography- ECD by QuEChERS method. M. Aruna, R. Madhusudhan Raju and K. Narasimha Reddy AINP on Pesticide Residues, Prof.Jayashankar Telangana State Agricultural University Rajendranagar, Hyderabad – 500030 Dept. of Chemistry, University College of Science, Osmania University, Hyderabad-500007 Received: 23 November 2015; Revised: 07 December2015; Accepted: 10 December 2015 Abstract: Fipronil belongs to a new class of insecticides known as phenylpyrozole. For the determination of amount of residues of insecticide fipronil and its toxic metabolites in citrus fruit and soil by QuEChERS method was developed based on analysis on Gas chromatography with Electronic Capture Detector. The supervised field trial was carried out in Citrus farm using a fipronil 80 WG granular formulation at the rate of 60 g a.i./ha and 120 g a.i./ha. Persistence behavior of fipronil and its metabolite were studied on citrus fruit. Fipronil 80WG sprayed twice with an interval of 10 days @ 60 and 120 g a.i. /ha initiating at fruit formation stage (Pea nut stage). The citrus fruit samples collected and analyzed on GC-ECD by adopting QuEhERS method. The results revealed that the initial deposits of fipronil alone recorded 0.31 mgkg -1 and 0.59 mgkg -1 respectively and including metabolites, was 0.41mgkg -1 and 0.75 mgkg -1 in the recommended dose and double the recommended doses respectively and dissipated to Below Detectable Level (BDL) of 0.005 mgkg -1 15 days and 20 days after the last application. Keywords: Fipronil, QuEChERS, GC- ECD, Citrus fruit and soil.