Analysis of Fluopicolide and Propamocarb Residues on Tomato and Soil Using QuEChERS Sample Preparation Method in Combination with GLC and GCMS

Abstract

Persistence of fluopicolide and propamocarb in tomato was studied following three applications of a combination formulation of Infinito 68.75 SC (fluopicolide 6.25 % + propamocarb 62.5 %) at 1500 and 3000 mL ha⁻¹ by 7 days interval, starting the spray at fruit development stage. QuEChERS method included extraction of sample with ethyl acetate and cleanup of dispersive solid-phase extraction was used for the determination of fluopicolide and propamocarb residues on tomato and soil. Residues of fluopicolide and propamocarb in tomato were estimated by gas–liquid chromatography and gas chromatograph–mass spectrometry, respectively. Half-lives for fluopicolide were found to be 2.58 and 2.31 days, whereas for propamocarb these values were observed to be 1.49 and 2.08 days at single and double the application rates, respectively. Residues of fluopicolide dissipated below its limit of quantification (LOQ) of 0.01 mg kg⁻¹ after 7 and 10 days at single and double the application dosage, respectively. Similarly, residues of propamocarb took 5 and 7 days to reach LOQ of 0.10 mg kg⁻¹, at single and double dosages, respectively. Soil samples collected after 15 days of the last application did not show the presence of fluopicolide and propamocarb at their detection limit of 0.01 and 0.10 mg kg⁻¹, respectively. The initial deposit of residues of propamocarb and fluopicolide for both the dosages were below the prescribed codex maximum residue limit values of 2 and 1 mg kg⁻¹, respectively. Therefore, a 1-day waiting period was suggested to reduce human health risks before consumption of tomato fruits.