title: A fast, inexpensive, and safe method for residue analysis of meptyldinocap in different fruits by liquid chromatography/tandem mass spectrometry.
abstract: An analytical method is reported for residue analysis of the fungicide meptyldinocap in different fruit matrixes that involves extraction with ethyl acetate, hydrolysis of the residues with ethanolamine, and determination by LC/MS/MS. The method involves extraction of 10 g sample with 10 mL ethyl acetate; evaporation of the ethyl acetate phase to dryness, and subsequent hydrolysis of the residues to 4,6-dinitro-2-(1-methylheptyl) phenol on reaction with 1% ethanolamine. The pH of this hydrolyzed product was neutralized with formic acid and analyzed by LC/MS/MS. The hydrolysis reaction followed pseudo-first-order kinetics, and the reaction product was spectroscopically confirmed as 2-(1-methylheptyl)-4,6-dinitrophenol. The method offered > 80% recoveries at an LOQ of 10 ng/g for grape and mango, 25 ng/g for pomegranate with intralaboratory Horwitz ratio < 0.5, and measurement uncertainties < 10% at LOQ levels. Considering first-order rate kinetics, activation energy, enthalpy of activation, and entropy of activation varied as solvent > mango > grape > pomegranate. Free energy of activation at 298 K was higher than at 280 K and was similar for solvent and three matrixes at both temperatures.
authors.affiliation: National Research Centre for Grapes, Manjri Farm, Pune, Maharashtra, India 412307. kbgrape@yahoo.com
authors.forename: Kaushik
authors.initials: K
authors.lastname: Banerjee
authors.forename: Soma
authors.initials: S
authors.lastname: Dasgupta
authors.forename: Manjusha R
authors.initials: MR
authors.lastname: Jadhav
authors.forename: Dattatraya G
authors.initials: DG
authors.lastname: Naik
authors.forename: Axel Patrick
authors.initials: AP
authors.lastname: Ligon
authors.forename: Dasharath P
authors.initials: DP
authors.lastname: Oulkar
authors.forename: Rahul H
authors.initials: RH
authors.lastname: Savant
authors.forename: Pandurang G
authors.initials: PG
authors.lastname: Adsule
mesh_terms: D000085:Acetates; D002851:Chromatography, High Pressure Liquid; D003365:Costs and Cost Analysis; D004136:Dinitrobenzenes / Q000032:analysis*; D005561:Formates; D005638:Fruit / Q000737:chemistry*; D005659:Fungicides, Industrial / Q000032:analysis*; D006868:Hydrolysis; D007202:Indicators and Reagents; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010573:Pesticide Residues / Q000032:analysis*; D012015:Reference Standards; D015203:Reproducibility of Results; D018401:Sample Size; D012996:Solutions; D012997:Solvents; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D053719:Tandem Mass Spectrometry; D013816:Thermodynamics
chemical_list: D000085:Acetates; D004136:Dinitrobenzenes; D005561:Formates; D005659:Fungicides, Industrial; D007202:Indicators and Reagents; D010573:Pesticide Residues; D012996:Solutions; D012997:Solvents; C030544:formic acid; C007650:ethyl acetate; C556327:meptyldinocap