title: Dispersive liquid-liquid microextraction for the determination of three cytokinin compounds in fruits and vegetables by liquid chromatography with time-of-flight mass spectrometry.
abstract: The paper presents a novel approach for the determination of three cytokinin compounds, thidiazuron (TDZ), 1,3-diphenylurea (1,3-DPU) and forchlorfenuron (CPPU), in fruit and vegetables samples using liquid chromatography with electrospray ionization and time-of-flight mass spectrometry (LC-ESI-TOFMS). Analytes were extracted from the sample matrix with ethanol, and the extract, after dilution with water, was submitted to dispersive liquid-liquid microextraction (DLLME). Once acetonitrile and 1,2-dichloroethane had been selected as extraction and disperser solvents, respectively, the influence of the following experimental parameters was studied using a Plackett-Burman design: volume of extraction and disperser solvents, sample mass and time and speed of centrifugation. The best analytical conditions were 250 µL 1,2-dichloroethane, 1.5 mL acetonitrile, 5 g sample mass, and centrifugation at 3000 rpm for 3 min. The optimized method provided DLs in the range 0.02-0.05 ng g(-1), depending on the compound. Satisfactory recovery values between 89 and 106% were obtained for spiked samples (kiwifruit, watermelon, grape and tomato) in the 0.2-1.0 ng g(-1) concentration range, depending on the compound. None of the target analytes was detected in any of the samples analyzed.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, E-30100 Murcia, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Campillo
authors.forename: P
authors.initials: P
authors.lastname: Viñas
authors.forename: G
authors.initials: G
authors.lastname: Férez-Melgarejo
authors.forename: M
authors.initials: M
authors.lastname: Hernández-Córdoba
mesh_terms: D000097:Acetonitriles; D029042:Actinidia / Q000737:chemistry; D002224:Carbanilides / Q000302:isolation & purification*; D029773:Citrullus / Q000737:chemistry; D004785:Environmental Pollutants / Q000302:isolation & purification*; D000431:Ethanol; D005025:Ethylene Dichlorides; D005163:Factor Analysis, Statistical; D005638:Fruit / Q000737:chemistry*; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D018551:Solanum lycopersicum / Q000737:chemistry; D010671:Phenylurea Compounds / Q000302:isolation & purification*; D011725:Pyridines / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013830:Thiadiazoles / Q000302:isolation & purification*; D014675:Vegetables / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D002224:Carbanilides; D004785:Environmental Pollutants; D005025:Ethylene Dichlorides; D010671:Phenylurea Compounds; D011725:Pyridines; D013830:Thiadiazoles; C016785:thidiazuron; D000431:Ethanol; C024565:ethylene dichloride; C116093:N-(2-chloro-4-pyridyl)-N'-phenylurea; C032159:acetonitrile
keywords: 1,3-Diphenylurea; Dispersive liquid—liquid microextraction (DLLME); Forchlorfenuron; Fruits; Liquid chromatography with time-of-flight mass spectrometry (LC—TOFMS); Thidiazuron