title: Simultaneous determination of eight neonicotinoid insecticide residues and two primary metabolites in cucumbers and soil by liquid chromatography-tandem mass spectrometry coupled with QuEChERS.
abstract: A new, rapid, sensitive, precise and validated high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of eight neonicotinoid insecticides with their two primary metabolites in cucumbers and soil based on QuEChERS as a pretreatment procedure. In QuEChERS procedure, cucumber samples were extracted with acetonitrile and cleaned using (C18 sorbent material), while soil samples were extracted with a mixture of acetonitrile:dichloromethane (8.3:16.7v:v). The LC-MS/MS conditions were optimized to provide good selectivity and specificity of the developed method where neonicotinoids were separated using gradient elution of water and acetonitrile both containing 0.1% formic acid with Gemini C18 column where the last compound was eluted at 9.5min. Average recoveries of the eight neonicotinoids and their metabolites ranged between 81.6% and 95.7% in fortified cucumber samples with relative standard deviations (RSDs) lower than 13.18% and between 80.3% and 104% in fortified soil samples with relative standard deviations (RSDs) lower than 8.44%. The limits of detection (LODs) and quantification (LOQs) for the ten compounds were in the ranges of (0.08-6.06ng/g) and (0.26-20ng/g), respectively. The method was applied successfully to determine residues and rate of disappearance of the eight neonicotinoids from cucumber and soil and their half-lives where a safety pre-harvest interval of 5days for acetampirid, 12days for imidacloprid, 15days for nitenpyram, 12days for thiamethoxam, 5days for flonicamid, 8days for clothianidin, 2days for Dinotefuran, and 1day for thiacloprid were suggested.
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: Maha F
authors.initials: MF
authors.lastname: Abdel-Ghany
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: Lobna A
authors.initials: LA
authors.lastname: Hussein
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of pharmacy, Ain Shams University, Cairo, Egypt. Electronic address: noha_3zab@yahoo.com.
authors.forename: Noha F
authors.initials: NF
authors.lastname: El Azab
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of pharmacy, Ain Shams University, Cairo, Egypt; Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: El-Khatib
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Linscheid
mesh_terms: D000691:Anabasine / Q000032:analysis* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D018553:Cucumis sativus / Q000378:metabolism*; D007306:Insecticides / Q000032:analysis* / Q000378:metabolism; D057230:Limit of Detection; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007306:Insecticides; D000691:Anabasine
keywords: Cucumber; MS/MS; Metabolites; Neonicotinoids; QuEChERS; Soil