title: Residue analysis of multi-class pesticides in watermelon by LC-MS/MS.
abstract: As watermelon is farmed primarily by protected and successive cultivation techniques, a number of pesticides are required for the control of pests and diseases. To evaluate the harmful effects of pesticides in watermelon and to guarantee consumers' safety, a rapid screening process for pesticides is required. A LC-MS/MS method was applied for the direct quantitation of 44 pesticide residues in watermelon. A Zorbax XDB-C(18) column was selected for analysis, with a mobile phase consisting of a gradient system of water and 5 mM methanolic ammonium formate. MS/MS experiments were performed in ESI positive ion and multiple reaction monitoring modes. The LOQs were in the range of 1-26 microg/kg, thereby indicating good sensitivity. Most of the recoveries ranged between 70-131% with RSDs < or = 20%. We suggested that the amount of pesticide residues such as pyroquilon (pyn), boscalid (bd), and dimethomorph (di) in amides (AM) and cinosulfuron (ci) in ureas (UR) may have been overestimated for the pesticides owing to increased alpha-error risk, whereas the amounts of pesticide residues, such as imibenconazole (ie) in the triazoles (TR) and fenpyroximate (fee) in the imidazoles (IM), may have been underestimated as the result of increased beta-error risk. The current method allowed for the rapid quantitation and identification of low pesticide levels in the watermelon samples. No pesticide residues were detected in any of the surveyed watermelons obtained from eight local markets in the Republic of Korea. Statistical analysis of the recoveries classified the 44 pesticides into nine groups and three overall categories.
authors.affiliation: Department of Chemistry and Research Institute of Life Science, Gyeongsang National University, Jinju, Republic of Korea.
authors.forename: Semin
authors.initials: S
authors.lastname: Park
authors.forename: Sung Joong
authors.initials: SJ
authors.lastname: Lee
authors.forename: Hae Gyeong
authors.initials: HG
authors.lastname: Kim
authors.forename: Won Young
authors.initials: WY
authors.lastname: Jeong
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Shim
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Jeong
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Lee
authors.forename: Soo Taek
authors.initials: ST
authors.lastname: Kim
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Shin
mesh_terms: D002851:Chromatography, High Pressure Liquid; D029773:Citrullus / Q000737:chemistry*; D015394:Molecular Structure; D010575:Pesticides / Q000032:analysis* / Q000145:classification; D011786:Quality Control; D012015:Reference Standards; D053719:Tandem Mass Spectrometry
chemical_list: D010575:Pesticides