Residue analysis of multi-class pesticides in watermelon by LC-MS/MS.
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.
Park
Semin
S
Department of Chemistry and Research Institute of Life Science, Gyeongsang National University, Jinju, Republic of Korea.
Lee
Sung Joong
SJ
Kim
Hae Gyeong
HG
Jeong
Won Young
WY
Shim
Jae-Han
JH
Abd El-Aty
A M
AM
Jeong
Sung Woo
SW
Lee
Won Sup
WS
Kim
Soo Taek
ST
Shin
Sung Chul
SC
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
D010575:Pesticides