Multiresidue analysis of pesticides with hydrolyzable functionality in cooked vegetables by liquid chromatography tandem mass spectrometry.
It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean-up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB-C(18) column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100gamma(ij) (%). A high matrix effect (<-30%) was detected for the seven polar pesticides, namely thiamethoxam, clothianidin, acetamiprid, aldicarb, thiacloprid, pirimicarb and methabenzthiazuron. The limits of detection were in the range of 0.1-8.1 microg/kg, indicating a good sensitivity. Most of the recoveries ranged from 70 to 131% with RSDs <or= 20%. The current method allowed rapid quantitation and identification of low pesticide levels in the cooked vegetable samples. Of the screened pesticide residues, only fluquinconazole and dimethomorph below the maximum residue levels established by the KFDA were detected in onion and cucumber samples.
Department of Chemistry, Gyeongsang National University, Jinju, Republic of Korea.
Sung Joong
SJ
Lee
Semin
S
Park
Jin Young
JY
Choi
Jae-Han
JH
Shim
Eun-Ho
EH
Shin
Jeong-Heui
JH
Choi
Soo Taek
ST
Kim
A M
AM
Abd El-Aty
Jong Sung
JS
Jin
Dong Won
DW
Bae
Sung Chul
SC
Shin
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006868:Hydrolysis; D007723:Korea; D010573:Pesticide Residues / Q000032:analysis* / Q000737:chemistry; D010575:Pesticides / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014675:Vegetables / Q000737:chemistry*
D010573:Pesticide Residues; D010575:Pesticides