title: Analytical method for the determination of meptyldinocap as the 2,4-dinitro-octylphenol metabolite in cucumber and soil using LC-MS/MS and a study of the residues in a Chinese cucumber field ecosystem.
abstract: BACKGROUND
  Meptyldinocap (2,4-DNOPC) is a novel powdery mildew (Erysiphe necator) fungicide which shows protectant and post-infective activities. However, there is no reliable validated LC-MS/MS method for measuring trace levels of meptyldinocap in cucumber. A method for the determination of 2,4-DNOPC using LC-MS/MS in cucumber and soil was developed. Additionally, the mode of degradation and the residue levels in cucumbers and soils were investigated.
  
  
  RESULTS
  Recoveries of meptyldinocap from cucumber and soil samples were found to be 81.4-95.1%. The limits of quantification were found to be 0.01 mg kg(-1) in cucumber and soil. The half-lives of metpyldinocap in cucumbers and soils were in the ranges of 1.6 to 2.2 days and 3.1 to 4.4 days. The harvest residue levels of meptyldinocap in cucumbers and soils were in the ranges of below 0.01 mg kg(-1) to 0.92 mg kg(-1) , and below 0.01 mg kg(-1) to 0.53 mg kg(-1) . 5 days after application; the harvest residue levels of meptyldinocap in cucumbers in all treatments were below 0.1 mg kg(-1) .
  
  
  CONCLUSIONS
  Compared with the MRL for meptyldinocap in cucumber (0.1 mg kg(-1) ), set by the EU, it is suggested that there should be a pre-harvest interval of 5 days at the recommended rate and times before harvest of cucumber.
authors.affiliation: Key Laboratory of Food Safety and Quality of Jiangsu Province/Key Laboratory of Food Safety Monitoring and Management of Ministry of Agriculture, Nanjing, 210014, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Weili
authors.initials: W
authors.lastname: Shan
authors.forename: Qiu
authors.initials: Q
authors.lastname: Jian
authors.forename: Wencheng
authors.initials: W
authors.lastname: Song
authors.forename: Yan
authors.initials: Y
authors.lastname: Shen
authors.forename: Xianjin
authors.initials: X
authors.lastname: Liu
mesh_terms: D002681:China; D002853:Chromatography, Liquid / Q000379:methods*; D018553:Cucumis sativus / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D004136:Dinitrobenzenes / Q000032:analysis* / Q000378:metabolism; D017753:Ecosystem; D005506:Food Contamination / Q000032:analysis; D005659:Fungicides, Industrial / Q000032:analysis* / Q000378:metabolism; D010573:Pesticide Residues / Q000032:analysis* / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004136:Dinitrobenzenes; D005659:Fungicides, Industrial; D010573:Pesticide Residues; D012989:Soil Pollutants; C556327:meptyldinocap
keywords: LC-MS/MS; cucumber; meptyldinocap; residues; soil