title: Simultaneous multi-determination and transfer of eight pesticide residues from green tea leaves to infusion using gas chromatography.
abstract: A method for determining eight pesticide (cyhalothrin, flufenoxuron, fenitrothion, EPN, bifenthrin, difenoconazole, triflumizole, and azoxystrobin) residues in made green tea as well as a tea infusion (under various brewing water temperatures; 60, 80, and 100°C) using gas chromatography (GC) micro-electron capture detector (μECD) was developed and validated. The extraction method adopted the relatively commonly used approach of solid sample hydration, with the green tea hydrated before being extracted through salting out with acetonitrile followed by a cleanup procedure. The analytes were confirmed using GC-coupled to tandem mass spectrometry (GC/MS/MS) with a triple quadrupole. The linearity of the calibration curves yielded determination coefficients (R(2)) >0.995. Recoveries were carried out using blank samples spiked with all analytes at two levels. The results demonstrated that all pesticides were recovered within the range of 77-116% with a relative standard deviation (RSD) ⩽14%. The quantification limits of 0.015-0.03 mg/kg were lower than the maximum residue limits (MRLs) set by the Korea Food and Drug Administration (KFDA) for all analytes (0.05-10mg/kg). The infusion study indicated that cyhalothrin, flufenoxuron, and bifenthrin did not infuse into the tea brew from the made tea. Increases in brewing time resulted in increased transfer of azoxystrobin, fenitrothion, and difenoconazole from the made tea to the brew; however, this was not the case with triflumizole or EPN. We conclude that transfer of pesticides appeared to be dependent on their water solubilities and drinking a cup of tea is recommended to be at a water temperature of 60°C.
authors.affiliation: National Agricultural Products Quality Management Service, Products Safety Inspection Laboratory, Gwangsan-Gu, Gwangju, Republic of Korea.
authors.forename: Soon-Kil
authors.initials: SK
authors.lastname: Cho
authors.affiliation: Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea; Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt. Electronic address: abdelaty44@hotmail.com.
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.affiliation: Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Md Musfiqur
authors.initials: MM
authors.lastname: Rahman
authors.affiliation: Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
authors.forename: Jeong-Heui
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea. Electronic address: jhshim@chonnam.ac.kr.
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Shim
mesh_terms: D028241:Camellia sinensis / Q000737:chemistry*; D002849:Chromatography, Gas / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry*; D056910:Republic of Korea; D013662:Tea / Q000737:chemistry*
chemical_list: D010573:Pesticide Residues; D013662:Tea
keywords: Dried leaves; Green tea; Infusion; Leaching; Pesticides