title: Pepper leaf matrix as a promising analyte protectant prior to the analysis of thermolabile terbufos and its metabolites in pepper using GC-FPD.
abstract: During gas chromatography (GC), the matrix can deactivate the active site during the transport of the compound from the injector to the detector. This deactivation capacity varies among matrices, as it is dependant on the concentrations of the different constituent compounds of each matrix. During the analysis of terbufos and its metabolites, two of its metabolites were highly thermolabile, and were readily decomposed inside the GC system. As the matrix can mask the active site, we carried out a matrix-matched calibration in an effort to protect the analyte against decomposition. As a component of our analysis, the pepper matrix was the first to be matched; however, it failed to completely protect the metabolites. Subsequently, a variety of different compounds, including 3-ethoxy-1,2-propanediol, gulonolactone, and sorbitol at 10, 1, and 1mg/mL were tested; however, none of these generated the desired effect. We surmised that some of the compounds may have decomposed inside the injection port, so we introduced a carbofrit inlet liner, which is highly inert. But, this step did not improve the protective qualities of the matrices. Finally, pepper leaf matrix was added to the pepper matrix, and we observed a profound protective effect for almost all of the analytes tested. A selective detector (flame photometric detector with phosphorus filter) was used to facilitate a high matrix concentration without interaction with the analyte. After resolving the problem of these two metabolites, terbufos and its five toxic metabolites were analyzed in pepper and pepper leaf samples. The recovery rates for terbufos and its metabolites were 73-114.5% with a relative standard deviation of <12%. This method was successfully applied to field samples, and terbufos sulfone, terbufos sulfoxide, and terbufoxon sulfoxide were found as residues in the suspected pepper and pepper leaf samples.
authors: Natural Products Chemistry Laboratory, College of Agriculture and Life Science, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea.
authors: Md Musfiqur
authors: MM
authors: Rahman
authors: Natural Products Chemistry Laboratory, College of Agriculture and Life Science, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea; Institute of Environmental Research, Faculty of Chemistry, Dortmund University of Technology, D-44227 Dortmund, Germany.
authors: Jeong-Heui
authors: JH
authors: Choi
authors: Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211-Giza, Egypt. Electronic address: abdelaty44@hotmail.com.
authors: A M
authors: AM
authors: Abd El-Aty
authors: Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors: Morad D N
authors: MD
authors: Abid
authors: Natural Products Chemistry Laboratory, College of Agriculture and Life Science, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea.
authors: Jong-Hyouk
authors: JH
authors: Park
authors: Natural Products Chemistry Laboratory, College of Agriculture and Life Science, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea.
authors: Tae Woong
authors: TW
authors: Na
authors: Department of Food Science and Technology, College of Life Science and Natural Resources, Sunchon National University, Sunchon 540-742, Republic of Korea.
authors: Yong-Doo
authors: YD
authors: Kim
authors: Natural Products Chemistry Laboratory, College of Agriculture and Life Science, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, Republic of Korea. Electronic address: jhshim@chonnam.ac.kr.
authors: Jae-Han
authors: JH
authors: Shim
mesh_terms: D002138:Calibration; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods; D009946:Organothiophosphorus Compounds / Q000032:analysis* / Q000378:metabolism; D029222:Piper nigrum / Q000737:chemistry* / Q000378:metabolism; D010936:Plant Extracts / Q000032:analysis* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism; D020011:Protective Agents / Q000032:analysis* / Q000378:metabolism; D014675:Vegetables / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009946:Organothiophosphorus Compounds; D010936:Plant Extracts; D020011:Protective Agents; C012568:terbufos
keywords: Analyte protectant; Gas chromatography; Matrix effect; Thermolabile pesticide; Unstable metabolite