title: "Cross-talk" in scheduled multiple reaction monitoring caused by in-source fragmentation in herbicide screening with liquid chromatography electrospray tandem mass spectrometry.
abstract: Interferences, or "cross-talk", have been found for the liquid chromatorgraphy mass spectrometry (LC-MS) determination of chlorophenoxy acid (CPA) herbicides. The time-scheduled multiple reaction monitoring (MRM) of m/z 161.0→125.0 and 163.0→127.0 transitions were produced by 2,4-dichlorophenol and 2,4-dichlorophenoxyacetic acid. Although MRM reduces the possibility of false positives when two transitions for LC/MS-MS are used for quantification and qualitative confirmation, in the case of the structurally related CPAs here, false positives still occurred when using a mixture of standards to identify the residues. It was necessary to analyze pure individual standards to compare with the extracted retention times of the candidate CPAs in food samples.
authors.affiliation: Total Diet and Pesticide Research Center, US Food and Drug Administration, Lenexa, Kansas 66214, United States. Fenhong.Song@fda.hhs.gov
authors.forename: Fenhong
authors.initials: F
authors.lastname: Song
mesh_terms: D055598:Chemical Phenomena; D002853:Chromatography, Liquid / Q000379:methods*; D006540:Herbicides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D006540:Herbicides