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Searching for non‐target chlorinated pesticides in food by liquid chromatography/time‐of‐flight mass spectrometry
Author(s) -
GarcíaReyes Juan F.,
Ferrer Imma,
Thurman E. Michael,
MolinaDíaz Antonio,
FernándezAlba Amadeo R.
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2127
Subject(s) - chemistry , mass spectrometry , procymidone , chromatography , pesticide , mass spectrum , pesticide residue , elemental analysis , iprodione , time of flight mass spectrometry , environmental chemistry , analytical chemistry (journal) , ion , ionization , organic chemistry , agronomy , biology
In this study the unique and most salient features of liquid chromatography/time‐of‐flight‐mass spectrometry (LC/TOFMS) were applied for the identification of non‐target chlorinated pesticides in complex food extracts ‘ a priori ’, i.e., without the use of standards. The combination of high sensitivity full‐scan spectra incorporating accurate mass measurements (routinely better than 2 ppm accuracy) of the protonated molecules with the evidence from resolved isotopic clusters provides the ability to obtain a reduced number of possible elemental compositions (typically 1–2). Databases were then used to find the identity of the suspected species using the elemental composition as a searching criterion. The accurate mass and the generated elemental composition of characteristic fragment ions of the suspected species provide further evidence for the proposed species. With this approach we have identified the following chlorinated pesticides in different market‐purchased fruit and vegetable extracts: Chlorotoluron (tomato), iprodione (apple), and procymidone (grapes). Finally, the confirmation and quantitation of these suspected species were successfully accomplished with standards. Other unknown compounds could be partially identified based on the data obtained within this study. As an example, a chlorinated species (‘ m/z 311’) is discussed; the elemental composition and possible structures were proposed and the analytical potential, advantages and disadvantages of the proposed approach critically discussed. Copyright © 2005 John Wiley & Sons, Ltd.