%0 Journal Article
%T General unknown screening of xenobiotics: the contribution of an acidic extraction Recherche large de x¨¦nobiotique : contribution de l¡¯extraction acide
%A Richeval C.
%A Wiart J.-F.
%A Humbert L.
%A Shbair M.
%J Annales de Toxicologie Analytique
%D 2011
%I 
%R 10.1051/ata/2011120
%X Objectives: Although general unknown screening (GUS) is often used to detect and identify exogenous compounds in biological matrices, some compounds are not detected for two main reasons: first the method carried out for the extraction, secondly, the lack of sensitivity in the detection of the unknown molecules. The aim of this study was to improve the detection, using an acidic extraction procedure and a MRM mode (ES+ or ES ). Methods: Blank sera were spiked with 42 substances, not detected in GUS. 1 mL was extracted after addition of internal standards and 500 ¦ÌL of acetate buffer by 3 mL of organic extraction solution (dichloromethane: ether: hexane: isoamyl alcohol; 30:50:20:0.5, v/v). Basic extraction was also carried out by substituting the sodium acetate buffer with saturated borate buffer. The extracts were analysed by UPLC-MS-MS, using MRM mode (ES+ or ES ). Results: All the non detected substances by the GUS method were indentified in this study, 25 in ES+ mode and 17 in ES  mode. Extraction yield was between 9 and 104%, and upper, compared to that after basic extraction. Conclusion: A rapid, sensitive and selective method using positive or negative MRM mode, with a triple quadrupole mass spectrometer and a simple acidic liquid-liquid extraction allows to identify, confirm and quantify 42 substances (drugs and pesticides) not detected by a routine GUS method. Objectifs: Bien que le screening large soit souvent utilis¨¦ pour d¨¦tecter et identifier les compos¨¦s exog¨¨nes dans les matrices biologiques, certains compos¨¦s ne sont pas d¨¦tect¨¦s pour deux raisons principales : une m¨¦thode d¡¯extraction utilis¨¦e non adapt¨¦e et un manque de sensibilit¨¦ dans la d¨¦tection pour les compos¨¦s inconnus. Le but de cette ¨¦tude a ¨¦t¨¦ d¡¯am¨¦liorer la d¨¦tection en utilisant une m¨¦thode d¡¯extraction acide et le mode MRM (ES+ ou ES ). M¨¦thodes : Le blanc s¨¦rum a ¨¦t¨¦ surcharg¨¦ avec 42 substances, non d¨¦tect¨¦es par le screening de recherche large. 1 mL d¡¯¨¦chantillon en pr¨¦sence d¡¯¨¦talons internes a ¨¦t¨¦ extrait avec 500 ¦ÌL de tampon ac¨¦tate et 3 mL d¡¯un m¨¦lange de solvants (dichlorom¨¦thane/ether/hexane/alcool isoamylique 30/50/20/0,5 v/v). L¡¯extraction basique a ¨¦galement ¨¦t¨¦ ¨¦valu¨¦e en substituant le tampon ac¨¦tate par du tampon borate. Les extraits sont analys¨¦s par UPLC-MS/MS, en utilisant le mode MRM (ES+ ou ES ). R¨¦sultats : Tous les compos¨¦s non d¨¦tect¨¦s par la m¨¦thode screening large ont ¨¦t¨¦ identifi¨¦s dans cette ¨¦tude, 25 en mode ES+ et 17 en mode ES . Les rendements d¡¯extraction ¨¦taient compris entre 9 et 104 %, et sup¨¦rieurs ¨¤ ceux obtenus apr¨¨s extraction basiqu
%K General unknown screening
%K acidic extraction
%K MRM mode detection
%K Screening large de recherche des x¨¦nobiotiques
%K extraction acide
%K d¨¦tection en mode MRM
%U http://dx.doi.org/10.1051/ata/2011120