title: Extraction of alkyl methylphosphonic acids from aqueous samples using a conventional polymeric solid-phase extraction sorbent and a molecularly imprinted polymer.
abstract: The analysis of alkyl methylphosphonic acids (AMPAs) constitutes an important subject for verifying the compliance to the Chemical Weapons Convention (CWC). Indeed, alkyl methylphosphonic acids are the degradation products of V and G nerve agents such as VX, sarin or soman. Lowering the limits of detection of analytical methods for complex aqueous matrices implies the introduction of concentration and clean-up steps in the whole analytical process. Therefore a molecular imprinted polymer (MIP) has been previously developed for the selective extraction and the concentration of the alkyl methylphosphonic acids. Unfortunately, the selective retention process on this MIP has involved the development of hydrogen bonds and so does not allow the direct percolation of aqueous samples. A change of solvent is then necessary and can be performed using solid-phase extraction (SPE) with conventional non selective hydrophobic sorbents. Two polymeric sorbents, Oasis HLB and HR-P resins, were selected for their high specific surface area. The extraction recoveries obtained on both sorbents were compared and the Oasis HLB sorbent was further selected and used for the percolation of acidified aqueous samples. An optimised SPE procedure was then applied to concentrate an aqueous soil extract spiked with isobutyl methylphosphonic acid (iBMPA) and cyclopentyl methylphosphonic acid (cPMPA) that was further cleaned-up by passing through the MIP. The resulting LC-MS full scan chromatograms highlight the clean-up effect of the SPE-MIP association by the removal of the matrix substances and the preservation of 95% of the compounds of interest.
authors.affiliation: Département Analyse Chimique, Centre d'Etudes du Bouchet, B.P. 3, 91710 Vert-le-Petit, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Le Moullec
authors.forename: Lina
authors.initials: L
authors.lastname: Truong
authors.forename: Cécile
authors.initials: C
authors.lastname: Montauban
authors.forename: Arlette
authors.initials: A
authors.lastname: Begos
authors.forename: Valérie
authors.initials: V
authors.lastname: Pichon
authors.forename: Bruno
authors.initials: B
authors.lastname: Bellier
mesh_terms: D009943:Organophosphorus Compounds / Q000302:isolation & purification*; D011108:Polymers / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D014867:Water / Q000032:analysis*; D014873:Water Pollutants / Q000302:isolation & purification
chemical_list: D009943:Organophosphorus Compounds; D011108:Polymers; D014873:Water Pollutants; D014867:Water; C032627:methylphosphonic acid