Environmental sample analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) traditionally incorporates off- or on-line sample preparation techniques such as solid phase extraction (SPE) or liquid-liquid extraction (LLE).  Environmental solids including sediments, soils, and sludges are extracted by solvents using sonication or by accelerated solvent extraction. Typically, SPE methods for aqueous samples generate solid and liquid wastes.  Regardless of the mode of extraction, only small fractions of the organic extracts generated are actually injected.  Direct, large-volume injection (LVI) strategies currently are receiving attention for the analysis of a wide range of contaminants in aqueous environmental samples and organic-solvent extracts.  Simple modifications of commercial HPLCs are needed to inject large volumes, such as the installation of 900-1,400 �L stainless steel loops.  Control of existing 6-way HPLC valves and divert valves positioned in front of the MS/MS aid in managing the flow of mobile phase through/around the injector and column effluent to or away from the MS/MS.  Examples of LVI of aqueous samples presented will include 1,800 �L direct injections of 1) raw wastewater for the determination of illicit drugs, 2) seawater for the determination of the surfactant components in the oil dispersant Corexit, and 3) pesticides in wine. For analytes characterized by lower aqueous solubilities, LVI strategies will be presented for their determination in organic extracts.  Anionic, cationic, and zwitterionic PFAS are concentrated from 900 �L ethyl acetate extracts of landfill leachate by an orthogonal chromatographic system comprised of amino propyl and silica guard columns placed in series with a C18 analytical column.  Alternatively, dioctyl sulfosuccinate, the anionic surfactant found in Corexit oil dispersant, extracted by methanol from ocean sediment is analyzed by a 'staged' 900 �L injection strategy. The advantages and limitations of direct LVI of aqueous samples and organic extracts will also be discussed.

Coupling large volume injection with tandem mass spectrometry: Strategies and environmental applications

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.