USGS-NWQL: O-2080-08: Pharmaceuticals in Water by SPE and HPLC-MS
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Official Method Name
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Determination of Human-Health Pharmaceuticals in Filtered Water by Chemically Modified Styrene-Divinylbenzene Resin-Based SPE and HPLC-MS |
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Current Revision
| 2008 |
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Media
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WATER |
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Instrumentation
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High Performance Liquid Chromatography with Mass Spectrometry |
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Method Subcategory
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Organic |
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Method Source
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Citation
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Furlong, Edward T., Werner, Stephen L., Anderson, Bruce D., and Cahill, Jeffery D., in production, Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of human-health pharmaceuticals in filtered water by chemically modified styrene-divinylbenzene resin-based solid-phase extraction and high-performance liquid chromatography/mass spectrometry: U.S. Geological Survey Techniques and Methods, book 5, chap. |
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Brief Method Summary
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One-liter water samples are filtered using a 0.7-micrometer nominal pore size glass fiber filter to remove suspended solids. The filtered samples are then passed through a chemically modified styrene-divinylbenzene resin-based solid-phase extraction (SPE) cartridge for analyte isolation and concentration. Analyte detection and quantitation is determined using a high performance liquid chromatography/mass spectrometry (HPLC/MS) system to separate the pharmaceuticals of interest from each other and co-extracted material. Immediately following separation, the pharmaceuticals are ionized by electrospray ionization operated in the positive ion mode, and the positive ions produced are detected, identified, and quantified using a quadrupole mass spectrometer. |
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Scope and Application
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This method was developed for the determination of low-level concentrations of pharmaceuticals and personal-care products in common use by humans in a broad range of filtered water types. A broad selection of pharmaceuticals were initially tested for this method, reflecting several factors: annual total prescriptions in the United States, typical active ingredient doses, likely persistence through human metabolism, and, after excretion, persistence through common wastewater-treatment processes. Acceptable performance during extraction, isolation and analysis determined which pharmaceuticals were included in the approved method. This method identifies and quantifies 14 commonly-used human pharmaceuticals; the concentrations of 12 pharmaceuticals are reported without qualification and the concentrations of two pharmaceuticals are reported as qualified estimates. |
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Applicable Concentration Range
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0.005 to 1.0 ug/L |
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Interferences
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(A) Co-extracted interferences can be sorbed onto the SPE surface, thereby reducing the efficiency of sorption of the selected pharmaceuticals. (B) The presence of large quantities of coextracted interferences present in the final sample extract may result in poor or irreproducible compound retention and decreased ability to chromatographically resolve closely eluting pharmaceuticals on the analytical column. (C) During electrospray ionization of the compound, complex sample matrix constituents that cannot be chromatographically resolved from the selected pharmaceutical peak may produce one or more of the ions that are characteristically produced by the pharmaceutical, which may change the ion area ratios used for identification. (D) Competition for available charge results in either an apparent enhancement or an apparent reduction of compound concentration because of the effects of unknown matrix constituents competing for charge with the internal standard or pharmaceutical when these compounds are ionized in the ion-source region of the analytical instrument (Furlong and others, 2000). Careful choice of internal standards and surrogates is necessary to minimize matrix enhancement or suppression effects. In addition to the quality-control samples, the inclusion of one or more matrix-spike samples along with a corresponding unfortified environmental sample can help identify interferences. |
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Quality Control Requirements
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Continuing calibration blank (CCB), Continuing calibration verification (CCV) sample, Third-party check standard, Set quality-control sample (either a reagent blank or reagent spike), Laboratory reagent blank (LRB), Limit of Quantitation (LOQ) standard, Field equipment blank (FEB), Laboratory matrix spike (LMS), Calibration solutions, Method surrogate spiking solution, Method compound spiking solution, Internal standard solution. |
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Sample Handling
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Filtration in the field with 14.2-cm diameter, pre-baked glass-fiber filters with a nominal 0.7-μm pore size. A positive displacement pumping system is used to process a 1-L water sample through the filter, which is contained in an aluminum filter holder. All materials are compatible with trace organic sampling and the cleaning procedures used to decontaminate the filtering system between samples. |
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Maximum Holding Time
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Samples (4 days at 4°C), extracts (35 days at 4°C) |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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Isolation/concentration with solid-phase extraction (SPE) cartridge. |
