EPA-OGWDW/TSC: 557: Haloacetic Acids, Bromate, and Dalapon in Drinking Water by IC-ESI-MS/MS
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Official Method Name
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Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry. |
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Current Revision
| Version 1.0 September 2009 |
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Media
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WATER |
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Instrumentation
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Ion Chromatography Electrospray Ionization Tandem Mass Spectometry |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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EPA, 2009: Method 557: Determination of Haloacetic acids, bromate, and dalapon in drinking water by ion chromatography electrospray ionization tandem mass spectrometry (IC-ESI-MS/MS): EPA Office of Water 815-B-09-012. |
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Brief Method Summary
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Residual chlorine present in drinking water samples is reacted with ammonium chloride to form chloramines, effectively preventing chlorine-mediated formation of method analytes during storage. In addition, the combined chlorine residual prevents microbial degradation in the sample. Prior to analysis, isotopically enriched analytes (monochloroacetic acid-2-13C, monobromoacetic acid-1-13C, dichloroacetic acid-2-13C, and trichloroacetic acid-2-13C) are added to the samples as internal standards. An aliquot of the sample is injected without cleanup or concentration onto an ion exchange column specifically designed to separate method analytes from the following common anions (matrix components) in drinking water: chloride, carbonate, sulfate, and nitrate. The matrix components in the column eluate are monitored via conductivity detection and then diverted to waste; the analytes of interest are directed into the ESI-MS/MS system. Acetonitrile is added post-column to enhance desolvation of the method analytes in the ESI interface. Each method analyte is qualitatively identified via a unique mass transition, and the concentration is calculated using the integrated peak area and the internal standard technique. |
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Scope and Application
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Method 557 is a direct-inject, ion chromatography, negative-ion electrospray ionization, tandem mass spectrometry (IC-ESI-MS/MS) method for the determination of haloacetic acids in finished drinking water. Bromate and dalapon (2,2-dichloropropionic acid) may be measured concurrently with the haloacetic acids. Real time, chromatographic separation of common anions in drinking water (matrix elimination) is a key feature of this method. |
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Applicable Concentration Range
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Dependent upon instrument calibration. |
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Interferences
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Matrix components may directly interfere by producing a signal at or near the retention time of an analyte peak. Matrix components may also suppress or enhance the signal of the method analytes. Common anions present in drinking water matrices, which would cause matrix suppression, are diverted from the MS. For a complete list of interferences see section 4, EPA 557. |
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Quality Control Requirements
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Quality Control (QC) requirements include the initial demonstration of capability and ongoing QC requirements. Section 9 of EPA 557 outlines each QC parameter. |
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Sample Handling
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Samples must be chilled during shipment and must not exceed 10 °C during the first 48 hours after collection. Samples must be confirmed to be at or below 10 °C when they are received at the laboratory. In the laboratory, samples must be stored at or below 6 °C and protected from light until analysis. Samples must not be frozen. |
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Maximum Holding Time
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Samples must be analyzed within 14 days of collection. Chlorinated field samples that are preserved in accordance with the method guidance should not exhibit biological degradation of analytes during the allotted 14-day storage time. The residency time in |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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