EPA-NERL: 552.1: Haloacetic Acids and Dalapon in Water Using GCECD
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Official Method Name
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Determination of Haloacetic Acids and Dalapon in Drinking Water by Ion-Exchange Liquid-Solid Extraction and Gas Chromatography with an Electron Capture Detector |
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Current Revision
| Revision 1.0, August 1992 |
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Media
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WATER |
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Instrumentation
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Gas Chromatography with Electron Capture Detection |
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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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Brief Method Summary
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A 100-mL volume of sample is adjusted to a slightly acidic pH and extracted with a preconditioned miniature anion exchange column or a liquid/solid extraction (LSE) disk. The acids and herbicides are eluted from the disk with small aliquots of acidic methanol and esterified directly in this medium after the addition of a small volume of methyl tert-butyl ether (MTBE) as co-solvent. The methyl esters are partitioned into the MTBE phase and identified and measured using a capillary column gas chromatography (GC) system equipped with an electron capture detector (ECD). |
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Scope and Application
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This method determines haloacetic acids the herbicide Dalapon in drinking water, ground water, raw source water, and water at any intermediate treatment stage. |
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Applicable Concentration Range
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Ranges differ depending on matrix and instrumentation used for detection. |
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Interferences
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(A) Glassware contamination: Thoroughly clean glassware, including baking or solvent rinse. (B) Solvent contamination: Use high purity solvents. Background correct using a reagent blank when background concentrations exceed 0.1 ug/L (observed with bromochloroacetic acid). (C) Ion interferences: Sulfate concentrations above 200 mg/L lower recovery by interfering with the ion exchange process. Dilute sample to mitigate this interference. (D) Neutralization/Adsorption: Acid-rinse glassware and acidify sodium sulfate reagent to prevent loss of organic acids. (E) Organics: Organic acids, phenols, phthalate esters, and chlorinated compounds that can interfere and can be partially removed with a methanol wash of the column. (F) Contamination from sample carryover: Rinsing apparatus with MTBE between analyses can minimize contamination. (G) Extracted interferences: Interference from extracted non-target compounds, with retention times similar to target compounds, can be reduced by using confirmation analysis. |
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Quality Control Requirements
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Initial demonstration of laboratory capability, determination of surrogate compound recoveries in each sample and blank, monitoring internal standard peak area or height in each sample and blank, analysis of laboratory reagent blanks (LRBs), laboratory fortified blanks (LFBs), laboratory fortified matrix samples, and QC samples. Additional QC practices are recommended. A MDL for each analyte must also be determined. |
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Sample Handling
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Grab samples must be collected in accordance with conventional sampling practices using amber glass containers with TFE-lined screw-caps and capacities in excess of 100 mL. Dechlorinate with crystalline ammonium chloride (NH4Cl) to produce a concentration of 100 mg/L in the sample. Alternatively add 1.0 mL of a 10 mg/mL aqueous solution of NH4Cl to the sample bottle for each 100 mL of sample bottle capacity. Store samples at 4oC away from light until analysis. |
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Maximum Holding Time
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28 days; extracts within 48 hours. |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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