EPA-OGWDW/TSC: 314.0: Perchlorate in Drinking Water by Ion Chromatography
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Official Method Name
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Determination of Perchlorate in Drinking Water Using Ion Chromatography |
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Current Revision
| Revision 1.0, November 1999. |
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Media
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WATER |
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Instrumentation
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Ion Chromatography |
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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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Brief Method Summary
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One milliliter of water is introduced directly into an ion chromatograph equipped with a guard column and a suppressor device. Perchlorate ions are separated and measured using an analytical column and a conductivity detector. |
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Scope and Application
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This methods determines perchlorate in reagent water, surface water, ground water and finished drinking water. Specific IC columns and analytical conditions are specified but other columns and conditions may be used. |
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Applicable Concentration Range
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4 - 400 ug/L |
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Interferences
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(A) Contamination: Interferences may be caused by contaminants in the reagent water, reagents, glassware, and other sample processing apparatus that lead to discrete artifacts or elevated baselines. (B) Coelution: Direct chromatographic coelution, concentration dependent coelution, and ionic displacement effects (which can shift rentention times) can all cause interferences by coelution. It may be possible to overcome adjusting chromatographic conditions (e.g., changing columns), diluting the sample, or using pretreatment cartridges. Care must be taken when using these steps to ensure that analyses are not adversely effected. (C) Anions: Sample matrices with high concentrations of common anions such as chloride, sulfate, and carbonate may destabilize the baseline. (D) Carry over: Carry over peaks from one analysis to another may also cause interferences as false positives. |
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Quality Control Requirements
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Initial Demonstration of Capability must show acceptable Demonstration of Accuracy (IDA) and Precision (IDP) and the Method Detection Limit (MDL) must be determined. Recovery for Laboratory Fortified Blanks (LFB) must be 85 - 115%. If samples have perchlorate levels that exceed the Matrix Conductivity Threshold (MCT) then pretreated LFBs must be used to reduce common anion levels and recovery must be 85 - 115%. Recovery of Laboratory Fortified Sample Matrix (LFM) samples or pretreated LFMs (when MCT is exceeded) must be 80 - 120%. Relative Percent Difference (RPD) for field or laboratory duplicates must be + or - 15% |
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Sample Handling
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Samples may be collected in clean plastic or glass bottles. Samples do not need to be shipped iced or stored cold, but should be protected from temperature extremes. No preservation is required. |
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Maximum Holding Time
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28 days |
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Relative Cost
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$51 to $200 |
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Sample Preparation Methods
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None |
