EPA-TSC/NERL: 531.1: Carbamates in Water Using HPLC w/ Post-Column Derivitization
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Official Method Name
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Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Water by Direct Aqueous Injection High Performance Liquid Chromatography with Post Column Derivitization |
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Current Revision
| Revision 3.1, 1995 |
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Media
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WATER |
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Instrumentation
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High Performance Chromatography with Post Column Derivitization and Fluorescence 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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An aliquot of a filtered water sample is injected into a reverse phase high performance liquid chromatography (HPLC) column. Separation of the analytes is achieved using gradient elution chromatography. After elution from the HPLC column, the analytes are hydrolyzed with sodium hydroxide. The methyl amine formed during hydrolysis is reacted with o-phthalaldehyde (OPA) and 2-mercaptoethanol to form a highly fluorescent derivative (post-column derivitization). The concentrations of analytes eluted from the HPLC column are measured by detecting the fluorescence of derivatives with a fluoresence detector. |
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Scope and Application
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This method determines certain N-methylcarbamoyloximes and N-methylcarbamates (analytes) in ground water and finished drinking water. |
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Applicable Concentration Range
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Not Provided. |
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Interferences
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(A) Glassware contamination: Thoroughly clean glassware, including baking or solvent rinse. (B) Reagent contamination: Use high purity reagents. (C) Contamination from sample carryover: Rinsing apparatus with water and purging equipment between analyses can minimize contamination. (D) Matrix interferences: Matrix interferences may be mitigated by using a different detector that operates on different chemical/physical principles than the original detector, or by using different chromatography columns. Alternative chromatography columns are described in the method. |
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Quality Control Requirements
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Initial demonstration of laboratory capability, monitoring internal standard peak area or height in each sample and blank (when internal standard calibration procedures are being employed), followed by analysis of laboratory reagent blanks (LRBs), laboratory fortified samples, laboratory fortified blanks (LFBs), and QC samples. 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 glass containers following conventional sampling practices without prerinsing the bottle before collection. Samples targeted for the analysis of oxamyl, 3-hydroxycarbofuran, aldicarb sulfoxide, and carbaryl must be preserved at pH 3. Add 1.8 mL of monochloroacetic acid buffer to the 60 mL sample bottle. Dechlorinate with 80 mg of sodium thiosulfate per liter of sample if residual chlorine is present. After collection, seal the sample bottle and shake vigorously for 1 minute. Store samples at 4oC until analysis. |
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Maximum Holding Time
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28 days. |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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