Standard Methods: 6610B: Pesticides in Water by HPLC
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Official Method Name
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High-Performance Liquid Chromatographic Method |
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Current Revision
| Standard Methods Online |
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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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The sample is filtered and injected into a reverse-phase HPLC column. The constituents are separated by gradient elution chromatography. After elution the N-methyl compounds are hydrolyzed with sodium hydroxide. The resulting methylamine is reacted with o-phthalaldehyde (OPA) and 2-mercaptoethanol (MERC) to form a highly fluorescent isoindole product that is detected with a fluorescence detector. |
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Scope and Application
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This method is appropriate for the determination of certain N-methylcarbamoyloxime and N-methylcarbamate pesticides in natural ground and surface waters. |
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Applicable Concentration Range
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None given |
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Interferences
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The post-column reaction generally is sensitive to primary amines. Interferences from contaminants in solvents, reagents, glassware, and sample-processing equipment. High chlorine concentrations cause interference and loss of some constituents. Matrix interferences may be caused by contaminants in the sample. Interfering contamination may occur when a low-level sample is analyzed immediately after a sample containing relatively high concentrations. |
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Quality Control Requirements
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A minimum QC program should include the following QA elements: initial demonstration of lab capabiility, lab control standards, monitoring of systems performance, blank samples, QC check samples, duplicate analyses, demonstration of adquate recoveries, assessment of matrix effects, and demonstration of storage stability. |
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Sample Handling
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Fill bottle only to shoulder with water to be sampled, leaving space for expansion on freezing. Add 8 mg sodium thiosulfate/100 mL sample if residual chlorine is present. Keep samples cold (4oC) from time of collection until receipt in the lab. Preserve samples for analysis of oxamyl, 3-hydrocarbofuran, and carbaryl by adjusting to pH 3 with monochloroacetic acid buffer. In the lab, store samples at 4oC. |
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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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