Chinchilla Scientifi: NO3 EasyChem: Nitrate in Water by Colorimetry
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Official Method Name
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EasyChem Methodology: Nitrate by Discrete Analysis, Chinchilla Easy (1-Reagent) Nitrate Method (Colorimetric, Automated, 1 Reagent) |
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Current Revision
| Rev. Feb. 2009 |
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Media
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WATER |
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Instrumentation
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Colorimeter |
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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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Easychem methodology for Nitrate by Discrete Analysis, Systea Easy (1-reagent) Nitrate Method (Colorimetric, Automated, 1 Reagent) |
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Brief Method Summary
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The automated procedure for the determination of nitrate utilizes the reaction whereby nitrate is reduced by a proprietary Chemical R1. The reduced nitrate is then treated with sulfanilamide and N-1-napthylethylenediamine dihydrochloride under acidic conditions to form a soluble dye which is measured colorimetrically at 546nm. The final product measured represents the nitrite ion originally present plus that formed from the nitrate. Regardless of the sample matrix used, recovery of NO3 to NO2 is consistently between 95-percent and 105-percent recovery. |
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Scope and Application
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This method is applicable to the analysis of nitrate in wastewater and drinking water. If this method is being used for compliance with the Clean Water Act the flexibility to modify this method as described in CFR 136.6 applies. |
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Applicable Concentration Range
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0.050-50 mg/L |
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Interferences
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Particulates create an interference, samples my be pre-filtered. Residual chlorine can produce a negative inteference by limiting reduction efficiency. Before analysis, samples should be checked and if required, dechlorinated with sodium thiosulfate. |
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Quality Control Requirements
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Sample Handling
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For nitrate sample chill to 4 deg C and analyze within 48 hrs, unless sample is chlorinated. If chlorinated chill and analyze within 14 days. For nitrite sample chill to 4 deg C and analyze with 48 hrs. For nitrate-nitrite sample acidify to pH < 2 with concentrated H2SO4, and analyze within 28 days. For wastewater samples, reaquirements are nearly identical, except sample to be analyzed for nitrate only must be analyzed within 48 hrs whether or not chlorine is present, and sample to be analyzed for nitrate-nitrite must be acidified to pH < 2 with H2SO4 and chilled to < 6 deg C and analyzed within 28 days. |
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Maximum Holding Time
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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