NEMI Method Summary

Method Summary Information

Method Number: D5315 Media: WATER
Revision: Reapproved 1998. Current edition approved Oct. 15, 1992. Published December 1992.
Method Source: ASTM International
Subcategory: ORGANIC Analytes in this method
Official Name: Standard Test Method for N-Methyl-Carbamoyloximes and N-Methylcarbamates in Water by Direct Aqueous Injection HPLC with Post-Column Derivatization
Descriptive Name Standard Test Method for Carbamates in Water
Source Info: ASTM International
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Citation: ASTM Volume 11.02
 
Brief Method
Summary:
 The water sample is filtered, and a 200 to 400-mL aliquot is injected into a reverse phase 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 (2.0 g/L NaOH) at 95oC. The methylamine formed during hydrolysis is reacted with o-phthalaldehyde (OPA) and 2-mercaptoethanol to form a highly fluorescent derivative that is detected by a fluorescence detector .
Scope And
Application:
 This is a high-performance liquid chromatographic (HPLC) test method applicable to the determination of certain n-methylcarbamoyloximes and n-methylcarbamates in ground water and finished drinking water.
Applicable
Conc Range:
 Varies with analyte. Generally from < 10 ug/L
Interferences: Test method interferences may be caused by contaminants in solvents, reagents, glassware, and other sample processing apparatuses that lead to discrete artifacts or elevated baselines in liquid chromatograms. Specific sources of contamination have not been identified. All reagents and apparatus must be routinely demonstrated to be free of interferences under the analysis conditions by running laboratory reagent blanks in accordance with 12.2. Glassware must be cleaned scrupulously. The use of high-purity reagents and solvents helps to minimize interference problems. Purification of solvents by distillation in all-glass systems may be required.
Interfering contamination may occur when a sample containing low concentrations of analytes is analyzed immediately after a sample containing relatively high concentrations of analytes. A preventive technique is between-sample rinsing of the sample syringe and filter holder with two portions of water. Analyze one or more laboratory method blanks after analysis of a sample containing high concentrations of analytes.
Matrix interference may be caused by contaminants present in the sample. The extent of matrix interference will vary considerably from source to source, depending upon the water sampled. Positive identifications must be confirmed.
QC Requirements: Minimum quality control (QC) requirements are as follows: an initial demonstration of laboratory capability; monitoring of the internal standard peak area or height in each sample and blank when internal standard calibration procedures are being used; and an analysis of laboratory reagent blanks, laboratory-fortified samples, laboratory-fortified blanks, and quality control samples.
Sample Handling: Collect the samples in accordance with Specification D 1192, Practices D 3370, or Practices D 3694. Additionally, grab samples must be collected in glass containers. Follow conventional sampling practices; however, the bottle must not be prerinsed with sample before collection.
Oxamyl, 3-hydroxycarbofuran, aldicarb sulfoxide, and carbaryl can all degrade rapidly in neutral and basic waters held at room temperature. This short-term degradation is of concern during the periods of time that samples are being shipped and that processed samples are held at room temperature in autosampler trays. Samples targeted for the analysis of these three analytes must be preserved at a pH of 3, as shown as follows. The pH adjustment also minimizes analyte biodegradation. Add 1.8 mL of monochloroacetic acid buffer solution (pH 3) to the 60-mL sample bottle. Add buffer to the sample bottle either at the sampling site or in the laboratory before shipping to the sampling site.
If residual chlorine is present, add 80 mg of sodium thiosulfate per litre of sample to the sample bottle prior to collecting the sample. After the sample is collected in a bottle containing buffer, seal the sample bottle and shake it vigorously for 1 min. Samples must be iced or refrigerated at 4oC from the time of collection until storage; they must be stored at - 10oC until analyzed.
Max Holding Time:
 28 days at pH 3 and - 10oC.
 
Relative Cost: $201 to $400
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