Method 8318 Water

N-Methylcarbamates by High Performance Liquid Chromatography (HPLC)


This method is for the determination of N-methylcarbamates from aqueous matrices by using high performance liquid chromatography (HPLC).

The aqueous sample is extracted with methylene chloride and solvent exchanged to methanol/ethylene glycol.  The extract is passed through a C-18 cartridge for cleanup, filtered, and then eluted on a C-18 analytical column for separation.  After separation, the analytes are hydrolyzed and derivitized post column and quantitated with a flourescence detector.

Per the method, no confirmation analysis is needed due to the specificity of the analysis.

N-methylcarbamates are known to have extreme instability in alkaline water so it's important to preserve the sample to pH 4-5 with 0.1N chloroacetic acid immediately after sample collection.  The analytes are also sensistive to alkaline hydrolysis so store the sample out of direct sunlight.


(EPA SW-846)

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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   7 days from collection to extraction; 40 days from extraction to analysis
Preservatives:   Adjust pH to 4-5 with 0.1 N chloroacetic acid immediately after collection and store at 4°C in the dark.
Required Preps:   None
Collection Method:   Grab sampling, SW-846 Chapter 9
Analytical Methodology:   HPLC with fluorescence detector
Documentation:   8318A

Analyte List*

Analyte Formula CAS Number Detection Limit
Propoxur (Baygon)
C11H15NO3
114-26-1
2.4
 µg/L
Aldicarb (Temic)
C7H14N2O2S
116-06-3
9.4
 µg/L
Carbofuran
C12H15NO3
1563-66-2
2
 µg/L
Aldicarb sulfone
C7H14N2O4S
1646-88-4
1.9
 µg/L
3-Hydroxycarbofuran
C12H15NO4
16655-82-6
2.6
 µg/L
Methomyl (Lannate)
C6H12N2O3S
16752-77-5
1.7
 µg/L
Methiocarb (Mesurol)
C11H15NO2S
2032-65-7
3.1
 µg/L
Promecarb
C12H17NO2
2631-37-0
2.5
 µg/L
Carbaryl (Sevin)
C12H11NO2
63-25-2
1.7
 µg/L
Dioxacarb
C11H13NO4
6988-21-2
2.2
 µg/L

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.