NEMI Method Summary

Method Summary Information

Method Number: 1640 Media: WATER
Revision: April 1997
Method Source: U.S. EPA Engineering and Analysis Division
Subcategory: INORGANIC Analytes in this method
Official Name: Determination of Trace Elements in Ambient Waters by On-Line Chelation Preconcentration and Inductively Coupled Plasma-Mass Spectrometry
Descriptive Name Trace Elements in Ambient Waters by On-Line Chelation
Source Info: 4303 USEPA Headquarters
Ariel Rios Building
1200 Pennsylvania Avenue, N. W.
Washington, DC 20460
Citation: EPA Method Guidance CD-ROM (includes MCAWW Methods, and most current EPA Methods)
224811 Byte file
Brief Method
Summary:
 A sample is acidified and solubilized by gentle refluxing (if total recoverable elements are desired). Elements in a sample are preconcentrated using an iminodiacetate functionalized chelating resin. Group I and II metals, as well as most anions, are selectively separated from the analytes by elution with ammonium acetate at pH 5.5. The elements are subsequently eluted into a simplified matrix consisting of dilute nitric acid and are determined by ICP-MS using a directly coupled on-line configuration.
Scope And
Application:
 This method determines dissolved elements in ambient waters at EPA water quality criteria (WQC) levels. It may also be used for determination of total recoverable element concentrations in these waters.
Applicable
Conc Range:
 Not Available.
Interferences: (A) Contamination by carryover.
(B) Contamination of apparatus by direct and indirect contact.
(C) Contamination by airborne particulate matter.
(D) Isobaric elemental interferences.
(E) Wing overlap of m/z peaks.
(F) Isobaric polyatomic ion interferences of similar m/z's
(G) Physical interferences.
(H) Competing chelators.
QC Requirements: The minimum requirements consist of an initial demonstration of laboratory capability, analysis of samples spiked with metals of interest to evaluate and document data quality, and analysis of standards and blanks as tests of continued performance.
Sample Handling: Collect samples as described in EPA Method 1669. For dissolved metals, samples and field blanks are filtered through a 0.45 um capsule filter at the field site. Preservation of samples and field blanks for both dissolved and total recoverable elements may be performed in the field when the samples are collected or in the laboratory. Preservation involves the addition of 10% HNO3 to bring the sample to pH < 2. For samples received at neutral pH, approximately 5 mL of 10% HNO3 per liter will be required. Store preserved sample for a minimum of 48 hours at 0-4oC. Sample bottles should be stored in polyethylene bags at 0-4oC until analysis.
Max Holding Time:
 6 months (after preservation)
Sample Prep Met None.
Relative Cost: $51 to $200
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