NEMI Method Summary

Method Summary Information

Method Number: 1630 Media: WATER
Revision: August 1998
Method Source: U.S. EPA Engineering and Analysis Division
Subcategory: INORGANIC Analytes in this method
Official Name: Methyl Mercury in Water by Distillation, Aqueous Ethylation, Purge and Trap, and CVAFS
Descriptive Name Methyl Mercury in Water
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)
  Byte file
Brief Method
Summary:
 The sample is distilled with reagents to form methylethyl mercury (MEM) from methyl mercury. The MEM is purged from the sample with nitrogen onto a graphitic carbon trap. The MEM is thermally desorbed into an inert gas that carries the released MEM first through a pyrolytic decomposition column and then into the cell of a cold-vapor atomic fluorescence spectrometer (CVAFS). The concentration of MEM determined at the CVAFS corresponds to the concentration of methyl mercury.
Scope And
Application:
 This method determines methyl mercury in filtered and unfiltered water.
Applicable
Conc Range:
 0.02-5 ng/L.
Interferences: (A) Labware contamination
(B) Reagent contamination
(C) Sampling equipment contamination
(D) Human contact
QC Requirements: The minimum requirements consist of an initial demonstration of laboratory capability, ongoing analysis of standards and blanks as a test of continued performance, and the analysis of matrix spikes (MS) and matrix spike duplicates (MSD) to assess accuracy and precision.
Sample Handling: Collect samples into rigorously cleaned fluoropolymer bottles with fluoropolymer or fluoropolymer-lined caps. Borosilicate glass bottles may be used if Hg and Hg species are the only target analytes. Filter samples through a 0.45-um capsule filter and preserve with 4 mL/L of concentrated HCl. Saline samples are preserved with 2 mL/L of 9 M H2SO4.
Max Holding Time:
 6 months (after preservation)
48 h (after sampling if not preserved at time of collection)
Sample Prep Met None.
Relative Cost: $51 to $200
5352
Page 1