USGS-NWQL: I-1462:  Mercury, dissolved, CVFAA

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Mercury, atomic absorption spectrometric, cold vapor, flameless
Current Revision
1985
Media
WATER
Instrumentation
Cold Vapor Atomic Absorption
Method Subcategory
Inorganic
Method Source
  USGS-NWQL
Citation
Methods for the Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the United States Geological Survey, Book 5, Chapter A1 Edited by Marvin J. Fishman and Linda C. Friedman
Brief Method Summary
The cold-vapor, flameless, atomic absorption procedure is based on the absorption of radiation at 253.7 nm by mercury vapor. Organic mercury compounds, if present, are decomposed by hot (95oC) digestion with potassium permanganate and potassium persulfate in acid solution. The mercuric ions are then reduced to the elemental state with stannous chloride, and the mercury vapor is subsequently removed from solution by aeration and passed through a cell positioned in the light path of an atomic absorption spectrometer. This method is based on a procedure described by Hatch and Ott (1968).
Scope and Application
This method may be used to analyze water containing at least 0.5 ug/L of mercury. Samples containing mercury concentrations greater than 10 ug/L need to be diluted. Industrial and sewage effluent may be analyzed, as well as samples of fresh and saline water.
Applicable Concentration Range
0.5 ug/L to 10 ug/L
Interferences
Some samples may contain volatile organic compounds that absorb radiation at 253.7 nm and that may be swept from the solution along with the mercury vapor. These constitute a positive interference, and the possibility of their presence must not be overlooked.
Selenium concentrations, either as selenate or selenite, up to 10,000 ug/L do not interfere; higher concentrations were not tested.
Quality Control Requirements
Calibrate instrument using calibration standards (CAL). Quality control samples (QCS) and laboratory blanks (LB) analyzed at a minimum of I each after every 10 samples
Sample Handling
Container Description: 250 mL Glass bottle, acid-rinsed
Treatment and Preservation: Filter through 0.45-um filter; use filtered sample to rinse containers and acidify collected sample with 10 mL of potassium dichromate preservative. (5 g pottassium dichromate/500 mL nitric acid)
Maximum Holding Time
180 days
Relative Cost
$51 to $200
Sample Preparation Methods