EPA-RCA: 7060A: Arsenic by GFAA
|
Official Method Name
|
Arsenic (Atomic Absorption, Furnace Technique) |
|---|---|
|
Current Revision
| Revision 1, September 1994 |
|
Media
|
VARIOUS |
|
Instrumentation
|
Graphite Furnace-Atomic Absorption Spectrometer |
|
Method Subcategory
|
Inorganic |
|
Method Source
|
|
|
Citation
|
|
|
Brief Method Summary
|
Aqueous samples are digested with hydrogen peroxide and nitric acid in order to convert organic forms of arsenic to inorganic forms, to minimize organic interferences, and to solubilize the sample. Sludge samples are digested using the procedure in Method 3050. Nickel nitrate (or equivalent modifier) is then added to an aliquot of the digestate. Concentrations of arsenic in the matrix are then measured using a graphite furnace atomic absorption (GFAA) system. |
|
Scope and Application
|
This method determines the concentration of arsenic in wastes, mobility procedure abstracts, soils, and ground water. |
|
Applicable Concentration Range
|
Aqueous: 5 - 100 ug/L Non-aqueous: varies with matrix type |
|
Interferences
|
(A) Loss of analyte: Elemental arsenic and its compounds are volatile, subsequently, some may be lost during sample preparation and/or analysis. Appropriate QC, including spiked samples and standard reference materials should be processed, as well as, adding a matrix modifier and choosing appropriate drying and charring cycles to detect and minimize volatilization losses. (B) Matrix interferences: Arsenic is susceptible to severe nonspecific absorption and light scattering during atomization. Aluminum is known be a positive interferent. In these instances, use an appropriate simultaneous background correction technique, such as Zeeman, in the case of aluminum. (C) Memory interferences: Arsenic can carry over if it is not completely volatilized, which can be detected by blank burns. The tube should be cleaned by regularly burning it at full power throughout the analysis. |
|
Quality Control Requirements
|
Refer to section 8.0 of Method 7000. |
|
Sample Handling
|
Aqueous samples must be acidified to a pH < 2 with nitric acid and then refrigerated until analysis. Waste samples do not need refrigeration, but refer to Chapter One for the minimum requirements for sample handling and storage. |
|
Maximum Holding Time
|
Not Available. |
|
Relative Cost
|
$51 to $200 |
|
Sample Preparation Methods
|
Methods 7060A or 3050 |
