EPA-NERL: 200.9: Trace Elements in Water by GFAA
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Official Method Name
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Determination of Trace Elements by Stabilized Temperature Graphite Furnace Atomic Absorption |
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Current Revision
| Revision 2.2, 1994 |
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Media
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WATER |
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Instrumentation
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Graphite Furnace-Atomic Absorption Spectrometer |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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Brief Method Summary
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For total recoverable elements in a solid or a particulate-containing aqueous samples, the solid/particulate is solubilized by gentle refluxing with nitric and hydrochloric acids. After cooling, the sample is brought up to volume and particulate is separated from the sample using a centrifuge or overnight settling. For dissolved elements or total recoverable elements where sample turbidity (particulate concentration) is low, the sample is prepared for analysis by adding nitric acid and diluting to a predetermined volume. The concentrations of elements in the prepared sample are measured using stabilized temperature platform (STP) graphite furnace atomic absorption (GFAA) spectroscopy. |
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Scope and Application
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This method determines dissolved and total recoverable elements in ground water, surface water, drinking water, storm runoff, industrial and domestic wastewater. This method also determines total recoverable elements in sediment, sludges, and soil. Total-recoverable determination data for aqueous samples should be reported as total (dissolved + suspended fractions) metal data. |
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Applicable Concentration Range
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Ranges differ for each analyte depending on matrix, instrumentation, and selected operating conditions. Unless otherwise noted, the analytical range extends from the laboratory determined MDL to the upper limit of the linear dynamic range. |
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Interferences
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Interferences can be classified as spectral, matrix, elemental, and memory. Please see the method for details on reducing the levels of these interferences. (1) Spectral interferences: Caused by the resulting absorbance of light by a molecule or atom that is not the analyte of interest or emission from black body radiation coming from the carbon platform. (2) Matrix interferences: Caused by sample components that inhibit formation of free atomic analyte atoms during the atomization cycle- can be chemical or physical. (3) Elemental interferences: Antimony, aluminum, arsenic, cadmium, lead, selenium, silver, and thallium. (4) Memory Interferences: Caused from analyzing a sample containing a high concentration of an element which cannot be removed quantitatively in one complete set of furnace steps. |
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Quality Control Requirements
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Method detection limit (MDL), initial precision and recovery (IPR), linear dynamic range (LDR), quality control sample (QCS), calibration verification solutions and blanks (CVs & CBs), method blanks (MBs), field blanks (FBs), equipment blanks (EBs), sampler check blanks, matrix spikes and matrix spike duplicates (MS/MSDs), and ongoing precision and recovery (OPR) |
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Sample Handling
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For dissolved metals: Filter through a 0.45 um capsule membrane filter at time of collection. Acidify filtrate to pH of <2 with 1:1 HNO3. For total recoverable metals: Acidify sample with 1:1 HNO3 to pH of <2, hold for 16 hours, verify pH, and add additional acid, if necessary. Solid samples usually require no preservation other than storage at 4oC. |
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Maximum Holding Time
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6 months for aqueous samples. No holding time limitation for solid samples. |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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