Standard Methods: 3030 E: Nitric Acid Digestion of Metals
|
Official Method Name
|
Nitric Acid Digestion of Metal Samples |
|---|---|
|
Current Revision
| Standard Methods Online |
|
Media
|
WATER |
|
Instrumentation
|
Preparatory Procedure |
|
Method Subcategory
|
Inorganic |
|
Method Source
|
|
|
Citation
|
|
|
Brief Method Summary
|
Nitric acid digests most samples. Some samples require the addition of perchloric, hydrochloric, or sulfuric acid to complete digestion. When using more than 100 mL of sample during digestion, determine recovery for each matrix to verify method validity. Add 5 mL concentrated HNO3 and a few boiling chips to a 50-100 mL aliquot of well-mixed sample in a 125 mL beaker. Bring sample to a slow boil and evaporate to about 10-20 mL, before precipitation occurs. Heat and add HNO3 as needed until digestion is complete as seen by a light-colored, clear solution. Wash sides of sample container with water and filter if needed (see abstract in Method 3030-B). Pour filtrate and washings in volumetric flask. Cool, dilute to 100 mL mark, and mix. Remove aliquots or concentrate sample (see abstract in Method 3030-D) for analysis. Samples totally digested by acid digestion yield comparable precision and bias, however, the minimal amount of acid should be used in the digestion as acid adds metals to the sample. |
|
Scope and Application
|
This method is applicable to the nitric acid digestion of samples containing metals. |
|
Applicable Concentration Range
|
|
|
Interferences
|
Metals introduced during preliminary treatment from equipment common to environmental labs. |
|
Quality Control Requirements
|
Check reagent grade acids for purity. Process blanks through all digestion and filtration steps. |
|
Sample Handling
|
Collect sample in plastic or glass container which has been rinsed with 1+1 HNO3. Adjust the pH of the sample to < 2 with HNO3. For dissolved metals, filter samples immediately. Analyze within 6 months. |
|
Maximum Holding Time
|
6 months |
|
Relative Cost
|
Less than $50 |
|
Sample Preparation Methods
|
