Standard Methods: 3500-V B: Vanadium by Gallic Acid Method
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Official Method Name
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3500-V B. Gallic Acid Method |
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Current Revision
| Standard Methods Online |
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Media
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WATER |
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Instrumentation
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Spectroscopy (Colorimetry; Photometry) |
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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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The concentration of trace amounts of vanadium in water is determined by measuring the catalytic effect it exerts on the rate of oxidation of gallic acid by persulfate in acid solution. Under the given conditions of concentrations of reactants, temperature, and reaction time, the extent of oxidation of gallic acid is proportional to the concentration of vanadium. Vanadium is determined by measuring the absorbance of the sample at 415 nm and comparing it with that of standard solutions treated identically. |
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Scope and Application
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The method is suitable for potable water samples. |
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Applicable Concentration Range
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Interferences
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The following substances interefere in the test: chromium, cobalt, copper(II), iron(II & III), molybdenum(VI), nickel(II), silver, uranium(VI), bromide, chloride, and iodide. A table in the method lists the concentrations at which they interfere. Because of the high sensitivity of the method, interfering substances in concentrations only slightly above tolerance limits can be rendered harmless by dilution. Traces of bromide and iodide interfere seriously and dilution alone will not always reduce the concentration below tolerance limits. |
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Quality Control Requirements
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See Section 3020 Quality Assurance/Quality Control. |
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Sample Handling
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Plastic or glass containers. Add HNO3 to pH <2. See Section 3010 for more details. |
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Maximum Holding Time
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6 months (See Section 1060) |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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