EPA-RCA: 6020A Rev. 1 (aqueous): Elements in water by ICP-MS
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Official Method Name
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EPA Method 6020A, Inductively Coupled Plasma-Mass Spectrometry, Revision 1, January 1998. |
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Current Revision
| EPA 6020B rev 2, July 2014 |
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Media
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WATER |
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Instrumentation
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Inductively Coupled Plasma - Mass Spectrometry |
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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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Method 6020, Revision 1 describes the multi-elemental determination of analytes by ICP-MS in environmental samples. The method measures ions produced by a radio-frequency inductively coupled plasma. Analyte species originating in a liquid are nebulized and the resulting aerosol is transported by argon gas into the plasma torch. The ions produced by high temperatures are entrained in the plasma gas and introduced, by means of an interface, into a mass spectrometer. The ions produced in the plasma are sorted according to their mass-to-charge ratios and quantified with a channel electron multiplier. Interferences must be assessed and valid corrections applied, or the data flagged to indicate problems. Interference correction must include compensation for background ions contributed by the plasma gas, reagents, and constituents of the sample matrix. Prior to analysis, samples which require total values must be acid digested using appropriate sample preparation methods. |
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Scope and Application
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This method covers the determination of elements in water samples and in waste extracts or digests. When dissolved constituents are required, samples must be filtered and acid-preserved prior to analysis. No digestion is required prior to analysis for dissolved elements in water samples. Acid digestion prior to filtration and analysis is required for groundwater, aqueous samples, industrial wastes, soils, sludges, sediments, and other solid wastes for which total (acid-leachable) elements are required. |
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Applicable Concentration Range
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Instrument detection limits, sensitivities, and linear ranges will vary with the matrices, instrumentation, and operating conditions. In relatively simple matrices, detection limits will generally be below 0.1 µg/L but may be 1.0 µg/L or higher for less sensitive elements. |
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Interferences
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(A) Isobaric elemental interferences: Determine and subtract signal for interfering element or use solid phase chelation. (B) Isobaric molecular and doubly-charged ion interferences: Correct with literature values of isotopic abundance of interferents or use solid phase chelation. (C) Physical interferences: Minimize solids levels to below 0.2%, use internal standard correction, or dilute the sample fivefold. (E) Memory interferences: Ensure rinse period is sufficient. |
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Quality Control Requirements
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Standard stock solutions, mixed calibration standard solutions, blanks (calibration, reagent, rinse), interference check solutions (ICSs), working ICSs, initial calibration verification solution (ICV), mass spectrometer tuning standard, serial dilution, post-digestion spike addition, laboratory control standard (LCS). |
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Sample Handling
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For dissolved analytes, filter and acidify. For total (acid-leachable) analytes, acid digestion prior to filtration. Only polyethylene or fluorocarbon containers are recommended for use in this method. |
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Maximum Holding Time
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Not stated but is 180 days for similar methods for these analytes. |
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Relative Cost
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$201 to $400 |
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Sample Preparation Methods
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Acid digestion for total (acid-leachable) elements is required. |
