NEMI Method Summary

Method Summary Information

Method Number: D5904 Media: WATER
Revision: Current edition approved Feb. 10, 1996.
Method Source: ASTM International
Subcategory: ORGANIC Analytes in this method
Official Name: Standard Test Method for Total Carbon, Inorganic Carbon, and Organic Carbon in Water by Ultraviolet, Persulfate Oxidation, and Membrane Conductivity Detection
Descriptive Name Carbon (all forms) in Water
Source Info: ASTM International
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Citation: ASTM Volume 11.02
 
Brief Method
Summary:
 The basic steps of this test method are: 1)Removal of IC, if desired, by vacuum degassing; 2)Conversion of remaining inorganic carbon to CO2 by action of acid in both channels and oxidation of total carbon to CO2 by action of acid-persulfate, aided by ultraviolet (UV) radiation in the TC channel; 3) Detection of CO2 that is swept out of the reactors by the liquid stream over membranes that allow the specific passage of CO2 to high purity water where change in conductivity is measured; and 4) Conversion of the conductivity detector signal to a display of carbon concentration in parts per million (ppm = mg/L) or parts per billion (ppb = ug/L). The IC channel reading is subtracted from the TC channel to give a TOC reading.
Scope And
Application:
 This method determines total carbon (TC), inorganic carbon (IC), and total organic carbon (TOC) in water.
Applicable
Conc Range:
 0.5 - 30 mg/L
Interferences: Chloride ion above 250 mg/L tends to interfere with oxidative reaction mechanisms in this test method. Follow manufacturer's instructions for dealing with this problem. Other interferences have been investigated and found to be minimal under most conditions.
Use of the vacuum degassing unit or sparging the sample may cause loss of volatile organic compounds, thus yielding a value lower than the true TOC level. At low TOC levels, the degassing unit may introduce a measurable TOC and IC background. The user should characterize the background and performance of the degassing module for their application. A removal efficiency of 97 % of the inlet IC is considered satisfactory.
QC Requirements: Instrument calibration must be checked at the start of each sample group.
A duplicate, blank, and continuing calibration check sample must be run at least every twenty samples.
Sample Handling: Collect the sample in accordance with Specification D 1192 and Practices D 3370.
To preserve samples for this analysis, store samples in glass at 4oC. To aid preservation, acidify the samples to a pH of 2. It should be noted that acidification will enhance loss of inorganic carbon. If the purgeable organic fraction is important, fill the sample bottles to overflowing with a minimum of turbulence and cap them using a fluoropolymer-lined cap, without headspace.
For monitoring of waters containing solids or immiscible liquids that are to be injected into the reaction zone, use a mechanical homogenizer or ultrasonic disintegrator. Filtering or screening may be necessary after homogenization to reject particle sizes that are too large for the sample inlet tube or autosampler needle. Volatile organics may be lost.
For accurate measurements of samples containing < 0.5 mg/L direct, on-line measurement should be used.
Max Holding Time:
 
Relative Cost: $51 to $200
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