ASTM D5904-02(2009)
(Test Method)Standard Test Method for Total Carbon, Inorganic Carbon, and Organic Carbon in Water by Ultraviolet, Persulfate Oxidation, and Membrane Conductivity Detection
Standard Test Method for Total Carbon, Inorganic Carbon, and Organic Carbon in Water by Ultraviolet, Persulfate Oxidation, and Membrane Conductivity Detection
SIGNIFICANCE AND USE
This test method is used for determination of the carbon content of water from a variety of natural, domestic, and industrial sources. In its most common form, this test method is used to measure organic carbon as a means of monitoring organic pollutants in high purity and drinking water. These measurements are also used in monitoring waste treatment processes.
The relationship of TOC to other water quality parameters such as chemical oxygen demand (COD) and total oxygen demand (TOD) is described in the literature.
SCOPE
1.1 This test method covers the determination of total carbon (TC), inorganic carbon (IC), and total organic carbon (TOC) in water in the range from 0.5 to 30 mg/L of carbon. Higher levels may be determined by sample dilution. The test method utilizes ultraviolet-persulfate oxidation of organic carbon, coupled with a CO2 selective membrane to recover the CO2 into deionized water. The change in conductivity of the deionized water is measured and related to carbon concentration in the oxidized sample. Inorganic carbon is determined in a similar manner without the requirement for oxidation. In both cases, the sample is acidified to facilitate CO2 recovery through the membrane. The relationship between the conductivity measurement and carbon concentration is described by a set of chemometric equations for the chemical equilibrium of CO2, HCO3−, H+, and the relationship between the ionic concentrations and the conductivity. The chemometric model includes the temperature dependence of the equilibrium constants and the specific conductances.
1.2 This test method has the advantage of a very high sensitivity detector that allows very low detection levels on relatively small volumes of sample. Also, use of two measurement channels allows determination of CO2 in the sample independently of organic carbon. Isolation of the conductivity detector from the sample by the CO2 selective membrane results in a very stable calibration, with minimal interferences.
1.3 This test method was used successfully with reagent water spiked with sodium bicarbonate and various organic materials. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices.
1.4 This test method is applicable only to carbonaceous matter in the sample that can be introduced into the reaction zone. The injector opening size generally limits the maximum size of particles that can be introduced.
1.5 In addition to laboratory analyses, this test method may be applied to on line monitoring.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D5904 − 02 (Reapproved 2009)
Standard Test Method for
Total Carbon, Inorganic Carbon, and Organic Carbon in
Water by Ultraviolet, Persulfate Oxidation, and Membrane
Conductivity Detection
This standard is issued under the fixed designation D5904; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 In addition to laboratory analyses, this test method may
be applied to on line monitoring.
1.1 This test method covers the determination of total
carbon (TC), inorganic carbon (IC), and total organic carbon 1.6 The values stated in SI units are to be regarded as
(TOC) in water in the range from 0.5 to 30 mg/L of carbon. standard. No other units of measurement are included in this
Higher levels may be determined by sample dilution. The test standard.
method utilizes ultraviolet-persulfate oxidation of organic
1.7 This standard does not purport to address all of the
carbon, coupled with a CO selective membrane to recover the
safety concerns, if any, associated with its use. It is the
CO into deionized water. The change in conductivity of the
2 responsibility of the user of this standard to establish appro-
deionized water is measured and related to carbon concentra-
priate safety and health practices and determine the applica-
tion in the oxidized sample. Inorganic carbon is determined in
bility of regulatory limitations prior to use.
asimilarmannerwithouttherequirementforoxidation.Inboth
cases,thesampleisacidifiedtofacilitateCO recoverythrough
2. Referenced Documents
the membrane. The relationship between the conductivity
2.1 ASTM Standards:
measurement and carbon concentration is described by a set of
D1129Terminology Relating to Water
chemometric equations for the chemical equilibrium of CO ,
D1192Guide for Equipment for Sampling Water and Steam
− +
HCO ,H , and the relationship between the ionic concentra-
in Closed Conduits (Withdrawn 2003)
tions and the conductivity. The chemometric model includes
D1193Specification for Reagent Water
the temperature dependence of the equilibrium constants and
D2777Practice for Determination of Precision and Bias of
the specific conductances.
Applicable Test Methods of Committee D19 on Water
1.2 This test method has the advantage of a very high
D3370Practices for Sampling Water from Closed Conduits
sensitivity detector that allows very low detection levels on
D5810Guide for Spiking into Aqueous Samples
relatively small volumes of sample.Also, use of two measure-
D5847Practice for Writing Quality Control Specifications
ment channels allows determination of CO in the sample
for Standard Test Methods for Water Analysis
independently of organic carbon. Isolation of the conductivity
detector from the sample by the CO selective membrane 3. Terminology
results in a very stable calibration, with minimal interferences.
3.1 Definitions—For definitions of terms used in this test
method, refer to Terminology D1129.
1.3 This test method was used successfully with reagent
water spiked with sodium bicarbonate and various organic
3.2 Definitions of Terms Specific to This Standard:
materials.Itistheuser’sresponsibilitytoensurethevalidityof
3.2.1 inorganic carbon (IC)—carbon in the form of carbon
this test method for waters of untested matrices.
dioxide, carbonate ion, or bicarbonate ion.
1.4 This test method is applicable only to carbonaceous
3.2.2 potassium hydrogen phthalate (KHP)—KHC H O .
8 4 4
matter in the sample that can be introduced into the reaction
3.2.3 refractory material—that which cannot be oxidized
zone. The injector opening size generally limits the maximum
completely under the test method conditions.
size of particles that can be introduced.
1 2
This test method is under the jurisdiction ofASTM Committee D19 on Water For referenced ASTM standards, visit the ASTM website, www.astm.org, or
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Organic Substances in Water. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 1, 2009. Published November 2009. Originally the ASTM website.
approved in 1996. Last previous edition approved in 2002 as D5904–02. DOI: The last approved version of this historical standard is referenced on
10.1520/D5904-02R09. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5904 − 02 (2009)
3.2.4 total carbon (TC)—the sum of IC and TOC. the IC concentration as part of the measurement.Alternatively,
the IC can be removed by acidifying and sparging the sample
3.2.5 total organic carbon (TOC)—carbon in the form of
prior to injection into the instrument.
organic compounds.
4.2 The basic steps of this test method are:
4. Summary of Test Method
4.2.1 Removal of IC, if desired, by vacuum degassing;
4.1 Fundamentals—Carbon can occur in water as inorganic
4.2.2 Conversion of remaining inorganic carbon to CO by
and organic compounds.This test method can be used to make
action of acid in both channels and oxidation of total carbon to
independent measurements of IC and TC and can also deter-
CO by action of acid-persulfate, aided by ultraviolet (UV)
mineTOCasthedifferenceofTCandIC.IfICishighrelative 2
radiation in the TC channel;
toTOCitisdesirabletouseavacuumdegassingunittoreduce
FIG. 1 Schematic Diagram of TOC Analyzer System
D5904 − 02 (2009)
TABLE 1 Blank Contribution and Inorganic Carbon (IC) Removal
Other interferences have been investigated and found to be
Efficiency of Vacuum Degassing Unit
minimal under most conditions. Refer to the references for
A A
Unit Number µg/L TOC µg/L IC IC Level with
more information.
Background Background
25 000µ g/L Input
6.3 Note that error will be introduced when the method of
1 3.2 8.2 55
2 3.2 22 61
difference is used to derive a relatively small level from two
3 2.4 8.0 105
large levels. For example, a ground water high in IC and low
4 4.2 13 89
inTOCwillgiveapoorerTOCvalueas(TC-IC)thanbydirect
5 2.8 13 30
6 3.0 8.0 70
measurement. In this case the vacuum degassing unit on the
7 4.8 8.9 67
instrument should be used to reduce the concentration of IC
8 4.7 8.3 63
prior to measurement. Alternatively, the sample can be acidi-
94.6 11 62
10 4.7 2.9 72
fied and sparged prior to introduction into the instrument. Use
A
Values are the difference between before and after addition of the degasser to a ofthevacuumdegassingunitorspargingthesamplemaycause
high purity (<5 µg/L) water stream.
lossofvolatileorganiccompounds,thusyieldingavaluelower
than the true TOC level.
6.4 Use of the vacuum degassing unit or sparging the
4.2.3 Detection of CO that is swept out of the reactors by
sample may cause loss of volatile organic compounds, thus
the liquid stream over membranes that allow the specific
yielding a value lower than the true TOC level. At low TOC
passage of CO to high purity water where change in conduc-
levels,thedegassingunitmayintroduceameasurableTOCand
tivity is measured; and
IC background. The user should characterize the background
4.2.4 Conversion of the conductivity detector signal to a
andperformanceofthedegassingmodulefortheirapplication.
display of carbon concentration in parts per million
A removal efficiency of 97% of the inlet IC is considered
(ppm=mg⁄L) or parts per billion (ppb=µg⁄L). The IC chan-
satisfactory. Table 1 provides typical IC removal performance
nel reading is subtracted from the TC channel to give a TOC
and background levels of the vacuum degassing unit.
reading. A diagram of suitable apparatus is given in Fig. 1.
References (1-5) provide additional information on this test
7. Apparatus
method.
7.1 Homogenizing Apparatus—Ahousehold blender is gen-
5. Significance and Use
erally satisfactory for homogenizing immiscible phases in
water.
5.1 Thistestmethodisusedfordeterminationofthecarbon
content of water from a variety of natural, domestic, and
7.2 Apparatus for Carbon Determination—Atypical instru-
industrial sources. In its most common form, this test method
ment consists of reagent and sample introduction mechanism,
is used to measure organic carbon as a means of monitoring 6
reaction vessel, detector, control system, and a display. Fig. 1
organic pollutants in high purity and drinking water. These
shows a diagram of such an arrangement.
measurements are also used in monitoring waste treatment
7.2.1 Vacuum degassing requires the manufacturer’s mod-
processes.
ule that includes a vacuum pump and a hollow fiber mem-
5.2 The relationship of TOC to other water quality param- brane assembly. Use of this vacuum degasser will remove
eterssuchaschemicaloxygendemand(COD)andtotaloxygen essentiallyallICaspartoftheanalysis.Themembranemodule
demand (TOD) is described in the literature. consists of a tube and shell arrangement of microporous
polypropylene hollow fibers. Sample flows along the inside of
6. Interferences and Limitations
the fibers, while air is passed on the shell side-counterflow to
6.1 The oxidation of dissolved carbon to CO is brought thesampleflow.Theshellsidepressureisreducedbymeansof
avacuumpumpontheairoutlet.Thesampleisacidifiedbefore
about at relatively low temperatures by the chemical action of
reactivespeciesproducedbyUV-irradiatedpersulfateions.Not introduction into the degasser to facilitate CO transport
through the hollow fibers. Sparging requires an inert vessel
all suspended or refractory material may be oxidized under
with a capacity of at least double the sample size with
these conditions; analysts should take steps to determine what
provision for sparging with 50 to 100 mL/min of carbon free
recovery is being obtained. This may be done by several
gas. This procedure will remove essentially all IC in 2 to 10
methods: by rerunning the sample under more vigorous reac-
min, depending on design.
tion conditions; by analyzing the sample by an alternative
methodknowntoresultinfullrecovery;orbyspikingsamples 7.2.2 Reaction—The sample flow is split after the addition
of reagents. Half of the flow passes to the delay coil while the
with known refractories and determining recovery.
other half passes into the oxidation reactor. The effluent from
6.2 Chloride ion above 250 mg/L tends to interfere with
bothstreamspassesoverindividualmembranesthatallowCO
oxidative reaction mechanisms in this test method. Follow
to pass through the membrane into prepurified water for
manufacturer’s instructions for dealing with this problem.
detection.
The boldface numbers given in parentheses refer to a list of references at the
end of this standard.
5 6
Handbook for Monitoring Industrial Wastewater, Section 5.3, U.S. Environ- Instruments manufactured and marketed by Sievers Instruments, Inc., 2500
mental ProtectionAgency,August 1973, pp. 5–12. Central Ave., Suite H1, Boulder, CO 80301, have been found satisfactory.
D5904 − 02 (2009)
7.2.3 Membrane—The membrane is a CO selective fluo- Sulfuric acid is prepared by diluting 336 mL of 95% reagent
ropolymer that is hydrophobic and non-porous. Refer to the (sp gr 1.84) to 1 L with reagent water. Phosphoric acid is
bibliography for additional details. prepared by diluting 410 mLof 85% reagent (sp gr 1.69) to 1
7.2.4 Detector—The CO that has passed through the mem- Lwithwater.Certificationofreagentassayshouldbeavailable.
brane into the purified water is measured by conductivity Reagentsinprepackagedcontainersfromtheinstrumentmanu-
sensors. The temperature of the conductivity cell is also facturer have been found to be acceptable.
automatically monitored so the readings can be corrected for
8.5 Organic Carbon, Standard Solution (2000 mg/L)—
changes in temperature.
Choose a water-soluble, stable reagent grade compound, such
7.2.5 Presentation of Results—The conductivity detector
as benzoic acid or anhydrous potassium hydrogen phthalate
outputisrelatedtostoredcalibrationdataandthendisplayedas
(KHC H O ). Calculate the weight of compound required to
8 4 4
parts per million, (ppm=milligrams of carbon per litre) or
make 1 L of organic carbon standard solution; for example,
partsperbillion,(ppb=microgramsofcarbonperlitre).Values
KHC H O =0.471 g of carbon per gram, so 1 L of 2 g/L of
8 4 4
are given for TC, IC, and TOC by difference.
standard requires 2/0.471, or 4.25, grams of KHP. Dissolve the
required amount of standard in some CO -free water in a 1-L
8. Reagents and Materials
volumetric flask, add 1 mL of sulfuric acid, and dilute to
8.1 Purity of Reagents—Reagent grade chemicals shall be
volume.Dilutionsofthisstocksolutioncontaining20mg/Lare
used in all tests. Unless otherwise indicated, it is intended that
to be used to calibrate and test performance of the carbon
all reagents conform to the specifications of the Committee on
analyzer.
AnalyticalReagentsoftheAmericanChemicalSociety, where
such specifications are available. Other grades may be used,
9. Sampling and Sample Preservation
provided it is first ascertained that the reagent is of sufficient
9.1 Collect the sample in accordance with Specification
purity to permit its use without lessening the accuracy of the
D1192 and Practices D3370.
determination.
9.2 To preserve samples for this analysis, store samples in
8.2 Purity of Water—Unless otherwise indicated, references
glass at 4°C. To aid preservation, acidify the samples to a pH
towatershallbeunderstoodtomeanreagentwaterconforming
of 2. It should be noted that acidification will enhance loss of
to Type I or Type II in Specification D1193. The indicated
inorganiccarbon.Ifthepurgeableorganicfractionisimportant,
specification does not actually specify inorganic carbon or
fill the sample bottles to overflowing with a minimum of
organiccarbonlevels.Theselevelscanaffecttheresultsofthis
turbulence and cap them using a fluoropolymer-lined cap,
test method, especially at progressively lower levels of the
without headspace.
carboncontentinthesamplestobemeasured.Whereinorganic
9.3 For monitoring of waters containing solids or immis-
carbon in reagent water is significant, CO -free water may be
cible liquids that are to be injected into the reaction zone, use
prepared from reagent water by acidifying to pH 2, then
amechanicalhomogenizerorultrasonicdisintegrator.Filtering
sparging with fritted-glass sparger using CO -free gas (time
or screening may be necessary after homogenization to reject
will depend on volume and gas flow rate, and should
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D 5904–96 Designation:D5904–02 (Reapproved 2009)
Standard Test Method for
Total Carbon, Inorganic Carbon, and Organic Carbon in
Water by Ultraviolet, Persulfate Oxidation, and Membrane
Conductivity Detection
This standard is issued under the fixed designation D5904; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of total carbon (TC), inorganic carbon (IC), and total organic carbon (TOC) in
water in the range from 0.5 to 30 mg/Lof carbon. Higher levels may be determined by sample dilution. The test method utilizes
ultraviolet-persulfateoxidationoforganiccarbon,coupledwithaCO selectivemembranetorecovertheCO intodeionizedwater.
2 2
The change in conductivity of the deionized water is measured and related to carbon concentration in the oxidized sample.
Inorganic carbon is determined in a similar manner without the requirement for oxidation. In both cases, the sample is acidified
to facilitate CO recovery through the membrane. The relationship between the conductivity measurement and carbon
− +
concentrationisdescribedbyasetofchemometricequationsforthechemicalequilibriumofCO ,HCO ,H ,andtherelationship
2 3
between the ionic concentrations and the conductivity. The chemometric model includes the temperature dependence of the
equilibrium constants and the specific conductances.
1.2 This test method has the advantage of a very high sensitivity detector that allows very low detection levels on relatively
small volumes of sample. Also, use of two measurement channels allows determination of CO in the sample independently of
organic carbon. Isolation of the conductivity detector from the sample by the CO selective membrane results in a very stable
calibration, with minimal interferences.
1.3 This test method was used successfully with reagent water spiked with sodium bicarbonate and various organic materials.
It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.
1.4 This test method is applicable only to carbonaceous matter in the sample that can be introduced into the reaction zone.The
injector opening size generally limits the maximum size of particles that can be introduced.
1.5 In addition to laboratory analyses, this test method may be applied to on line monitoring.
1.6
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1192 SpecificationGuide for Equipment for Sampling Water and Steam in Closed Conduits
D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D-19D19 on Water
D3370 Practices for Sampling Water from Closed Conduits Practices for Sampling Water from Closed Conduits
D5810 Guide for Spiking into Aqueous Samples
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
This test method is under the jurisdiction of ASTM Committee D-19 D19 on Water and is the direct responsibility of Subcommittee D19.06 on Methods for Analysis
for Organic Substances in Water.
Current edition approved Feb. 10, 1996. Published April 1996.
Current edition approved Oct. 1, 2009. Published November 2009. Originally approved in 1996. Last previous edition approved in 2002 as D5904–02. DOI:
10.1520/D5904-02R09.
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
, Vol 11.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5904–02 (2009)
3. Terminology
3.1 Definitions: —ForFor definitions of terms used in this test method, refer to Terminology D 1129D1129.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 inorganic carbon (IC)—carbon in the form of carbon dioxide, carbonate ion, or bicarbonate ion.
3.2.2 potassium hydrogen phthalate (KHP)—KHC H O .
8 4 4
3.2.3 refractory material—that which cannot be oxidized completely under the test method conditions.
3.2.4 total carbon (TC)—the sum of IC and TOC.
3.2.5 total organic carbon (TOC)—carbon in the form of organic compounds.
4. Summary of Test Method
4.1 Fundamentals—Carbon can occur in water as inorganic and organic compounds. This test method can be used to make
independentmeasurementsofICandTCandcanalsodetermineTOCasthedifferenceofTCandIC.IfICishighrelativetoTOC
it is desirable to use a vacuum degassing unit to reduce the IC concentration as part of the measurement.Alternatively, the IC can
be removed by acidifying and sparging the sample prior to injection into the instrument.
4.2 The basic steps of this test method are:
4.2.1 Removal of IC, if desired, by vacuum degassing;
FIG. 1 Schematic Diagram of TOC Analyzer System
D5904–02 (2009)
4.2.2 ConversionofremaininginorganiccarbontoCO byactionofacidinbothchannelsandoxidationoftotalcarbontoCO
2 2
by action of acid-persulfate, aided by ultraviolet (UV) radiation in the TC channel;
4.2.3 Detection of CO that is swept out of the reactors by the liquid stream over membranes that allow the specific passage
of CO to high purity water where change in conductivity is measured; and
4.2.4 Conversion of the conductivity detector signal to a display of carbon concentration in parts per million (ppm=mg/L) or
parts per billion (ppb=µg/L). The IC channel reading is subtracted from the TC channel to give a TOC reading. A diagram of
suitable apparatus is given in Fig. 1. References (1-5) provide additional information on this test method.
5. Significance and Use
5.1 Thistestmethodisusedfordeterminationofthecarboncontentofwaterfromavarietyofnatural,domestic,andindustrial
sources.Initsmostcommonform,thistestmethodisusedtomeasureorganiccarbonasameansofmonitoringorganicpollutants
in high purity and drinking water. These measurements are also used in monitoring waste treatment processes.
5.2 The relationship of TOC to other water quality parameters such as chemical oxygen demand (COD) and total oxygen
demand (TOD) is described in the literature.
6. Interferences and Limitations
6.1 TheoxidationofdissolvedcarbontoCO isbroughtaboutatrelativelylowtemperaturesbythechemicalactionofreactive
species produced by UV-irradiated persulfate ions. Not all suspended or refractory material may be oxidized under these
conditions; analysts should take steps to determine what recovery is being obtained. This may be done by several methods: by
rerunning the sample under more vigorous reaction conditions; by analyzing the sample by an alternative method known to result
in full recovery; or by spiking samples with known refractories and determining recovery.
6.2 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. Refer to the references for more information.
6.3 Note that error will be introduced when the method of difference is used to derive a relatively small level from two large
levels. For example, a ground water high in IC and low in TOC will give a poorer TOC value as (TC-IC) than by direct
measurement. In this case the vacuum degassing unit on the instrument should be used to reduce the concentration of IC prior to
measurement.Alternatively, the sample can be acidified and sparged prior to introduction into the instrument. Use of the vacuum
degassingunitorspargingthesamplemaycauselossofvolatileorganiccompounds,thusyieldingavaluelowerthanthetrueTOC
level.
6.4 Use of the vacuum degassing unit or sparging the sample may cause loss of volatile organic compounds, thus yielding a
value lower than the trueTOC level.At lowTOC levels, the degassing unit may introduce a measurableTOC and IC background.
The user should characterize the background and performance of the degassing module for their application.Aremoval efficiency
of 97% of the inlet IC is considered satisfactory. Table 1 provides typical IC removal performance and background levels of the
vacuum degassing unit.
7. Apparatus
7.1 Homogenizing Apparatus—A household blender is generally satisfactory for homogenizing immiscible phases in water.
7.2 Apparatus for Carbon Determination—A typical instrument consists of reagent and sample introduction mechanism,
reaction vessel, detector, control system, and a display. Fig. 1 shows a diagram of such an arrangement.
The boldface numbers given in parentheses refer to a list of references at the end of this standard.
Handbook for Monitoring Industrial Wastewater, Section 5.3, U.S. Environmental Protection Agency, August 1973, pp. 5–12.
Instruments manufactured and marketed by Sievers Instruments, Inc., 2500 Central Ave., Suite H1, Boulder, CO 80301, have been found satisfactory.
TABLE 1 Blank Contribution and Inorganic Carbon (IC) Removal
Efficiency of Vacuum Degassing Unit
A A
Unit Number µg/L TOC µg/L IC IC Level with
Background Background 25 000µ g/L Input
1 3.2 8.2 55
2 3.2 22 61
3 2.4 8.0 105
4 4.2 13 89
5 2.8 13 30
6 3.0 8.0 70
7 4.8 8.9 67
8 4.7 8.3 63
94.6 11 62
10 4.7 2.9 72
A
Values are the difference between before and after addition of the degasser to
a high purity (<5 µg/L) water stream.
D5904–02 (2009)
7.2.1 Vacuum degassing requires the manufacturer’s module that includes a vacuum pump and a hollow fiber membrane
assembly. Use of this vacuum degasser will remove essentially all IC as part of the analysis. The membrane module consists of
a tube and shell arrangement of microporous polypropylene hollow fibers. Sample flows along the inside of the fibers, while air
is passed on the shell side-counterflow to the sample flow. The shell side pressure is reduced by means of a vacuum pump on the
air outlet. The sample is acidified before introduction into the degasser to facilitate CO transport through the hollow fibers.
Sparging requires an inert vessel with a capacity of at least double the sample size with provision for sparging with 50 to 100
mL/min of carbon free gas. This procedure will remove essentially all IC in 2 to 10 min, depending on design.
7.2.2 Reaction—The sample flow is split after the addition of reagents. Half of the flow passes to the delay coil while the other
half passes into the oxidation reactor. The effluent from both streams passes over individual membranes that allow CO to pass
through the membrane into prepurified water for detection.
7.2.3 Membrane—The membrane is a CO selective fluoropolymer that is hydrophobic and non-porous. Refer to the
bibliography for additional details.
7.2.4 Detector—The CO that has passed through the membrane into the purified water is measured by conductivity sensors.
The temperature of the conductivity cell is also automatically monitored so the readings can be corrected for changes in
temperature.
7.2.5 Presentation of Results—The conductivity detector output is related to stored calibration data and then displayed as parts
per million, (ppm=milligrams of carbon per litre) or parts per billion, (ppb=micrograms of carbon per litre). Values are given
for TC, IC, and TOC by difference.
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee onAnalytical Reagents of theAmerican Chemical Society, where such
specificationsareavailable.Othergradesmaybeused,provideditisfirstascertainedthatthereagentisofsufficientpuritytopermit
its use without lessening the accuracy of the determination.
8.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Type I orType II in Specification D 1193D1193.The indicated specification does not actually specify inorganic carbon or organic
carbon levels.These levels can affect the results of this test method, especially at progressively lower levels of the carbon content
in the samples to be measured. Where inorganic carbon in reagent water is significant, CO -free water may be prepared from
reagent water by acidifying to pH 2, then sparging with fritted-glass sparger using CO -free gas (time will depend on volume and
gas flow rate, and should be determined by test).The carbon contribution of the reagent water should be determined and its effect
allowed for in preparation of standards and other solutions. CO -free water should be protected from atmospheric contamination.
Glass containers are required for storage of water and standard solutions.
8.3 Persulfate Reagent (15 % w/v)—Prepare ammonium persulfate to a concentration of 15% w/v by dissolving 15 g of
ammonium peroxydisulfate in water and diluting to 100 mL. Verify that it contains less than 2000 µg/L organic carbon
contamination. Certification of reagent assay should be available. Reagents in prepackaged containers from the instrument
manufacturer have been found to be acceptable.
8.4 Acid Reagent (6M)—Prepare acid solution to a concentration of 6M and verify that it contains less than 600 µg/L organic
carbon contamination. Since halogens are potential interferences, use only sulfuric or phosphoric acid for reagents. Sulfuric acid
is prepared by diluting 336 mL of 95% reagent (sp gr 1.84) to 1 L with reagent water. Phosphoric acid is prepared by diluting
410mLof85%reagent(spgr1.69)to1Lwithwater.Certificationofreagentassayshouldbeavailable.Reagentsinprepackaged
containers from the instrument manufacturer have been found to be acceptable.
8.5 Organic Carbon, Standard Solution (2000 mg/L)—Chooseawater-soluble,stablereagentgrade
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