ASTM D5085-02(2008)
(Test Method)Standard Test Method for Determination of Chloride, Nitrate, and Sulfate in Atmospheric Wet Deposition by Chemically Suppressed Ion Chromatography
Standard Test Method for Determination of Chloride, Nitrate, and Sulfate in Atmospheric Wet Deposition by Chemically Suppressed Ion Chromatography
SIGNIFICANCE AND USE
This test method is useful for the determination of the anions: chloride, nitrate, and sulfate in atmospheric wet deposition.
Fig. X1.1 in the appendix represents cumulative frequency percentile concentration plots of chloride, nitrate, and sulfate obtained from analyses of over 5000 wet deposition samples. These data may be used as an aid in the selection of appropriate calibration solutions. (3)
SCOPE
1.1 This test method is applicable to the determination of chloride, nitrate, and sulfate in atmospheric wet deposition (rain, snow, sleet, and hail) by chemically suppressed ion chromatography (1) . For additional applications refer to Test Method D 4327.
1.2 The concentration ranges for this test method are listed below. The range tested was confirmed using the interlaboratory collaborative test (see Table 1 for statistical summary of the collaborative test).
MDL (mg/L) (2)Range of
Method
(mg/L)Range
Tested
(mg/L) Chloride0.030.09–2.00.15–1.36 Nitrate0.03 0.09–5.0 0.15–4.92 Sulfate 0.03 0.09–8.0 0.15–6.52
1.3 The method detection limit (MDL) is based on single operator precision (2) and may be higher or lower for other operators and laboratories. The precision and bias data presented are insufficient to justify use at this low level, however, many workers have found that this test method is reliable at lower levels than those that were tested.
1.4 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. Specific precautionary statements are given in Section 9.
General Information
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D5085 − 02(Reapproved 2008)
Standard Test Method for
Determination of Chloride, Nitrate, and Sulfate in
Atmospheric Wet Deposition by Chemically Suppressed Ion
Chromatography
This standard is issued under the fixed designation D5085; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method is applicable to the determination of
D883Terminology Relating to Plastics
chloride, nitrate, and sulfate in atmospheric wet deposition
D1129Terminology Relating to Water
(rain, snow, sleet, and hail) by chemically suppressed ion
D1193Specification for Reagent Water
chromatography (1) . For additional applications refer to Test
D1356Terminology Relating to Sampling and Analysis of
Method D4327.
Atmospheres
1.2 The concentration ranges for this test method are listed
D2777Practice for Determination of Precision and Bias of
below. The range tested was confirmed using the interlabora-
Applicable Test Methods of Committee D19 on Water
tory collaborative test (see Table 1 for statistical summary of
D3670Guide for Determination of Precision and Bias of
the collaborative test).
Methods of Committee D22
D4210Practice for Intralaboratory Quality Control Proce-
Range of Range
Method Tested
dures and a Discussion on Reporting Low-Level Data
MDL (mg/L) (2) (mg/L) (mg/L)
(Withdrawn 2002)
Chloride 0.03 0.09–2.0 0.15–1.36
Nitrate 0.03 0.09–5.0 0.15–4.92 D4327Test Method forAnions in Water by Suppressed Ion
Sulfate 0.03 0.09–8.0 0.15–6.52
Chromatography
D5012Guide for Preparation of Materials Used for the
1.3 The method detection limit (MDL) is based on single
Collection and Preservation of Atmospheric Wet Deposi-
operator precision (2) and may be higher or lower for other
tion
operators and laboratories. The precision and bias data pre-
IEEE/ASTM SI-10Standard for Use of the International
sented are insufficient to justify use at this low level, however,
System of Units (SI): The Modern Metric System
many workers have found that this test method is reliable at
E694Specification for Laboratory Glass Volumetric Appa-
lower levels than those that were tested.
ratus
1.4 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1 Definitions—For definitions of terms used in this test
priate safety and health practices and determine the applica-
method, refer to Terminologies D883, D1129, and D1356 and
bility of regulatory limitations prior to use. Specific precau-
Test Method D4327 and Practice IEEE/ASTM SI-10.
tionary statements are given in Section 9.
4. Summary of Test Method
4.1 Ionchromatographycombinesconductometricdetection
with the separation capabilities of ion exchange resins. (1) A
This test method is under the jurisdiction of ASTM Committee D22 on Air
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient
Atmospheres and Source Emissions. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 1, 2008. Published September 2008. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1990. Last previous edition approved in 2002 as D5085–02. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D5085-02R08. the ASTM website.
2 4
The boldface numbers in parentheses refer to references at the end of this test The last approved version of this historical standard is referenced on
method. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5085 − 02 (2008)
TABLE 1 Precision and Bias for Chloride, Nitrate, and Sulfate Determined from the Synthetic Atmospheric Wet Deposition Samples
Used in the Interlaboratory Comparison Study
Precision mg/L
Amount Mean
Bias, Significant
A 95 % 95 %
Analyte Added, Recovery, n
B
C D
mg/L Bias
S Reproducibility S Repeatability
t o
mg/L mg/L
Limit Limit
Chloride 0.15 0.157 36 0.0535 0.150 0.0116 0.0325 0.007 no
0.30 0.293 35 0.0554 0.155 0.0291 0.0815 −0.007 no
0.68 0.652 36 0.0549 0.154 0.0237 0.0664 −0.028 biased low
1.36 1.368 36 0.1 0.28 0.0431 0.121 0.008 no
Nitrate 0.15 0.138 24 0.0362 0.101 0.0289 0.0809 −0.012 no
1.08 1.077 24 0.0495 0.139 0.0421 0.118 −0.003 no
2.44 2.486 22 0.0197 0.0552 0.0183 0.0512 0.046 biased high
4.92 4.999 24 0.126 0.353 0.075 0.21 0.079 biased high
Sulfate 0.15 0.172 36 0.055 0.154 0.0304 0.085 0.022 no
1.43 1.442 35 0.0683 0.191 0.0369 0.103 0.012 no
3.23 3.358 36 0.13 0.364 0.046 0.129 0.128 biased high
6.52 6.775 36 0.37 1.04 0.109 0.305 0.255 biased high
A
Number of samples included in final statistical analysis after removal of outlier data.
B
95 % confidence level.
C
Between laboratory precision, reproducibility.
D
Within laboratory precision (pooled single operator precision), repeatability.
filtered aliquot of the sample, ranging in size from 50 to 250 adjacentpeak.Decreasingtheeluentconcentrationorflowrate,
µL, is pumped through an ion exchange column where the increasing column length, or decreasing sample size may
anions of interest are separated. Each ion’s affinity for the correct this problem.
exchange sites, known as its selectivity quotient, is largely
6.2 Interferences may be caused by ions with retention
determined by its radius and valence. Because different ions
timesthataresimilartotheanionofinterest.Theretentiontime
have different selectivity quotients, the sample ions elute from
of sulfite may be similar to nitrate or sulfate. Other possible
the column as discrete bands. Each ion is identified by its
interfering ions are bromide and phosphate. Before analyzing
retention time within the exchange column. The sample ions
precipitation samples, measure the retention times of these
are selectively eluted off the separator column and onto a
possibleinterferingions.Interferenceiscommoninsometypes
suppressorcolumn,wheretheconductivityoftheeluentionsis
of wet deposition samples. If this interference is anticipated,
reducedandthesampleionsareconvertedtotheircorrespond-
decreasing the eluent concentration or flow rate, increasing
ing strong acids. The separated anions are detected by a
column length, or decreasing sample size will result in im-
conductance cell. The chromatograms produced are displayed
proved peak resolution.
on a strip chart recorder or other data acquisition device.
6.3 Water from the sample injection will cause a negative
Measurement of peak height or area is used for quantitation.
The ion chromatograph is calibrated with standard solutions peak (water dip) in the chromatogram when it elutes because
its conductance is less than that of the suppressed eluent.
containing known concentrations of the anion(s) of interest.
Calibration curves are constructed from which the concentra- Chloride may elute near the water dip and must be sufficiently
resolved from the dip to be accurately quantified. This can be
tion of each analyte in the unknown sample is determined. For
additional information on ion chromatography refer to Test achieved by changing the eluent concentration or decreasing
the flow rate. The potential interference of the negative peak
Method D4327.
can be eliminated by adding an equivalent of 100 µl of a
5. Significance and Use prepared eluent concentrate (solution that is 100 times more
concentrated than the eluent used for analysis) per 10.0 mLof
5.1 This test method is useful for the determination of the
sample. Identical eluent additions must also be included in
anions: chloride, nitrate, and sulfate in atmospheric wet depo-
calibration and quality control solutions.
sition.
6.4 Decreases in retention times and resolution are symp-
5.2 Fig. X1.1 in the appendix represents cumulative fre-
toms of column deterioration which may be caused by the
quency percentile concentration plots of chloride, nitrate, and
buildup of contaminants on the exchange resin. Refer to the
sulfate obtained from analyses of over 5000 wet deposition
manufacturer’s guidelines for instructions on cleaning the
samples. These data may be used as an aid in the selection of
column resin and column filter beds. Excising the contami-
appropriate calibration solutions. (3)
nated portion of the column and changing the filters may also
improve performance. If the procedure in this section do not
6. Interferences
restore the retention times, replace the column.
6.1 Unresolved peaks will result when the concentration of
one of the sample components is 10 to 20 times higher than 6.5 Contaminated valves and sample lines may also reduce
another component that appears in the chromatogram as an system performance causing decreased retention times and
D5085 − 02 (2008)
resolutions. Refer to the manufacturer’s guidelines for instruc- approximately 6 µL coupled with a meter capable of reading
tions on cleaning the valves and replacing the lines. from 0 to 1000 µs/cm on an analog or digital scale.
7.1.7 Pump—Use a pump capable both of delivering a
NOTE 1—Review operational details and refer to the trouble shooting
constant flow rate of approximately 1 to 5 mL/min and of
guide in the Operator’s Manual to determine the cause of decreased
tolerating a pressure 1379 to 13 790 kPa.Aconstant pressure,
retention times and resolution prior to extensive cleaning or changing of
all valves, columns, filters, sample lines, or all of the above.
constant flow pump is recommended for enhanced baseline
stability.All interiorpumpsurfaces that will beincontact with
6.6 The presence of air bubbles in the columns, tubing, or
samples and standards must be manufactured from inert,
conductivity detector cell may cause baseline fluctuations and
non-metallic materials.
peak variability. Prevent introducing air into the system when
7.1.8 Data Acquisition System:
injectingsamplesandstandards.Theuseofdegassedwaterfor
7.1.8.1 Recorder—This must be compatible with the maxi-
eluents and regenerants may help to minimize the introduction
mum conductance detector output with a full-scale response
of air (See 8.2).
time of 0.5 s or less.Atwo pen recorder with variable voltage
6.7 For more information on interferences refer to Test
input settings is recommended.
Method D4327.
7.1.8.2 Integrator—If an integrating system is employed,
thedataacquisitionunitmustbecompatiblewiththemaximum
7. Apparatus
detector output to quantitate the peak height or area. If an
7.1 Ion Chromatograph—Select an instrument equipped
integrator is used, the maximum peak height or area measure-
with an injection valve, a sample loop, separator column(s),
ment must be within the linear range of the integrator.
suppressor column(s), pump(s), and detector meeting require-
7.1.9 Sample Loop—Selectasampleloopwithacapacityof
ments specified. Peripheral equipment includes compressed
50 to 250 µL.
gas, a suitable data acquisition device such as a strip chart
7.1.10 Sample Introduction System—Select one of the fol-
recorder, an integrator, or computer, and may include an
lowing:
automatic sampler.
7.1.10.1 Syringe—A syringe equipped with a male fitting
7.1.1 Tubing—Tubing that comes in contact with samples
with a minimum capacity of 2 mL.
and standards must be manufactured from inert material such
7.1.10.2 Autosampler—An autosampling system capable of
as polyethylene plastics or TFE-fluorocarbon.
precisedelivery,equippedwithadustcovertoreduceairborne
7.1.2 Anion Guard Column—Also called a precolumn, it is
contamination.
placed before the separator column. The guard column con-
7.2 Eluent and Regenerant Reservoirs—Select containers
tains the same resin as the separator column and is used to
witha4to20L capacity that are designed to minimize
protectitfrombeingfouledbyparticulatesororganicconstitu-
introduction of air into the flow system for storing eluents and
ents. Using an anion guard column will prolong the life of the
regenerants.
separator column.
7.1.3 Anion Separator Column—This is a column packed
7.3 Glassware—Glassware, including volumetric pipettes
with a pellicular low-capacity anion exchange resin con-
and flasks, must be dedicated for use on atmospheric wet
structedofpolystyrene-divinylbenzenebeadscoatedwithquar-
deposition samples only.Volumetric pipettes should be used to
tenary ammonium active sites.
measurethestocksolutions.Thepipettesmaybeeitherfixedor
7.1.4 Anion Suppressor Column—Place following the sepa-
variable volume and either glass or plastic. Volumetric glass-
rator column. This may be in the form of an anion micro-
ware must meet the requirement for Class A items given in
membranesuppressororananionself-regeneratingsuppressor.
Specification E694. Pipettes with disposable tips are preferred
The first type of suppressor utilizes a semipermeable mem-
in order to reduce contamination. The pipettes must have a
brane containing anion exchange sites to suppress eluent
precision and a bias of 1% or better. Precision and bias are
conductance. The second type of suppressor uses the neutral-
determined by weighing a minimum of ten separately pipetted
ized cell effluent as the source of water for the regenerant
aliquots.
chamber water.
7.4 Laboratory Facilities—Laboratories used for the analy-
7.1.5 Compressed Gas (Nitrogen or Air)—Use ultra-high
sis of wet deposition samples must be free from sources of
purity 99.999% (v/v) compressed gas that is oil, particulate,
contamination.The use of laminar flow clean air work stations
and water free to actuate the valves and to pressurize the
is recommended for sample processing and preparation to
regenerant flow system as needed.
avoidtheintroductionofairbornecontaminants.Samplesmust
7.1.6 Detector—Select a flow-through, temperature-
always be capped or covered prior to analysis. A positive
compensated, electrical conductivity cell with a volume of
pressure environment within the laboratory is also recom-
mended to minimize the introduction of external sources of
Dionex P/N 030986 (AG3) available from Dionex Corp., 1228 Titan Way, PO
contaminantgasesandparticulates.Roomtemperaturefluctua-
Box 3603, Sunnyvale, CA, 94088-3603, or equivalent has been found to be
tionsmustbecontrolledtowithin 6°Ctopreventbaselinedrift
satisfactory.
and changes in detector response. Windows within the labora-
Dionex P/N 030985 (AS3) available from Dionex Corp., 1228 Titan Way, PO
Box 3603, Sunnyvale, CA, 94088-3603, or equivalent has been found to be
tory must be kept closed at a
...
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:D5085–95 Designation:D5085–02 (Reapproved 2008)
Standard Test Method for
Determination of Chloride, Nitrate, and Sulfate in
Atmospheric Wet Deposition by Chemically Suppressed Ion
Chromatography
This standard is issued under the fixed designation D5085; 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 Thistestmethodisapplicabletothedeterminationofchloride,nitrate,andsulfateinatmosphericwetdeposition(rain,snow,
sleet, and hail) by chemically suppressed ion chromatography (1) using a two pen variable setting recorder and integrator. For
additional applications refer to Test Method D4327. For additional applications refer to Test Method D4327.
1.2 The concentration ranges for this test method are listed below. The range tested was confirmed using the interlaboratory
collaborative test (see Table 1 for statistical summary of the collaborative test).
Range of Range
Method Tested
MDL (mg/L) (2) (mg/L) (mg/L)
Chloride 0.03 0.09–2.0 0.15–1.36
Nitrate 0.03 0.09–5.0 0.15–4.92
Sulfate 0.03 0.09–8.0 0.15–6.52
1.3 The method detection limit (MDL) is based on single operator precision (2) and may be higher or lower for other operators
andlaboratories.Theprecisionandbiasdatapresentedareinsufficienttojustifyuseatthislowlevel,however,manyworkershave
found that this test method is reliable at lower levels than those that were tested.
1.4 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. Specific precautionary statements are given in Section 9.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D-19D19 on Water
D3670 Guide for Determination of Precision and Bias of Methods of Committee D-22 D22
D4210 Practice for Interalaboratory Quality Control Procedures and a Discussion on Reporting Low-Level Data
D4327 Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
D5012 Guide for Preparation of Materials Used for the Collection and Preservation of Atmospheric Wet Deposition
E380Practice for Use of the International System of Units (SI) (the Modernized Metric System) IEEE/ASTM SI-10 Standard
for Use of the International
System of Units (SI): The
Modern Metric System
E694 Specification for Laboratory Glass Volumetric Apparatus
This test method is under the jurisdiction ofASTM Committee D-22 on Sampling andAnalysis ofAtmospheres and is the direct responsibility of Subcommittee D22.06
on Atmospheric Deposition.
Current edition approved Jan. 15, 1995. Published March 1995. Originally published as D5085–90. Last previous edition D5085–90.
This test method is under the jurisdiction ofASTM Committee D22 onAir Quality and is the direct responsibility of Subcommittee D22.03 onAmbientAtmospheres
and Source Emissions.
Current edition approved Aug. 1, 2008. Published September 2008. Originally approved in 1990. Last previous edition approved in 2002 as D5085–02.
The boldface numbers in parentheses refer to references at the end of this test method.
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
, Vol 08.01.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.
D5085–02 (2008)
TABLE 1 Precision and Bias for Chloride, Nitrate, and Sulfate Determined from the Synthetic Atmospheric Wet Deposition Samples
Used in the Interlaboratory Comparison Study
Precision mg/L
Amount Mean
Bias, Significant
A 95 % 95 %
Analyte Added, Recovery, n
B
C D
mg/L Bias
S Reproducibility S Repeatability
t o
mg/L mg/L
Limit Limit
Chloride 0.15 0.157 36 0.0535 0.150 0.0116 0.0325 0.007 no
0.30 0.293 35 0.0554 0.155 0.0291 0.0815 −0.007 no
0.68 0.652 36 0.0549 0.154 0.0237 0.0664 −0.028 biased low
1.36 1.368 36 0.1 0.28 0.0431 0.121 0.008 no
Nitrate 0.15 0.138 24 0.0362 0.101 0.0289 0.0809 −0.012 no
1.08 1.077 24 0.0495 0.139 0.0421 0.118 −0.003 no
2.44 2.486 22 0.0197 0.0552 0.0183 0.0512 0.046 biased high
4.92 4.999 24 0.126 0.353 0.075 0.21 0.079 biased high
Sulfate 0.15 0.172 36 0.055 0.154 0.0304 0.085 0.022 no
1.43 1.442 35 0.0683 0.191 0.0369 0.103 0.012 no
3.23 3.358 36 0.13 0.364 0.046 0.129 0.128 biased high
6.52 6.775 36 0.37 1.04 0.109 0.305 0.255 biased high
A
Number of samples included in final statistical analysis after removal of outlier data.
B
95 % confidence level.
C
Between laboratory precision, reproducibility.
D
Within laboratory precision (pooled single operator precision), repeatability.
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminologies D883, D1129, and D1356 and Test
Method D4327 and Practice E380.
3.1.1method detection limit (MDL)—the minimum concentration of an analyte that can be reported with 99% confidence that
the value is above zero based on a standard deviation of greater than seven repetitive measurements of a solution containing the
analyte at a concentration near the low standard. The solution used should not be greater than five times the estimated MDL. (3)
4. Summary of Test Method
4.1 Ion chromatography combines conductometric detection with the separation capabilities of ion exchange resins. (1) A
filtered aliquot of the sample, ranging in size from 50 to 250 µL, is pumped through an ion exchange column where the anions
of interest are separated. Each ion’s affinity for the exchange sites, known as its selectivity quotient, is largely determined by its
radius and valence. Because different ions have different selectivity quotients, the sample ions elute from the column as discrete
bands. Each ion is identified by its retention time within the exchange column. The sample ions are selectively eluted off the
separator column and onto a suppressor column, where the conductivity of the eluent ions is reduced and the sample ions are
converted to their corresponding strong acids. The separated anions are detected by a conductance cell. The chromatograms
produced are displayed on a strip chart recorder or other data acquisition device. Measurement of peak height or area is used for
quantitation. The ion chromatograph is calibrated with standard solutions containing known concentrations of the anion(s) of
interest. Calibration curves are constructed from which the concentration of each analyte in the unknown sample is determined.
For additional information on ion chromatography refer to Test Method D4327.
5. Significance and Use
5.1 This test method is useful for the determination of the anions: chloride, nitrate, and sulfate in atmospheric wet deposition.
5.2 Fig. X1.1 in the appendix represents cumulative frequency percentile concentration plots of chloride, nitrate, and sulfate
obtained from analyses of over 5000 wet deposition samples. These data may be used as an aid in the selection of appropriate
calibration solutions. (4(3)
6. Interferences
6.1 Unresolvedpeakswillresultwhentheconcentrationofoneofthesamplecomponentsis10to20timeshigherthananother
component that appears in the chromatogram as an adjacent peak. Decreasing the eluent concentration or flow rate, increasing
column length, or decreasing sample size may correct this problem.
6.2 Interferencesmaybecausedbyionswithretentiontimesthataresimilartotheanionofinterest.Theretentiontimeofsulfite
may be similar to nitrate or sulfate. Other possible interfering ions are bromide and phosphate. Before analyzing precipitation
samples, measure the retention times of these possible interfering ions. Interference is common in some types of wet deposition
samples.Ifthisinterferenceisanticipated,decreasingtheeluentconcentrationorflowrate,increasingcolumnlength,ordecreasing
sample size will result in improved peak resolution.
6.3 Water from the sample injection will cause a negative peak (water dip) in the chromatogram when it elutes because its
conductanceislessthanthatofthesuppressedeluent.Chloridemayelutenearthewaterdipandmustbesufficientlyresolvedfrom
the dip to be accurately quantified. This can be achieved by changing the eluent concentration or decreasing the flow rate. The
D5085–02 (2008)
potential interference of the negative peak can be eliminated by adding an equivalent of 100 µl of a prepared eluent concentrate
(solution that is 100 times more concentrated than the eluent used for analysis) per 10.0 mLof sample. Identical eluent additions
must also be included in calibration and quality control solutions.
6.4 Decreases in retention times and resolution are symptoms of column deterioration which may be caused by the buildup of
contaminants on the exchange resin. Refer to the manufacturer’s guidelines for instructions on cleaning the column resin and
column filter beds. Excising the contaminated portion of the column and changing the filters may also improve performance. If
the procedure in this section do not restore the retention times, replace the column . column.
6.5 Contaminated valves and sample lines may also reduce system performance causing decreased retention times and
resolutions. Refer to the manufacturer’s guidelines for instructions on cleaning the valves and replacing the lines.
NOTE 1—Review operational details and refer to the trouble shooting guide in the Operator’s Manual to determine the cause of decreased retention
times and resolution prior to extensive cleaning or changing of all valves, columns, filters, sample lines, or all of the above.
6.6 The presence of air bubbles in the columns, tubing, or conductivity detector cell may cause baseline fluctuations and peak
variability. Prevent introducing air into the system when injecting samples and standards. The use of degassed water for eluents
and regenerants may help to minimize the introduction of air (See 8.2).
6.7 For more information on interferences refer to Test Method D4327.
7. Apparatus
7.1 Ion Chromatograph—Selectaninstrumentequippedwithaninjectionvalve,asampleloop,separatorcolumn(s),suppressor
column(s), pump(s), and detector meeting requirements specified. Peripheral equipment includes compressed gas, a suitable data
acquisition device such as a strip chart recorder, an integrator, or computer, and may include an automatic sampler.
7.1.1 Tubing—Tubing that comes in contact with samples and standards must be manufactured from inert material such as
polyethylene plastics or TFE-fluorocarbon.
7.1.2 Anion Guard Column—Also called a precolumn, it is placed before the separator column.The guard column contains the
same resin as the separator column and is used to protect it from being fouled by particulates or organic constituents. Using an
anion guard column will prolong the life of the separator column.(See Table 2.)
7.1.3 Anion Separator Column—This is a column packed with a pellicular low-capacity anion exchange resin constructed of
polystyrene-divinylbenzene beads coated with quartenary ammonium active sites.(See Table 2.)
7.1.4 Anion Suppressor Column—Placefollowingtheseparatorcolumn.Thismaybeintheformofapackedbedcolumn,fiber
suppressor,orananionmicro-membranesuppressor.Thefirsttypeofcolumnispackedwithahigh-capacitycationexchangeresin
in the protonated form capable of converting the eluent to a low or negligible background conductance and converting the sample
anions to their corresponding strong acids. The second two types of suppressors utilize a semipermeable membrane containing
anion exchange sites to suppress eluent conductance. (See Table 2.) —Place following the separator column. This may be in the
form of an anion micro-membrane suppressor or an anion self-regenerating suppressor. The first type of suppressor utilizes a
semipermeable membrane containing anion exchange sites to suppress eluent conductance. The second type of suppressor uses
the neutralized cell effluent as the source of water for the regenerant chamber water.
7.1.5 Compressed Gas (Nitrogen or Air)— Use ultra-high purity 99.999% (v/v) compressed gas that is oil, particulate, and
water free to actuate the valves and to pressurize the regenerant flow system as required. needed.
7.1.6 Detector—Select a flow-through, temperature-compensated, electrical conductivity cell with a volume of approximately
6 µL coupled with a meter capable of reading from 0 to 1000 µs/cm on an analog or digital scale.
7.1.7 Pump—Use a pump capable both of delivering a constant flow rate of approximately 1 to 5 mL/min and of tolerating a
pressure2001379to1000psi.13790kPa.Aconstantpressure,constantflowpumpisrecommendedforenhancedbaselinestability.
All interior pump surfaces that will be in contact with samples and standards must be manufactured from inert, non-metallic
materials.
7.1.8 Data Acquisition System:
7.1.8.1 Recorder—This must be compatible with the maximum conductance detector output with a full-scale response time of
0.5 s or less. A two pen recorder with variable voltage input settings is recommended.
7.1.8.2 Integrator—If an integrating system is employed, the data acquisition unit must be compatible with the maximum
detector output to quantitate the peak height or area. If an integrator is used, the maximum peak height or area measurement must
be within the linear range of the integrator.
Annual Book of ASTM Standards, Vol 11.01.
Dionex P/N 030986 (AG3) available from Dionex Corp., 1228 Titan Way, PO Box 3603, Sunnyvale, CA, 94088-3603, or equivalent has been found to be satisfactory.
Annual Book of ASTM Standards, Vol 11.03.
Dionex P/N 030985 (AS3) available from Dionex Corp., 1228 Titan Way, PO Box 3603, Sunnyvale, CA, 94088-3603, or equivalent has been found to be satisfactory.
Annual Book of ASTM Standards, Vol 14.02.
Dionex P/N 35350 (AFS) or Dionex P/N 38019 (AMMS) available from Dionex Corp., 1228 Titan Way, PO Box 3603,
...
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