ASTM D5827-09(2015)

Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography

SIGNIFICANCE AND USE
4.1 This test method provides for the qualitative and quantitative determination of common anions in engine coolant in the milligrams per litre to low percent range and requires only a few millilitres or microlitres of sample per test, with results available in less than 30 min. Acceptable levels of chloride and other anions vary with manufacturer's blending specifications and applicable ASTM minimum or maximum specifications.
SCOPE
1.1 This test method covers the chemical analysis of engine coolant for chloride ion by high-performance ion chromatography (HPIC). Several other common anions found in engine coolant can be determined in one chromatographic analysis by this test method.  
1.2 This test method is applicable to both new and used engine coolant.  
1.3 Coelution of other ions may cause interferences for any of the listed anions. In the case of unfamiliar formulations, identification verification should be performed by either or both fortification and dilution of the sample matrix with the anions of interest.  
1.4 Analysis can be performed directly by this test method without pretreatment, other than dilution, as required by the linear ranges of the equipment. Table 1 indicates several applicable anions and approximate detection limits. (A) Determined using 100-μL sample volume. Sample diluted 99 + 1 (v/v) with chromatographic eluant 30-μS/cm full scale, suppressed conductivity detection. Dionex AS4ASC column with AG4ASC guard columns. Other systems will require MDL determinations using chosen dilution factors, eluants, columns, and detector.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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 its use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2015
• ICS: 71.100.45 - Refrigerants and antifreezes
• Technical Committee: D15 - Engine Coolants and Related Fluids
• Drafting Committee: D15.04 - Chemical Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D5827 − 09 (Reapproved 2015)
Standard Test Method for
Analysis of Engine Coolant for Chloride and Other Anions
by Ion Chromatography
This standard is issued under the fixed designation D5827; 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* E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers the chemical analysis of engine
E177Practice for Use of the Terms Precision and Bias in
coolant for chloride ion by high-performance ion chromatog-
ASTM Test Methods
raphy (HPIC). Several other common anions found in engine
coolant can be determined in one chromatographic analysis by
3. Summary of Test Method
this test method.
3.1 A small volume of working sample is prepared by
1.2 This test method is applicable to both new and used
dilution of the sample with the method eluant. This diluted
engine coolant.
sample is filtered and pumped through two ion exchange
1.3 Coelution of other ions may cause interferences for any
columnsandasuppressorandintoaconductivitydetector.Ions
of the listed anions. In the case of unfamiliar formulations,
are separated based on their affinity for exchange sites of the
identification verification should be performed by either or
resin with respect to the resin’s affinity for the eluant. The
both fortification and dilution of the sample matrix with the
suppressor increases the sensitivity of the method by both
anions of interest.
increasing the conductivity of the analytes and decreasing the
conductivity of the eluant. The suppressor converts the eluant
1.4 Analysis can be performed directly by this test method
and the analytes to the corresponding hydrogen form acids.
without pretreatment, other than dilution, as required by the
Anions are quantitated by integration of their response com-
linear ranges of the equipment. Table 1 indicates several
pared with an external calibration curve and are reported as
applicable anions and approximate detection limits.
milligrams per litre (mg/L).
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Significance and Use
standard.
4.1 This test method provides for the qualitative and quan-
1.6 This standard does not purport to address all of the
titative determination of common anions in engine coolant in
safety concerns, if any, associated with its use. It is the
the milligrams per litre to low percent range and requires only
responsibility of the user of this standard to establish appro-
a few millilitres or microlitres of sample per test, with results
priate safety and health practices and determine the applica-
availableinlessthan30min.Acceptablelevelsofchlorideand
bility of regulatory limitations prior to its use.
other anions vary with manufacturer’s blending specifications
and applicable ASTM minimum or maximum specifications.
2. Referenced Documents
2.1 ASTM Standards: 5. Interferences
D1193Specification for Reagent Water
5.1 Interferences can be caused by substances with similar
D1176Practice for Sampling and Preparing Aqueous Solu-
retention times, especially if they are in high concentration
tionsofEngineCoolantsorAntirustsforTestingPurposes
compared to those of the analyte of interest. Sample dilution
will be used to minimize or solve most interference problems.
This test method is under the jurisdiction ofASTM Committee D15 on Engine
5.2 A water dip (solvent system peak) can cause interfer-
Coolants and Related Fluids and is the direct responsibility of Subcommittee
ence with some integrators.This is eliminated by dilution with
D15.04 on Chemical Properties.
theeluantifthesampledilutionfactoris49+1(v/v)orgreater.
Current edition approved May 1, 2015. Published June 2015. Originally
ε1
Below this dilution, it is best to add a spike of eluant
approved in 1995. Last previous edition approved in 2009 as D5827-09 . DOI:
10.1520/D5827-09R15.
concentrate to the sample such that the sample is not diluted
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
significantly and the resulting test solution matches the eluant
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
used in the system. One method is the addition of 100 µL of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 100X eluant concentrate to 10.0 mL of sample or standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5827 − 09 (2015)
TABLE 1 Analytes and Minimum Detection Limits
A
Analyte Detection Limit, mg/L
−
Chloride (Cl)2.0
−
Nitrite (NO)5.0
Bromide (Br) 4.0
−
Nitrate (NO)7.1
2−
o-Phosphate (HPO ) 20.0
2−
Sulfate (SO ) 8.0
2−
Oxalate (C O ) 12.0
2 4
A
Determined using 100-µL sample volume. Sample diluted 99 + 1 (v/v) with
chromatographic eluant 30-µS/cm full scale, suppressed conductivity detection.
Dionex AS4ASC column with AG4ASC guard columns. Other systems will require
MDL determinations using chosen dilution factors, eluants, columns, and detector.
5.3 Method interferences can be caused by the contamina-
tion of glassware, eluant, reagents, etc. Great care must be
taken to ensure that contamination, especially by chloride, is
kept at the lowest possible levels.
5.4 Pre-rinsing of the sample preparation containers with
deionized water is mandatory.
5.5 The use of latex gloves is highly recommended to
prevent contamination.
6. Apparatus
FIG. 1 Sample Run—Chloride Peak at 1.7 min
6.1 Analytical Balance, capable of weighing accurately to
0.0001 g.
6.2 Ion Chromatograph—Analytical system with all re-
American Chemical Society, where such specification are
quired accessories including syringes, columns, suppressor, 3
available. Other grades may be used, provided it is first
gasses, and detector. Column life and performance are en-
ascertained that the reagent is of sufficiently high purity to
hanced by the use of a two-eluant channel gradient pump, if
permit its use without lessening the accuracy of the determi-
available.
nation.
6.3 Guard Column, for protection of the analytical column
7.2 Purity of Water—Unless otherwise indicated, references
from strongly retained constituents. Better separations are
to water shall be understood to mean reagent water as defined
obtained with additional plates.
by Type II of Specification D1193. It is recommended that all
6.4 Anion Separator Column, capable of producing analyte waterbefilteredthrougha0.2-µmfilter.Foreluantpreparation,
separation equivalent to or better than that shown in Fig. 1.
degas the water by sparging with helium or vacuum degassing
and sonication.
6.5 Anion Suppressor Device—Micro membrane suppressor
or equivalent.Acation exchange column in the hydrogen form
7.3 Eluant Buffer Stock Solution—Sodium bicarbonate
has been used successfully, but it will periodically need to be (NaHCO ) 1.5 mM and sodium carbonate (Na CO ) 1.2 mM.
3 2 3
regenerated as required, being indicated by a high background
Dissolve 2.5203 6 0.0005 g of NaHCO and 2.5438 6 0.0005
conductivity and low analyte response. gofNa CO inreagentwaterina1000-mLTypeAvolumetric
2 3
flask and dilute to 1 L. Dilute 100.0 mL of this stock solution
6.6 Conductivity Detector, low volume (<2 µL) and flow,
to 2000 mL in a 2-L Type A volumetric flask with degassed
temperature compensated, capable of at least 0 to 1000 µS/cm
reagent water. The pH of the stock solution is 10.1 to 10.3
on a linear scale.
(based on pK calculation). The eluant solution used may be
a
6.7 Integrator or Chromatography Data System Software,
different if other system or analytical columns are used.
capable of obtaining approximately the same detection limits
7.4 Stock Bromide Solution—Dry approximately2gof
as are listed in Table 1.
sodium bromide (NaBr) for6hat 150°C and cool in a
6.8 Drying Oven, controlled at 105, 150, and 600 6 5°C.
desiccator. Weigh and dissolve 1.2877 g of the dried salt in
6.9 Desiccator. reagent water and dilute to 1 L (1.00 mL=1.00 mg bromide).
7. Reagents
7.1 Purity of Reagents—Reagent grade or higher purity
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
chemicals shall be used for the preparation of all samples,
listed by the American Chemical Society, see Analar Standards for Laboratory
standards, eluants, and regenerator solutions. Unless otherwise
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
indicated, it is intended that all reagents conform to the
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
specifications of the Committee onAnalytical Reagents of the MD.
D5827 − 09 (2015)
TABLE 2 Chromatographic Conditions
7.5 Stock Chloride Solution—Dry approximately2gof
sodium chloride (NaCl) for1hat 600°C and cool in a Analyte Peak No. Retention Time, min
A
desiccator. Weigh and dissolve 1.6485 g and dilute to 1 Lwith Chloride 2 1.7
−
Nitrite 3 2.1
reagent water (1.00 mL=1.00 mg Cl ).
Bromide 4 3.3
Nitrate 5 3.7
7.6 Stock Formate Solution—Dry approximately2gof
Phosphate 6 7.7
sodium formate (NaHCO ) at 105°C for 6 h and cool in a
Sulfate 7 10.5
desiccator. Weigh and dissolve 1.4775 g of the salt in reagent
Oxalate 8 13.3
water and dilute to 1 L (1.00 mL=1.00 mg formic acid). A
Fluoride, acetate, formate, and glycolate will all elute before chloride, and poor
resolution of these species often precludes the quantitation of any, or all four, of
7.7 Stock Glycolic Acid Solution—Weigh and dissolve
them.
1.0000 g of the solid acid in reagent water and dilute to 1 L
(1.00 mL=1.00 mg glycolate).
7.8 Stock Nitrate Solution—Dry approximately2gofso-
9.3 Prepare concentrations of chloride at 0.08, 0.4, 0.8, and
dium nitrate (NaNO ) for 24 h at 105°C and cool in a
4.0 mg/Lfrom the stock solution.All final solutions should be
desiccator. Weigh and dissolve 1.3707 g and dilute to 1 Lwith
−
made with eluant as described in 5.2. Calibrate the ion
reagent water (1.00 mL=1.00 mg NO ).
chromatograph with at least five levels of the analyte, starting
7.9 Stock Nitrite Solution—Dry approximately2gofso-
nearbutabovetheminimumdetectionlimit(MDL)andfurther
dium nitrite (NaNO ) for 24 h in a desiccator containing
defining the working range in samples subsequent to dilution.
concentratedsulfuricacid(relativedensityof1.84).Weighand
These chloride analyte examples reflect a dilution of 99+1
dissolve 1.4998 g and dilute to 1 L with reagent water (1.00
(v/v)witheluant.Ifitisdesirabletocalibrateforanotheranion
−
mL=1.00mgNO ).Refrigerateandprepareweeklybec
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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.
´1
Designation: D5827 − 09 D5827 − 09 (Reapproved 2015)
Standard Test Method for
Analysis of Engine Coolant for Chloride and Other Anions
by Ion Chromatography
This standard is issued under the fixed designation D5827; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Updated research report information in Footnote 5 editorially in May 2009.
1. Scope*
1.1 This test method covers the chemical analysis of engine coolant for chloride ion by high-performance ion chromatography
(HPIC). Several other common anions found in engine coolant can be determined in one chromatographic analysis by this test
method.
1.2 This test method is applicable to both new and used engine coolant.
1.3 Coelution of other ions may cause interferences for any of the listed anions. In the case of unfamiliar formulations,
identification verification should be performed by either or both fortification and dilution of the sample matrix with the anions of
interest.
1.4 Analysis can be performed directly by this test method without pretreatment, other than dilution, as required by the linear
ranges of the equipment. Table 1 indicates several applicable anions and approximate detection limits.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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 its use.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
3. Summary of Test Method
3.1 A small volume of working sample is prepared by dilution of the sample with the method eluant. This diluted sample is
filtered and pumped through two ion exchange columns and a suppressor and into a conductivity detector. Ions are separated based
on their affinity for exchange sites of the resin with respect to the resin’s affinity for the eluant. The suppressor increases the
sensitivity of the method by both increasing the conductivity of the analytes and decreasing the conductivity of the eluant. The
suppressor converts the eluant and the analytes to the corresponding hydrogen form acids. Anions are quantitated by integration
of their response compared with an external calibration curve and are reported as milligrams per litre (mg/L).
4. Significance and Use
4.1 This test method provides for the qualitative and quantitative determination of common anions in engine coolant in the
milligrams per litre to low percent range and requires only a few millilitres or microlitres of sample per test, with results available
This test method is under the jurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and is the direct responsibility of Subcommittee D15.04 on
Chemical Properties.
Current edition approved March 1, 2009May 1, 2015. Published April 2009June 2015. Originally approved in 1995. Last previous edition approved in 20022009 as
ε1
D5827-95(02).-09 . DOI: 10.1520/D5827-09E01.10.1520/D5827-09R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5827 − 09 (2015)
TABLE 1 Analytes and Minimum Detection Limits
A
Analyte Detection Limit, mg/L
−
Chloride (Cl ) 2.0
−
Nitrite (NO ) 5.0
Bromide (Br) 4.0
−
Nitrate (NO ) 7.1
2−
o-Phosphate (HPO ) 20.0
2−
Sulfate (SO ) 8.0
2−
Oxalate (C O ) 12.0
2 4
A
Determined using 100-μL sample volume. Sample diluted 99 + 1 (v/v) with
chromatographic eluant 30-μS/cm full scale, suppressed conductivity detection.
Dionex AS4ASC column with AG4ASC guard columns. Other systems will require
MDL determinations using chosen dilution factors, eluants, columns, and detector.
in less than 30 min. Acceptable levels of chloride and other anions vary with manufacturer’s blending specifications and applicable
ASTM minimum or maximum specifications.
5. Interferences
5.1 Interferences can be caused by substances with similar retention times, especially if they are in high concentration compared
to those of the analyte of interest. Sample dilution will be used to minimize or solve most interference problems.
5.2 A water dip (solvent system peak) can cause interference with some integrators. This is eliminated by dilution with the
eluant if the sample dilution factor is 49 + 1 (v(v/v)⁄v) or greater. Below this dilution, it is best to add a spike of eluant concentrate
to the sample such that the sample is not diluted significantly and the resulting test solution matches the eluant used in the system.
One method is the addition of 100 μL of 100X eluant concentrate to 10.0 mL of sample or standard.
5.3 Method interferences can be caused by the contamination of glassware, eluant, reagents, etc. Great care must be taken to
ensure that contamination, especially by chloride, is kept at the lowest possible levels.
5.4 Pre-rinsing of the sample preparation containers with deionized water is mandatory.
5.5 The use of latex gloves is highly recommended to prevent contamination.
6. Apparatus
6.1 Analytical Balance, capable of weighing accurately to 0.0001 g.
6.2 Ion Chromatograph—Analytical system with all required accessories including syringes, columns, suppressor, gasses, and
detector. Column life and performance are enhanced by the use of a two-eluant channel gradient pump, if available.
6.3 Guard Column, for protection of the analytical column from strongly retained constituents. Better separations are obtained
with additional plates.
6.4 Anion Separator Column, capable of producing analyte separation equivalent to or better than that shown in Fig. 1.
6.5 Anion Suppressor Device—Micro membrane suppressor or equivalent. A cation exchange column in the hydrogen form has
been used successfully, but it will periodically need to be regenerated as required, being indicated by a high background
conductivity and low analyte response.
6.6 Conductivity Detector, low volume (<2 μL) and flow, temperature compensated, capable of at least 0 to 1000 μS/cm on a
linear scale.
6.7 Integrator or Chromatography Data System Software, capable of obtaining approximately the same detection limits as are
listed in Table 1.
6.8 Drying Oven, controlled at 105, 150, and 600 6 5°C.
6.9 Desiccator.
7. Reagents
7.1 Purity of Reagents—Reagent grade or higher purity chemicals shall be used for the preparation of all samples, standards,
eluants, and regenerator solutions. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the
Committee on Analytical Reagents of the American Chemical Society, where such specification are available. Other grades may
be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy
of the determination.
Reagent Chemicals, American Chemical Society Specifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D5827 − 09 (2015)
FIG. 1 Sample Run—Chloride Peak at 1.7 min
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by
Type II of Specification D1193. It is recommended that all water be filtered through a 0.2-μm filter. For eluant preparation, degas
the water by sparging with helium or vacuum degassing and sonication.
7.3 Eluant Buffer Stock Solution—Sodium bicarbonate (NaHCO ) 1.5 mM and sodium carbonate (Na CO ) 1.2 mM. Dissolve
2 3
2.5203 6 0.0005 g of NaHCO and 2.5438 6 0.0005 g of Na CO in reagent water in a 1000-mL Type A volumetric flask and
3 2 3
dilute to 1 L. Dilute 100.0 mL of this stock solution to 2000 mL in a 2-L Type A volumetric flask with degassed reagent water.
The pH of the stock solution is 10.1 to 10.3 (based on pK calculation). The eluant solution used may be different if other system
a
or analytical columns are used.
7.4 Stock Bromide Solution—Dry approximately 2 g of sodium bromide (NaBr) for 6 h at 150°C and cool in a desiccator. Weigh
and dissolve 1.2877 g of the dried salt in reagent water and dilute to 1 L (1.00 mL = 1.00 mg bromide).
7.5 Stock Chloride Solution—Dry approximately 2 g of sodium chloride (NaCl) for 1 h at 600°C and cool in a desiccator. Weigh
−
and dissolve 1.6485 g and dilute to 1 L with reagent water (1.00 mL = 1.00 mg Cl ).
7.6 Stock Formate Solution—Dry approximately 2 g of sodium formate (NaHCO ) at 105°C for 6 h and cool in a desiccator.
Weigh and dissolve 1.4775 g of the salt in reagent water and dilute to 1 L (1.00 mL = 1.00 mg formic acid).
7.7 Stock Glycolic Acid Solution—Weigh and dissolve 1.0000 g of the solid acid in reagent water and dilute to 1 L (1.00
mL = 1.00 mg glycolate).
7.8 Stock Nitrate Solution—Dry approximately 2 g of sodium nitrate (NaNO ) for 24 h at 105°C and cool in a desiccator. Weigh
−
and dissolve 1.3707 g and dilute to 1 L with reagent water (1.00 mL = 1.00 mg NO ).
7.9 Stock Nitrite Solution—Dry approximately 2 g of sodium nitrite (NaNO ) for 24 h in a desiccator containing concentrated
−
sulfuric acid (relative density of 1.84). Weigh and dissolve 1.4998 g and dilute to 1 L with reagent water (1.00 mL = 1.00 mg NO
). Refrigerate and prepare weekly because nitrite is oxidized easily.
7.10 Stock Oxalic Acid Solution—Weigh and dissolve 1.4002 g of oxalic acid dihydrate (C H O ·2H O) in reagent water and
2 2 4 2
dilute to 1 L (1.00 mL = 1.00 mg oxalic acid).
7.11 Stock Phosphate Solution—Weigh and dissolve 1.4330 g of potassium dihydrogen phosphate (KH PO ) and dilute to 1 L
2 4
−3
with reagent water (1.00 mL = 1.00 mg PO ).
7.12 Stock Sulfate Solution—Dry approximately 2 g of anhydrous sodium sulfate (Na SO ) for 1 h at 105°C and cool in a
2 4
−2
desiccator. Weigh and dissolve 1.4790 g and dilute to 1 L with reagent water (1.00 mL = 1.00 mg SO ).
7.13 Suppressor Solution for Membrane Suppressor—0.025 N H SO . Carefully add 13.7 mL of reagent sulfuric acid (relative
2 4
density of 1.84) to approximately 500 mL reagent water in a 1-L volumetric flask. Dilute to 1000 mL with reagent water. Dilute
100 mL of this concentrate to 2000 mL with reagent water for the final working suppressor solution.
D5827 − 09 (2015)
7.14 Stability—Standard stock solutions are stable for at least one month when stored at 4°C. Fresh nitrite and phosphate
standards must be prepared weekly.
8. Sampling
8.1 Collect the sample in a scrupulously clean glass or polyethylene bottle in accordance with Test Method Practice D1176.
Collect at least 100 mL of sample.
9. Calibration and Standardization
9.1 Analyze each standard solution separately to determine the analyte’s retention time.
9.2 Set the chromatograph up in accordance with the conditions specified in Table 2 and Fig. 2. The use of other equipment,
eluants, or flows requires calculation of suitable dilution factors and instrument settings that permit the analyst to obtain the
resolution and detection limits given in Fig. 1 and Table 1, respectively.
9.3 Prepare concentrations of chloride at 0.08, 0.4, 0.8, and 4.0 mg/L from the stock solution. All final solutions should be made
with eluant as described in 5.2. Calibrate the ion chromatograph with at least five levels of the analyte, starting near but above the
minimum detection limit (MDL) and further defining the working range in samples subsequent to dilution. These chloride analyte
examples reflect a dilution of 99 + 1 (v/v) with eluant. If it is desirable to calibrate for another anion species, these may be
combined in the preceding five calibration standards once the retention times have been established individually. Concentrations
of these other anions in the calibration solutions must bracket the expected range for these species and include a level near the
MDL for each species.
NOTE 1—Ion chromatography equipment other than that described in this test method may require that standards be prepared at higher or lower levels.
9.4 Analyze a blank containing only the eluant as described in Section 10.
9.5 A mid-range standard must be used to verify the resolution of anions, regardless of a desire to quantitate all of them.
9.6 Analytical curves must be established at only one detector scale setting in order to prevent a change of slope affecting the
analytical curve.
9.7 The analytical calibration curve and an eluant blank shall be verified daily prior to the analysis of samples to verify the
system resolution, calibration, and sensitivity.
9.8 The analytical calibration curve, analyte retention times and resolution, and an eluant blank shall be verified subsequent to
a change of the system eluant.
9.9 Conditions:
Column: ion chromatography Flow: 2 mL/min
Detector: see 6.6 Suppressor flow: 2 mL/min
Eluant: see 7.3 Sample loop: 50 μL
NOTE 2—If a gradient pump is available, refer to Fig. 2 for an example of a step gradient that has proven successful for cleaning the column of strongly
retained species such as polyphosphates and molybdate, which would otherwise elute in subsequent runs.
NOTE 3—The sample loop volume will vary based on the column capacity, sensitivity, and other factors. Refer to ion chromatography equipment
manuals and column information for machine-specific details.
10. Proce
...