ASTM D1287-11(2020)
(Test Method)Standard Test Method for pH of Engine Coolants and Antirusts
Standard Test Method for pH of Engine Coolants and Antirusts
SIGNIFICANCE AND USE
4.1 pH is a measure of the hydrogen ion concentration and indicates whether an engine coolant, antirust, or a solution of these compounds is acidic, alkaline, or neutral.
4.2 The pH range includes values from 0 to 14. Values from 0 to 7 represent the acidic half of the scale. Values from 7 to 14 represent the alkaline or basic half of the scale. The pH value 7 is considered neutral, as it is neither acidic nor alkaline.
4.3 pH is sometimes used for production quality control. It is generally desirable that engine coolants have an alkaline pH.
4.4 pH is not significant from the standpoint of predicting service life. The pH of used engine coolants or antirust solutions is not a dependable indication of either existing effectiveness or remaining life of the solution.
SCOPE
1.1 This test method covers the determination of the pH of unused engine coolants and antirusts, and used or unused aqueous dilutions of the concentrated products.
Note 1: Antirusts in solid form are not included in this test method.
Note 2: It is believed that this procedure gives all the information required for determining the pH of samples of engine coolant or antirust likely to be encountered. Should additional information on pH determinations be needed, reference should be made to Test Method E70.
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D1287 − 11 (Reapproved 2020)
Standard Test Method for
pH of Engine Coolants and Antirusts
This standard is issued under the fixed designation D1287; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
NOTE 3—The readings of the meter in the case of the concentrated
1. Scope
products are not pH values according to the accepted definition, but are
1.1 This test method covers the determination of the pH of
apparent pH values which are useful in the interpretation of the condition
unused engine coolants and antirusts, and used or unused of the product.
aqueous dilutions of the concentrated products.
4. Significance and Use
NOTE 1—Antirusts in solid form are not included in this test method.
NOTE 2—It is believed that this procedure gives all the information 4.1 pH is a measure of the hydrogen ion concentration and
required for determining the pH of samples of engine coolant or antirust
indicates whether an engine coolant, antirust, or a solution of
likely to be encountered. Should additional information on pH determi-
these compounds is acidic, alkaline, or neutral.
nations be needed, reference should be made to Test Method E70.
4.2 ThepHrangeincludesvaluesfrom0to14.Valuesfrom
1.2 This standard does not purport to address all of the
0to7representtheacidichalfofthescale.Valuesfrom7to14
safety concerns, if any, associated with its use. It is the
represent the alkaline or basic half of the scale. The pH value
responsibility of the user of this standard to establish appro-
7 is considered neutral, as it is neither acidic nor alkaline.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 4.3 pH is sometimes used for production quality control. It
isgenerallydesirablethatenginecoolantshaveanalkalinepH.
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4.4 pH is not significant from the standpoint of predicting
ization established in the Decision on Principles for the
service life. The pH of used engine coolants or antirust
Development of International Standards, Guides and Recom-
solutions is not a dependable indication of either existing
mendations issued by the World Trade Organization Technical
effectiveness or remaining life of the solution.
Barriers to Trade (TBT) Committee.
5. Apparatus
2. Referenced Documents
5.1 The pH meter, glass electrode, and calomel electrode,
2.1 ASTM Standards:
shall be as specified in the Annex.
D1176Practice for Sampling and Preparing Aqueous Solu-
NOTE 4—In pH operation, the meter may be set up to perform one-,
tionsofEngineCoolantsorAntirustsforTestingPurposes
two-,oruptofive-pointstandardizationsormaybesetuptoautomatically
E70Test Method for pH of Aqueous Solutions With the recognize U.S. standard (pH 4, 7 and 10) buffers, NIST/International (pH
1.68, 4.01, 6.86, 9.18 and 12.46) buffers, or a custom user-centered set of
Glass Electrode
buffers, or both.
3. Summary of Test Method
6. Reagents
3.1 Asample, as received or after dilution with a specified
6.1 Purity of Reagents—Reagent grade chemicals shall be
volume of distilled water, is placed in a beaker or sample cup
used in all tests. Unless otherwise indicated, it is intended that
and the pH measured with a pH meter and combination
all reagents shall conform to the specifications of the Commit-
electrode or associated glass-saturated calomel electrode pair.
tee onAnalytical Reagents of theAmerican Chemical Society,
where such specifications are available. Other grades may be
This test method is under the jurisdiction ofASTM Committee D15 on Engine
used, provided it is first ascertained that the reagent is of
Coolants and Related Fluids and is the direct responsibility of Subcommittee
D15.04 on Chemical Properties.
Current edition approved Jan. 1, 2020. Published January 2020. Originally
approved in 1953 as D1287–53T. Last previous edition approved in 2011 as Reagent Chemicals, American Chemical Society Specifications, American
D1287–11. DOI: 10.1520/D1287–11R20. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1287 − 11 (2020)
sufficiently high purity to permit its use without lessening the 6.11 Standard Buffer Solution pH=12.46, (Buffer pH 12.46
accuracy of the determination. fromFisherScientificFCPartNumber13-620-837)orequiva-
lent could be used.
6.2 Purity of Water—Unless otherwise indicated, references
towatershallbeunderstoodtomeandistilledwaterorwaterof
6.12 Potassium Chloride Electrolyte—Prepare a saturated
equal purity. Distilled water shall be boiled thoroughly, or solution of potassium chloride (KCl) in water.
purged with carbon dioxide-free air, to remove carbon dioxide
and shall be protected with a soda-lime tube or its equivalent
7. Sampling
while cooling and in storage. The pH of the water shall be
7.1 Sample material in accordance with Practice D1176.
between 6.2 and 7.2 at 25°C.
6.3 Standard Buffer Solutions—The buffer solutions for
8. Preparation of Electrode System
calibrating the pH meter and electrode pair shall be prepared
8.1 Maintenance of Electrodes—Cleantheglasselectrodeor
from salts sold specifically for use, either singly or in
combination electrode at frequent intervals (not less than once
combination, as pH standards. The salts shall be dried for 1 h
every week during continual use) in accordance with the
at110°Cbeforeuse,exceptinthecaseofboraxwhichshallbe
manufacturer’s instructions. Drain the calomel electrode at
used as the decahydrate. The solutions with pH less than 9.5
least once each week and fill with KCl electrolyte. Keep the
shall be stored in chemically resistant bottles. The alkaline
electrolyte level in the calomel electrode above that of the
phosphatesolutionshallbestoredinglassbottlescoatedonthe
solutionbeingtestedatalltimes.Whennotinuse,immersethe
side with paraffin.
lower halves of the electrodes in distilled water, or the
NOTE 5—Commercially available buffer tablets or prepared buffer
appropriate buffer solution recommended by the manufacturer.
solutions may be used.
Do not immerse the electrodes in the solution being tested for
6.4 Standard Buffer Solution pH = 1.68, (Buffer pH 1.68
any appreciable period of time between determinations. Al-
from Fisher Scientific FC Part Number 13–620–836) or
though the electrodes are not extremely fragile, they should be
equivalent could be used.
handled carefully at all times.
8.1.1 A combination electrode system can also be used for
6.5 Potassium Hydrogen Phthalate Buffer Solution(0.05 M,
this test method.
pH = 4.01 at 25°C)—Dissolve 10.21 g of potassium hydrogen
phthalate (KHC H O ) in water, and dilute to 1 L. Standard
8.2 Preparation of Electrodes—Beforeandafterusing,wipe
8 4 4
BufferSolutionpH=4.0,PotassiumHydrogenPhthalate(Red,
the electrode or combination electrode thoroughly with a clean
pH 4.01) from Fisher Scientific (FC Part Number: SB
cloth, or a soft absorbent tissue, and rinse with distilled water.
101–500; NIST–SRM 185 g) or equivalent could be used.
Follow the manufacturer’s recommendations if further prepa-
ration is required. Prior to each pH determination, soak the
6.6 Neutral Phosphate Buffer Solution (0.025 M with re-
prepared electrode in distilled water for at least 2 min.
spect to each phosphate salt, pH = 6.86 at 25°C)—Dissolve
Immediately before use, touch the tips of the electrodes with a
3.40 g of potassium dihydrogen phosphate (KH PO ) and 3.55
2 4
dry cloth or tissue to remove excess water.
g of anhydrous disodium hydrogen phosphate (Na HPO)in
2 4
water and dilute to 1 L. Standard Buffer Solution pH = 6.86,
9. Standardization and Testing of Electrode System in
Potassium Phosphate (pH 6.86 from Fisher Scientific, or
pH Units
NIST–SRM 186 le/lle) or equivalent could be used.
9.1 The assembly shall always be standardized with more
6.7 Standard Buffer Solution pH = 7.0, Potassium Phos-
than one of the standard buffer solutions.Asingle standardiza-
phate Monobasic (Yello, pH 7.00) from Fisher Scientific (FC
tion point serves to establish the electrodes actual zero
Part Number: SB 107–500) or equivalent could be used.
potential,buttheelectrode’sslopeisassumedtobeadefaultor
6.8 Borax Buffer Solution (0.01 M, pH=9.18 at 25°C)—
already known value. A pH measurement with one-point
Dissolve 3.81 g of disodium tetraborate decahydrate
standardizationshouldberestrictedtoanarrowpHrange,very
(Na B O ·10H O) in water, and dilute to 1 L. Protect this
2 4 7 2
near the standardization point. A second standard buffer solu-
solutionfromatmosphericcarbondioxide;stopperthebottleat
tion shall be used to check the linearity of the response of the
alltimesexceptwhenactuallyinuse.StandardBufferSolution
electrodes at different pH values and to detect a faulty glass
pH=9.18, Sodium Tetraborate × 10 H O (borax) (pH 9.18)
electrode or incorrect temperature compensation. The two
fromFisherScientificorNIST–SRM187c)orequivalentcould
buffer solutions selected should bracket the anticipated pH of
be used.
the solutions being tested.
6.9 Standard Buffer Solution pH=10.00, Potassium
9.1.1 Turn on the instrument, allow it to warm up, and
Carbonate, Potassium (Blue, Buffer pH 10.00 from Fisher
adjust according to the manufacturer’s instructions. Immerse
ScientificFCPartNumberSB115-500)orequivalentcouldbe
the tips of the electrodes in the standard buffer solution chosen
used.
and allow sufficient time for the temperature of the buffer
6.10 Alkaline Phosphate Buffer Solution (0.01 M trisodium solution and the electrodes to equalize. Set the temperature
phosphate, pH=11.72 at 25°C)—Dissolve 1.42 g of anhy- knob at the temperature of the buffer solution. Adjust the
drous disodium hydrogen phosphate (Na HPO ) in 100 mLof standardization or asymmetry potential control until the meter
...
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