ASTM D4608-89(1995)e1

Standard Test Method for Citrate in Detergents

SCOPE
1.1 This test method covers a potentiometric titration procedure for the determination of citrate in liquid and powder detergents.  
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 and health practices and determine the applicability of regulatory limitations prior to use. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage. Specific safety precautions are given in Section 8.

General Information

• Status: Historical
• Publication Date: 31-Dec-1994
• Technical Committee: D12 - Soaps and Other Detergents
• Drafting Committee: D12.12 - Analysis and Specifications of Soaps, Synthetics, Detergents and their Components

Relations

• Replaced By: ASTM D4608-89(2003) - Standard Test Method for Citrate in Detergents
• Effective Date: 26-May-1989

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: D 4608 – 89 (Reapproved 1995)
Standard Test Method for
Citrate in Detergents
This standard is issued under the fixed designation D 4608; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Keywords were added editorially in February 1995.
1. Scope etc. will titrate as citrate in this method. For accurate citrate
determinations, such complexing agents must be absent.
1.1 This test method covers a potentiometric titration pro-
cedure for the determination of citrate in liquid and powder
6. Apparatus
detergents.
6.1 pH Meter, with millivolt capability.
1.2 This standard does not purport to address all of the
6.2 Copper Ion Selective Electrode.
safety concerns, if any, associated with its use. It is the
6.3 Calomel Reference Electrode.
responsibility of the user of this standard to establish appro-
6.4 Glass Electrode Triple Purpose.
priate safety and health practices and determine the applica-
6.5 Buret, semi-micro, 25 mL capacity with 0.1 mL gradu-
bility of regulatory limitations prior to use. Material Safety
ations.
Data Sheets are available for reagents and materials. Review
6.6 Magnetic Stirrer, and TFE-fluorocarbon-coated mag-
them for hazards prior to usage. Specific safety precautions are
netic stirring bars.
given in Section 8.
7. Reagents
2. Referenced Documents
7.1 Purity of Reagents—Reagent grade chemicals shall be
2.1 ASTM Standards:
used in all tests. Unless otherwise indicated, it is intended that
E 70 Test Method for pH of Aqueous Solutions with the
2 all reagents shall conform to specifications of the Committee
Glass Electrode
on Analytical Reagents of the American Chemical Society,
E 180 Practice for Determining the Precision of ASTM
2 where such specifications are available. Other grades may be
Methods for Analysis and Testing of Industrial Chemicals
used, provided it is first ascertained that the reagent is of
3. Summary of Test Method sufficiently high purity to permit its use without lessening the
accuracy of the determination.
3.1 The sample is titrated in an aqueous solution buffered at
7.2 Purity of Water—Unless otherwise indicated, reference
pH 8.5, with standard copper sulfate solution. The endpoint is
to water shall be understood to mean distilled water or water of
detected potentiometrically using a copper ion selective elec-
equal purity.
trode. The citrate content is calculated from the amount of
7.3 Hydrochloric Acid Solution (1 + 1)—Slowly mix 1 vol-
standard copper sulfate solution consumed.
ume of concentrated hydrochloric acid (sp gr 1.19) with 1
4. Significance and Use volume of water.
7.4 Sodium Hydroxide Solution (20 %)—Prepare a 20 %
4.1 This test method is suitable in research, development,
aqueous solution of sodium hydroxide.
and manufacturing control to monitor the level of citrate, a
7.5 Sodium Hydroxide Solution (0.1 N)—Prepare a 0.1 N
sequestering agent, in powder and liquid detergents.
aqueous solution of sodium hydroxide.
4.2 Accurate determination of sequestering agent is impor-
tant in evaluating cost and performance of detergent products.
An automatic titrator may be used.
5. Interferences
Orion Model 94-29A or equivalent has been found suitable for this purpose.
5.1 Other complexing agents such as nitrilotriacetic acid
Available from Orion Inc.
Orion Model 90-22 or equivalent has been found suitable for this purpose.
(NTA), ethylenedinitrilotetraacetic acid (EDTA), phosphates,
Available from Orion Inc.
Corning Model No. 476022 or equivalent has been found suitable for this
purpose. Available from Corning Inc.
1 7
This test method is under the jurisdiction of ASTM Committee D-12 on Soaps Reagent Chemicals, American Chemical Society Specifications, American
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Analysis of Soaps and Synthetic Detergents. listed by the American Chemical Society, see Analar Standards for Laboratory
Current edition approved May 26, 1989. Published July 1989. Originally Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
published as D 4608 – 86. Last previous edition D 4608 – 88. and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 15.05. MD.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4608
7.6 Hydrochloric Acid Solution (0.1 N)—Prepare a 0.1 N with a magnetic stirrer, adjust the pH between 8 and 9 with
aqueous solution of hydrochloric acid. dropwise additions of HCl (1 + 1) or NaOH (20 %). Add 25
7.7 Borate Buffer Solution (pH 8.5)—Dissolve 12.8 g of mL borate buffer (pH 8.5). If necessary, carefully adjust the pH
sodium borate (Na B O ·10H O) and 16.6 g of boric acid to 8.5 with NaOH (0.1 N) or HCl (0.1 N). Remove the glass
2 4 7 2
(H BO ) in about 900 mL of water. Adjust pH to 8.5 with 20 % electrode and insert the copper ion selective
3 3
8 3
NaOH solution. Transfer quantitatively into a 1-L volumetric electrode. Set the pH meter on millivolt and begin to add
flask. Dilute to volume with water. Mix well. copper sulfate solution in 1.0-mL increments. Near the end
7.8 Sodium Thiosulfate Solution, Standard (0.1 N)— point add in 0.2-mL increments. Record the millivolt readings
Dissolve 25 g of sodium thiosulfate (Na S O 5H O) crystals in after each increment. Add at least five 0.2-mL increments past
2 2 3 2
freshly boiled and cooled water and dilute to 1 L. Add 0.01 g the end point. Calculate the end point by the second derivative
of sodium carbonate and 0.5 mL of chloroform. Pr
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