ASTM D4954-89(2003)
(Test Method)Standard Test Method for Determination of Nitrilotriacetates in Detergents
Standard Test Method for Determination of Nitrilotriacetates in Detergents
SIGNIFICANCE AND USE
This test method is suitable in research, development, and manufacturing control to monitor the level of NTA, a sequestering agent, in powder and liquid detergents.
Accurate determination of a sequestering agent is important in evaluating cost and performance of detergent products.
SCOPE
1.1 This test method describes the determination of nitrilotriacetates (NTA) in 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. For specific safety precautions, see 6.5.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D4954 – 89 (Reapproved 2003)
Standard Test Method for
Determination of Nitrilotriacetates in Detergents
This standard is issued under the fixed designation D4954; 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.
1. Scope 5.6 Single Junction Reference Electrode (Orion Model 90-
01), filled with Orion 90-00-01 solution.
1.1 This test method describes the determination of nitrilo-
5.7 pH Combination Electrode.
triacetates (NTA) in detergents.
5.8 Burets, 10-mL, 25-mL, 50-mL.
1.2 This standard does not purport to address all of the
5.9 pH Meter, with millivolt capabilities.
safety concerns, if any, associated with its use. It is the
5.10 Automatic Titrator—may be substituted for 5.8 and
responsibility of the user of this standard to establish appro-
5.9.
priate safety and health practices and determine the applica-
5.11 Magnetic Stirrer/Hot Plate.
bility of regulatory limitations prior to use. For specific safety
5.12 Balance, with 1-mg sensitivity.
precautions, see 6.5.
6. Reagents
2. Summary of Test Method
6.1 Purity of Reagents—Reagent grade chemicals shall be
2.1 A known excess amount of copper nitrate solution is
used in all tests. Unless otherwise indicated, it is intended that
added to the detergent sample under controlled pH conditions.
all reagents shall conform to specifications of the Committee
The uncomplexed copper is back-titrated potentiometrically
on Analytical Reagents of the American Chemical Society,
with a standard NTA solution using a copper ion specific
where such specifications are available. Other grades may be
electrode. The millimoles of NTAin the sample are equivalent
substituted, provided it is first ascertained that the reagent is of
to the millimoles of copper added, less the millimoles of the
sufficiently high purity to permit its use without lessening the
NTA titrant.
accuracy of the determination.
3. Significance and Use
6.2 DisodiumEthylenediaminetetraacetate(EDTA), 0.1 M.
6.3 Nitric Acid, concentrated.
3.1 This test method is suitable in research, development,
6.4 Sodium Hydroxide, 50 % reagent solution.
and manufacturing control to monitor the level of NTA, a
6.5 SodiumHydroxide, 20 % solution. Mix 40 g of the 50 %
sequestering agent, in powder and liquid detergents.
solution with 60 g of water. Cool. Wear a face shield during
3.2 Accurate determination of a sequestering agent is im-
mixing.
portant in evaluating cost and performance of detergent prod-
6.6 Cupric Nitrate, 0.1 M. Weigh (to the nearest 0.1 g) 6.3
ucts.
gofcoppermetalandtransferintoa600-mLbeaker.Addabout
4. Interferences
100 mL of water. Place a magnetic bar into the beaker and
place on a stirrer/hotplate. Add 30 mL of concentrated nitric
4.1 The presence of substances that will make copper
acid while stirring and heat gently. Stir until the copper metal
complex like citrate, formate, ethylenediaminetetraacetate, and
dissolves. Add more nitric acid if undissolved metal remains.
phosphonate, will interfere positively in the determination of
After dissolution, cool and transfer quantitatively to a 1-L
NTA.
volumetric flask. Dilute to the mark and mix the solution well.
5. Apparatus
6.6.1 Alternatively, weigh out (to the nearest 1 g) 23 g of
reagent grade cupric nitrate, 2 ⁄2 hydrate crystals, and transfer
5.1 Volumetric Flasks, 200-mL, 500-mL, 1000-mL.
to a 600-mL beaker. Add 400 mL of water. Stir to dissolve the
5.2 Beakers, 200-mL (tall form), 250-mL, 1000-mL.
crystals and add 5 mL of concentrated nitric acid. Transfer to
5.3 Pipets, 25-mL, 100-mL.
a 1-L volumetric flask, dilute to the mark and mix well.
5.4 Graduated Cylinders, 10-mL, 25-mL.
6.7 Trisodium Nitrilotriacetate Monohydrate (NTA), 0.3 M.
5.5 Copper Ion Electrode (Orion Model 94-29).
Weigh out (to the nearest 1 g) 41 g of NTAand dissolve in 400
This test method is under the jurisdiction of ASTM Committee D12 on Soaps
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on
Analysis of Soaps and Synthetic Detergents. American Chemical Society, 1155 16th St., NW, Washington, DC 20036.
Current edition approved May 26, 1989. Published July 1989. DOI: 10.1520/ EDTA solution is available from J. T. Baker Inc., already standardized against
D4954-89R03. NIST Reference Material Calcium Carbonate.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4954 – 89 (2003)
mL of water in a 600-mL beaker. Transfer to a 500-mL Molarity of Cupric Nitrate 5 ~M 3V!/25 (1)
volumetric flask, dilute to the mark and mix well.
6.8 Sodium Acetate Buffer Solution, Dissolve 68 g of re-
where:
agent sodium acetate, trihydrate, in 500 mL of water in a 1-L
M = molarity of EDTA, and
beaker. Add 30 g of glacial acetic acid. Transfer to a 1-L
V = mL of EDTA.
volumetric flask, dilute with water to the mark and mix well.
The pH of this solution should be 4.6 to 4.8.
8. Standardization of NTA Solution
8.1 Proceed as for the standardization of the 0.1-M cupric
7. Standardization of 0.1-M Cupric Nitrate
nitrate; except in this case, the titrant will be the NTAsolution
7.1 Add50mLofwaterintoa200-mLtallformbeaker.Add
rather than EDTA solution. Use a 10-mL buret for the NTA
3 mL of concentrated nitric acid from a graduated cylinder.
titrant.
Transfer by pipet a 25-mLaliquot of the cupric nitrate solution
8.2 The first 6 mL can be added rapidly, then continue with
into the beaker.
0.5-mL increment additions. Determine the endpoint in accor-
7.2 Place the pH combination electrode into the solution.
dance with Table 1.
Adjust the pH to 1.0 to 1.1 by dropwise addition of 50 %
8.3 Calculate the molarity of the NTA as follows:
NaOHsolution.About2mLmayberequ
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