ASTM D2330-88(1995)e1

Standard Test Method for Methylene Blue Active Substances

SCOPE
1.1 This test method covers the determination of compounds that react with methylene blue under the conditions specified in the test procedure. They are referred to as methylene blue active substances (MBAS), and are calculated and reported in terms of the reference material, linear alkyl benzene sulfonate, LAS.  
1.2 This test method is applicable for determining MBAS in water and wastewater. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices.  
1.3 This test method is a simple, rapid, control procedure suitable for monitoring the effectiveness of a biodegradation or other linear alkyl benzene sulfonate (LAS) removal process. For greater specificity and interference removal, the pretreatment procedure in Annex A1 should be used. Data derived without the pretreatment procedure should be interpreted with care. This test method is applicable in the range from 0.03 to 1.5 mg/L for a 100-mL sample.  
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. For a specific hazard statement, see Note 2.

General Information

• Status: Historical
• Publication Date: 31-Dec-1994
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.06 - Methods for Analysis for Organic Substances in Water

Relations

• Replaced By: ASTM D2330-02 - Standard Test Method for Methylene Blue Active Substances (Withdrawn 2011)
• Effective Date: 10-Jul-2002

Standards Content (Sample)

e1
Designation: D 2330 – 88 (Reapproved 1995)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Methylene Blue Active Substances
This standard is issued under the fixed designation D 2330; 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.
This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and
Standards for the specific year of issue which has been adopted by the Department of Defense.
e NOTE—Editorial changes were made throughout in June 1995.
1. Scope D 3856 Guide for Good Laboratory Practices in Laborato-
ries Engaged in Sampling and Analysis of Water
1.1 This test method covers the determination of com-
D 4210 Practice for Intralaboratory Quality Control Proce-
pounds that react with methylene blue under the conditions
dures and a Discussion on Reporting Low-Level Data
specified in the test procedure. They are referred to as
E 60 Practice for Photometric and Spectrophotometric
methylene blue active substances (MBAS), and are calculated
Methods for Chemical Analysis of Metals
and reported in terms of the reference material, linear alkyl
E 131 Terminology Relating to Molecular Spectroscopy
benzene sulfonate, LAS.
E 275 Practice for Describing and Measuring Performance
1.2 This test method is applicable for determining MBAS in
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
water and wastewater. It is the user’s responsibility to ensure
eters
the validity of this test method for waters of untested matrices.
1.3 This test method is a simple, rapid, control procedure
3. Terminology
suitable for monitoring the effectiveness of a biodegradation or
3.1 Definitions—For definitions of terms used in this test
other linear alkyl benzene sulfonate (LAS) removal process.
method, refer to Terminology D 1129 and E 131.
For greater specificity and interference removal, the pretreat-
3.2 Definitions of Terms Specific to This Standard:
ment procedure in Annex A1 should be used. Data derived
3.2.1 alkyl benzene sulfonate (ABS) —the generic name
without the pretreatment procedure should be interpreted with
applied to the neutralized product resulting from the sulfona-
care. This test method is applicable in the range from 0.03 to
tion of a branched-chain alkylated benzene. See also Termi-
1.5 mg/L for a 100-mL sample.
nology D 459.
1.4 This standard does not purport to address all of the
3.2.2 linear alkyl benzene sulfonate (LAS) —a form of
safety concerns, if any, associated with its use. It is the
alkyl benzene sulfonate (ABS) in which the alkyl group is
responsibility of the user of this standard to establish appro-
linear rather than a branched chain. See also Terminology
priate safety and health practices and determine the applica-
D 459.
bility of regulatory limitations prior to use. For a specific
hazard statement, see Note 2. 4. Summary of Test Method
4.1 This test method is based upon the formation of a
2. Referenced Documents
blue-colored chloroform extractable ion pair by the reaction of
2.1 ASTM Standards: cationic methylene blue and an anionic surfactant (including
D 459 Terminology Relating to Soap and Other Detergents LAS, other sulfonates, and sulfate esters).
D 1129 Terminology Relating to Water 4.2 The sample is mixed with an acidified, aqueous solution
D 1193 Specification for Reagent Water of methylene blue. Any resulting hydrophobic ion pair which
D 2777 Practice for Determination of Precision and Bias of may be formed is extracted successfully with chloroform. The
Applicable Methods of Committee D-19 on Water combined chloroform extracts are washed with an acid solution
D 3370 Practices for Sampling Water from Closed Con- to remove the less hydrophobic ion pairs (having low partition
duits coefficients) that can be formed by potentially interfering
1 4
This test method is under the jurisdiction of ASTM Committee D-19 on Water Annual Book of ASTM Standards, Vol 03.05.
and is the direct responsibility of Subcommittee D19.06 on Methods of Analysis for Annual Book of ASTM Standards, Vol 03.06.
Organic Substances in Water. For a more complete discussion of terms relating to synthetic detergents and
Current edition approved Jan. 29, 1988. Published May 1988. Originally their significance, refer to “Syndets and Waste Disposal” by McKinney, R. E.,
published as D2330 – 65 T. Last previous edition D2330 – 82. Sewage and Industrial Wastes, Vol 29, Part 6, June 1957, pp. 654–666.
2 7
Annual Book of ASTM Standards, Vol 15.04. Adopted from “Surfactants (Anionic) Methylene Blue Methods,” Standard
Annual Book of ASTM Standards, Vol 11.01. Methods for the Examination of Water and Waste Water, Twelfth Ed., 1965.
D 2330
TABLE 1 Evaluation of Potential Interferences in the Methylene
substances. The chloroform layer retains the highly hydropho-
Blue Method
bic methylene blue-LAS ion pairs.
Concentration, Indicated LAS,
4.3 The intensity of the blue color remaining in the chloro-
Added to 1.0 mg/L LAS Solution
mg/L mg/L
form extract is measured photometrically at the wavelength of
Acetic acid 100 1.0
maximum absorption near 650 nm. This intensity is related to
Ammonium diethylphosphorodithioate 20 1.1
the concentration of LAS by means of a calibration curve or
Benzene sulfonic acid 100 1.3
chart. Cholesterol 100 1.0
2,4-dichlorophenol 100 1.0
Diethanolamine 1000 1.0
5. Significance and Use
Disodium phenylphosphate 10 1.0
5.1 The widespread use and discharge of detergents into Isopropylamine 14 1.0
Leucine 10 1.0
surface waters can result in a lowering of its aesthetic quality
N-1-(naphthylethylenediamine) hydrochloride 100 0.9
by foam formation and by causing toxicity to aquatic wildlife.
Nonyl phenol + 9 EtO 100 1.0
Phenol 100 1.0
This test method is capable of detecting small concentrations of
Picric acid 5 4.6
detergents as MBAS so that they can be controlled to prevent
Potassium chloride 100 1.0
such problems.
Potassium cyanate 100 1.0
Potassium nitrate 100 1.0
5.2 Biodegradable linear alkyl benzene sulfonates (LAS)
Potassium thiocyanate 2 1.0
have replaced the branched-chain alkyl benzene sulfonates
Potassium thiocyanate 100 4.1
(ABS) in detergent formulations, which were more resistant to
Proteins (Knox gelatine) 100 0.9
Sodium dodecyl sulfate 10 14.6
biodegradation. Differentiation between linear and branched-
Sodium dodecane sulfonate 5 5.0
chain alkyl benzene sulfonates, as well as differentiation of the
Sodium naphthalene sulfonate 5 5.1
various positional isomers of either type, is not possible by this
Sodium stearate 100 1.0
test method. While the methylene blue method may be em-
ployed to monitor studies designed to measure biodegradabil-
TABLE 2 Evaluation of Potential Interferences in the Methylene
ity, it cannot be used to predict this quality.
Blue Method with Pretreatment Described in Annex A1
Added to 1.0 mg/L LAS Concentration, Indicated LAS,
6. Interferences
Solution mg/L mg/L
6.1 Any organic or inorganic compound that will form a
Sodium dodecane sulfonate 5 3.7
chloroform extractible ion pair will interfere by producing high
Sodium benzene sulfonate 100 1.2
Sodium dodecyl sulfate 10 0.9
results, unless the ion pair formed is eliminated by the
Potassium thiocyanate 100 1.0
treatment described in 4.1. These positive interferences include
Picric acid 10 1.0
organic sulfonates, carboxylates, phosphates, and phenols, as
well as inorganic cyanates, chlorides, nitrates, and thiocyan-
measurement at a wavelength in the region near 650 nm and
ates.
equipped with 50-mm and 10-mm light path absorption cells.
6.2 Any compound effectively competing with methylene
blue to form a LAS ion pair will give negative results. This
NOTE 1—Photometers and photometric practices prescribed in this test
negative interference is demonstrated by some amines and has
method shall conform to Practice E 60. Spectrophotometers shall conform
analytical significance in the case of quaternary ammonium
to Practice E 275.
compounds.
7.2 Separatory Funnels, 250-mL size, Squibb-type, glass-
6.3 An evaluation of the effect of various potential interfer-
stoppered, preferably with TFE-fluorocarbon stopcocks.
ences is summarized in Table 1. The listed compounds, in the
concentrations indicated, were added to solutions containing 1
8. Reagents and Materials
mg/L LAS.
8.1 Purity of Reagents—Reagent grade chemicals shall be
6.4 When interferences are present, the pretreatment proce-
used in all tests. Unless otherwise indicated, it is intended that
dure described in Annex A1 should be used. Table 2 shows the
all reagents shall conform to the specifications of the Commit-
interferences that can be present even though the pretreatment 8
tee on Analytical Reagents of the American Chemical Society.
was used.
Other grades may be used, provided it is first ascertained that
6.5 When a concentrated acid chromate cleaning solution is
the reagent is of sufficiently high purity to permit its use
used to clean glassware, including separatory funnels, between
without lessening the accuracy of the determination.
samples, care must be taken to completely flush all of the acid
8.2 Purity of Water—Unless otherwise indicated, references
chromate cleaning solution from all surfaces and, in particular,
to water shall be understood to mean reagent water conforming
from the space between the barrel and plug of the separatory
to Specification D 1193, Type II.
funnel stopcock. Failure to remove the acid can result in an
8.3 Chloroform (CHCl ).
error in results.
6.5.1 Never use a detergent to clean any glassware used in
this test method as a detergent is difficult to remove from Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
surfaces. Any residual detergent could cause a high result.
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
7. Apparatus
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
7.1 Filter Photometer or Spectrophotometer, suitable for MD.
D 2330
NOTE 2—Warning: Chloroform (CHCl ) is toxic and is suspected of
preserved sample as soon as possible, or within 1 week after
being a possible carcinogen: avoid ingestion, inhalation, or absorption
collection. Data on decomposition are not available.
through the skin. Use a well-ventilated fume hood to carry off chloroform
9.3 Rinse the sample container and cap well to free them of
vapors during analysis.
detergent if they have been used previously and cleaned prior
8.4 Linear Alkyl Benzene Sulfonate Solution, Stock (1.0
to recycling.
mL 5 1.0 mg LAS)—Weigh the amount of reference material
10. Preparation of Apparatus
necessary to provide the equivalent of 1.000 g of LAS on a
100 % active basis. Dissolve in water and dilute to 1 L, mixing
10.1 Glassware Conditioning:
gently to prevent foam formation. Record the molecular weight
10.1.1 All glassware used for the determination of LAS
of the LAS reference material as supplied. The stock solution
should be free of scratches and etch marks because of the
may be stored at 4°C in the dark for 12 months in a
tendency of surface-active materials to adsorb on this type of
well-stoppered flask without deterioration.
surface. All volumetric flasks and photometer cells, projected
8.5 Linear Alkyl Benzene Sulfonate Standard Solution, (1.0
for use in LAS determinations, should, as instructed herein, be
mL 5 0.01 mg LAS)—Dilute 10.0 mL of the foam-free stock
preconditioned as follows: Obtain the chloroform extract from
solution (8.4) to 1 L with water that has been previously
12.0 mL of the standard LAS solution as described in 11.4.
adjusted to pH 2 with sulfuric acid and mix. The standard
Transfer sequentially to each of the volumetric flasks and
solution may be stored at 4°C in the dark for at least 12 months
photometer cells and permit a minimum contact time, in each
in a well-stoppered flask without deterioration.
case, of 5 min. Rinse thoroughly with chloroform and drain
8.6 Methylene Blue Solution (30 mg/L)—Dissolve 0.1 g of
(Warning—see Note 2).
methylene blue chloride in 100 mL of water. Transfer 30 mL of
11. Calibration
this solution to a 1-L volumetric flask and add 500 mL of water.
Add carefully 50 mL of 14 % sulfuric acid stock solution
11.1 Prepare a series of standards by adding the standard
(8.10) and 50 g of sodium dihydrogen phosphate monohydrate solution (8.5) from a 25-mL buret to a series of 250-mL
(NaH PO ·H O). Shake until solution is complete and then
separatory funnels (see 6.5) and dilute the standards to 100 mL
2 4 2
dilute to 1 L with water and mix. volume with water, yielding solutions as follows:
8.7 Phenolphthalein Indicator Solution (5.0 g/L)—Dissolve
0.5 g of phenolphthalein in 50 mL of 95 % ethyl alcohol and
Standard, mL (1.0 mL 5 LAS, mg (per 100 mL
0.01 mg LAS) of extract)
dilute to 100 mL with water and mix.
0.00 0.00
1.00 0.01
NOTE 3—Specially denatured ethyl alcohol conforming to Formula No.
3.00 0.03
3A or 30 of the U. S. Bureau of Alcohol, Tobacco, and Firearms may be
5.00 0.05
substituted for 95 % ethyl alcohol.
7.00 0.07
9.00 0.09
8.8 Phosphate Wash Solution—Dissolve 50 g of sodium
12.00 0.12
dihydrogen phosphate monohydrate (NaH PO ·H O) in 500
2 4 2
NOTE 4—If desired, additional standards in the range from 0.00 to 0.12
mL of water in a 1-L volumetric flask. Add carefully 50 mL of
mg of LAS may be prepared for the calibration series.
14 % sulfuric acid stock solution (8.10) and dilute to volume
with water and mix. The solution has a pH of approximately 11.2 Add 3 drops of phenolphthalein solution (8.7) and just
1.8.
enough sodium hydroxide solution (8.9) to produce a pink
8.9 Sodium Hydroxide Solution (10 g/L)—Dissolve 10 g of color. Add dilute sulfuric acid solution (8.11), in small incre-
sodium hydroxide (NaOH) in water, dilute to 1 L and mix.
ments until the pink color is barely discharged.
8.10 Sulfuric Acid Stock Solution (14 % volume per
11.3 Add 25 mL of methylene blue solution (8.6) and mix.
volume)—Add carefully 140 mL of concentrated sulfuric acid
Add 25 mL of chloroform (Warning—see Note 2) and mix
(H SO , sp gr 1.84) to 700 mL of cold (0 to 5°C) water with
thoroughly for 30 s with shaking. Vent carefully, permit the
2 4
good stirring, dilute to 1 L with water and mix.
phases to separate and then drain the chloroform layer into a
8.11 Sulfuric Acid Solution, Dilute (0.7 % volume per
second 250-mL sep
...