172 TM 112-2008 AATCC Technical Manual/2009
Developed in 1965 by AATCC Committee
RR68; reaffirmed 1968, 1972, 1989,
1998, 2003; revised 1975, 1978, 1982,
1984, 1993; technical correction 1983;
editorially revised 1985, 1986; editorially
revised and reaffirmed (with new title)
1990, 2008.
1. Purpose and Scope
1.1 This test method is applicable to
textile fabrics that may release formalde-
hyde, particularly fabrics finished with
chemicals containing formaldehyde. It
provides accelerated storage conditions
and an analytical means for determining
the amount of formaldehyde released un-
der the conditions of accelerated storage
(see Section 5 and 10.1).
1.2 An optional accelerated incubation
procedure is available (see 13.5).
2. Principle
2.1 A weighed fabric specimen is sus-
pended over water in a sealed jar. The jar
is placed in an oven at a controlled tem-
perature for a specified length of time
(see 13.5). The amount of formaldehyde
absorbed by the water is then determined
colorimetrically.
3. Terminology
3.1 formaldehyde release, n.—that
formaldehyde exuded from textiles under
the accelerated storage conditions of this
test, including that which is free (un-
bound or occluded) from unreacted
chemicals, or from finish degradation as
a result of this test.
4. Safety Precautions
NOTE: These safety precautions are
for information purposes only. The pre-
cautions are ancillary to the testing proce-
dures and are not intended to be all inclu-
sive. It is the user’s responsibility to use
safe and proper techniques in handling
materials in this test method. Manufac-
turers MUST be consulted for specific
details such as material safety data sheets
and other manufacturer’s recommenda-
tions. All OSHA standards and rules
must also be consulted and followed.
4.1 Good laboratory practice should be
followed. Wear safety glasses in all labo-
ratory areas.
4.2 When handling glacial acetic acid
to prepare Nash reagent, use chemical
goggles or face shield, impervious gloves
and an impervious apron during prepara-
tion. Concentrated acids should be han-
dled only in an adequately ventilated lab-
oratory hood. CAUTION: Always add
acid to water.
4.3 Formaldehyde is a sensory irritant
and potential sensitizer. Its chronic toxic-
ity has not been fully established. Use in
an adequately ventilated laboratory hood.
Avoid inhalation or skin contact. Use
chemical goggles or face shield, impervi-
ous gloves and an impervious apron
when working with formaldehyde.
4.4 An eyewash/safety shower should
be located nearby and a self-contained
breathing apparatus should be readily
available for emergency use.
4.5 Exposure to chemicals used in this
procedure must be controlled at or below
levels set by governmental authorities
(e.g., Occupational Safety and Health
Administration’s [OSHA] permissible
exposure limits [PEL] as found in 29
CFR 1910.1000 of January 1, 1989). In
addition, the American Conference of
Governmental Industrial Hygienists
(ACGIH) Threshold Limit Values (TLVs)
comprised of time weighted averages
(TLV-TWA), short term exposure limits
(TLV-STEL) and ceiling limits (TLV-C)
are recommended as a general guide for
air contaminant exposure which should
be met (see 13.7).
5. Uses and Limitations
5.1 The procedure is intended for use
in the range of releaseable formaldehyde
on the fabric up to about 3500 µg/g. The
upper limits are 500 µg/g if a 1:1 ratio of
Nash reagent to sample solution is used
in the analytical portion of the test and
3500 µg/g if a 10:1 ratio is used. The pro-
cedure promotes formaldehyde release
from odor-free, fully cured durable press
fabrics that have been afterwashed (Vail,
S. L. and B. A. K. Andrews, Textile
Chemist and Colorist, Vol. 11, No. 1, Jan-
uary 1979, p. 48). For these reasons, the
procedure should not be used to estimate
µg/g formaldehyde in air for compliance
with any mandated or voluntary stan-
dards. The procedure was originally de-
veloped to measure the “propensity of a
resin-treated fabric to liberate an exces-
sive amount of formaldehyde under hot,
humid conditions.” (Nuessle, A. C.,
American Dyestuff Reporter, Vol. 55, No.
17, 1966, pp. 48-50; also Reid, J. D., R.
L. Arcenaux, R. M. Reinhardt and J. A.
Harris, American Dyestuff Reporter, Vol.
49, No. 14, 1960, pp. 29-34.)
AATCC Test Method 112-2008
Formaldehyde Release from Fabric, Determination of:
Sealed Jar Method
Fig. 1—The wire mesh basket detailed on the left is suspended in a sealed jar
with one fabric specimen as shown on the right.
Copyright The American Association of Textile Chemists and Colorists
Provided by IHS under license with AATCC
Not for ResaleNo reproduction or networking permitted without license from IHS
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AATCC Technical Manual/2009 TM 112-2008 173
6. Apparatus and Materials
6.1 Mason or equivalent canning jars,
0.95 L (1 qt) and gas sealing caps.
6.2 Small wire mesh baskets (or other
suitable means for suspending fabric
above the water level inside the jars; see
13.1). As an alternative to the wire mesh
baskets, a double strand of sewing thread
may be used to make a loop in the fabric
that has been folded in half twice, sus-
pended above the water level. The two
double-thread ends are draped over the top
of the jar and held securely by the jar cap.
6.3 Thermostatically controlled oven,
49 ± 1°C (120 ± 2°F) (see 13.5).
6.4 Nash reagent prepared from ammo-
nium acetate, acetic acid and acetylace-
tone and water (see 7.1).
6.5 Formaldehyde solution, approxi-
mately 37%.
6.6 Volumetric flasks, 50, 500 and
1000 mL.
6.7 Mohr pipettes, graduated in tenths
of a mL; and 5, 10, 15, 20, 25, 30 and 50
mL volumetric pipettes, all calibrated “to
deliver” and meeting Class B volume ac-
curacy and flow time requirements (see
13.2).
6.8 Graduated cylinders, 10 and 50
mL, graduated in mL, calibrated “to de-
liver” and meeting Class A volume accu-
racy requirements (see 13.2).
6.9 Photoelectric colorimeter or spec-
trophotometer (see 10.6).
6.10 Test tubes or colorimeter tubes
(see 13.2).
7. Preparation of Nash Reagent
7.1 In a 1000 mL volumetric flask, dis-
solve 150 g of ammonium acetate in
about 800 mL of distilled water; add 3
mL of glacial acetic acid and 2 mL of
acetylacetone. Make up to the mark with
distilled water and mix. Store in a brown
bottle.
7.2 The reagent darkens in color
slightly on standing over the first 12 h.
For this reason the reagent should be held
12 h before use. Otherwise, the reagent is
usable over a considerable period of time,
at least 6-8 weeks. However, since the
sensitivity may change slightly over a
long period of time, it is good practice to
run a calibration curve weekly to correct
for slight changes in the standard curve.
8. Preparation of Standard Solution and
Calibration (Caution)
8.1 Prepare an approximately 1500 µg/
mL stock solution of formaldehyde by di-
luting 3.8 mL of reagent grade formalde-
hyde solution (approximately 37%) to
one liter with distilled water. Equilibrate
the stock solution for at least 24 h before
standardization. Determine the concen-
tration of formaldehyde in the stock solu-
tion by a standard method (see 13.6 or
any other suitable procedure such as so-
dium sulfite titration using 0.1 N HCl.
Reference: J. Frederick Walker, Formal-
dehyde, 3rd Ed. Reinhold Publ. Co., New
York, 1964, p. 486). Record the actual
concentration of this standardized stock
solution. This stock solution will keep for
at least four weeks and is used to prepare
standard dilutions. A 1:10 dilution of the
standardized formaldehyde stock solution
is prepared by pipetting 25 mL of the
standardized stock solution into a 250 mL
volumetric flash and diluting to the mark
with distilled water. If the stock solution
is titrated and found to be different than
1500 µg/mL, three methods that can be
used for preparing the calibration curves
are:
8.1.1 Calculate new volumes of stock
solution aliquots to pipette to achieve ex-
actly 1.5, 3.0, 4.5, 6.0 and 9.0 µg/mL, re-
spectively. (For example, if the formalde-
hyde stock solution were found to be
1470 µg/mL by titration, not 1500 µg/
mL, pipette 5.1 mL, 10.2 mL, 15.3 mL,
20.4 mL and 30.6 mL of the 147 µg/mL
dilution into a 500 mL volumetric flask
and dilute to mark with distilled water.)
(NOTE: It is easy to make errors using a
graduated pipette!)
8.1.2 Pipette 5, 10, 15, 20 and 30 mL
of the 1:10 dilution into a 500 mL volu-
metric flask and dilute to mark with dis-
tilled water. (If, for example, the stan-
dardized stock solution were found to be
1470 µg/mL by titration, calculate new
values for the calibration curve abscissa;
i.e., 1.47, 2.94, 4.41, 5.88, 8.82 µg/mL.)
This is the preferred method for those
with a microprocessor spectrophotometer
or computer. However, it is harder to plot
manually.
8.1.3 Calculate a concentration correc-
tion factor for each sample. Correct the
concentration for the dilution value using
this factor. Plot the curve as if each of the
dilutions were exactly 1.5, 3.0, 4.5, 6.0
and 9.0 µg/mL. Calculate the correct con-
centration for each of these values using
the factor. For example, if the standard-
ized stock solution were found to be 1470
µg/mL by titration, then the correction
factor (CF) is:
8.2 When 5, 10, 15, 20 and 30 mL ali-
quots of the 1:10 dilution of the standard-
ized stock solution from 8.1 are diluted
with distilled water in 500 mL volumetric
flasks, formaldehyde solutions contain-
ing approximately 1.5, 3.0, 4.5, 6.0 and
9.0 µg/mL formaldehyde respectively
will be obtained. Record accurately the
concentration of solutions. The equiva-
lent concentrations of the formaldehyde
in the test fabric based on the weight of
CF Actual
Nominal
--------------------- 1470
1500
------------ 0.980= = =
1 g of the test fabric and 50 mL of water
in the test jars, will be 50 times the accu-
rate concentrations of these standard so-
lutions.
8.3 Use 5 mL aliquots of each of the
standard solutions and the procedure de-
scribed in 10.4-10.7 to prepare a calibra-
tion chart in which µg/mL formaldehyde
are plotted against absorbance.
9. Test Specimens
9.1 Cut approximately 1 g specimens;
weigh each one to ± 0.01 g.
10. Procedures
10.1 Place 50 mL of distilled water in
the bottom of each jar. Suspend one fab-
ric specimen above the water in each jar,
using a wire mesh basket or other means
(see Fig. 1). Seal the jars and place them
in the oven at 49 ± 1°C (120 ± 2°F) for
20 h (see 13.5).
10.2 Remove and cool the jars for at
least 30 min.
10.3 Remove the fabric and baskets, or
other support, from the jars. Recap the
jars and shake them to mix any condensa-
tion formed on the jar sides.
10.4 Pipette 5 mL of Nash reagent into
a suitable number of test tubes, small (50
mL) Erlenmeyer flasks, or other suitable
flasks (colorimeter or spectrophotometer
tubes can be used directly, see 13.2) and
pipette 5 mL of the reagent into at least
one additional tube for a reagent blank.
Add 5 mL aliquots from each of the sam-
ple incubation jars to the tubes and 5 mL
of distilled water to the tube which is
used as a reagent blank.
10.5 Mix and place the tubes in a 58 ±
1°C water bath for 6 min. Remove and
cool.
10.6 Read the absorbance in the colo-
rimeter or spectrophotometer against the
reagent blank using a blue filter or a
wavelength of 412 nm. Caution: Expo-
sure of the developed yellow color to di-
rect sunlight for a period of time will
cause some fading. If there is appreciable
delay in reading the tubes after color de-
velopment and strong sunlight is present,
care should be exercised to protect the
tubes such as by covering them with a
cardboard box or by similar means. Oth-
erwise the color is stable for considerable
time (at least overnight) and reading may
be delayed.
10.7 Determine the µg/mL formalde-
hyde (HCHO) in the sample solutions us-
ing the prepared calibration curve (see
8.3 and 13.3).
11. Calculation
11.1 Calculate the amount of formalde-
hyde released for each specimen to the
nearest µg/g using the following equation:
F = (C) (50)/W
Copyright The American Association of Textile Chemists and Colorists
Provided by IHS under license with AATCC
Not for ResaleNo reproduction or networking permitted without license from IHS
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174 TM 112-2008 AATCC Technical Manual/2009
where:
F = concentration of formaldehyde
(µg/g),
C = concentration of formaldehyde in
solution as read from the calibra-
tion curve, and
W = weight of the test specimen, g.
12. Precision and Bias
12.1 Precision.
12.1.1 Interlaboratory tests. Two inter-
laboratory studies (ILS) of AATCC
Method 112 were conducted in 1990 and
1991, with a 20 h incubation at 49°C and
a 5/5 sample to Nash solution ratio. Sin-
gle operators in each participating labora-
tory ran triplicate determinations on each
fabric. In the first ILS, results from nine
laboratories testing one fabric each at
three low formaldehyde levels in the
range of 100-400 µg/g were analyzed by
analysis of variance (ANOVA). In the
second ILS, results from eight laborato-
ries testing ten fabrics of nominal 0 µg/g
were analyzed by ANOVA. The analyses
have been deposited for reference in the
RA68 committee files.
12.1.2 Critical differences were calcu-
lated for zero-formaldehyde fabrics,
shown in Table I, and for low level-form-
aldehyde fabrics shown in Table II.
12.1.3 When two or more laboratories
wish to compare test results, it is recom-
mended that laboratory level be estab-
lished between them prior to beginning
test comparisons.
12.1.4 If comparisons are made be-
tween laboratories on a single fabric level
of formaldehyde release, the critical dif-
ferences in the column, single level, in
Table II should be used.
12.1.5 If comparisons are made be-
tween laboratories on a series of fabrics
of a range of formaldehyde levels, the
critical differences in the column, multi-
ple levels, in Table II should be used.
12.1.6 The number of determinations
per laboratory average (det/avg) also de-
termines the critical difference.
12.2 Bias.
12.2.1 The formaldehyde release of a
fabric can be defined only in terms of a
test method. There is no independent
method for determining the true value. As
a means of estimating formaldehyde re-
leased from a fabric under the conditions
of accelerated storage in AATCC Method
112, the method has no known bias.
12.2.2 AATCC Method 112 generally
is accepted by the textile and apparel in-
dustries as a referee method.
13. Notes
13.1 A simple cloth support for insertion in
the mason jars can be constructed as follows:
A piece of aluminum wire screening 15.2 ×
14.0 cm (6.0 × 5.5 in.) is bent around a length
of wood 3.8 cm (1.5 in.) square and fastened
together to form a rectangular, open-ended
cage. One side is cut at the corners about half-
way up the side and the cut section folded in-
ward and fastened. This folded piece forms
the bottom of the wire basket while the other
three sides form the support legs. Fastening
can be accomplished by twisting short lengths
of wire through or around the appropriate part.
13.2 The ratio of reagent to sample solu-
tions can be adjusted, within limits, to suit the
individual absorbance range and optical path
length of the sampling tubes or cuvettes of the
particular photometric instrument being used.
For example, although 5 mL reagent to 5 mL
sample solution has been found convenient for
several types of instruments, other 1:1 ratios,
such as a ratio of 2 mL reagent to 2 mL sam-
ple may be more suitable for others. The same
ratio should be used with the standards as with
the sample. The use of colorimeter or spectro-
photometer tubes directly for color develop-
ments avoids the transfer step, test tubes to
spectrophotometer cells, and may save consid-
erable time when many determinations are to
be made. Repipettes or similar devices can be
used for reagent dispensing, and Oxford or
Eppendorf disposable tip automatic pipettes
can be used for the sample solutions.
13.3 The procedure in Section 10 has been
set up to cover the range from about 0 µg/g on
the weight of the fabric to about 500 µg/g. In
fabrics containing releasable formaldehyde in
the range from 500 µg/g on the weight of the
fabric to about 3500 µg/g, it is recommended
that a ratio of 10 mL Nash reagent to 1 mL
sample be used. If this is done, it is necessary
to prepare an additional calibration chart with
10:1 ratios of standard solutions to Nash re-
agent by diluting 5, 10, 15 and 20 µg/mL, re-
spectively, of the approximately 1500 µg/mL
standardized stock solution of formaldehyde
to the mark with distilled water in 500 mL vol-
umetric flasks. Formaldehyde solutions con-
taining approximately 15, 30, 45 and 60 µg/
mL respectively will be obtained (see 8.3).
13.4 The chromotropic acid colorimetric
method can be used as an alternate to the Nash
reagent for the determination of the formalde-
hyde content of the sample jars after oven in-
cubation. It should be noted that the Precision
and Bias Statement was not developed using
the chromotropic acid method. A suitable pro-
cedure is given in J. Frederick Walker, Form-
aldehyde, 3rd Edition, Reinhold Publishing
Co., NY, 1964, p470. When using this method
a change may be necessary in the size of both
the aliquots taken from the sample jars (see
10.2) and the standard formaldehyde solutions
used in preparing the calibration curve (see
8.3). Caution! Since concentrated sulfuric
acid is used with the chromotropic acid
method, adequate care should be exercised to
protect operating personnel and spectrophoto-
metric equipment.
13.5 Incubation conditions of 65 ± 1°C
(149 ± 4°F) for 4 h can be used as an alternate
to the incubation conditions of 49 ± 1°C (120
± 2°F) for 20 h (see 5.3 and 10.1). The incuba-
tion conditions of time and temperature must
be reported. Upon completion of the 4-h incu-
bation period, remove and cool the jars for at
least 30 min and remove the fabric from the
jars. Recap the jars and shake them to mix any
condensation formed on the jar sides. Proce-
dures for sample preparation and color devel-
opment following the incubation period are
performed as outlined in 10.4-10.7.
13.6 Standardization of Formaldehyde
Stock Solution. General: The stock solution
containing approximately 1500 µg/mL of
formaldehyde must be accurately standardized
in order to make precise calculations from the
calibration curve used in colorimetric analysis.
An aliquot of the stock solution is reacted
with an excess of sodium sulfite followed by a
back-titration with standard acid solution in
the presence of thymolphthalein as indicator.
Apparatus: 10-mL volumetric pipette, 50-
mL volumetric pipette, 50-mL burette, 150-
mL Erlenmeyer flask.
Reagents: 1 M sodium sulfite (126 g Anhy-
drous Na2SO3/L), 0.1% Thymolphthalein Indi-
cator in ethanol, 0.02 N sulfuric acid (can be
purchased in standardized form from chemical
supply companies or must be standardized
from standard NaOH solution). Do not use
commercial standardized sulfuric acid that has
been stabilized with formaldehyde. If there is
a doubt, check with the chemical supplier.
Procedure: A. Pipette 50 mL of 1 M
Na2SO3 into the Erlenmeyer flask. B. Add 2
drops of thymolphthalein indicator. C. Add a
few drops of standard acid until blue color dis-
appears (if necessary). D. Pipette 10 mL of the
stock formaldehyde solution to the flask.
(Blue color will reappear.) E. Titrate the solu-
tion with the standard 0.02 N H2SO4 until the
blue color is discharged. Record the volume of
acid used. (The volume of acid should be in
the range of 25 mL for 0.02 N acid.)
Calculations:
C = (30,030) (A) (N)/10
where:
C = Wt/Vol concentration of formalde-
hyde (µg/mL)
A = Vol of acid used (mL)
N = Normality of acid
Perform the standardization in duplicates.
Average the results and use the accurate con-
centration in preparing the calibration curve
for the colorimetric analysis.
13.7 Available fr