Formaldehyde Test of Textile Items

1. Bureau Veritas
Consumer Products Services (HK) Ltd.
For the benefit of business and people

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BVCPS(HK) 2003 - 31/07/2003
Introduction
1. This training material serves to cover the following aspects:
1. Background information,
2. Testing techniques,
3. Method of evaluation, and
4. Important notes
for the subsequent test in order to ensure the testing uniformity, result
consistency & reproducibility.
• As this training material focuses on the general information only, it is anticipated
for trainee without background knowledge. Experienced staff, however, can refer
the materials as reference guidelines.
• Practical training followed with an assessment is highly recommended to testify
and reinforce the understanding of the trainee on the subsequent test.
• A procedure checklist is available for the assessment

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Determination of Formaldehyde -
Part 1: Free and Hydrolized
Formaldehyde (Water Extraction
Method)
(ISO 14184-1: 1998)

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BVCPS(HK) 2003 - 31/07/2003
Summary
1. Scope & Principle
2. Apparatus
3. Sample Preparation (Accompanied with movie illustration)
4. Test Procedures (Accompanied with movie illustration)
5. Confirmation Test
6. Calibration Curve
7. Result Evaluation
8. Example of Formaldehyde Calculation
9. AATCC, JIS, ISO & BS Test Comparison
Free and Hydrolized Formaldehyde (ISO 14184-1)

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1 Scope & Principle
• To determinate the amount of free formaldehyde and formaldehyde extracted
partly through hydrolysis by means of water extraction method
• It is applicable to testing of textile samples in any form
• Formaldehyde is extracted from textile sample with water at 40°C. The amount
of formaldehyde is then determined colorimetrically
• The procedure is intended for use in the range of free and hydrolysed
formaldehyde on the fabric between 20mg/kg and 3500mg/kg when
determined by this method. The lower limit is 20mg/kg.
• Below this limit the result is reported as “not detectable”
Free and Hydrolized Formaldehyde (ISO 14184-1)

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2 Apparatus
Spectrophotometer or colorimeter
Free and Hydrolized Formaldehyde (ISO 14184-1)

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3 Sample Preparation
1. Cut two specimens approximately 1g of pieces. If the formaldehyde content is
low, increase the test specimen weight to 2.5 g.
2. Put the weighed pieces into 250ml flask with stopper and add 100ml of water.
3. Stopper tightly and place in a water bath at 40 ± 2°C for 60 ± 5 min with
shaking at least every 5 min.
Free and Hydrolized Formaldehyde (ISO 14184-1)
4. Filter the solution into another
flask through a filter.
Important Notes:
• Do not condition the test
specimen before test
• Storage the test specimen in a
polyethylene bag and wrapped
in aluminum foil.
Movie

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5 Test Procedures Free and Hydrolized Formaldehyde (ISO 14184-1)
5 ml filtered
test specimen
solution
5 ml standard
formaldehyde
solution
0.15
ppm
0.75
ppm
5 ml Nash
reagent
5 ml filtered
test specimen
solution
5 ml filtered
test specimen
solution + 5ml
Nash reagent
5 ml standard
formaldehyde
solution + 5ml
Nash reagent
5 ml Nash
reagent +
5ml water
5 ml filtered
test specimen
solution + 5ml
water
Aliquot & Blank Solution Preparation
1. Prepare four Test Tube A to D as
follows:
1. Tube A: 5ml of the filtered
test specimen solution + 5ml
of Nash reagent
2. Tube B: 5ml of the standard
formaldehyde solutions +
5ml of Nash reagent
3. Tube C: 5ml of Nash reagent
+ 5ml of water (Blank)
4. Tube D: 5ml of filtered test
specimen solution + 5ml of
water (Blank)

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5 Test Procedures
Aliquot & Blank Solution Preparation
2. Keep the Tubes A & B in a water
bath at 40 + 2C for 30 + 5min
and then at ambient temperature
for 30±5min
3. Measure the absorbances using
a spectrometer in a 10mm
absorption cell at a wavelength
of 412mm against water.
Free and Hydrolized Formaldehyde (ISO 14184-1)
Important Notes
• Exposure of the developed yellow colour to direct sunlight for a period of time will
cause some fading. Care should be taken to protect the tubes such as by covering
them with a formaldehyde free enclosure

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5
• Confirmation test (using dimedone) can be carried out to confirm the
absorption is due to formaldehyde or extracted colouring agent.
• Dimedone reacts with formaldehyde , and thus no colour resulting from
formaldehyde reaction will be observed.
Test procedures:
1. 5ml of sample solution (5ml water for blank solution) mix with 1ml
of ethanol solution of dimedone and shake
2. Warm the solution in water bath at 40oC for 10min
3. Add 5ml Nash reagent, shake and continue warm in the same
water bath for 30min
4. Cool down the solution to room temperature for 30min
5. Determine the absorbance of sample & blank solution at 412nm
6. Theoretically, no absorbance will be observed at 412nm
Free and Hydrolized Formaldehyde (ISO 14184-1)
Confirmation Test

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5
Formaldehyde Stock Solution (1500 mg/l) Preparation
Dilute 3.5 ml of formaldehyde solution to one liter with water.
Record the accurate concentration of this standardized stock solution by
reacting the formaldehyde solution with an excess of sodium sulfite
followed by a back-titration with acid solution in the presence of
thymolphthalein as indicator.
The stock Solution will keep for up to four weeks and is used to prepare
standard dilutions.
Calibration solutions Preparation
Dilute aliquots (1, 2, 5, 10, 15, 20, 30 & 40ml) of the standard solution with
distilled water in 500 mL volumetric flasks to give standard formaldehyde
solutions containing approximately (0.15, 0.30, 0.75, 1.50, 2.25, 3.00, 4.50 &
6.00) g/mL formaldehyde respectively.
Free and Hydrolized Formaldehyde (ISO 14184-1)
Calibration Curve

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6 Result Evaluation
Absorbance of the test specimen:
A = As - Ab - (Ad)
• A = corrected absorbance
• As = measured absorbance of the test specimen (Tube A)
• Ab = measured absorbance of the blank reagent (Tube C)
• Ad = measured absorbance of the blank specimen (Tube D), only in case of discoloration or the
contamination
Amount of the formaldehyde extracted for each specimen (F) to the nearest mg/kg
F = (C x 100) / W
• C = concentration of formaldehyde in solution (in mg/l) as read form the calibration graph
• W = Mass
If the result is less than 20mg/kg report as “not detectable”
Free and Hydrolized Formaldehyde (ISO 14184-1)

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5 Example of
Formaldehyde Calculation
For Example:
1. Calibration
curve
development
2. Measure the
absorbance
of aliquot
3. Find the
intersection point
4. Formaldehyde
content in the
aliquot
Free and Hydrolized Formaldehyde (ISO 14184-1)

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9 AATCC, JIS, ISO &
BS Test Comparison
Determination of Total & Free Formaldehyde (BS 6806 )
AATCC 112 JIS A & B (L1041) ISO 14184-1 BS 6806 Part 2 & 3
Scope
For released
Formaldehyde
For free
formaldehyde
For free
formaldehyde
For free & released formaldehyde
Weight of
specimen
1.0 g
2.5 g for A
1.0 g for B
1 g
2.0g for free formaldehyde
1.0g for released formaldehyde
Extraction
temperature
65o
C 40o
C 40o
C
25o
C for free formaldehyde
49o
C for released formaldehyde
Extraction time 4 hrs 1 hr 1 hr
20 min or free formaldehyde
20 hrs for released formaldehyde
Reagent for
reaction with
formaldehyde
Nash Nash Nash Chromotropic acid
Wavelength for
absorbance
measurement
412 nm 415 nm 412 nm 570 nm
Comparison of AATCC 112, JIS S & B (L 1041), ISO 14184-1 & BS 6806 standards on formaldehyde

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B U R E A U V E R I T A S
CONSUMER PRODUCTS SERVICES (Hong Kong) LTD.
Kowloon Bay Office:
Pacific Trade Centre, 1/F.,
2 Kai Hing Road, Kowloon Bay,
Hong Kong.
Tel: 852-2331 0888 Fax: 852-2331 0889
Website: www.mtl-acts.com
Kwai Chung Office:
Unit 1319, 13/F., Vanta Industrial Centre,
21 – 33 Tai Lin Pai Road, Kwai Chung,
New Territories, Hong Kong.
Tel: 852-2418 1222 Fax: 852-2480 6666
Website: www.mtl-acts.com