GB/T 34683-2017 PDF English
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Determination of formaldehyde content in water-borne coatings - High performance liquid chromatographic method
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GB/T 34683-2017: Determination of formaldehyde content in water-borne coatings - High performance liquid chromatographic method
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT34683-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 87.040
G 50
Determination of formaldehyde content in water-borne
coatings - High performance liquid chromatographic
method
ISSUED ON: NOVEMBER 01, 2017
IMPLEMENTED ON: MAY 01, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 5
4 Reagents or materials ... 5
5 Instruments and equipment ... 6
6 Sample ... 6
7 Test steps ... 6
8 Test data processing ... 9
9 Detection limit ... 9
10 Precision ... 9
Annex A (informative) Determination conditions for high performance liquid
chromatographic method ... 11
Determination of formaldehyde content in water-borne
coatings - High performance liquid chromatographic
method
WARNING -- Personnel using this standard shall have practical experience in
formal laboratory work. This standard does not address all possible safety issues.
Users are responsible for taking appropriate safety and health measures and
ensuring compliance with relevant national regulations.
1 Scope
This Standard specifies the testing principles, reagents or materials, instruments and
equipment, samples, test procedures, test data processing, detection limits and precision
for the determination of formaldehyde content in water-borne coatings using high
performance liquid chromatographic method.
This Standard is applicable to the determination of formaldehyde content in water-
borne coatings. The determination of formaldehyde content in raw materials for water-
borne coatings can also refer to this method.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 3186, Paints, varnishes and raw materials for paints and varnishes --
Sampling
GB/T 6682-2008, Water for analytical laboratory use -- Specification and test
methods
GB/T 12807, Laboratory glassware -- Graduated pipettes
GB/T 12808, Laboratory glassware -- One mark pipettes
GB/T 23993-2009, Determination of formaldehyde content of waterborne coatings
-- Spectrophotometric method with acetylacetone
3 Principle
Acetonitrile is used as the extraction solvent. Formaldehyde in the sample is extracted
using a method combining ultrasonic extraction and centrifugal separation. The extract
is derivatized with 2,4-dinitrophenylhydrazine under acidic conditions to form 2,4-
dinitrophenylhydrazone. Use high performance liquid chromatographic method or
currently effective methods that can meet accuracy requirements (such as liquid
chromatography-mass spectrometry, liquid chromatography-tandem mass spectrometry,
etc.) for detection. According to the standard working curve, calculate the formaldehyde
content in the sample.
4 Reagents or materials
Unless otherwise specified, only reagents confirmed to be analytically pure or above
and grade one water that meets the requirements of GB/T 6682-2008 are used in the
analysis.
4.1 Acetonitrile: HPLC grade.
4.2 Phosphoric acid: content is greater than or equal to 85% (mass fraction).
4.3 Derivatization reagent: Weigh about 1 g (based on dry matter) of 2,4-
dinitrophenylhydrazine and place it in a 100 mL brown volumetric flask (see 5.5).
Dilute to the volume with phosphoric acid (see 4.2). Shake well. This solution is
unstable and shall be prepared immediately before use.
NOTE: 2,4-Dinitrophenylhydrazine can be further purified by recrystallization from an aqueous
solution with an acetonitrile content of 25% (mass fraction).
4.4 Formaldehyde solution: content is about 37% (mass fraction).
4.5 Formaldehyde standard stock solution (formaldehyde content is about 1 g/L): Use
a graduated pipette (see 5.6) to pipette 2.8 mL of formaldehyde solution (see 4.4) and
place it in a 1000 mL volumetric flask (see 5.5). Dilute to the volume with water. Mix
well. Calibrate its accurate concentration according to the method specified in GB/T
23993-2009. Formaldehyde standard stock solution shall be stored in the dark below
4°C. It shall be valid for 3 months.
NOTE: Certified formaldehyde solution standard materials with known concentrations can also be
used directly.
4.6 Formaldehyde standard solution (formaldehyde content is about 10 mg/L): Use a
single-marked pipette (see 5.7) to pipette 1.0 mL of formaldehyde standard stock
solution (see 4.5). Place in a 100 mL volumetric flask (see 5.5). Dilute to the volume
with acetonitrile (see 4.1). Mix well. This solution is unstable and shall be prepared
Weigh approximately 2.5 g of specimen (accurate to 1 mg) into a 25 mL volumetric
flask (see 5.5). Record the specimen mass m. Dilute to the volume with acetonitrile (see
4.1). Shake thoroughly to maximize the dispersion of the specimen. Make a specimen
solution. Record the constant volume V. After ultrasonic extraction for 10 min with an
ultrasonic extraction instrument (see 5.3), use a graduated pipette (see 5.6) to transfer
about 7 mL of the above solution into a centrifuge tube (the volume of the solution for
centrifugation can also be adjusted according to actual conditions). Centrifuge for 20 ~
30 min under the condition that the centrifuge cavity temperature does not exceed 40°C
until clear liquid A appears in the upper layer.
NOTE: If the centrifugation effect is not good and effective stratification cannot be achieved, the
speed can be increased appropriately or the centrifugation time can be increased appropriately.
7.2.2 Derivatization
Use a graduated pipette (see 5.6) to pipette 4.0 mL of clear liquid A (see 7.2.1), 4.0 mL
of water, and 0.4 mL of derivatization reagent (see 4.3). Mix evenly in a 10 mL
centrifuge tube (the amounts of clear liquid A, water, derivatization reagents, and
containers used for derivatization can be adjusted according to actual conditions.
However, the volume ratio of clear liquid A, water and derivatization reagent
participating in the derivatization reaction shall be maintained at 1:1:0.1). Seal the tube
lid. Place in a (25±5)℃ environment away from light for 24 h for derivatization. Filter
with 0.22 μm organic phase microporous filter membrane (see 5.8). Retain filtrate A for
HPLC analysis.
NOTE: If insoluble matter is produced after derivatization, the supernatant can be obtained by
centrifugation.
7.3 Blank test
Without adding a specimen, repeat step 7.2 to perform high performance liquid
chromatographic method analysis. A blank test shall be done for each batch of samples
(less than 20) or every 20 samples.
7.4 Chromatographic conditions
Choose the best test conditions based on the performance of the high-performance
liquid chromatograph used and the actual situation of the specimen.
Since the test results depend on the instrument used, universal parameters for
chromatographic analysis cannot be given. The parameters listed in Annex A, A.1, have
been proven to be suitable for the test.
The type of detector used for chromatographic analysis shall be noted in the test report.
7.5 Drawing of standard working curve
7.5.1 Preparation of formaldehyde standard working solution
Use a graduated pipette (see 5.6) or a single-mark pipette (see 5.7) to pipette 0 mL, 0.1
mL, 0.2 mL, 0.5 mL, 1.0 mL, 2.0 mL, 5.0 mL, and 10.0 mL of formaldehyde standard
solution respectively (see 4.6) in a 10 mL volumetric flask (see 5.5). Dilute to the
volume with acetonitrile (see 4.1). Mix evenly to prepare formaldehyde standard
working solution.
NOTE: The concentration range of the formaldehyde standard working solution can be adjusted
according to the instrument used and the specimen.
7.5.2 Derivatization
Use a graduated pipette (see 5.6) to pipette 4.0 mL of formaldehyde standard working
solution (see 7.5.1), 4.0 mL of water, and 0.4 mL of derivatization reagent (see 4.3).
Mix evenly in a 10 mL centrifuge tube (the dosage of formaldehyde standard working
solution, water, derivatization reagent and the container used for derivatization can be
adjusted according to the actual situation. However, the volume ratio of formaldehyde
standard working solution, water and derivatization reagent participating in the
derivatization reaction shall be maintained at 1:1:0.1). Seal the tube lid. Place in a
(25±5)℃ environment away from light for 24 h for derivatization. Filter with 0.22 μm
organic phase microporous filter membrane (see 5.8). Retain filtrate B for HPLC
analysis.
7.5.3 Drawing of standard working curve
Determine filtrate B according to the chromatographic conditions of 7.4 (see 7.5.2).
Injections are repeated twice. The relative deviation of the peak areas of the two
measurements shall be ≤5%. Take the average of the peak areas of the two
measurements. Using the concentration of the formaldehyde standard working solution
as the abscissa and the peak area of 2,4-dinitrophenylhydrazone (minus the peak area
of 2,4-dinitrophenylhydrazone in the unstandardized working solution) as the ordinate,
draw the standard working solution curve. The linear correlation coefficient R2 of the
standard working curve shall be greater than 0.99, otherwise a new standard working
curve shall be redrawn. For the chromatogram of the formaldehyde standard working
solution derivative, see A.2.
7.6 Sample determination
Determine filtrate A according to the chromatographic conditions of 7.4 (see 7.2.2). Use
retention time for characterization. Quantify based on the peak area of 2,4-
dinitrophenylhydrazone (subtract the peak area of 2,4-dinitrophenylhydrazone in the
blank test). The formaldehyde concentration c is obtained through the standard working
curve.
If the formaldehyde concentration in the specimen solution exceeds the concentration
range of the standard working curve, the specimen amount weighed during sample
pretreatment shall be appropriately adjusted and re-measured.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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