GB/T 26713-2011 PDF in English
GB/T 26713-2011 (GB/T26713-2011, GBT 26713-2011, GBT26713-2011)
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Footwear -- Chemical tests -- Determination of dimethyl fumarate (DMF)
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Standards related to: GB/T 26713-2011
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GB/T 26713-2011: PDF in English (GBT 26713-2011) GB/T 26713-2011
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 61.060
Y 78
Footwear - Chemical tests -
Determination of dimethyl fumarate (DMF)
ISSUED ON: JUNE 16, 2011
IMPLEMENTED ON: DECEMBER 01, 2011
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 4
4 Reagents and materials ... 4
5 Apparatus ... 5
6 Test procedure ... 5
7 Blank test ... 10
8 Result calculation ... 10
9 Determination of recovery rate ... 10
10 Result representation ... 10
11 Low detection limits ... 11
12 Precision ... 11
Appendix A (Informative) GC-MS selective ion monitoring standard
spectrograms of dimethyl fumarate ... 12
Appendix B (Informative) GC-MS-MS standard spectrograms of dimethyl
fumarate ... 14
Footwear - Chemical tests -
Determination of dimethyl fumarate (DMF)
1 Scope
This Standard specifies the test methods for dimethyl fumarate in footwear and
footwear components - gas chromatography-mass spectrometry and gas
chromatography-secondary mass spectrometry.
This Standard applies to the determination of dimethyl fumarate in footwear and
footwear components.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB/T 22049 Footwear - Standard atmospheres for conditioning and testing
of footwear and components for footwear
3 Principle
Use dehydrated ethyl acetate to ultrasonically extract dimethyl fumarate in the
specimen. After the extract is purified, use gas chromatography-mass
spectrometry (GC-MS) or gas chromatography-secondary mass spectrometry
(GC-MS-MS) to determine and confirm; use external standard method to
quantify.
Note: When the matrix interference determined by GC-MS is serious, and the content of
dimethyl fumarate is low, only GC-MS-MS can be used.
4 Reagents and materials
Unless otherwise specified, only use analytically-pure reagents or higher-purity
reagents.
4.1 Ethyl acetate: It shall be dehydrated by 5A molecular sieve.
materials shall also be sampled and determined respectively. If the lining and
the upper cannot be separated, the lining and the upper shall be sampled and
determined together. The determination method shall also be in accordance
with the lining material.
6.2 Specimen treatment
6.2.1 Textiles, artificial leather, synthetic leather and fillers
Weigh about 5.0 g (accurate to 0.001 g) from the cut small test pieces; place
the specimen in a conical flask with stopper (5.8). Add 30 mL of ethyl acetate
(4.1) dehydrated by 5A molecular sieve; close the conical flask and vigorously
oscillate; so that all the specimens are immersed in the liquid (if the specimens
are not completely submerged in the liquid, add an appropriate amount of
dehydrated ethyl acetate until the specimens are completely submerged in
liquid). Ultrasonically extract in an ultrasonic extractor (5.6) for 10 min; filter the
extract into a round-bottom flask (5.10). Use 20 mL of dehydrated ethyl acetate
to repeat the above steps once; combine the extracts. Finally, use 10 mL of
dehydrated ethyl acetate to rinse the conical flask and the specimen; shake
vigorously; combine the extracts. Concentrate the extract to about 3 mL on the
rotary evaporator (5.4); transfer into a measuring cylinder with stopper (5.5);
use a small amount of dehydrated ethyl acetate to rinse the round-bottom flask;
incorporate the washing liquid into the measuring cylinder with stopper. Finally,
use dehydrated ethyl acetate to dilute the volume to 5.0 mL to prepare a test
solution. If the test solution is turbid or has precipitation, use a syringe (5.7) to
suck a small amount of test solution into a centrifuge (5.12) with a 2 mL
centrifuge tube (5.13) for centrifugation and layering for 5 min~10 min (speed
is 8000 r/min). The supernatant after centrifugation is filtered by a syringe filter
(5.14) and immediately analyzed by a gas chromatograph-mass spectrometer
(5.2).
6.2.2 Leather samples
Weigh about 5.0 g (accurate to 0.001 g) from the cut small test pieces; place
the specimen in a conical flask with stopper (5.8). Add 30 mL of ethyl acetate
(4.1) dehydrated by 5A molecular sieve; close the conical flask and vigorously
oscillate; so that all the specimens are immersed in the liquid (if the specimens
are not completely submerged in the liquid, add an appropriate amount of
dehydrated ethyl acetate until the specimens are completely submerged in
liquid). Ultrasonically extract in an ultrasonic extractor (5.6) for 10 min; filter the
extract into a round-bottom flask (5.10). Use 20 mL of dehydrated ethyl acetate
to repeat the above steps once; combine the extracts. Finally, use 10 mL of
dehydrated ethyl acetate to rinse the conical flask and the specimen; shake
vigorously; combine the extracts. Concentrate the extract to about 1 mL on the
rotary evaporator. Pour 5 mL of n-hexane into the neutral alumina cartridge (4.3)
to activate the cartridge; and then add 5 mL of dehydrated ethyl acetate to rinse
the cartridge. Then, transfer the concentrated extract to the cartridge. After
cartridge purification, the test solution is collected by a measuring cylinder with
stopper. Use a small amount of dehydrated ethyl acetate to rinse the round-
bottom flask several times; pour the washing liquid into the cartridge; combine
the purification liquid and dilute to 5 mL. If the test solution is turbid or has
precipitation, use a syringe to suck a small amount of test solution into a
centrifuge with a 2 mL centrifuge tube for centrifugation and layering for 5 min
(speed is 8000 r/min). The supernatant after centrifugation is filtered by a
syringe filter and immediately analyzed by a gas chromatograph-mass
spectrometer.
6.3 Preparation of standard solutions
Accurately weigh 0.02 g (accurate to 0.001 g) of standard dimethyl fumarate
(4.2) in a 25 mL volumetric flask with stopper (5.11); use dehydrated ethyl
acetate (4.1) to dissolve and dilute to the mark, shake well. Then, use
dehydrated ethyl acetate to dilute step by step, to prepare standard working
solutions with concentrations of 0.1 mg/L, 0.5 mg/L, 1.0 mg/L, 5.0 mg/L, 10.0
mg/L, 20.0 mg/L, and 50.0 mg/L respectively. Store in a refrigerator at 4 °C and
protected from light for later use. The expiry date is 1 month.
6.4 Determination of gas chromatography-mass spectrometry (GC-MS)
6.4.1 Gas chromatography-mass spectrometry analysis conditions
Since the test results depend on the instrument used, it is impossible to give
general parameters for gas chromatography-mass spectrometry. The set
parameters shall ensure that the measured component and other components
can be effectively separated during chromatographic determination. The
following parameters are proved to be feasible:
a) Chromatographic column: DB-5MS column; 30 m×0.25 mm (inner
diameter)×0.25 μm, or equivalent;
b) Inlet temperature: 250 °C;
c) Gas chromatography-mass spectrometry interface temperature: 280 °C;
d) Injection mode: Splitless injection; open the valve after 1 min;
e) Carrier gas: Helium; its purity is ≥99.999%. Control method: Constant flow
rate is 1.0 mL/min;
f) Column temperature: Rise from 60 °C to 100 °C at a rate of 5 °C/min; then
rise to 280 °C at a rate of 25 °C/min and keep it for 10 min;
parameters shall ensure that the measured component and other components
can be effectively separated during chromatographic determination. The
following parameters are proved to be feasible:
a) Chromatographic column: DB-5MS column; 30 m×0.25 mm (inner
diameter)×0.25 μm, or equivalent;
b) Inlet temperature: 100 °C;
c) Gas chromatography-mass spectrometry interface temperature: 280 °C;
d) Injection mode: Splitless injection; open the valve after 1 min;
e) Carrier gas: Helium; its purity is ≥99.999%. Control method: Constant flow
rate is 1.0 mL/min;
f) Column temperature: Rise from 60 °C to 100 °C at a rate of 5 °C/min; then
rise to 280 °C at a rate of 25 °C/min and keep it for 10 min;
g) Injection volume: 1 μL;
h) Ion source: EI source;
i) Ionization energy: 70 eV;
j) Scan mode: Secondary mass spectrometry (MS-MS); qualitative ion m/z:
85, 53, 113; quantitative ion m/z: 85;
k) Pyrolysis method: Resonance;
l) Excitation storage level: 49.6 m/z;
m) Excitation pyrolysis voltage: 0.5 V;
n) Solvent delay time: 3 min.
6.5.2 Gas chromatography-secondary mass spectrometry analysis and
confirmation of positive results
According to the content of dimethyl fumarate in the test solution, select
standard working solutions with similar concentrations. The response values of
dimethyl fumarate in the standard working solution and in the test solution shall
be within the linear range of the instrument. Under the above-mentioned GC-
MS-MS conditions, the retention time of dimethyl fumarate is about 6.5 min.
In the total ion chromatograms of the test solution and the standard working
solution, if there are chromatographic peaks at the same retention time, it shall
confirm it based on the characteristic ion fragments of dimethyl fumarate and
their abundance ratio.
Qualitative ion (m/z): 85, 53, 113 (the abundance ratio is 100:11:5);
Quantitative ion (m/z): 85.
Note: Refer to Appendix B for the GC-MS-MS standard spectrograms of dimethyl fumarate.
7 Blank test
Except that no specimen is added, proceed according to the above 6.2~6.5
determination steps, to prove that there is no dimethyl fumarate component in
the reagents and materials used in the test process.
8 Result calculation
Calculate the content of dimethyl fumarate according to formula (1):
Where:
X - The content of dimethyl fumarate in the specimen, in milligrams per kilogram
(mg/kg);
c - The mass concentration of dimethyl fumarate in the specimen solution
obtained from the standard working curve, in milligrams per liter (mg/L);
V - The constant volume of the test solution, in milliliters (mL);
m - The mass of the specimen, in grams (g).
9 Determination of recovery rate
Add a standard solution with a content of dimethyl fumarate equal to that in the
sample into a round-bottom flask containing 60 mL of ethyl acetate. Then follow
the determination steps of 6.2~6.5. The recovery rate of dimethyl fumarate shall
be greater than 80%.
10 Result representation
Take the average of the results of two parallel determinations. The result is
rounded to two decimal places.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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