GB/T 38268-2019 PDF in English
GB/T 38268-2019 (GB/T38268-2019, GBT 38268-2019, GBT38268-2019)
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Determination of short chain chlorinated paraffins in textiles dyeing and finishing auxiliaries
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Standards related to (historical): GB/T 38268-2019
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GB/T 38268-2019: PDF in English (GBT 38268-2019) GB/T 38268-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.40
G 70
Determination of short chain chlorinated paraffins in
textiles dyeing and finishing auxiliaries
ISSUED ON: DECEMBER 10, 2019
IMPLEMENTED ON: NOVEMBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 4
4 Reagents and materials ... 5
5 Instruments and equipment... 7
6 Determination steps ... 7
7 Blank test ... 9
8 Test data processing ... 9
9 Lower limit of determination, recovery rate, precision ... 10
10 Test report ... 10
Annex A (informative) Standard reference chromatogram of C10, C11, C12, C13
n-alkane ... 12
Annex B (normative) Qualitative confirmation analysis method ... 13
Determination of short chain chlorinated paraffins in
textiles dyeing and finishing auxiliaries
WARNING - Personnel using this Standard shall have practical experience
in formal laboratory work. This Standard does not indicate all possible
safety issues. The user is responsible for taking appropriate safety and
health measures and ensuring compliance with the conditions specified
by relevant national laws and regulations.
1 Scope
This Standard specifies the principle, reagents and materials, instruments and
equipment, determination steps, blank test, test data processing as well as
lower limit of determination, recovery rate, precision and test report for
determination of short chain chlorinated paraffins in textiles dyeing and finishing
auxiliaries.
This Standard is applicable to the determination of content of short chain
chlorinated paraffins C10~C13) in textiles dyeing and finishing auxiliaries.
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 6682, Water for analytical laboratory use - Specification and test
methods (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 8170-2008, Rules of rounding off for numerical values & expression
and judgement of limiting values
3 Principle
Use n-hexane to shake and extract the sample. Purify the extract and set
constant volume. Through palladium catalytic dichlorination, short chain
chlorinated paraffins become C10~C13 normal alkanes. Use a gas
chromatograph (GC-FID) equipped with a flame ionization detector to test. Use
external standard method of standard short chain chlorinated paraffins with a
flasks. Use n-hexane (4.3) to dilute to the scale then obtain 100μg/mL mixed
standard stock solution.
NOTE: Store the standard stock solution at 0°C~4°C. It shall be valid for 12 months.
4.15 Mixed standard working solution: Respectively draw appropriate amount
of n-alkane mixed standard stock solution (4.14). Use n-hexane (4.3) to dilute
and prepare 0.5μg/mL, 1.0μg/mL, 2.0μg/mL, 5.0μg/mL, 10.0μg/mL, 20.0μg/mL
mixed standard working solutions.
NOTE: Store the mixed standard working solution at 0°C~4°C. It shall be valid for 3 months.
4.16 Glass beads with palladium catalyst: Weigh 0.04g of palladium chloride
(4.6) and add 5mL of acetic acid solution (4.13). Under slow stirring, use boiling
water bath to fully dissolve palladium chloride. Then transfer to an evaporating
dish containing 9.5g of glass beads (4.20) (use a small amount of water to wash
and transfer to an evaporating dish). Place the evaporating dish on the water
bath. In the boiling water bath, heat and stir to evaporate the water. Add water
to immerse the glass beads. Use ammonia (4.1) to adjust the pH to 8.8~9.1.
Use the boiling water bath to evaporate the water again. Transfer the glass
beads with palladium catalyst on the surface to a 100mL sand core funnel. Use
25mL cyclopentane (4.5) to rinse the glass beads. Dry the glass beads for later
use.
4.17 Deactivated splitless liner: Match with chromatograph inlet.
4.18 Reaction liner: In the deactivated splitless liner (4.17), load 5mm silanized
glass wool (4.22), 2mm calcium carbonate (4.7), 20mm glass beads (4.16) with
palladium catalyst and 5mm silanized glass wool (4.22) from bottom to top. The
filling height of the liner shall be such that the injection needle does not touch
the palladium catalyst layer during injection. Otherwise, the filling height shall
be adjusted. The filled liner needs to be aged for 1h at the inlet of the gas
chromatograph at 300°C before use. Use standard working solution of short
chain chlorinated paraffins (4.11) to determine the catalytic efficiency r of the
reaction liner. Guarantee r≥80%.
4.19 pH test paper: precision pH test paper, measuring range: 8.0~9.7.
4.20 Glass beads: diameter is 180μm~250μm.
4.21 Solid phase extraction cartridge: Flori silica, 1g/6mL. It shall be rinsed and
activated with 5mL of n-hexane (4.3) before use.
4.22 Silanized glass wool: the highest temperature resistance is 500°C.
5 Instruments and equipment
5.1 Gas chromatograph: equipped with hydrogen flame ionization detector
(FID).
5.2 Oscillator: oscillation frequency is (260±30) r/min.
5.3 Vortex mixer.
5.4 Centrifuge: speed is controlled stable at 3000r/min.
5.5 Water bath.
5.6 Nitrogen blowing instrument.
5.7 Centrifuge tube with stopper: 50mL.
5.8 Glass centrifuge tube with stopper: 10mL.
5.9 Analytical balances: resolutions are 0.0001g and 0.01g.
5.10 Sand core funnel: 100mL.
6 Determination steps
6.1 Extraction
Weigh 1.0g of (to the nearest of 0.01g) sample into a 50mL centrifuge tube with
stopper (5.7). Add 20mL of n-hexane (4.3). Use an oscillator to oscillate and
extract for 30min. Centrifuge the extract with a centrifuge at 3000r/min for 5min.
Place still. Take 10mL of the upper n-hexane solution. Transfer to the glass
centrifuge tube with stopper (5.8). Concentrate and dilute to 2mL by nitrogen
blowing at 40°C. The concentrate is to be purified.
6.2 Purification
Add 5mL of concentrated sulfuric acid (4.8) to the concentrated solution after
extraction. Vortex for 5min at room temperature. Sulfonate to transparent
solution. Centrifuge the sulfonated solution at 3000r/min for 5min. Discard the
concentrated sulfuric acid layer. Add another 5mL of water. Vortex for 5min at
room temperature. Take the n-hexane layer for testing.
NOTE: Perform further purification if necessary. Take 1mL of sulfonated upper layer
solution. Transfer to the pre-activated solid phase extraction cartridge (4.21). Use 2mL of
n-hexane (4.3) to rinse first. Discard the eluent. Then use 5mL of elution solution (4.9) to
elute. Collect the eluate. Concentrate to dryness by blowing nitrogen. Use 1mL of n-hexane
solution, in micrograms per milliliter (μg/mL);
coi - Numerical value of n-alkane concentration converted from blank sample
solution, in micrograms per milliliter (μg/mL);
V - Value of the final constant volume, in milliliters (mL);
m - Value of sample mass, in grams (g);
f - Dilution factor;
0.461 - Conversion factor of short chain chlorinated paraffins with chlorine
content z = 55.5% (mass fraction).
The calculation result is expressed as the arithmetic mean of the two parallel
determination results. Round off according to the comparison method of
rounding value in 4.3.3 of GB/T 8170-2008, expressing to one decimal place.
When it is lower than the lower limit of determination (9.1), the test result shall
be "not detected".
9 Lower limit of determination, recovery rate, precision
9.1 Lower limit of determination
The lower limit of determination of this method is 20mg/kg.
9.2 Recovery rate
The recovery rate of this method for short chain chlorinated paraffins is greater
than 80% [calculated as short chain chlorinated paraffins with an average
chlorine content of 55.5% (mass fraction)].
9.3 Precision
In the same laboratory, the same operator uses the same equipment, according
to the same test method, in a short period of time, the absolute difference
between the two independent test results obtained by independent tests on the
same object under test is not more than 20% of the arithmetic mean of the two
measured values. It is assumed that the arithmetic mean value of these two
measured values does not exceed 20% and this situation shall not exceed 5%.
10 Test report
The test report shall at least give the following information:
a) Sample source and description;
Annex B
(normative)
Qualitative confirmation analysis method
B.1 General
This appendix is used for further qualitative confirmation analysis on the test
results of palladium-catalyzed hydrogen flame gas chromatography.
B.2 Method principle
Because short chain chlorinated paraffins contain a lot of halogen elements,
have very high response on the electron capture detector, and it can eliminate
the interference of other compounds that do not contain halogen elements. But
the negative chemical source GC/MS instrument can select the characteristic
ion scanning of short chain chlorinated paraffins, which has high selectivity.
Use gas chromatograph equipped with electron capture detector or GC/MS with
negative chemical source. Perform qualitative confirmation based on retention
time and shape of co-eluting peak.
B.3 Instruments and equipment
Gas chromatograph equipped with electron capture detector or GC/MS with
negative chemical source.
B.4 Chromatography / mass spectrometry conditions
B.4.1 Analysis conditions of gas chromatography-electron capture
detector
Select the best analysis conditions according to different equipment. The
reference conditions for analysis of gas chromatography-electron capture
detector are as follows:
a) Chromatographic column: DB-5, (30m×0.25mm×0.25μm), or equivalent;
b) Chromatographic column temperature:
c) Inlet temperature: 280°C (using conventional split liner);
d) Detector temperature: 300°C;
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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