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GB/T 38409-2019 English PDF (GBT38409-2019)

GB/T 38409-2019 English PDF (GBT38409-2019)

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GB/T 38409-2019: Leather -- Chemical tests -- Determination of N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) content

This standard specifies the determination method of N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) content in leather and its products. This standard is applicable to the determination of NMP and NEP in various leather and its products.
GB/T 38409-2019
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 59.140.30
Y 46
Leather - Chemical tests - Determination of N-methyl-
2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP)
content
[ISO 19070:2016, Leather - Chemical determination of N-methyl-2-pyrrolidone (NMP) in leather, MOD]
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Principles ... 5
4 Reagents and materials ... 5
5 Apparatus and equipment ... 6
6 Test procedure ... 6
7 Calculation and presentation of results ... 8
8 Test report ... 8
Appendix A (Informative) Structural changes of this standard compared with ISO 19070:2016 ... 10
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009. This standard uses the redrafting method to modify and adopt ISO 19070:2016 "Leather - Chemical determination of N-methyl-2-pyrrolidone (NMP) in leather". Compared with ISO 19070:2016, this standard has many adjustments in
structure. Appendix A gives a list of comparisons of clause numbers between this standard and ISO 19070:2016.
Compared with ISO 19070:2016, this standard has made the following technical modifications:
- Regarding normative references, this standard has adjusted the technical differences; the adjustments are collectively reflected in Chapter 2
"Normative references". The specific adjustments are as follows:
??? ADD the reference to GB/T 6682;
??? USE the QB/T 2716 which modifies and adopts international standard
to replace ISO 4044;
??? DELETE the ISO 2418.
- ADJUST the expression of "3 Principles" in ISO 19070:2016, which is more in line with China's habits.
- ADJUST the "5.4 Micropipette" in ISO 19070:2016 to "5.4 Appropriate
Pipette", for easy operation.
- ADJUST and MODIFY the "6.1.1 NMP standard stock solution" in ISO
19070:2016 to "4.5 NMP and NEP mixed standard stock solution (1000
??g/mL)". At the same time, ADD the storage requirements and validity
period of the stock solution, for easy understanding and use.
- In "6.1 Drawing the standard working curve", ADD the standard solution, which has a concentration of 0.5 ??g/mL, to make the concentration range covered by the standard curve more reasonable.
- In ISO 19070:2016 "6.3 Extraction procedure", DELETE the repeated
provision that "the test of filtrate shall be finished within 24 hours", MODIFY the extraction time from "(1.0 ?? 0.1) h" to "(60 ?? 2) min"; MODIFY the
refrigerator's temperature from "(4 ?? 2) ??C " to "0 ??C ~ 4 ??C", which is consistent with similar standards in China.
- ADJUST the "Appendix A Chromatographic analysis" in ISO 19070:2016
Leather - Chemical tests - Determination of N-methyl-
2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP)
content
1 Scope
This standard specifies the determination method of N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) content in leather and its products. This standard is applicable to the determination of NMP and NEP in various leather and its products.
2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this standard.
GB/T 6682 Water for analytical laboratory use - Specification and test
methods (GB/T 6682-2008, ISO 3696:1987, MOD)
QB/T 2716 Leather - Preparation of chemical test samples (QB/T 2716-2018, ISO 4044:2008, MOD)
3 Principles
Under specified conditions, the sample is ultrasonically extracted by acetone. The obtained extract is analyzed by gas chromatography-mass spectrometry (GC-MS); it is quantified by external standard method.
4 Reagents and materials
4.1 General requirements: Unless otherwise specified, all reagents used are of analytical grade; the test water shall meet the requirements of Grade 3 water in GB/T 6682.
4.2 Acetone, chromatographically pure.
then increase to 300 ??C at 30 ??C/min; hold for 1 min.
6.4.2 Mass spectrometry conditions
Ionization method: EI.
Ionization energy: 70 eV.
Detection method (SIM/SCAN mode): SIM: m/z = 99 (NMP), m/z = 98 (NEP).
Ion source's temperature: 230 ??C.
Temperature at interface of chromatography-mass spectrometry: 280 ??C.
Solvent delay: 2.5 min.
7 Calculation and presentation of results
According to formula (1), calculate the content of NMP and NEP in the
specimen:
Where:
w - The content of NMP or NEP in the specimen, in milligrams per kilogram (mg/kg), (accurate to 0.1 mg/kg);
??S - The mass concentration of NMP or NEP, which is read from the standard curve, in micrograms per milliliter (??g/mL);
V - Extraction volume (V = 10 mL under standard conditions), in milliliter (mL); m - The mass of the specimen, in grams (g).
The detection limit of this method is 5 mg/kg.
8 Test report
The test report shall include the following:
a) Number of this standard;
b) The name, number, type, manufacturer (or trademark) of specimen;
c) The content of NMP and NEP as extracted from the specimen, mg/kg;

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