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Home > News > Technical ArticlesHere is the English translation of the Chinese standard **GB/T 30157-2013**.
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**GB/T 30157-2013**
**Textiles—Determination of total lead and total cadmium content**
**Foreword**
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China National Textile and Apparel Council.
This standard is under the jurisdiction of the Subcommittee on Basic Standards of the National Technical Committee on Textiles of Standardization Administration of China (SAC/TC 209/SC 1).
Drafting organizations of this standard: China Textile Science and Testing Center (Beijing) Certification and Testing Co., Ltd., National Center for Quality Supervision and Testing of Textile Products, Ningbo Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China.
Principal drafters of this standard: Zhang Hui, Jing Tingting, Zheng Yuxiu, Bao Qibei, Feng Yun, Fu Kejie.
**Textiles—Determination of total lead and total cadmium content**
**Warning:** Personnel using this standard shall have practical experience in regular laboratory work. This standard does not address all safety concerns, if any. It is the responsibility of the user to establish appropriate safety and health practices and ensure compliance with any national regulatory conditions.
**1 Scope**
This standard specifies the method for the determination of total lead and total cadmium content in textile products.
This standard is applicable to all types of textile products.
**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
**3 Principle**
The test specimen is digested with concentrated acid. After dilution and constant volume, the digestion solution is analyzed using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) to measure the emission intensity of lead and cadmium under appropriate conditions, or using an Atomic Absorption Spectrophotometer to measure the absorbance of lead and cadmium. The concentration of each metal ion is determined against a standard working curve, and the total content of heavy metals in the specimen is calculated.
**4 Reagents and materials**
Unless otherwise specified, only reagents of analytical grade or higher and grade 2 water or higher as specified in GB/T 6682 shall be used.
4.1 Concentrated nitric acid (HNO₃)
4.2 3% (volume fraction) nitric acid: Transfer 3 mL of concentrated nitric acid (4.1) into a 100 mL volumetric flask and dilute to the mark with grade 2 water.
4.3 Fluoroboric acid (HBF₄)
4.4 Hydrofluoric acid (HF)
4.5 Hydrogen peroxide (H₂O₂)
4.6 Standard stock solutions: Standard stock solutions for each element can be obtained from certified reference materials or prepared as follows.
4.6.1 Lead (Pb) standard stock solution (1000 μg/mL)
Weigh 0.160 g of lead nitrate [Pb(NO₃)₂], dissolve in 10 mL of nitric acid (1+9), transfer to a 100 mL volumetric flask and dilute to the mark.
4.6.2 Cadmium (Cd) standard stock solution (1000 μg/mL)
Weigh 0.203 g of cadmium chloride (CdCl₂·H₂O), dissolve in 10 mL of nitric acid (1+9), transfer to a 100 mL volumetric flask and dilute to the mark.
NOTE: Unless otherwise specified, the standard stock solution is stable for 6 months when stored at room temperature (15℃ to 25℃). It should be re-prepared if turbidity, precipitation, or color change occurs.
4.7 Standard working solution (50 μg/mL)
Accurately pipette 2.50 mL of the standard stock solution into a volumetric flask and dilute to 50 mL with 3% nitric acid (4.2).
NOTE: The standard working solution is generally stable for two weeks at room temperature (15℃ to 25℃). It should be re-prepared if turbidity, precipitation, or color change occurs.
**5 Apparatus and equipment**
5.1 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) or Atomic Absorption Spectrophotometer (AAS)
5.2 Microwave digestion system: with programmable temperature control function.
5.3 Digestion vessels.
5.4 Disposable blades.
5.5 Volumetric flasks: 50 mL, 100 mL.
5.6 Pipettes: 0.5 mL, 1.0 mL, 2.0 mL.
5.7 Aqueous phase filtration membrane: pore size 0.45 μm.
5.8 Balance: with a precision of 0.01 mg.
**6 Analysis procedure**
**6.1 Preparation and processing of test specimen**
6.1.1 Preparation
Take a representative test specimen. Cut the specimen into small pieces of approximately 5 mm × 5 mm. Weigh about 0.2 g of the specimen, accurate to 0.0001 g.
6.1.2 Digestion
Add 5.0 mL of concentrated nitric acid (4.1) to the digestion vessel containing the test specimen and to a blank digestion vessel. Allow the specimen and acid to react completely at room temperature. Seal the digestion vessel and place it in the microwave digestion system (5.2). Heat to (175 ± 5) ℃ over 10 min, and maintain at (175 ± 5) ℃ for 5 min. Allow the vessel to cool for at least 5 min, then remove it from the microwave digestion system. Before opening the digestion vessel, cool it to room temperature in a fume hood or cool for at least 30 min.
NOTE 1: Due to different models of digestion systems, different laboratories may use different digestion programs, provided that the sample is completely digested.
NOTE 2: For coating samples that are difficult to digest, such as PU, appropriate amounts of fluoroboric acid, hydrofluoric acid, and hydrogen peroxide may be added.
NOTE 3: If hydrofluoric acid is used in the test, add 30 mL of 4% boric acid to each vessel to complex the hydrofluoric acid and protect the quartz plasma torch.
6.1.3 Constant volume of sample solution
Transfer the digested solution to a 50 mL volumetric flask (5.5). Rinse the digestion vessel three times with small amounts of water and combine the rinses into the volumetric flask. Dilute to the mark with water and mix well. Filter through an aqueous phase filtration membrane (5.7). The filtrate should be analyzed as soon as possible using ICP-AES or AAS (5.1).
NOTE: For pretreatment methods of accessories and decorative components of textile products, refer to Appendix A.
**6.2 ICP-AES analysis and determination**
6.2.1 Analytical wavelengths for elements by ICP-AES
Analytical wavelength for Pb: 220.3 nm.
Analytical wavelength for Cd: 214.4 nm.
NOTE: To eliminate spectral interference from other elements, another wavelength line can be selected simultaneously as a reference.
6.2.2 Determination
6.2.2.1 Determination of the working curve
According to the test requirements and instrument conditions, dilute the standard working solution (4.7) stepwise with water to prepare a series of working solutions of appropriate concentrations. Set up the instrument's analytical conditions and ignite the plasma. After the plasma stabilizes, measure the spectral intensities of the elements to be tested in the series of working solutions at the corresponding wavelengths, starting from low to high concentration. Plot the working curve with spectral intensity as the ordinate and element concentration (μg/mL) as the abscissa.
6.2.2.2 Determination of sample solutions
Under the instrument conditions set in 6.2.2.1, measure the spectral intensities of the elements to be tested in the blank solution and the sample solution (6.1.3). Calculate the concentration of each element to be tested from the working curve.
NOTE 1: If the concentration of lead or cadmium in the sample solution exceeds 1.5 times the highest point of the calibration curve, the solution should be appropriately diluted and re-analyzed.
NOTE 2: The concentration of lead and cadmium in the blank and sample solutions can also be determined using Flame Atomic Absorption Spectrometry. When using this method, attention should be paid to correcting possible interferences, and the method used should be indicated in the report.
NOTE 3: Analysis conditions may vary for different instruments. Refer to Appendix B for working conditions of some ICP spectrometers and analytical wavelengths for elements to be tested.
6.2.2.3 Quality control
A quality control calibration check should be performed after every 20 tests to ensure the accuracy of the test results.
**7 Calculation of results**
7.1 The content of heavy metal element *i* in the specimen is calculated according to Equation (1):
Wi = [(Ci - C0) × V] / m
Where:
Wi — Total content of heavy metal element *i* in the specimen, in milligrams per kilogram (mg/kg);
Ci — Mass concentration of heavy metal element *i* measured in the sample solution, in micrograms per milliliter (μg/mL);
C0 — Mass concentration of heavy metal element *i* measured in the blank solution, in micrograms per milliliter (μg/mL);
V — Total volume of the sample solution, in milliliters (mL);
m — Mass of the specimen, in grams (g).
7.2 The calculated result is reported to the nearest integer. When the result is below the limit of determination, it is reported as "not detected".
**8 Limit of determination and precision**
8.1 Detection limit of the method
The detection limit of this method is 2.50 mg/kg for lead and 0.25 mg/kg for cadmium. The detection limit may differ if Flame Atomic Absorption Spectrometry is used.
8.2 Precision
The relative standard deviation of two independent test results obtained in the same laboratory, by the same operator using the same equipment, following the same test method, and on the same test material within a short period of time, shall not exceed 10%, provided that the absolute difference between the two results exceeding 10% of their arithmetic mean occurs in not more than 5% of cases.
**9 Test report**
The test report shall at least include the following information:
a) Number of the standard used (i.e., this standard);
b) Source and description of the sample;
c) Test results;
d) Any details deviating from this standard;
e) Date of the test.
**Appendix A**
(Informative)
**Pretreatment methods for accessories and decorative components of textile products**
**A.1 Reagents**
A.1.1 Reagents listed in Clause 4.
A.1.2 Concentrated hydrochloric acid (HCl).
**A.2 Apparatus and equipment**
A.2.1 Instruments and equipment listed in Clause 5.
A.2.2 Metal cutter.
A.2.3 Rotary mill.
A.2.4 Cryogenic grinder.
**A.3 Analysis procedure**
A.3.1 Sample pretreatment
A.3.1.1 Preparation of coated samples
Scrape off the surface coating using a disposable blade, avoiding scraping the substrate. Weigh 20 mg to 100 mg of the scraped coating as the test specimen, accurate to 0.1 mg. Place it in a microwave digestion vessel (5.3) and proceed according to 6.1.2 to 6.1.3.
A.3.1.2 Preparation of uncoated samples
A.3.1.2.1 Metallic materials
Cut the sample into small pieces using a metal cutter (A.2.2) or grind it using a rotary mill (A.2.3). Weigh 30 mg to 100 mg of the specimen, accurate to 0.1 mg, and place it in a microwave digestion vessel (5.3).
Add 4.5 mL of concentrated nitric acid (4.1) and 1.5 mL of concentrated hydrochloric acid (A.1.2) to the vessel containing the test specimen and to a blank digestion vessel. Allow the specimen and acid to react completely. Seal the vessel and place it in the microwave digestion system (5.2). Heat to (175 ± 5) ℃ over 5.5 min, and maintain at (175 ± 5) ℃ for 4.5 min. Allow the vessel to cool for at least 5 min, then remove it. Before opening, cool the vessel to room temperature in a fume hood or cool for at least 30 min.
Transfer the digested solution to a suitable volumetric flask (5.5) based on the sample weight. Rinse the digestion vessel with small amounts of water, combine the rinses into the volumetric flask. Dilute to the mark with water, mix well, and filter through an aqueous phase filtration membrane (5.7). This solution is used for analysis and determination by ICP-AES or AAS (5.1) according to 6.2.
NOTE: Generally, when the sample weight is 20 mg to 49 mg, transfer the digested solution to a 10 mL volumetric flask; when the sample weight is 50 mg to 100 mg, transfer to a 25 mL volumetric flask.
A.3.1.2.2 Non-siliceous materials such as plastics, polymers
Grind the sample using a cryogenic grinder (A.2.4) or cut it into pieces not larger than 1 mm × 1 mm × 1 mm. Weigh 30 mg to 100 mg of the ground specimen, accurate to 0.1 mg, and place it in a microwave digestion vessel.
Add 8.0 mL of concentrated nitric acid to the vessel containing the test specimen and to a blank digestion vessel. Allow the specimen and acid to react completely. Seal the vessel and place it in the microwave digestion system. Heat to (210 ± 5) ℃ over 20 min, and maintain at (210 ± 5) ℃ for 10 min. Allow the vessel to cool for at least 5 min, then remove it. Before opening, cool the vessel to room temperature in a fume hood or cool for at least 30 min.
Transfer the digested solution to a suitable volumetric flask (5.5) based on the sample weight. Rinse the digestion vessel with small amounts of water, combine the rinses into the volumetric flask. Dilute to the mark with water, mix well, and filter through an aqueous phase filtration membrane (5.7). This solution is used for analysis and determination by ICP-AES or other suitable instruments (5.1) according to 6.2.
A.3.1.2.3 Siliceous materials such as crystal, glass
Grind the sample using a cryogenic grinder (A.2.4). Weigh 30 mg to 100 mg of the ground specimen, accurate to 0.1 mg, and place it in a microwave digestion vessel.
Add 3 mL of concentrated nitric acid (4.1) and 1 mL of hydrofluoric acid (4.4) to the vessel containing the test specimen and to a blank digestion vessel. Allow the specimen and acid to react completely. Seal the vessel and place it in the microwave digestion system. Heat to (175 ± 5) ℃ over 5.5 min, and maintain at (175 ± 5) ℃ for 9.5 min. Allow the vessel to cool for at least 5 min, then remove it. Before opening, cool the vessel to room temperature in a fume hood or cool for at least 30 min.
Transfer the digested solution to a suitable volumetric flask (5.5) based on the sample weight. Rinse the digestion vessel with small amounts of water, combine the rinses into the volumetric flask. Dilute to the mark with water, mix well, and filter through an aqueous phase filtration membrane (5.7). This solution is used for analysis and determination by ICP-AES or other suitable instruments (5.1) according to 6.2.
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Source: National Standard of the People's Republic of China GB/T 30157-2013
