GB/T 42908-2023Determination of organic halogen content in textile dyeing and finishing auxiliaries (English PDF)

Foreword

This document was issued on 6 August 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 March 2024.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 42908-2023 gives the determination of organic halogen content in textile dyeing and finishing auxiliaries. Organic halogens reach a fabric through the auxiliaries rather than the dyes - the fluorinated water repellents, the chlorinated carriers and the brominated flame retardants that are added at the finishing stage - and they are the substances most restricted by international buyers, so a mill needs to know what is in the drum before it goes into the bath. The standard describes the principle, the reagents and materials, the instruments and equipment, the test procedure, the processing of the data, the lower limit of determination, the recovery and precision, and the test report, with informative annexes on the purification of the activated carbon and on the halide ion separation chromatogram. It covers organic fluorine, chlorine, bromine and iodine and took effect on 1 March 2024.

This document describes the method for the determination of organic halogen content

in textile dyeing and finishing auxiliaries.

This document applies to the determination of organic halogen content in various types

of textile dyeing and finishing auxiliaries, including organic fluorine, organic chlorine,

and organic bromine.

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 8170-2008 Rules of rounding off for numerical values & expression and

judgement of limiting values

3 Terms and definitions

For the purpose of this document, the following term and definition apply.

3.1

organic halogen

Halogens combined with organic compounds.

NOTE 1: The organic halogen compounds in this document include organic compounds of fluorine

(F), chlorine (Cl), and bromine (Br), except iodine (I).

NOTE 2: Under the test conditions of this document, some inorganic halogen compounds will also

be determined as organic halogens if they are not removed from the test.

4 Principle

Disperse or dissolve the sample in a nitric acid aqueous solution, use activated carbon

to adsorb the organic halide in the solution, and put the activated carbon adsorbed with

the organic halide into a high-temperature furnace for combustion, cracking, and

gasification. Its product, hydrogen halide (hydride of fluorine, chlorine, bromine), is

absorbed by alkaline aqueous solution, and then the halogen ions are separated and

determined by ion chromatography and quantified by the external standard method.

5 Reagents or materials

Unless otherwise specified, only use reagents confirmed to be of analytical grade and

first-grade water specified in GB/T 6682. It is recommended that the containers used

be cleaned with nitric acid solution (5.8) before use, and then rinsed with water.

5.1 Activated carbon: granular (0.5 mm ~ 2.5 mm). See Annex A for purification

preparation method.

5.2 Oxygen: purity greater than or equal to 99.995 % (volume fraction).

5.3 Argon gas: purity greater than or equal to 99.99 % (volume fraction).

5.4 Nitric acid.

5.5 Potassium hydroxide, guaranteed reagent.

5.6 Anhydrous sodium carbonate, guaranteed reagent.

5.7 Sodium bicarbonate, guaranteed reagent.

5.8 Nitric acid solution, 1 mol/L: PIPETTE 67 mL of nitric acid (5.4), ADD water to

make the volume to 1000 mL.

5.9 Sodium nitrate solution, 0.85 g/L: WEIGH 17 g of sodium nitrate and DISSOLVE

it in a small amount of water, ADD 1.4 mL of nitric acid (5.4), TRANSFER it to a 1000

mL volumetric flask, and DILUTE to the mark with water. Then use a pipette to transfer

50 mL of the solution, and then dilute to 1000 mL with water.

5.10 Organic halogen reference solutions, 0.25 mg/mL: WEIGH 184.4 mg of 4-

fluorobenzoic acid, 110.3 mg of 4-chlorobenzoic acid, and 62.9 mg of 4-bromobenzoic

acid, ADD water to dissolve respectively and DILUTE to 100 mL to prepare reference

solutions of organic fluorine, organic chlorine and organic bromine with mass

concentrations of 0.25 mg/mL. Dilute as needed when using.

NOTE: Stored in an airtight plastic container at 4 °C, the validity period is 12 months.

5.11 Potassium hydroxide solution, 30 mmol/L: WEIGH 1.68 g of potassium hydroxide

(5.5), DISSOLVE it in water and DILUTE to 1000 mL.

5.12 Mixed solution of 3.2 mmol/L sodium carbonate and 1.0 mmol/L sodium

bicarbonate: WEIGH 0.3392 g of anhydrous sodium carbonate (5.6) and 0.0840 g of

sodium bicarbonate (5.7), DISSOLVE with water and DILUTE to 1000 mL.

5.13 Halogen ion mixed standard stock solution, 1 mg/mL: BAKE the reference

reagents of sodium fluoride, sodium chloride, and sodium bromide at 105 °C for 120

min (or burn at 500 °C for 30 min), COOL and PLACE in a desiccator. WEIGH 2.2105

g of sodium fluoride, 1.6485 g of sodium chloride, and 1.2877g of sodium bromide

after drying, DISSOLVE them in water and DILUTE to 1000 mL. The mass

concentrations of F-, Cl-, and Br- ions in the stock solution are all 1 mg/mL. Or purchase

commercially available standard solutions.

NOTE: Stored in an airtight plastic container at 4 °C, the validity period is 12 months.

5.14 Halogen ion mixed standard working solution: DILUTE the halide ion mixed

standard stock solution (5.13) with water, and prepare halide ion mixed standard

working solution with an appropriate series of concentrations as needed. It is

recommended that the mass concentration of F-, Cl-, and Br- ions be in the range of 0.10

mg/L ~ 2 .00 mg/L.

NOTE: Stored in an airtight plastic container at 4 °C, the validity period is 12 months.

6 Instruments and equipment

6.1 Ion chromatograph: equipped with conductivity detector.

6.2 High-temperature combustion device: It consists of a tube furnace, a cracking tube,

a quartz boat, and a controller. The schematic diagram is shown in Figure 1, or

equivalent. The tube furnace can control the temperature within the range of 500 °C ~

1000 °C, with an error of less than 10 °C.

Halogen-free gloves shall be worn during sample collection, and samples shall be

sealed and stored in polyethylene bags or bottles. If the sample analysis cannot be

completed within 7 days after sampling, it shall be stored frozen to reduce

biodegradation and reduce the loss of volatile halogen compounds.

Take at least 0.5 g of a representative sample, and weigh no less than 2 homogeneous

samples of 10 mg ~ 50 mg (accurate to 0.1 mg).

7.2 Activated carbon adsorption

7.2.1 PUT the weighed sample into a 100 mL Erlenmeyer flask (6.3) with a ground

stopper, ADD 50 mL of sodium nitrate solution (5.9), and ADJUST the pH value to less

than 2 with nitric acid solution (5.8).

7.2.2 ADD 50 mg of activated carbon (5.1) to the Erlenmeyer flask, COVER it with a

ground stopper, PLACE it in the oscillator (6.4) to oscillate and absorb at room

temperature for 12 hours. After adsorption, TRANSFER the solution and activated

carbon to the filtration device (6.5) for filtration, and then WASH the activated carbon

particles several times with 25 mL of sodium nitrate solution (5.9). Then PUT the

activated carbon particles into the quartz boat and proceed with combustion and

cracking according to step 7.3.

7.3 Combustion and cracking

7.3.1 WARM UP the tube furnace in advance, ADJUST the oxygen flow rate to more

than 160 mL/min, and VENTILATE for more than 10 minutes to stabilize the

instrument.

7.3.2 CONNECT the outlet end of the cracking tube to the absorption tube (6.6)

containing 10 mL of potassium hydroxide solution (5.11).

7.3.3 MOVE the quartz boat filled with activated carbon particles to the dry area of the

combustion tube, LET IT STAND for more than 5 minutes. There shall be no water

condensation in the low temperature area of the combustion tube.

7.3.4 PUSH the quartz boat into the high-temperature area of the combustion tube (set

to 950 °C) for full combustion and cracking. The duration shall not be less than 3

minutes.

7.3.5 MOVE the quartz boat to the low temperature area and continue to blow oxygen

for cooling for more than 2 minutes. TAKE OUT the absorption tube, FILTER the

absorption solution through the needle filter head (6.9), for determination.

7.4 Analytical methods

7.4.1 Chromatographic conditions

The best analysis conditions can be selected according to different instruments and

equipment. The reference conditions for chromatographic analysis are as follows.

a) Chromatographic conditions one:

* Chromatographic column: hydroxide selectivity, anion exchange column, 250

mm x 4 mm (inner diameter);

* Column temperature: 30 degrees C;

* Eluent: potassium hydroxide solution (5.11);

* Flow rate:1.0 mL/min;

* Sample injection volume: 25 uL.

b) Chromatographic conditions two:

* Chromatographic column: carbonate selectivity, anion exchange column, 150

mm x 4 mm (inner diameter);

* Column temperature: 30 degrees C;

* Eluent: a mixed solution of 3.2 mmol/L sodium carbonate and 1.0 mmol/L

sodium bicarbonate (5.12);

* Flow rate: 0.7 mL/min;

* Sample injection volume: 20 uL.

7.4.2 Qualitative analysis

Analyze the halide ion mixed standard working solution (5.14) and absorption solution

(7.3.5) in sequence according to the analysis conditions of 7.4.1, and conduct qualitative

analysis based on the retention time of F-, Cl- or Br- ions. The halide ion separation

chromatogram of the standard working solution is shown in Figure B.1 and Figure B.2

in Annex B.

7.4.3 Quantitative analysis

Plot a standard working curve with the mass concentration of F-, Cl- or Br- ions in the

halide ion mixed standard working solution (5.14) as the abscissa and the corresponding

peak area as the ordinate. According to the chromatographic peak area of F-, Cl- or Br-

ions in the absorption solution (7.3.5), use the external standard method for

quantification. The response value of the target substance in the sample solution shall

be within the linear range of testing of the instrument. If the content exceeds the range

of the standard working curve, the sample solution shall be diluted to an appropriate

concentration before analysis.

The lower limit of determination of organic fluorine, organic chlorine or organic

bromine in this document is 25.0 mg/kg.

9.2 Recovery rate

The standard-adding recovery rates of organic fluorine, organic chlorine or organic

bromine in this document are all 85 % ~ 110 %.

9.3 Precision

The absolute difference between the two independent test results obtained in the same

laboratory, by the same operator using the same equipment, according to the same test

method, by testing the same tested object independently of each other in a short period

of time, is not greater than 10 % of the arithmetic mean of the two measured values,

provided that the case, where it is greater than 10 % of the arithmetic mean of the two

measured values, does not exceed 5 %.