GB/T 29493.3-2023Determination of harmful substances in textile dyeing and finishing auxiliaries—Part 3: Determination of organotins (English PDF)

1 Scope

This document describes a method for the determination of organotin compounds in textile dyeing and finishing auxiliaries using gas chromatography-mass spectrometry (GC-MS).

This document is applicable to the determination of 18 organotin compounds (see Annex A) in textile 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 8170-2008, Rules of rounding off for numerical values and expression and judgement of limiting values

3 Terms and definitions

There are no terms or definitions to be defined in this document.

4 Principle

After the specimen is extracted with a methanol-ethanol mixed solvent added with sodium diethyldithiocarbamate. Under the conditions of pH=4.5, the organotin compounds are converted into the corresponding volatile ethylated derivatives by reacting with sodium tetraethylborate. Extract with n-hexane. Determine by gas chromatography-mass spectrometry. Use the internal standard method to quantify.

5 Reagents or materials

Continuously fill a screw-capped sample bottle with an inert gas (such as nitrogen, argon). Pipette 10 mL of tetrahydrofuran into a screw-capped sample bottle. Open the 2 g package of sodium tetraethylborate. Quickly add to sample bottle. Seal. Dissolve. If sodium tetraethylborate is packaged in 5 g, increase the volume of tetrahydrofuran added accordingly. Ensure that the mass concentration of sodium tetraethylborate is 0.2 g/mL.

5.16 Organotin standard stock solution, 1000 µg/mL: Weigh each organotin standard material (5.10) according to Table A.1 (accurate to 0.1 mg). Dissolve in methanol (5.3) respectively and set the volume to 25 mL.

NOTE: Organotin standard stock solution is stored in the dark at 0°C~4°C. Validity period is 1 year.

5.17 Organotin intermediate concentration mixed solution, 10 µg/mL: Pipette 1 mL of organotin standard stock solution (5.16) into a 100 mL volumetric flask. Set the volume to the scale with methanol (5.3).

NOTE: The mixed solution of organotin with intermediate concentration shall be stored in the dark at 0°C~4°C. Validity period is 1 month.

5.18 Organotin standard mixed solution, 1 µg/mL: Pipette 10 mL of organotin intermediate concentration mixed solution (5.17) with a mass concentration of 10 µg/mL into a 100 mL volumetric flask. Set the volume to the scale with methanol (5.3).

NOTE: Organotin standard mixed solution shall be stored in the dark at 0°C~4°C. Validity period is 2 weeks.

5.19 Internal standard stock solution, 1000 µg/mL: Weigh (accurate to 0.1 mg) each internal standard material (5.11) according to Table A.2. Dissolve in methanol (5.3) and set the volume to 25 mL.

NOTE: The internal standard stock solution is stored in the dark at 0°C~4°C. Validity period is 1 year.

5.20 Internal standard intermediate concentration mixed solution, 10 µg/mL: Pipette 1 mL of internal standard stock solution (5.19) into a 100 mL volumetric flask. Set the volume to the scale with methanol (5.3).

NOTE: The internal standard intermediate concentration mixed solution is stored in the dark at 0°C~4°C. Validity period is 1 month.

5.21 Internal standard mixed solution, 1 µg/mL: Pipette 10 mL of the internal standard intermediate concentration mixed solution (5.20) with a mass concentration of 10 µg/mL into a 100 mL volumetric flask. Set the volume to the scale with methanol (5.3).

NOTE: The internal standard mixed solution is stored in the dark at 0°C~4°C. Validity period is 2 weeks.

6 Instruments and equipment

6.1 Gas chromatography-mass spectrometer.

6.2 Analytical balance: sensitivity is 0.1 mg.

6.3 Screw cap test tubes: 50 mL, 70 mL.

6.4 Shaker: speed is controllable at 300 r/min.

6.5 Ultrasonic generator: working frequency is (40±5) kHz, with temperature controllable.

6.6 pH meter: Equipped with glass composite electrode; measuring range (pH value) is 0~14, accurate to 0.01 pH unit.

6.7 Pipette gun: According to the needs of use, select an appropriate measuring range; equipped with a disposable tip.

7 Test steps

8 Test data processing

The determination results are expressed as the detection results of various organotin cations/organotins, respectively.

The content of various organotin cations/organotin in the specimen is calculated as Xi.

Values are expressed in milligrams per kilogram (mg/kg). Calculate according to formula (1):

Where, Ai - The value of the peak area of the target organotin ethylated derivative/organotin in the specimen solution;

rhois - The value of the target organotin cation/organotin mass concentration in the standard working solution, in micrograms per liter (µg/L);

V - The value of the volume of n-hexane extraction solution, in milliliters (mL);

Aisc - The value of the peak area of the internal standard ethylated derivative/organotin in the standard working solution;

Ais - The value of the peak area of the target organotin ethylated derivative/organotin in the standard working solution;

m - The value of the specimen mass, in grams (g);

Aiss - The value of the peak area of the internal standard ethylated derivative/organotin in the specimen solution;

V0 - The value of the volume of sodium diethyldithiocarbamate solution used for ultrasonic extraction, in milliliters (mL);

V1 - The value of the volume of the extract used for derivatization, in milliliters (mL);

f - The dilution factor.

9 Lower limit of determination, recovery rate, precision

10 Test report

The test report shall at least provide the following content:

a) Sample source and description;

b) Reference to this document;

c) Deviations from this document;

d) Abnormal situations occurred during the test;

e) Test results;

f) Test date. […]