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In this standard, Annex A is normative and Annex B is informative.
This standard was proposed by China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of SAC/TC 134 the National Technical Committee on Dyestuff of Standardization Administration of China.
Determination of the Content of Chlorinated Phenols in Dye Products
1 Scope
This standard specifies the method of determining the content of chlorinated phenols (2, 3, 5, 6-tetrachlorophenol and pentachlorophenol) in dye products.
This standard is applicable to the determination of chlorinated phenols (2,3,5,6-tetrachlorophenol and pentachlorophenol) in commercial dyes, dye products, dye intermediates and textile dyeing auxiliaries with the gas chromatography method-mass selective detector (GC-MSD) and gas chromatography method-electron capture detector (GC-ECD).
2 Normative References
The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply.
GB/T 6682-2008 Water for Analytical Laboratory Use – Specification and Test Methods (ISO 3696: 1987, MOD)
GB/T 8170-2008 Rules of Rounding off for Numerical Values & Expression and Judgment of Limiting Values
3 Theory
Chlorinated phenols in specimens shall be extracted with potassium carbonate solution. The extracting solution shall be acetylated through aceticanhydride and then subjected to chlorinated phenol acetates extraction with n-hexane. The extract shall be determined by gas chromatograph-mass selected detector (GC-MSD) and gas chromatography method-electron capture detector (GC-ECD) and quantified by external standard method.
4 Test Methods
4.1 General requirements
Unless otherwise specified, only recognized analytical reagent and Grade 3 water (specified in GB/T 6682-2008) shall be used. Judgment of the inspection result shall be carried out according to the rounding-off value comparison method specified in 4.3.3 of GB/T 8170-2008.
4.2 Reagents and solutions
a) anhydrous potassium carbonate;
b) acetic anhydride;
c) n-hexane;
d) anhydrous sodium sulfate: dry for 4 h at 650 ℃, and then put it in a desiccator for future use;
e) potassium carbonate solution: 0.1 mol/L of aqueous solution, weight 13.8 g of anhydrous potassium carbonate and dissolve it in water, and then dilute to 1,000 mL;
f) sodium sulfate solution: 20 g/L;
g) standards of chlorinated phenols in Annex A: content (mass fraction) ≥ 99%.
4.3 Preparation of chlorinated phenol standard solution
4.3.1 Single stock standard solution
Respectively weigh 0.01 g (accurate to 0.0001 g) of the chlorinated phenol standards listed in Annex A, dissolve with potassium carbonate solution, and dilute it to the 25 mL-volumetric flask to prepare a single stock standard solution. Single stock standard solution is valid for one year.
4.3.2 Mixed standard solution
According to the requirements of Table 1, the above single stock standard solutions are respectively extracted into a 25 mL-volumetric flask, dilute it to constant volume with potassium carbonate solutions and prepare it into a mixed standard solution. The mixed standard solution is valid for three months.
Table 1 Preparation of Mixed Standard Solution In mL
Components Volume value of components
Single standard solution 0.10 0.20 0.50 1.00
Potassium carbonate solution 24.9 24.8 24.5 24.0
4.4 Apparatus
a) gas chromatograph: equipped with a mass selective detector (GC-MSD);
b) gas chromatograph: equipped with an electron capture detector (GC-ECD);
c) ultrasonic generator: the operating frequency is 40 kHz;
d) microinjector: 10 μL;
e) extractor: made of hard glass, tubular, with closed bottle block, 100 mL;
f) separating funnel: 150 mL;
g) 0.45 μm-PTFE film filter head;
h) ground centrifugal tube with stopper: 10 mL;
i) centrifuge: 4,000 r/min.
4.5 Determination procedures
4.5.1 Extraction
Weigh 1g (accurate to 0.0001 g) of the sample and put it into an extractor. Accurately add 30.0 mL of potassium carbonate solution to the extractor, shake it well and put it into an ultrasonic bath for 20 min's extraction. Suck and filter the extracting solution, wash the solid portion twice with 10 mL of potassium carbonate solutions, then mix the filtered solutions.
4.5.2 Acetylation
Place the filtered solution in a 150 mL-separating funnel, then add in 2 mL of acetic anhydride, shake the funnel for 2 min, after that, accurately add in 10 mL of N-hexane, shake it for another 2 min, keep the funnel still for layering and then discard the substratum. Add 50 mL of sodium sulfate solution to the upper n-hexane phase, shake it for 2 min, and then discard the substratum. Transfer the n-hexane to a centrifugal tube, then add in 1 g of anhydrous sodium sulfate, shake the tube for 1 min, and then centrifuge it for 3 min at a speed of 4,000 r/min. Take the supernatant for gas chromatography.
4.5.3 Preparation of standard working solutions
Pipette a certain volume of mixed standard solution at a suitable concentration to a 150 mL-separating funnel and add in 30 mL of potassium carbonate solution, the remaining procedures are operated according to 4.5.2.
4.5.4 Chromatographic analysis
4.5.4.1 Gas chromatographic analysis conditions
As the test result depends on the instrument used, it is hard to give general parameters for the chromatographic analysis. The following parameters (see Tables 2 and 3) have been proved appropriate for the test.
Foreword i
1 Scope
2 Normative References
3 Theory
4 Test Methods
5 Determination Lower Limit, Recovery Rate and Precision
6 Test Report
Annex A (Normative) Category of Chlorinated Phenols
Annex B (Informative) Standard Sample Figure of Chlorinated Phenol Acetate
