This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of chemical reagent thymol blue. This standard applies to the inspection of chemical reagent thymol blue. GB/T 15353-1994 Chemical reagent thymol blue GB/T15353-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Thymol
Chemical reagent
Thymol blue
This reagent is a brown-green crystalline powder, insoluble in water, soluble in ethanol. Molecular formula: C2H30O.S
Structural formula:
Relative molecular mass: 466.60 (according to the 1991 international relative atomic mass) Subject content and scope of application
GB/T15353--94
This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of the chemical reagent thymol blue. This standard applies to the inspection of the chemical reagent thymol blue. 2 Reference standards
GB/T 604
GB/T 619
GB/T 6682wwW.bzxz.Net
GB/T 9721
GB/T9741
HG 3—-119
3 Technical requirements
Chemical reagentsAcid-base indicatorsGeneral method for determination of pH color rangeSampling and acceptance rules for chemical reagents
Specifications and test methods for water in analytical laboratoriesGeneral rules for molecular absorption spectrophotometry (ultraviolet and visible light parts)Chemical reagents
Chemical reagents
Chemical reagents
General method for determination of ignition residue
Packaging and marking
3.1 pH color range: 1.2 (red) ~ 2.8 (yellow), 8.0 (yellow) ~ 9.6 (blue). 3.2 Mass absorption coefficient (L/cm·g): ≥71.0. 3.3 Maximum impurity content:
Approved by the State Administration of Technical Supervision on December 22, 1994, and implemented on October 1, 1995
Ethanol dissolution test
Ignition residue (calculated as sulfate), %
Test method
GB/T 15353--94
The pH buffer solution in this test method, unless otherwise specified, shall be prepared in accordance with the provisions of GB/T604, and the experimental water shall comply with the third-grade water specifications in GB/T6682.
4.1 Determination of pH color change range
Determined in accordance with the provisions of GB/T604.
4.2 Determination of mass absorption coefficient
Determine in accordance with the provisions of GB/T9721, where: 4.2.1 Determination conditions
Light source: iodine tungsten lamp;
Wavelength: 598nm,
Thickness of absorption cell: 1cm,
Reference solution: water.
4.2.2 Determination method
Weigh 8mg of ground sample to an accuracy of 0.00001g. Place in a 100mL volumetric flask, dissolve with ethanol (absolute ethanol), dilute to scale, and shake well. Measure 2.50mL of the above solution, place in a 25mL volumetric flask, dilute to scale with pH9.8 buffer solution, and shake well. Determine the absorbance.
4.2.3 Determination results
The mass absorption coefficient is calculated as follows:
Where: α——mass absorption coefficient, L/cm·g, A—absorbance,
b——thickness of absorption cell, cm
concentration of sample solution, mg/L,
conversion factor.
4.3 Impurity determination
The sample must be weighed accurately to 0.01g.
4.3.1 Ethanol solubility test
Weigh 0.1g of ground sample, add 100mL of ethanol solution (1+1), heat and stir in a 70℃ water bath until the sample is dissolved, cool to room temperature, and dilute to 100mL with ethanol solution (1+1). The solution should be transparent. 4.3.2 Ignition residue
Weigh 0.5g of sample and determine according to the provisions of Article 4.1 of GB/T9741. The results are calculated according to the provisions of Chapter 5 of GB/T9741. 5 Inspection rules
Sampling and acceptance are carried out according to the provisions of GB/T619. Packaging and marking
6.1 Packaging
According to the provisions of HG3-119, among which:
Inner packaging form: G2-3;
Outer packaging form: W-1.W-5,
Packaging unit: Class 2 and 3.
According to the provisions of HG 3-119.
Additional instructions:
GB/T15353-94
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Beijing Chemical Reagent General Factory. This standard is drafted by Shanghai Chemical Reagent Research Institute. The main drafters of this standard are Duan Qiaoyun, Shi Peifen and Hong Ruonan. From the date of implementation of this standard, the former Ministry of Chemical Industry Standard HG3-1223-79 "Chemical Reagent Thymol Blue" will be invalid.
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