This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of the chemical reagent bromocresol green. This standard applies to the inspection of the chemical reagent bromocresol green. GB/T 15349-1994 Chemical reagent bromocresol green GB/T15349-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical reagent
Bromocresol green
This reagent is a light yellow or light gray powder, insoluble in water, soluble in ethanol and dilute alkali solution. Molecular formula: CaHuO, Br, S
Structural formula:
Relative molecular mass: 698.02 (according to the 1991 international relative atomic mass) 1 Subject content and scope of application
GB/T15349-94
This standard specifies the technical requirements, test methods, inspection rules, packaging and marking of the chemical reagent bromocresol green. This standard applies to the inspection of the chemical reagent bromocresol green. 2. Reference standards
GB/T603 Preparation of preparations and products used in chemical reagent test methods GB/T 604 General method for determination of pH color range of acid-base indicators for chemical reagents GB/T 619
Rules for sampling and acceptance of chemical reagents
GB/T 6682
GB/T 9721
GB/T 9741
Specifications and test methods for water used in analytical laboratories General rules for molecular absorption spectrophotometry of chemical reagents (ultraviolet and visible light parts) General method for determination of ignition residue of chemical reagents HG 3-119
Packaging and marking
Chemical reagents
3 Technical requirements
3.1 pH color range: 3.8 yellow-green) ~ 5.4 blue). 3.2 Maximum absorption wavelength (nm):
(pH3.8)...bZxz.net
A2(pH5.4)-
3.3 Mass absorption coefficient (L/cm·g): approved by the State Bureau of Technical Supervision on December 22, 1994?440~445;
615~618.
1995-10-01 implementation
α(ApH3.8, dry sample)
α2(^2, pH5. 4, dry sample).
3.4 ​​Maximum impurity content:
Ethanol dissolution test
Loss on drying
Ignition residue (calculated as sulfate)
Test method
GB/T 15349-94
.24-28,
·53~58.
Instructions
The preparations, products and pH buffer solutions in this test method shall be prepared in accordance with the provisions of GB/T603 and GB/T604 unless otherwise specified. The water used in the experiment shall meet the specifications of Grade 3 water in GB/T6682. 4.1 Determination of pH color range
Determine in accordance with the provisions of GB/T604.
4.2 Determination of maximum absorption wavelength
Determine in accordance with the provisions of GB/T9721, where: 4.2.1 Determination conditions
Thickness of absorption cell: 1cm;
Reference solution water;
Scanning range: 400～700 nm.
4.2.2 Determination method
Weigh 0.100g of the sample that has been dried to constant weight at 105±2℃ in advance, accurate to 0.0001g. Add 25mL of ethanol (95%) to dissolve, place in a 250mL volumetric flask, dilute to the scale with water without carbon dioxide, and shake well. Measure 5.00mL and 2.50mL of the above sample solution, place each in a 100mL volumetric flask, dilute to the scale with pH3.8 and pH5.4 buffer solutions respectively, and shake well. According to the provisions of Article 7.2.1 of GB/T9721, measure the maximum absorption wavelength and the corresponding absorbance A (A is used to calculate the mass absorption coefficient).
4.3 Mass absorption coefficient
The mass absorption coefficient is calculated according to formula (1):
Mass absorption coefficient, L/cm*g,
Where: α
A——absorbance measured in Article 4.2.2; 6
Thickness of the absorption cell, cm;
Concentration of the sample solution, g/L.
4.4 Impurity determination
The sample must be weighed accurately to 0.01g.
4.4.1 Ethanol dissolution test
Weigh 0.1g of sample, dissolve in 50mL ethanol (absolute ethanol), dilute with water to 100mL, it should be completely dissolved and clear without mechanical impurities. 4.4.2 Loss on drying
Weigh 1g of sample, accurate to 0.0001g. Place in a weighing bottle that has been dried to constant weight at 105±2℃, and dry in an electric oven at 105±2℃ to constant weight.
Loss on drying is calculated according to formula (2):
Where: X
Loss on drying, %
Mass of sample before constant weight, %
Mass of sample after constant weight, 8.
4.4.3 Residue on ignition
GB/T 15349 -- 94
X= ml=m2 × 100
Weigh 1g of sample and measure according to the provisions of Article 4.1 of GB/T9741. The result is calculated according to the provisions of Chapter 5 of GB/T9741. 5 Inspection rules
Sampling and acceptance shall be carried out in accordance with the provisions of GB/T619. 6 Packaging and marking
In accordance with the provisions of HG3--119, among which:
Inner packaging form: Gz-3;
Outer packaging form: W-1;
Packing unit: Class 2.
Additional instructions:
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 Beijing Chemical Factory. The main drafters of this standard are Guan Bao, Qiang Jinglin, Liu Dongyuan and Hao Yulin. From the date of implementation of this standard, the former Ministry of Chemical Industry standard HG3-1220-79 "Chemical Reagent Bromocresol Green" shall be used. 1139
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