GB/T 3143-1982 Color determination method for liquid chemical products (Hazen unit—platinum-cobalt color number)

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: GB 3143—82
• UDC: 661:535.65
• Chinese full name: Color determination method for liquid chemical products (Hazen unit—platinum-cobalt color number)
• English name: Color determination method of liquid chemicals (Hazen unit—platinum-cobalt scale)
• Replacement relationship: not provided in the available source
• Publication/implementation: published on 1982-07-20, implemented on 1983-03-01
• Proposed/administrated/drafted: proposed by the Ministry of Petroleum Industry of the People's Republic of China, administrated by the Research Institute of Petroleum Processing, and drafted by Dalian No. 7 Petroleum Plant

2. Scope of application and non-applicability

• Applicable to the determination of the color of liquid chemical products that are transparent or slightly close to the reference platinum-cobalt color number, and this color characteristic is usually "brownish yellow".
• Not applicable: not provided in the available source.

3. Method principle

The color of the test sample is visually compared with the color of the standard platinum-cobalt colorimetric solution, and the result is expressed in Hazen (platinum-cobalt) color units. The Hazen (platinum-cobalt) color unit is: the color of a solution containing 1 milligrams of platinum (calculated as chloroplatinic acid) and 2 milligrams of cobalt chloride hexahydrate per liter of solution.

4. Reagents and materials (purity / preparation)

• 3.1 Cobalt chloride hexahydrate (CoCl₂·6H₂O): analytical reagent.
• 3.2 Hydrochloric acid: analytical reagent, meeting the requirements of GB 622 "Hydrochloric Acid".
• 3.3 Chloroplatinic acid (H₂PtCl₆): preparation method of chloroplatinic acid: in a glass dish or porcelain dish, using a boiling water bath heating method, dissolve 1.00 grams of platinum in sufficient aqua regia; after the platinum dissolves, evaporate the solution to dryness, add 4 milliliters of hydrochloric acid solution and evaporate to dryness again, repeat this operation more than two times, thus obtaining 2.10 grams of chloroplatinic acid.
• 3.4 Potassium chloroplatinate (K₂PtCl₆): analytical reagent.
• 4.1 Preparation of standard colorimetric stock solution (500 Hazen units): in a 1000 milliliter volumetric flask, dissolve 1.00 grams of cobalt chloride hexahydrate (CoCl₂·6H₂O) and the equivalent of 1.05 grams of chloroplatinic acid or 1.245 grams of potassium chloroplatinate in water, add 100 milliliters of hydrochloric acid solution, dilute to the mark, and mix uniformly.
  • Note: The standard colorimetric stock solution can be checked with a spectrophotometer using a 1 centimeter cuvette at the following wavelengths, and its extinction value ranges are:

• 4.2 Preparation of standard platinum-cobalt comparison solutions: in two groups of volumetric flasks, 10 flasks of 500 milliliters and 14 flasks of 250 milliliters, respectively add the volumes of standard colorimetric stock solution shown in the table below, dilute to the mark with distilled water, and mix uniformly.

(Note: The original 4.2 table is laid out in two columns left and right; the above table is organized according to the correspondence of "volumetric flask specification—stock solution volume—Hazen units"; the correspondence between the 500 milliliter group and the 250 milliliter group requires confirmation against the source standard (source-text extraction), among which the conversion relationship between the stock solution volume of the 250 milliliter group and Hazen units must be based on the original table.)

• 4.3 Storage: The standard colorimetric stock solution and diluted solutions are placed in stoppered brown glass bottles and kept in the dark. The standard colorimetric stock solution can be stored for 1 years, and the diluted solution can be stored for 1 months, but freshly prepared solutions are best used.

5. Instruments and equipment

• 2.1 72 type spectrophotometer or a similar spectrophotometer.
• 2.2 Nessler colorimetric tube: 50 or 100 milliliters, with a scale mark 100 millimeters above the bottom.
• 2.3 Colorimetric tube rack: generally the bottom of the colorimetric tube rack is lined with a white base plate, and a reflector may also be installed at the bottom to improve the effect of color observation.

6. Recommended operating conditions

• Colorimetric observation conditions: under sunlight or fluorescent lamp illumination, facing a white background, observe from top to bottom, avoiding side observation.
• Spectrophotometer check of standard colorimetric stock solution: 1 centimeter cuvette, wavelengths 430, 455, 480, 510 millimicrons, extinction value ranges see 4.1 note.

7. Sampling and sample preparation

• 5.1 Inject a certain amount of test sample into a Nessler colorimetric tube, filling it to the scale mark.
• Other requirements for sample preparation: not provided in the available source.

8. Analysis procedure

• 5.1 Inject a certain amount of test sample into a Nessler colorimetric tube, filling it to the scale mark; similarly, inject a standard platinum-cobalt comparison solution with a similar color into another Nessler colorimetric tube, filling it to the scale mark.
• 5.2 Compare the color of the test sample with the standard platinum-cobalt comparison solution. During color comparison, under sunlight or fluorescent lamp illumination, facing a white background, observe from top to bottom, avoiding side observation, and propose the closest color.

9. Qualitative and quantitative determination and calculation formula

• The color of the test sample is expressed in Hazen (platinum-cobalt) color units of the standard platinum-cobalt comparison solution closest to the test sample.
• If the color of the test sample does not match any standard platinum-cobalt comparison solution, estimate a close platinum-cobalt color number as far as possible and describe the observed color.
• Calculation formula: not provided in the available source (visual colorimetric method, no calculation formula).

10. Precision

Not provided in the available source.

11. Report

• 6 Result report: The color of the test sample is expressed in Hazen (platinum-cobalt) color units of the standard platinum-cobalt comparison solution closest to the test sample. If the color of the test sample does not match any standard platinum-cobalt comparison solution, estimate a close platinum-cobalt color number as far as possible and describe the observed color.

12. Referenced documents

• GB 622 "Hydrochloric Acid" (see 3.2).

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Q&A