SH/T 0406-1992 Determination of ultraviolet absorbance of petrolatum

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: SH/T 0406-92
• Chinese name: Determination of ultraviolet absorbance of petrolatum
• English name: not provided in the available source
• Replacement relationship: replaces ZB FA2 010-89 (the source writes "replaces ZB FA2 010-89", source-text extraction doubt: the numbering format after ZB requires confirmation against the source standard (source-text extraction))
• Adoption relationship: equivalently adopts the absorbance in the British Pharmacopoeia BP-80 "Medicinal Petrolatum" (see additional notes in the source)

2. Applicable scope and non-applicability

• Applicable to the determination of the absorbance of an isooctane solution of petrolatum according to 0.5 g/L at the wavelength 290 nm (the solution concentration and measurement wavelength are garbled in the source transcription and remain unverified).
• Not applicable: not provided in the available source.

3. Method principle

The determination of the ultraviolet absorbance of petrolatum is carried out under specified conditions using a quartz absorption cell with an optical path length of 1.0 cm, testing the ultraviolet absorbance of an isooctane solution of petrolatum according to 0.5 g/L at the wavelength 290 nm. (The source "1.0." is source-text extraction noise, requires confirmation against the source standard (source-text extraction))

4. Reagents and materials (purity / preparation)

• 5.1 Isooctane (2,2,4-trimethylpentane): spectroscopically pure. Using a 1.0 cm absorption cell with distilled water as reference, the absorbance is less than 0.05 over the entire spectral range 240 to 300 nm; if it does not comply, it may be purified using an activated silica gel column, see the solvent purification section in GB/T 7363.
• 5.2 Distilled water: shall comply with the provisions in GB/T 7363.

5. Instruments and equipment

• 6.1 Spectrophotometer: in the spectral region 220 to 400 nm, the spectral bandwidth is 2 nm or narrower (the spectral range and bandwidth are garbled in the source transcription and require verification); the repeatability of the instrument's absorbance measurement, when the absorbance is around 0.4, shall be no greater than 0.005 A; the repeatability of wavelength measurement shall be within ±0.2 nm (the wavelength-repeatability tolerance is unclear in the source transcription and remains unverified).
• 6.2 Absorption cell: one or more pairs of matched fused quartz absorption cells with an optical path length of 1.00 cm ± 0.005 cm or better. (The source number "3.32" is suspected to be a misrecognition of "6.2" source-text extraction, requires confirmation against the source standard (source-text extraction))
• 6.3 Volumetric flask: 100 mL. (The source "100MLo" is source-text extraction noise, requires confirmation against the source standard (source-text extraction))

6. Recommended operating conditions

• Wavelength: 290 nm
• Absorption cell optical path: 1.0 cm quartz absorption cell
• Reference: solvent (isooctane) as reference
• Sample solution concentration: 0.5 g/L
• Other recommended operating conditions: not provided in the available source.

7. Sampling and sample preparation

• 7.1 Preparation of an isooctane solution of petrolatum according to 0.5 g/L: weigh 0.05 g of sample by the decrement method, weighed to the nearest 0.0002 g, add to a clean 100 mL volumetric flask, add isooctane to the flask until half full, and shake to dissolve the sample, then add isooctane to the mark, and mix well. (The source "0.058", "0.00028", and "IOOML" are source-text extraction noise; based on 0.5 g/L and the 100 mL volumetric flask, they should be 0.05 g, 0.0002 g, requires confirmation against the source standard (source-text extraction))
• Note: If the sample cannot dissolve rapidly, the volumetric flask must be placed in a warm water bath to heat; after the sample dissolves, cool to room temperature, add isooctane to the mark, and mix well.

8. Analytical procedure

• 7.2 Transfer the test solution into a 1.0 cm quartz absorption cell, cover with the lid, use the solvent as reference, and immediately test the ultraviolet absorbance of the sample solution at the wavelength 290 nm.

9. Qualitative and quantitative determination and calculation formulas

• Terms and formulas (source Chapter 3):
  • 3.1 Transmittance T: the ratio of the radiant energy transmitted by the sample solution in the absorption cell to the radiant energy transmitted by the "solvent blank" in the same absorption cell, as in formula (1): T = 10^(-a·b·c) (the source formula source-text extraction is severely incomplete, requires confirmation against the source standard (source-text extraction))
  • 3.2 Absorbance A: the logarithm to the base 10 of the reciprocal of transmittance T, as in formula (2): A = -log10 T (the source formula source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction))
  • 3.3 Absorptivity a: absorbance divided by the product of optical path and concentration, as in formula (3): a = A / (b·c) (the source formula source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction))
  • Symbols: a— absorptivity; b— optical path length of the absorption cell, cm; c— concentration of the solution, g/L; A— absorbance.
• Expression of quantitative results: report the ultraviolet absorbance of the sample solution at the wavelength 290 nm, to two decimal places.

10. Precision

not provided in the available source.

11. Report

Report the ultraviolet absorbance of the sample solution at the wavelength 290 nm, to two decimal places.

12. Referenced documents

• GB/T 7363 Test method for polycyclic aromatic hydrocarbons in paraffin wax

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