SH/T 0615-1995 Determination of C₂~C₅ hydrocarbons in gasoline (gas chromatography)

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Card type: Test method

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

• Standard number: SH/T 0615-95 (confirmed in 2004)
• Chinese name: Determination of C₂~C₅ hydrocarbons in gasoline (gas chromatography)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Adoption relationship: non-equivalent adoption of the American Society for Testing and Materials standard ASTM D2427-92 "Determination of C₂~C₅ hydrocarbons in gasoline by gas chromatography"
• Approval/implementation: approved by China Petrochemical Corporation 1995-06-15, implemented on 1995-10-01
• Responsible body: Research Institute of Petroleum Processing; drafting: Fushun Research Institute of Petroleum and Petrochemicals; main drafters: Hu Yanqiu, Cai Xiudang

2. Scope of application and non-applicability

• This standard specifies the determination method for C₂~C₅ alkanes and monoalkenes in samples.
• Applicable to gasoline and naphtha.
• Not applicable: not provided in the available source.

3. Method principle

Inject the sample into a capillary chromatographic column. As the sample passes through the capillary chromatographic column with the carrier gas, the hydrocarbon components are separated into individual components, enter the hydrogen flame ionization detector for detection, and the chromatographic peaks are recorded on the data processor. Calculate the content of each component by the area normalization method. Components with more than five carbon atoms can be added together and calculated as the total amount of components with six or more carbons.

4. Reagents and materials (purity / preparation)

5.1 Reagents

The purity of the standard samples used for qualitative analysis shall be greater than 99% (m/m).

• 5.1.1 Ethylene, ethane
• 5.1.2 Propane
• 5.1.3 Isobutane
• 5.1.4 1- Butene, isobutylene
• 5.1.5 n-Butane
• 5.1.6 trans-2- Butene
• 5.1.7 cis-2- Butene (the source text source-text extraction writes "lid-2- butene", requires confirmation against the source standard (source-text extraction))
• 5.1.8 3- Methyl-1- butene
• 5.1.9 Isopentane
• 5.1.10 1- Pentene
• 5.1.11 2- Methyl-1- butene
• 5.1.12 n-Pentane
• 5.1.13 trans-2- Pentene
• 5.1.14 cis-2- Pentene
• 5.1.15 2- Methyl-2- butene

5.2 Materials

• 5.2.1 Hydrogen: purity greater than 99.99%
• 5.2.2 Compressed air: dehydrated and purified with molecular sieve
• 5.2.3 High-purity nitrogen: purity greater than 99.99%
• 5.2.4 Solid carbon dioxide

5. Instruments and equipment

• 6.1 Gas chromatograph: a capillary chromatograph with a temperature-programmed heating column oven, a hydrogen flame ionization detector, and an amplifier. The detector sensitivity must ensure that when determining the sample, the 1- pentene contained in it at 0.1% (V/V) produces a chromatographic peak on the recording paper higher than 5 mm.
• 6.2 Data processor: C-R3A type data processor or other types of data processors that can meet the requirements of this standard. The recorder range is 1 mV, and its full-scale response time is less than 1 s.
• 6.3 Chromatographic column: It is recommended to use a commercially available standard OV-1 fused silica capillary column with a length of 50 m and an inner diameter of 0.2 mm, or other capillary chromatographic columns that can meet the precision requirements of this standard. The resolution of adjacent component chromatographic peaks is required to be greater than or equal to 0.80.
• 6.4 Microsyringe: 1 μL.
• 6.5 Wide-mouth thermos bottle.

6. Recommended operating conditions

• 7.1 Vaporization chamber temperature: 250 ℃
• 7.2 Detection chamber temperature: 250 ℃
• 7.3 Column oven temperature: 40 ℃
• 7.4 Split ratio: 1:1000
• 7.5 Injection volume: 0.2~0.5 μL
• 7.6 Carrier gas: nitrogen, inlet pressure 0.1 MPa, post-column linear velocity 12 cm/s
• 7.7 Makeup gas: nitrogen, flow rate 15~20 mL/min
• 7.8 Fuel gas: hydrogen, inlet pressure 0.1 MPa, flow rate 30 mL/min ± 5 mL/min
• 7.9 Combustion-supporting gas: air, flow rate 500 mL/min ± 50 mL/min
• 7.10 Paper speed: 5 mm/min

7. Sampling and sample preparation

• 8.3 Prepare the C₂~C₅ hydrocarbon sample according to method SH/T 0062, and record the volume percentage of this sample in gasoline (or naphtha). Immediately store the sample and the syringe used for the test in a thermos bottle containing solid carbon dioxide until use.
• Other sampling requirements: not provided in the available source.

8. Analysis steps

• 8.1 For the first test, operate according to the chromatographic conditions described in Chapter 7, then program the temperature at a heating rate of 8 ℃/min to bring the column oven temperature to 220 ℃, hold at constant temperature for 2 h to remove components that may remain in the chromatographic column, and then cool to room temperature.
• 8.2 Operate according to the chromatographic conditions described in Chapter 7. As needed, program the determination and calculation program on the data processor so that it is in a normal and stable state.
• 9.1 Draw an appropriate amount (about 0.2~0.5 μL) of sample with a microsyringe, and quickly inject it into the vaporization chamber. At the same time, press the timing key, start the data processor, and record the chromatographic peaks and peak times.
• 9.2 After all chromatographic peaks in the sample have eluted, perform automatic calculation using the programmed determination and calculation program. After data processing is completed, the second sample determination can be carried out. Note: When the performance of the chromatographic column deteriorates, repeat the operation of clause 8.1.
• 9.3 The typical chromatograms obtained by separation are shown in Figure 1 and Figure 2. The separated components can be qualitatively identified using pure component standard samples. When no standard sample is available, use the literature Kovats retention index for qualitative identification. The relative retention values of each separated component are given in Appendix A.

9. Qualitative and quantitative analysis and calculation formulas

• Qualitative: use pure component standard samples for qualitative identification; when no standard sample is available, use the literature Kovats retention index for qualitative identification. The relative retention values of each separated component are given in Appendix A.
• Quantitative: use the area normalization method for quantification. Report to the nearest 0.1%.
• Since this standard uses a hydrogen flame ionization detector, the response values for the hydrocarbon compounds involved in this standard method are similar, so the relative mass correction factor of each component is taken as 1.0.
• The mass percentage content Xᵢ of component i in the sample is calculated according to formula (1): Xᵢ = (Aᵢ / ΣAᵢ) × 100 Where: Aᵢ—peak area of component i; n— number of chromatographic peaks of components in the sample.
• When this standard is used in combination with GB/T 11132 and SH/T 0062 to determine the hydrocarbon composition in gasoline fractions, the determination results need to be expressed in volume percentage. The volume percentage content Yᵢ of component i in gasoline in the sample is calculated according to formula (2): Yᵢ = (Aᵢ / ρᵢ) / (Σ(Aᵢ / ρᵢ)) × E Where: Aᵢ—peak area of component i; n— number of chromatographic peaks of components in the sample; ρᵢ—relative density of component i (see Appendix B); E— volume percentage of the sample in gasoline, % (V/V).
• Take the arithmetic mean of the repeated determination results as the sample determination result.

10. Precision

Use the following provisions to judge the reliability of the test results (95% confidence level).

• 11.1 Repeatability: For the same sample by the same operator, using the same chromatograph, and operating according to the test conditions specified in this standard, the difference between the two determination results obtained shall not exceed the value listed in Table 1.
• 11.2 Reproducibility: For the same sample by different laboratories and different operators, operating according to the test conditions specified in this standard, the difference between the two determination results obtained shall not exceed the value listed in Table 1.

Table 1 Precision

Note: In Table 1, the correspondence between the values in the repeatability and reproducibility columns in the "alkanes" section, source-text extraction there is a suspected misalignment in the extracted results, requires confirmation against the source standard (source-text extraction).

• 11.3 If the concentrations of individual hydrocarbons are added together to provide the results for total olefins at or below C₅ and C₅ and the results for total alkanes at or below C₅ and C₅, then use the following precision:

11. Report

• Report to the nearest 0.1%.
• Take the arithmetic mean of the results of duplicate determinations as the test result of the sample.
• Other reporting requirements: not provided in the available source.

12. Normative references

• GB/T 11132 Standard test method for hydrocarbon types in liquid petroleum products (fluorescent indicator adsorption method)
• SH/T 0062 Standard test method for depentanization of gasoline and naphtha
• ASTM D2427-92 (not equivalent adoption)

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-reference Q&A