ASTM D8369
Guide to ASTM D8369: Detailed Hydrocarbon Analysis Using GC-VUV
Introduction to ASTM D8369
ASTM D8369, issued under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, establishes a standardized test method for detailed hydrocarbon analysis. This method utilizes high-resolution gas chromatography coupled with vacuum ultraviolet absorption spectroscopy (GC-VUV) to determine the composition of hydrocarbons by percent mass or volume up to a final boiling point of 225 °C, as defined by Test Method D86.
Scope and Applicability
This method is suitable for analyzing a wide range of petroleum and biofuel products, including blend stocks, naphthas, reformates, alkylates, FCC gasoline, liquefied petroleum gas (LPG), alcohols, ethers, and spark-ignition engine fuels. It allows for the identification and quantification of individual compounds and compound classes, providing detailed insight into the composition of complex hydrocarbon mixtures.
Test Method and Procedure
Equipment and Materials
The procedure requires a gas chromatograph equipped with a vacuum ultraviolet absorption spectroscopy detector and specific components, including a 60 m nonpolar phase capillary column, carrier and purge/makeup gases, and various standards for calibration and validation.
Calibration and Standardization
Calibration involves establishing a retention index file, preparing the system with specific mixtures for system validation, and ensuring accuracy through precise measurement and control settings as outlined in the standard.
Sample Preparation and Analysis
Samples are prepared according to ASTM practices for sampling and handling, with the analysis involving the introduction of the sample into the GC system, separation of compounds, and detection by the VUV detector. The procedure includes detailed steps for operating the equipment, processing the data, and calculating the concentrations of hydrocarbon classes and individual compounds.
Significance and Applications
The ASTM D8369 method provides critical information for assessing the quality and performance of hydrocarbon streams and automotive fuels. It enables the detailed characterization of fuel composition, including the identification of oxygenates and aromatics, which is essential for compliance with fuel standards and regulations.
Safety and Environmental Considerations
Given the nature of the samples and the equipment used, adherence to safety, health, and environmental practices is emphasized to mitigate potential risks associated with the analysis.
Conclusion
ASTM D8369 represents a sophisticated approach to hydrocarbon analysis, offering precise and detailed compositional data. By combining gas chromatography with vacuum ultraviolet absorption spectroscopy, this method addresses the need for a comprehensive analysis of petroleum products and biofuels, facilitating quality control, research, and regulatory compliance in the petroleum industry.