Determination of mono- and polyaromatic hydrocarbons in diesel fuels with AZURA® Analytical HPLC system using RI detection

Significance of the topic

Aromatic hydrocarbons in diesel fuel influence combustion characteristics and exhaust emissions. Controlling their content improves engine performance and reduces environmental impact. Regulations such as DIN EN 12916 set limits to protect public health and the environment.

Study objectives and overview

This study aims to quantify mono- and polyaromatic hydrocarbons in diesel fuel following the DIN EN 12916 standard. The analytes include 1,2 dimethylbenzene, fluorene and phenanthrene. An isocratic normal phase HPLC method with refractive index detection was developed and validated.

Methodology and instrumentation

A detailed description of the method and setup is provided below

• System configuration
  • Pump AZURA P6.1L isocratic
  • Autosampler AZURA AS 6.1L
  • Detector AZURA RID 2.1L
  • Thermostat AZURA CT 2.1L
  • Column ZORBAX NH2 normal phase
• Chromatographic conditions
  • Mobile phase n heptane
  • Flow rate 1.2 mL per minute
  • Column temperature 25 degrees Celsius
  • Injection volume 5 microliters
  • Run time 12 minutes
• Calibration using three concentration levels of each analyte
• Sample preparation by diluting diesel fuel to 10 percent in n heptane

Main results and discussion

The method achieved baseline separation of all target analytes with retention time RSD below 0.06 percent and peak area RSD below 0.22 percent. The calibration curves showed correlation coefficients greater than 0.9999. Analysis of a diesel sample revealed 19.26 percent 1,2 dimethylbenzene, 1.53 percent fluorene and 0.04 percent phenanthrene. These results demonstrate high precision, linearity and robustness of the method.

Practical benefits and applications

The presented method offers

• Compliance with international standards for fuel analysis
• Rapid and reproducible quantification of aromatic hydrocarbons
• Minimal solvent consumption and simple sample preparation
• Applicability in quality control laboratories in the fuel industry

Future trends and potential uses

Advances may include

• Integration with mass spectrometric detection for enhanced sensitivity
• Use of alternative green solvents to reduce environmental footprint
• Automation and inline monitoring for real time quality control
• Method adaptation for related petroleum products and biofuels

Conclusion

The isocratic AZURA analytical HPLC system coupled with refractive index detection provides a reliable and efficient approach for determining mono- and polyaromatic hydrocarbons in diesel fuel. The method meets DIN EN 12916 requirements and supports environmental and quality assurance objectives.

Reference

DIN EN 12916 Petroleum products – Determination of aromatic hydrocarbon types in middle distillates – High performance liquid chromatography method with refractive index detection German version