Analysis of HC with Complementary Spectroscopic Methods

Significance of the Topic

Reliable hydrocarbon analysis is vital for quality assurance and process control in fuel production, lubrication management and environmental monitoring.
A combination of molecular and elemental spectroscopic techniques provides complementary information on organic composition and trace contaminants, supporting robust analytical workflows.

Objectives and Study Overview

This study reviews analytical approaches for hydrocarbon characterization using complementary spectroscopic methods.
It aims to illustrate applications ranging from biodiesel assessment to lubricant degradation and soot quantification, demonstrating instrumentation capabilities.

Methodology and Instrumentation

The molecular spectroscopic methods include:

• FTIR with ATR sampling for functional group analysis
• UV-Vis-NIR and Raman fluorescence for additional molecular insights

Elemental analysis techniques comprise:

• Energy dispersive X ray fluorescence (EDX)
• Atomic absorption spectrometry (AAS)
• Inductively coupled plasma optical emission spectrometry (ICP AES)
• Inductively coupled plasma mass spectrometry (ICP MS)

Samples and procedures:

• FAME quantitation in biodiesel by ATR FTIR using the carbonyl peak at 1747.82 cm-1
• Lubricant degradation monitoring via O-H, C-O and C-N bond intensities
• Soot content determination in engine oils by ATR FTIR at 1850 cm-1
• XRF analysis of wear and additive metals in oils at ppm levels
• ICP AES evaluation of 22 elements in used and new lubricants per ASTM D5185

Main Results and Discussion

FTIR ATR analysis enabled rapid and reproducible quantitation of FAME in biodiesel with minimal sample preparation.
Degradation markers in lubricants such as moisture, oxidation and nitration were effectively tracked by characteristic IR bands.
Soot calibration curves demonstrated linear responses down to 0.2 mass percent soot in engine oil.
EDX XRF achieved sensitive detection of wear metals and additives in waste oil with low detection limits and multiple acquisition modes.
ICP AES delivered accurate multi element data for essential additives and contaminants with robust calibration and oxygen free plasma conditions.

Practical Benefits and Applications

• Non destructive and high throughput analysis using ATR FTIR without complex sample prep
• Comprehensive monitoring of lubricant health and fuel composition for maintenance and compliance
• Trace metal detection in oils supports wear diagnostics and additive efficacy evaluation
• Alignment with ASTM standards ensures data reliability across laboratories

Future Trends and Opportunities

• Integration of inline spectroscopic sensors for real time process monitoring
• Advanced chemometric models to enhance quantitation and speciation in complex matrices
• Miniaturized and portable instrumentation for field and on site testing
• Coupled techniques combining molecular and elemental data for holistic sample characterization

Conclusion

A complementary suite of spectroscopic methods offers a powerful toolkit for detailed hydrocarbon analysis.
By leveraging molecular FTIR and elemental XRF and ICP technologies, laboratories can achieve accurate, reproducible and efficient characterization of fuels, lubricants and related materials.