EN 14105 Determination of Free and Total Glycerol and mono-, di,- triglycerides in Fatty Acid Methyl Esters (FAME)

Significance of the Topic

Determination of residual glycerol and glycerides in biodiesel is critical to ensure fuel quality and compliance with international standards. Excess free or bound glycerol can impair engine performance, promote deposits and reduce oxidation stability. The EN 14105 method provides a standardized approach for quantifying free and total glycerol, monoglycerides, diglycerides and triglycerides in fatty acid methyl esters (FAME).

Objectives and Study Overview

This application note demonstrates how the AC Biodiesel All-in-One GC system fulfills the EN 14105:2011 requirements. Key aims include verifying method compliance, presenting calibration strategies for glycerol and glycerides, and evaluating instrument performance via relative response factors and pass/fail criteria.

Methodology and Instrumentation

Samples are first derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) to convert glycerol into volatile trimethylsilyl ethers. The derivatized extract is introduced through a Temperature Programmable Inlet (TPI) into a PDMS capillary column. Temperature programming involves:

• Initial oven temperature: 50 °C (1 min)
• Ramp 1: 15 °C/min to 180 °C
• Ramp 2: 7 °C/min to 230 °C
• Ramp 3: 10 °C/min to 370 °C (5 min hold)

Carrier flow is held at 3 mL/min. Detection is by flame ionization detector (FID) at 380 °C with H₂, air and N₂ make-up gases.

Calibration and Instrument Performance

Free glycerol is quantified against an internal standard of 1,2,4-butanetriol, yielding a linear calibration curve (R² ≈ 0.9999). Mono-, di- and triglycerides are each calibrated using category-specific internal standards. Relative response factors (RRF) are calculated for glyceryl dinonadecanoate versus glyceryl trinonadecanoate according to EN 14105:

RRF = (Area_DI / Area_TRI) × (M_TRI / M_DI)

Sample results are automatically compared with specification limits and annotated as pass or fail.

Key Results and Discussion

The AC Biodiesel All-in-One meets all EN 14105 criteria for resolution, sensitivity and repeatability. Calibration curves show excellent linearity and the system reliably discriminates free glycerol from bound species. Automated reporting streamlines validation and accelerates sample throughput.

Benefits and Practical Applications

• All-in-One solution: integrates EN 14105 and other biodiesel methods (ASTM D6584, EN 14103, EN 14110, prEN 16300, EN 15779) without column changes.
• Dual programmable oven enhances flexibility and reduces downtime.
• Dedicated QC materials and software facilitate compliance and rapid adoption.

Future Trends and Potential Applications

Advances in GC column technologies and detector sensitivity will further improve low-level glycerol detection. Integration with automated sample preparation and inline monitoring may enable real-time quality control in biodiesel production. Expansion to alternative feedstocks and bio-derived polymers is also anticipated.

Conclusion

The AC Biodiesel All-in-One GC system delivers a robust, user-friendly platform for EN 14105 analysis, ensuring accurate quantification of free and total glycerol plus glycerides in FAME. Its versatility across multiple biodiesel standards and streamlined operation support efficient laboratory workflows.

References

EN 14105:2011 Determination of free and total glycerol and mono-, di- and triglycerides in FAME. PAC L.P. Application Note 00.00.186 (2012).