Validation of a GC–IDMS method for the metrologically traceable quantification of selected FAMEs in biodiesel

Hasibe Yilmaz,Valle Morales,Mine Bilsel,Ahmet C Goren,Andrea Held,Simay Gündüz

doi:10.1007/s00769-015-1144-1

Abstract

Current methods for the analysis of fatty acid methyl esters (FAMEs) in rapeseed oil-based biodiesel refer to operationally defined measurands, which is a practical solution for routine analysis. In this paper, a new method for the SI-traceable quantification of selected FAMEs in biodiesel and its validation are described. This method has the potential to be a reference method for applications requiring structurally defined measurands and traceability to the SI as it allows direct comparisons to well-characterised calibrants through the use of isotopically labelled analogues of the analytes as well as establishing a full uncertainty budget. The method is based on gas chromatography–isotope dilution mass spectrometry. Its performance is demonstrated through its implementation and validation in two independent laboratories and is shown to provide reliable and traceable results for selected FAMEs in biodiesel test samples.

Highlights

The European Union sets goals to reach a market share of energy from renewable sources in the transport sector of 10 % in 2020 [1]
The fatty acid composition of biodiesel was determined by capillary gas chromatography with flame ionisation detection (GC–FID) using analytical conditions identical to those prescribed in EN 14103 [6] in combination with a different quantification approach using experimentally determined relative response factors for the target fatty acid methyl esters (FAMEs)
The traceability of the measured values obtained using the described GC–isotope dilution mass spectrometry (IDMS) methods is established on the one hand by measuring structurally well-defined individual FAMEs, which is ensured by the mass spectrometric

Summary

Introduction

The European Union sets goals to reach a market share of energy from renewable sources in the transport sector of 10 % in 2020 [1]. The CRMs used to assess the trueness of the developed methods were prepared in the same way as the biodiesel samples by taking the amount of material that comprises a final concentration of FAMEs between the limits of the calibration ranges and spiking it with labelled FAMEs. The CRMs were analysed together with the biodiesel samples and the calibration solutions. The fatty acid composition of biodiesel was determined by capillary gas chromatography with flame ionisation detection (GC–FID) using analytical conditions identical to those prescribed in EN 14103 [6] in combination with a different quantification approach using experimentally determined relative response factors for the target FAMEs. five in-house prepared FAME mix solutions were analysed using experimental conditions identical to

Method validation

Method

Conclusions