Ester content in biodiesel
The following alternative test method for measuring the methyl ester content for biodiesel has been approved for use.
Allowance for naturally occurring ester
The need to allow an amendment of the prescribed test method for ester content (EN 14103) to account for the presence of naturally occurring C-17 methyl ester, which is used as an internal standard, has been acknowledged internationally, and has — for example — been provided for in the the Australian Biodiesel Standard Amendment 2009.
The alternative method is in line with the modification proposed in the scientific paper "Ester content evaluation in biodiesel from animal fats and lauric oils" by international specialists in this area. The Australian amendment is based on this paper as well.
Approved method
This alternative method is available for use to establish compliance with the methyl ester content requirements for biodiesel prescribed in Schedule 3, Engine Fuel Specifications Regulations.
Engine Fuel Specifications Regulations — Schedule 3(external link)
This method:
- modifies prescribed test method for ester content — EN 14103
- replaces the previous alternative test method — Ester content in Biodiesel approved in July 2009
- was approved and is available for use from 3 December 2010.
Ester content in biodiesel alternative method: December 2010
Test Method: EN 14103:2003 (Fat and oil derivatives. Fatty acid methyl esters (FAME). Determination of ester and linolenic acid methyl ester contents) with the following amendments. Specific changes are in bold and within the shaded formula.
8 Preparation of the sample
8.1 Accurately weigh approximately 250 mg of sample in a 10 ml vial (4.1), then add 5 ml of heptane (5.1) using a pipette (4.3).
8.2 Accurately weigh approximately 250 mg of sample in a 10 ml vial (4.1), then add 5 ml of methyl heptadecanoate solution (5.3) using a pipette (4.3).
10 Expression of results
10.1 Determination of ester content
The ester C content, expressed as a mass fraction in percent, is calculated using the following formula:
Where:
ΣA is the total peak area from the methyl ester in C14 to that in C24:1 in 8.2;
AE is the peak area corresponding to methyl heptadecanoate in 8.1;
AEI is the peak area corresponding to methyl heptadecanoate in 8.2;
CEI is the concentration, in milligrams per millilitre, of the methyl heptadecanoate solution (5.3) being used;
VEI is the volume, in millilitres, of the methyl heptadecanoate solution (5.3) being used;
m1 is the mass, in milligrams, of the sample in 8.1;
m2 is the mass, in milligrams, of the sample in 8.2.
10.2 Determination of linolenic acid methyl ester
The linolenic acid methyl ester content L, expressed as a mass fraction in percent, is calculated using the following formula:
Where:
ΣA is the total peak area from the methyl ester in C14 to that in C24:1 in 8.2;
AE is the peak area corresponding to methyl heptadecanoate in 8.1;
AEI is the peak area corresponding to methyl heptadecanoate in 8.2;
AL is the peak area corresponding to linolenic acid methyl ester in 8.2;
m1 is the mass, in milligrams, of the sample in 8.1;
m2 is the mass, in milligrams, of the sample in 8.2.