Determination of antioxidants by ion chromatographic analysis
The Antioxidants vitamin E and Baynox®
Quality monitoring
The oxidation stability
of fatty acids and of the fatty acid methyl esters synthesized
from them can be improved by the addition of antioxidants.
Biodiesel based on rapeseed oil already contains an outstanding
natural protection against oxidation – vitamin E (d-a-tocopherol).
In addition, Baynox®, whose structure was inspired by
that of vitamin E, is added to the biodiesel as a stabilizer.
This inhibits both oxidation to corrosive acids
and the formation of insoluble polymers and
thus prevents the injection nozzles from being blocked. Both
these substances are therefore determined within the context
of quality monitoring and for determining the amounts of additives
to be added.
Antioxidant analysis
Because of their structural similarities, vitamin
E and Baynox® can be determined
together in a single analysis. To improve solubility, dichloromethane
is added to the eluent and analyte solutions. The biofuel
samples should be diluted 1:1000. The analytes are separated
at 35 °C and then determined quantitatively using UV
detection.
Ion Chromatography by Metrohm
For the determination of antioxidants for quality assurance
purposes, Metrohm recommends the 844 UV/VIS Compact
IC with built-in column heating. This unique instrument
in the ion chromatography sector combines the advantages of
a compact IC system with a diode array detector (DAD) in a
single housing. The method can be completely automated by
combination with the 838 Advanced Sample Processor.
This saves both processing time and costs.
Product Information
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Biofuel
Analysis 
