Alternative fuel sources such as biodiesel are often a topic of news. Within the GC world of biodiesel analysis, EN 14110 is a method that measures methanol in finished biodiesel ranging from 0.01% to 0.50% (m/m).
Fuel Analysis to Determine Methanol Concentration
This is very similar to the methanol analysis carried out a while ago in crude oil experiments as both use static headspace GC to determine percentage level ranges of methanol.
The headspace chromatographic profile is simpler for biodiesel as it has fewer volatile components than light crude oil. This is demonstrated in Figure 1. There are only three notable peaks in the biodiesel headspace chromatogram: oxygen, water and methanol (all of which are easily identified by their absorbance spectra).
Figure 1. Shows a biodiesel headspace chromatogram with 0.50% (m/m) methanol. The inset plot shows the absorbance spectrum of methanol, which is distinct from water and oxygen.
Methanol Headspace Analysis
As shown in Figure 2, after the initial screening, the methanol percent range of 0.01% – 0.50% was examined and the method detections limits were found to be below 0.005%. The experiment was done again with calibration standards at 0.5%, 0.1% and 0.01%, in triplicate, and the curve was found to be linear (Figure 3). This analysis demonstrates that methanol headspace analysis can be carried out in multiple fuel sources.
Figure 2. Shows 0.50% – 0.005% (m/m) of methanol in biodiesel. Under the current method conditions, methanol can be observed below 0.005%.
Figure 3. Shows a triplicate calibration curve covering 0.01%-0.50% (m/m), similar to the calibration curve used in the EN 14110 method, with an r2 of 0.998.
This information has been sourced, reviewed and adapted from materials provided by VUV Analytics.
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