142
M. Talebi et al.
6.3.2 Biodiesel
Biodiesel, an alternatively derived fuel, is obtained from different biological sources
of fatty acids. Animal fats, vegetable oils, recyclable cooking oils, and plant and
waste products are usually processed for extraction of fatty acid methyl esters [63].
A petroleum-based diesel is often blended with a biomass-based diesel before consumer use. Due to the overlap between the petroleum-based compounds of saturated
and aromatic hydrocarbons in blended biodiesel, the FAME profile elucidation is
difficult to see using traditional GC stationary phases [64–69]. The importance of
fatty acid ester analysis in biofuel and fuel samples is twofold. First, the analysis is
used to monitor cross-contamination in tankers and storage facilities used for multiple fuel types [64]. This is specifically important in case of fuels that are used
in aviation and other specialized fuels employed by defense forces where small
amounts of FAME contamination contribute to poor thermal and storage stability
of the fuel [70]. Second, the analysis is used to investigate the influence of FAME
chemical structure on exhaust emissions [68]. Studies have shown that the hydrocarbon chain length and degree of unsaturation can affect the carbon monoxide (CO)
levels and nitrogen oxide (NO x ) emissions from combustion of fatty esters [71–73].
According to the UNI EN 14331 procedure, a hydrocarbon liquid chromatography
(LC) preseparation step is required before gas chromatographic determination of
the FAME profile [74]. This procedure can be time- and labor-intensive. Therefore,
a simple, rapid, and less expensive approach to effectively separate the FAMEs from
the petroleum-based portion appears to be necessary. Fast analysis of biodiesel can
be achieved on SLB-IL100 and SLB-IL-111 micro-bore columns [65, 68]. The key
feature of these stationary phases, namely extremely high polarity, allows excellent
separation of the FAME components from the less-retained petroleum-based hydrocarbons. Figure 6.5 shows that the analysis of the soybean B20 biodiesel blend on
the micro-bore SLB-IL100 (12 m × 0.1 mm × 0.08 μm d f ) column resulted in the
separation of compounds before 2.5 min. Particularly, the methyl palmitate (C16:0)
eluted after C26 (n-hexacosane), the last significant n-alkane in the sample [65].
Biodiesel samples obtained through the transesterification reaction of different vegetable oils were analyzed utilizing a customized narrow-bore SLB-IL111 (14 m ×
0.1 mm × 0.08 μm d f ) column [68]. This fast method could be used to quantify the
FAME content in basic and acidic transesterified vegetable oils and to control the
quality of biodiesel using routine analyses.
6.3.3 Biological Samples
The Rhodobacter sphaeroides is a rod-shaped, gram negative, purple non-sulfur
bacterium utilized as a model microorganism for anoxygenic photosynthesis and
carbon fixation [46, 56, 75–80]. The use of a 100 m SLB-IL111 column allowed
effective separation of geometrical isomers of monounsaturated C16:1 and C18:1
M. Talebi et al.
6.3.2 Biodiesel
Biodiesel, an alternatively derived fuel, is obtained from different biological sources
of fatty acids. Animal fats, vegetable oils, recyclable cooking oils, and plant and
waste products are usually processed for extraction of fatty acid methyl esters [63].
A petroleum-based diesel is often blended with a biomass-based diesel before consumer use. Due to the overlap between the petroleum-based compounds of saturated
and aromatic hydrocarbons in blended biodiesel, the FAME profile elucidation is
difficult to see using traditional GC stationary phases [64–69]. The importance of
fatty acid ester analysis in biofuel and fuel samples is twofold. First, the analysis is
used to monitor cross-contamination in tankers and storage facilities used for multiple fuel types [64]. This is specifically important in case of fuels that are used
in aviation and other specialized fuels employed by defense forces where small
amounts of FAME contamination contribute to poor thermal and storage stability
of the fuel [70]. Second, the analysis is used to investigate the influence of FAME
chemical structure on exhaust emissions [68]. Studies have shown that the hydrocarbon chain length and degree of unsaturation can affect the carbon monoxide (CO)
levels and nitrogen oxide (NO x ) emissions from combustion of fatty esters [71–73].
According to the UNI EN 14331 procedure, a hydrocarbon liquid chromatography
(LC) preseparation step is required before gas chromatographic determination of
the FAME profile [74]. This procedure can be time- and labor-intensive. Therefore,
a simple, rapid, and less expensive approach to effectively separate the FAMEs from
the petroleum-based portion appears to be necessary. Fast analysis of biodiesel can
be achieved on SLB-IL100 and SLB-IL-111 micro-bore columns [65, 68]. The key
feature of these stationary phases, namely extremely high polarity, allows excellent
separation of the FAME components from the less-retained petroleum-based hydrocarbons. Figure 6.5 shows that the analysis of the soybean B20 biodiesel blend on
the micro-bore SLB-IL100 (12 m × 0.1 mm × 0.08 μm d f ) column resulted in the
separation of compounds before 2.5 min. Particularly, the methyl palmitate (C16:0)
eluted after C26 (n-hexacosane), the last significant n-alkane in the sample [65].
Biodiesel samples obtained through the transesterification reaction of different vegetable oils were analyzed utilizing a customized narrow-bore SLB-IL111 (14 m ×
0.1 mm × 0.08 μm d f ) column [68]. This fast method could be used to quantify the
FAME content in basic and acidic transesterified vegetable oils and to control the
quality of biodiesel using routine analyses.
6.3.3 Biological Samples
The Rhodobacter sphaeroides is a rod-shaped, gram negative, purple non-sulfur
bacterium utilized as a model microorganism for anoxygenic photosynthesis and
carbon fixation [46, 56, 75–80]. The use of a 100 m SLB-IL111 column allowed
effective separation of geometrical isomers of monounsaturated C16:1 and C18:1