Page 13 - Shimadzu Journal vol.4 Issue1

New Energy

Analysis of Hydrocarbons Using PCI-GC-MS

Kyoko Yamada, Shimadzu Techno-research Inc., Jun Nagata, Shimadzu Corporation

Interest in hydrocarbon-producing microalgae is growing in the field Sample
of renewable energy development. Since the hydrocarbons produced
by microalgae contain no oxygen and are similar in properties to heavy Squalane was decomposed using a catalyst, the products of
decomposition were diluted in mesitylene solvent, and this sample
oil, they can be a convenient substitution for existing liquid fuels, and
was analyzed using GC-MS.
it is advantageous that an energy resource do not compete with food
The sample was provided by Prof. Keiichi Tomishige, Department of
production. Research is being performed into obtaining petrochemical
Applied Chemistry, Graduate School of Engineering, Tohoku
raw material from the hydrocarbons produced by microalgae, and
University.
mass spectrometry is used in identification of these products.
Gas chromatography-mass spectrometry (GC-MS) normally uses
electron ionization (EI) to produce ions for analysis, but when using Analytical Conditions
this EI method for hydrocarbon analysis, the larger the carbon number
the more difficult it becomes to confirm the molecular ions on a mass Analysis was performed using both the EI method and the PCI method
spectrum. The ion-molecule reactions that occur with positive of ionization. For analysis by the PCI method, a specialized PCI ion
chemical ionization (PCI), however, tend to produce protonated source was used with methane as the reagent gas. For both the PCI
molecules and dehydride molecules, from which information about method and the EI method, process conditions were optimized
molecular mass is easier to obtain compared to the EI method. automatically by autotuning before performing analysis.
In this article, we describe a case example of using PCIGC-MS to Analytical conditions are shown in detail in Table 1.
measure hydrocarbons obtained from the catalytic decomposition of
squalane, a compound obtained from microalgae.

Table 1 Analytical Conditions

Shimadzu Gas Chromatograph
Mass Spectrometer : GCMS-QP2010 Ultra
GC
®
Column : Rtx -1 PONA
(Shimadzu GLC Ltd.: P/N 314-100)
100 m × 0.25 mm I.D., 0.5 µm
Carrier Gas : He
Control Mode : Linear Velocity (21.2 cm/sec)
Injection Mode : Split
Split Ratio : 26.8

Oven Temperature : 40 ˚C (10 min) ˠ ˚C/min ˠ 300 ˚C (45 min)
Sample Injection Volume : 1.0 µL (2.0 µL for the PCI method)
MS (EI Method)
Ion Source Temperature :200 ˚C
Interface Temperature : 300 ˚C
Tuning Mode : High concentration
Measurement Mode : Scan (m/z 10 to 500)
Event Time : 0.3 sec
Ionization Voltage : 70 V
MS (PCI Method)
Reagent Gas : Methane
Ion Source Temperature :170 ˚C
Interface Temperature : 300 ˚C
Tuning Mode : Standard
Measurement Mode : Scan (m/z 45 to 500)
Event Time : 0.3 sec
Ionization Voltage : 70 V

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