Understanding the fundamental chemical processes that govern combustion phenomena offer the opportunity to optimize combustion for improved engine efficiency and minimization of pollutant formation. The jet stirred reactor (JSR) is a continuously stirred tank reactor, which realistically simulates the chemical transformation in combustion engines under well-defined conditions. The JSR-system in conjunction with a Q Exactive Orbitrap Mass Spectrometer is used to investigate the oxidation chemistry of various alternative fuels and fuel component molecules.
Instruments used for this project is:
Jet Stirred Reactor (JSR) –
The JSR, based on the design by Dagaut et al.46, is a fused-silica sphere of approximately 4 cm diameter and 33.5 cm3 volume. Its four injection jets are situated in the equatorial plane of the reactor at opposite directions in order to ensure a homogenous mixture of the reactant gasses. This reactor design is commonly used in combustion chemistry investigations for the development of computational kinetic models.DART: The exhaust from the JSR flows through a 24 cm fused silica transfer line and is ionized using a DART ionization source. This technique enables ambient soft ionization, resulting in minimal fragmentation and preserving the integrity of molecular ions for downstream analysis. DART allows for mass spectrometric detection and quantification of analytes via the formation of protonated or deprotonated molecules. Ionization in DART occurs through gas-phase reactions involving electronic or vibronic excited-state species.
ORBITRAP –
Orbitrap mass spectrometry is a sensitive, high-resolution mass spectrometry method that uses the principles of harmonic motion of charged particles in an electric field to determine the m/z values of analyte species with high accuracy. The instrument used in this investigation is a ThermoFisher Q-Exactive Orbitrap Mass Spectrometer (QEO-MS) which has a total range of m/z = 50-6000, a mass resolution of up to 140,000 FWMH at m/z = 200, and the ability to be operated to detect both positive and negative ions.
DART –
DART is a soft chemical ionization technique that enables the real-time detection of analytes in open air with minimal sample preparation. The DART source (IonSense), now owned by Bruker, operates at atmospheric pressure and facilitates the ionization of moderately polar species with minimal fragmentation, making it well-suited for coupling with mass spectrometry to analyze thermally desorbed compounds from gas or condensed phases.