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Photochemistry reactors are an important part of research in atmospheric chemistry. The general purpose of photochemical reactors is to simulate atmospheric photochemistry under well-controlled conditions. Each reactor comes with specific design and function to accommodate specific scientific needs. The reactors located in the Zhao group are shown here:
Aqueous-phase photochemical reactor
This reactor simulates aqueous-phase photochemistry taking place in cloud and fog waters. The reactor is comprised of an enclosure surrounded by 16 UV lamps. Three types of lamps are available to emit light centered at different wavelengths: 254 nm (UVC), 315 nm (UVB) and 350 nm (UVA). This allows us to study the effect of wavelength on the photochemistry taking place within the reactor.
(Coming soon!) Flow Tube Reactor
This figure shows the concept of a flow tube reactor currently in the design stage. Flow tube reactors are tubular reactors in which reactants are injected from the inlet (left side of the figure). The injected reactants flow through the tube with a controlled flow rate and hence experience a controlled reaction time inside the tube. In the example shown in the figure above, O3 and α-pinene are injected as reactants. They react with each other while traveling down the tube, forming secondary organic aerosol (SOA). The chemical compositions inside the flow tube reactor are monitored with both online and offline instruments.
(Coming soon!) Potential Aerosol Mass (PAM) oxidation tube reactor
(left) A PAM reactor under operation in a field campaign (Ortega et al. 2016 Atmos. Chem. Phys.); (right) The inside of a PAM reactor (PAM wiki page, https://sites.google.com/site/pamwiki/)
The PAM oxidation tube reactor is a commercialized flow tube reactor. The oxidation power of the reactor is powerful, such that simulations for photochemistry up to 10 days in the ambient atmosphere becomes possible. A PAM reactor will be purchased from Aerodyne Inc.
Lab Equipment and Instruments
Our lab is equipped with a number of advanced analytical instruments to study the chemical composition of aerosol. The lab will see a rapid growth in the next few months, as more equipment will be purchased.
A newly renovated lab!
Our brand new lab is located at Gunning/Lemieux Chemistry Centre, W4-12. Now it is time to fill it up with stuff!
Ion Chromatography (IC)
We have a Dionex ICS 3000 IC system. This instrument will be employed in the measurement of ionic compounds, organic acids, and sugars present in aerosol.
High Performance Liquid Chromatography (HPLC)
We have a Varian ProStar HPLC system. This instrument is comprised of a binary pumping system, a UV-Vis detection flow cell, as well as a fraction collection device. Fraction collection allows us to collect analytes eluting from the HPLC column at specific retention times. Thus, the analytes can be separated and be further analyzed using other techniques.
NOx and O3 detector
Source: Teledyne website http://www.teledyne-api.com/products/oxygen-compound-instruments/t204
The Teledyne API T204 instrument allows concurrent, online measurement of reactive nitrogen species (NOx) and ground level ozone (O3). These species are key players in photochemical smog.
(Coming soon!) LTQ Linear Ion Trap Mass Spectrometer
Source: LTQ MS hardware manual, Thermo Scientific
This instrument is a powerful mass spectrometer for detailed chemical analysis. The linear ion trap mass filter allows concurrent detection of all the m/z within a certain mass range. It is also equipped with the MSn function for structural elucidation of organic analytes. The ionization source can be alternated between an electrospray ionization (ESI) and an atmospheric pressure chemical ionization (APCI) module. Unique modifications will also be added to the instrument to make it capable of measuring air pollutants in all the possible forms: vaporized in the gas phase, dissolved in the liquid, and incorporated as part of aerosol.