Comprehensive chemical comparison of fuel composition and aerosol particles emitted from a ship diesel engine by gas chromatography atmospheric pressure chemical ionisation ultra-high resolution mass spectrometry with improved data processing routines

Abstract

The analysis of petrochemical materials and particulate matter originating from combustion sources remains a challenging task for instrumental analytical techniques. A detailed chemical characterisation is essential for addressing health and environmental effects. Sophisticated instrumentation, such as mass spectrometry coupled with chromatographic separation, is capable of a comprehensive characterisation, but needs advanced data processing methods. In this study, we present an improved data processing routine for the mass chromatogram obtained from gas chromatography hyphenated to atmospheric pressure chemical ionisation and ultra high resolution mass spectrometry. The focus of the investigation was the primary combustion aerosol samples, i.e. particulate matter extracts, as well as the corresponding fossil fuels fed to the engine. We demonstrate that utilisation of the entire transient and chromatographic information results in advantages including minimisation of ionisation artefacts and a reliable peak assignment. A comprehensive comparison of the aerosol and the feed fuel was performed by applying intensity weighted average values, compound class distribution and principle component analysis. Certain differences between the aerosol generated with the two feed fuels, diesel fuel and heavy fuel oil, as well as between the aerosol and the feed were revealed. For the aerosol from heavy fuel oil, oxidised species from the CHN and CHS class precursors of the feed were predominant, whereas the CHO class is predominant in the combustion aerosol from light fuel oil. Furthermore, the complexity of the aerosol increases significantly compared to the feed and incorporating a higher chemical space. Coupling of atmospheric pressure chemical ionisation to gas chromatography was found to be a useful additional approach for characterisation of a combustion aerosol, especially with an automated utilisation of the information from the ultra-high resolution mass spectrometer and the chromatographic separation.

Two-dimensional mass spectrometry: new perspectives for tandem mass spectrometry

“…The most common way to correlate precursors and fragments is to isolate a single m / z ratio before fragmenting it (MS/MS) (Biemann 2002 ). MS/MS can be coupled with separation techniques to reduce the instantaneous complexity of the sample and to reduce ionization competition and Coulombic repulsion between ions (Peng et al 2003 ; Ruger et al 2017 ; Wootton et al 2017 ). Because a choice is made for each MS/MS spectrum on which m / z ratio is isolated and fragmented (a decision that is usually made algorithmically by the computer running the instrument: the acquisition switches between MS and MS/MS.…”

Atmospheric Pressure Single Photon Laser Ionization (APSPLI) Mass Spectrometry Using a 157 nm Fluorine Excimer Laser for Sensitive and Selective Detection of Non- to Semipolar Hydrocarbons

“…After peak picking (≥S/N 9), the data were exported by self-written Visual basic scripts. 38,39,9 Subsequently, the exported data were processed by a self-written MATLAB-based (MATLAB R2019b) graphical user interface named CERES (Computing enhanced resolution spectra). An error of 2 ppm for 175 elemental composition attribution was applied.…”

“…A commercial GC-APCI II source (Bruker Daltonics, Bremen, Germany) was modified for atmospheric with a heating rate of 10 K/min. Further details on the gas chromatographic 38,9 and thermogravimetric 17,39 hyphenation to the atmospheric pressure ionization source of the ultrahigh resolution mass spectrometer can be found elsewhere. For both cases, the transferline was kept at 280 °C.…”

Integrated Parameter Test System for Dual Fuel Engines of Special Heavy Vehicles

“…With increasingly stringent emission regulations and energy constraints (Rüger et al 2017), finding clean and efficient alternative energy sources is the top priority for the internal combustion engine industry. Natural gas fuel has great potential as an alternative fuel for petroleum, which can save oil consumption and effectively reduce harmful emissions such as NOx and PM.…”