ChromSoc & RSC SSG – Emerging Separations Technologies
London, 30th March 2017

Edward Wilmot
PhD, University of Southampton

I am currently in my third year of a PhD at the University of Southampton, supervised by Prof. John Langley, funded by the EPSRC and Innospec. My work focuses on the analysis of gasoline samples using mass spectrometry and chromatography, namely differences between different gasoline samples, which may be related to deposition within modern fuel injection systems.

Engine design and gasoline composition are closely related, often with an advancement in one, resulting in a change within the other:

Fuel composition influencing engine design
A good example of this, is the fuel additive tetra¬-ethyl lead (TEL), added in the 1920s to gasoline to improve octane rating and cushioning the impact of the valves on cylinder head within the engine prevented damage and performance loss.

TEL in gasoline was phased out of gasoline blends within the early 1970s, due to its cumulative neurotoxicity and its damaging effect on catalytic converters. Although, this would result in a drop in octane rating and thus resulted in a replacement octane booster. Although due to the dual properties of TEL, engine designed changed and gasoline engines began to incorporate hardened valve seats in an attempt to reduce damage previously mitigated by TEL.

Engine design influencing fuel composition
Engine design is ever evolving, more power and better efficiency is desired. The process by which fuel and air is mixed prior to combustion (fuel injection) is a major area in which engine technology has advanced.

Initially, fuel and air were mixed together via a carburettor (Venturi principle), as technology advanced, high pressure injector systems began to replace the carburettors. With port fuelled injection in the 1980s and most recently direct injection. The higher pressure and better control of the fuel air mixture has resulted in performance increases. Although associated problems have also been observed, i.e. deposits within the fuel injection system, reducing fuel and air flow, and in turn decreasing performance. Thus, the fuel additives within the gasoline have had evolved over time to combat each of the new issues.

With this complex relationship between engine design and fuel composition, and ever evolving environmental legislation, it is important for automotive manufactures and the petrochemical industry to understand the composition of gasoline samples, which ever changing engine design.

Gasoline is a refined product from the complex matrix of crude oil, whilst simplified this intricate mixture of hydrocarbons is further complicated by the addition of additives, typically analytical methods utilise GC-FID or GC-MS, although this is typically not applicable to all of the molecules present within the mixture, i.e. thermally labile and high molecular weight compounds.

I believe embracing separation techniques typically not applied to gasoline analysis will aid in the quest to understand each samples composition.

Attending the Conference

Attending the meeting at Burlington house exposed me to various separation techniques and applications, some of which I was unfamiliar to, although will prove useful within my future.

During a PhD it is possible to become fixated with the specific area of interest, while neglecting other applications of a technique.

My work focuses on mass spectrometry, either solely or in combination with gas chromatography or ultra-high pressure supercritical fluid chromatography (UHPSFC). Typically working with hydrocarbons and fuel additives, the biopharmaceuticals presentations were not directly applicable to my work, although nevertheless, were fascinating. It was interesting to see how the presenters structured their research and overcame the issues presented.

Being subject to the wider area of separation science at meetings is interesting and increases my knowledge of the subject area, particularly useful for my viva, my career and the future.

Listening to and interacting with the range of conference participants encouraged me to think about my future after I finish my PhD. I enjoy the discovery aspect of science, which from my observations, is shared between academics and the industrial scientists, thus leaving both career paths of interest to me.

The talk by Dr Gesa Schad, on the supercritical fluid chromatograph (SFC) was of particular interest. I have found SFC to be a vital form of chromatography with respect to the analysis of gasolines. This is due to the affinity of gasoline to the CO2 mobile phase when compared to the aqueous mobile phase of reversed phase HPLC. As a beginner in the field of SFC I found this talk intriguing. I believe UHPSFC is a key tool for the future analysis of petrochemical analysis, especially when couple to atmospheric pressure ionisation mass spectrometry, complementary to gas chromatography.

I enjoyed the talk by James Stratta and Dr Paul Ferguson, titled “advanced polymer chromatographic instrumentation and the application to the characterisation of pharmaceutical excipients”. The talk focuses on the advances in polymer analysis using the WatersTM advanced polymer characterisation (APC) instrument. I was unfamiliar APC as a technique, although within my PhD I have worked with polymeric gasoline additives, and I have begun to think about how APC could be applied to my work.

My favourite talk was by Dr Chris Lapthorn, on the ion-mobility spectrometry (IMS). IMS is orthogonal to both chromatography and mass spectrometry, allowing separation of a mixture within another dimension based on an ions cross sectional area. The talk took the audience through the history and development of IMS to the state of the art, predictive simulations of the performance of ion mobility. This technique really appeals to me, and I hope to work with it in the future.

There were some good take homes messages from the final presentation by Prof. Apryll Stalcup on future of chromatography, and how it is perceived by people outside the field. Especially as my work is primarily mass spectrometry and secondarily chromatography based.
Attending the emerging separations technologies meeting allowed me to interact with other students, academics, industrial scientist and instrument manufactures with a range of experience. I thoroughly enjoyed the day and I believe it is important to attend meetings as a student as it gives a view of the wider applications of separation science and particular solutions to problems within the area of study.

I would like to thank the Chromatographic Society for supplying me with this bursary allowing me to attend the interesting and useful day.