Abstract: A Fischer-Tropsch derived fuel component is provided in a fuel composition to alter the spectroscopic response of the composition to the presence of a spectroscopically active indicator. The Fischer-Tropsch derived component may be used to increase the detectability of the indicator, and/or to increase the resolution of an analytical test subsequently carried out on the composition. Also provided is a method for investigating a property of a fuel composition, by adding a spectroscopically active indicator and detecting a subsequent spectroscopic response in the composition, wherein the composition contains a Fischer-Tropsch derived fuel component. Further provided is a fuel composition containing a spectroscopically active indicator and a Fischer-Tropsch derived fuel component. The spectroscopic response may be a visible response such as a colour change.

Abstract: A method of operating a fuel consuming system in a restricted ventilatioan area is provided. The level of regulated emissions is reduced from a fuel consuming system running on the Fischer-Tropsch derived fuel composition.

Abstract: In a fuel composition containing a static dissipator additive, a lubricity enhancing additive is blended for the purpose of increasing the electrical conductivity of the composition, and/or for reducing the concentration of the static dissipator additive in the composition. The fuel composition is preferably an automotive diesel fuel composition and preferably contains a Fischer-Tropsch derived fuel component.