Separation and detection of fuel components in gasoline gum content (IP 131; ASTM D381) by utilising UHPSFC-MS

New ultra-high pressure supercritical chromatography - mass spectrometry (UHPSFC-MS) methods have been developed to separate and detect gasoline gum components that were undetected by GC-MS. The different techniques reveal distinct compounds within the gasoline gum samples, e.g. using UHPSFC-MS carrier oils and detergents are observed. The gum samples were prepared following the IP 131; ASTM D381 standard method and then analysed by UHPSFC using different ionisation processes. UHPSFC uses supercritical carbon dioxide and a polar modifier to provide separation of involatile and large molecules in the gum samples. Data are visualised using an ion map, utilising a graphic representation of m/z, retention time and ion intensity. These ion maps can be used to screening of fuel samples where the different classes of compounds can be readily observed.