Hyphenating supercritical fluid chromatography and inductively coupled plasma mass spectrometry: a proof of concept†
The speciation analysis of complex mixtures of chemicals requires an efficient separation method and supercritical fluid chromatography (SFC) is one such technique that has been used for these purposes. Hyphenation of SFC to inductively coupled plasma mass spectrometry (ICP-MS) can provide elemental speciation information. However, the hyphenation of modern SFC instrumentation to ICP-MS has not yet been tested. The aim of this study was to develop a novel interface to hyphenate ICP-MS and modern HPLC-like SFC systems that enable the use of organic solvent gradients and packed columns. For this, an optimization of the most important parameters, such as SFC back pressure, gas temperature and position of the interface within the whole set up, was carried out, and quantitative analyses in flow injection analysis (FIA) mode of two biolubricants and one pyrolysis oil were accomplished, reaching DLs at the ppb level with the tested mobile phase compositions. In addition, in order to test the performance of this novel interface with real samples, chromatographic separation experiments of one pyrolysis oil and one coal tar using a 2-picolylamine column were carried out, confirming the stability of this new interface and its potential to become a powerful speciation technique in the future.