Coupling paper spray ionization with the flexible microtube plasma for the determination of low polar biomarkers in mass spectrometry

Abstract

A fast and precise analysis of complex biological samples is one of the most important challenges in clinical- and life-sciences. In this field, the paper spray ionization (PSI) becomes a more and more successful ambient ionization technique for mass spectrometry. The PSI is based on the electrospray mechanism and is limited to polar target analytes. In this work, a transition from the paper spray ionization to a corona discharge under standard PSI conditions is observed and evaluated by using a complex liver sample. This evaluation leads to an advancement of the PSI by adding a flexible microtube plasma (FμTP) that is more efficient in respect to non- and low polar molecules. The combination of the PSI and the FμTP in a sequential way allows the determination of polar lipids as well as non-polar compounds like cholesterol and possible lung cancer biomarkers. As add-on for PSI, this approach enhances the number of detectable species in one single measurement and seems to be a powerful tool for the rapid analysis of complex biological samples in clinical- and life-sciences.