In the scientific community, biomedical and pharmaceutical analysis are mostly associated with methods to identify and quantify organic compounds in human or animal tissues or body fluids. The respective methods include, but are not limited to liquid and gas chromatographic (LC and GC) as well as capillary electrophoretic (CE) separations, molecular spectroscopy as well as electrospray mass spectrometry (ESI-MS). Rarely, plasma-based methods find major recognition in these important fields of Analytical Chemistry, as only a limited number of biologically relevant molecules contains electropositive heteroatoms that can be detected by the most commonly applied methods of elemental analysis.

However, inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ICP-MS provide unique opportunities for biomedical and pharmaceutical analysis, particularly with respect to quantification. While separations coupled to ESI-MS may be subject to massive ion suppression in complex matrices, atomization in the plasma-based methods delivers the rare opportunity of substance-independent quantification. With this feature, ICP-MS and ICP-OES are excellent complementary methods to ESI-MS with high resolution (HR) mass analyzers, additional fragmentation capabilities and ion mobility spectrometry, which are outstanding tools for the identification of unknown compounds in complex biological samples.

The combination of elemental and molecular mass spectrometry allows to obtain valuable chemical information that cannot be generated using any other method: In the field of speciation analysis, a chromatographic separation is coupled, either subsequently or simultaneously, with ESI-HR-MS and ICP-MS to identify and quantify heteroatom-containing xenobiotics or endogenous analytes. This allows to distinguish between different molecules, which contain the same heteroatom and to quantify the respective substances even without substance-specific calibration standards. Similarly, laser ablation (LA)-ICP-MS can be used as powerful tool for heteroatom-based quantification and imaging, which complements molecular information obtained by spatially resolved matrix-assisted laser desorp¬tion/ionization (MALDI)-MS imaging particularly well.

In recent years, plasma-based molecular analysis methods as LA-atmospheric pressure chemical ionization (APCI)-MS or LA-dielectric barrier discharge ionization (DBDI)-MS have shown potential for molecular imaging of analytes with moderate to high polarity, thus expanding the range of compounds accessible by MALDI-MS imaging. Using LA and split-stream ICP-MS and APCI-MS, even simultaneous molecular and elemental mass spectrometric imaging can be carried out.

The general concepts and applications of plasma-based methods in biomedical and pharmaceutical analysis will be presented and discussed within this keynote.