Element and molecular mass spectrometry - an emerging analytical dream team in the life sciences

The recent literature on the combined applications of element (ICP, inductively coupled plasma) mass spectrometry and molecular (ESI, electrospray ionisation and MALDI, matrix assisted laser desorption ionisation) mass spectrometry in the life sciences is reviewed. Emphasis is put on investigations where both techniques have been used in a synergistic way with the aim of an analytical result with molecular specificity. Multi-element specificity and quantification are the key features of element MS, whereas molecular weight determination and structural information are those contributed by ESI and MALDI MS. The analytical applications cover the study of selenoproteins, phosphoproteins, metalloproteins, unmodified proteins, metallothioneins, phytochelatins, nucleic acids, arsenosugars, thyroid hormones, cobalamines, drugs and drug metabolites. Supported by on-line or off-line coupling to chromatographic or electrophoretic separation methods, the combined application of element and molecular mass spectrometry in all these studies has created the basis for new structural and/or quantitative insights, demonstrating the analytical excellence of this approach.