A reflection on the role of ICP-MS in proteomics: Update and future perspective

Mass spectrometry is the technique of reference for the identification and quantification of proteins. Whereas ESI and MALDI ionization sources are inherently not quantitative being highly influenced by the chemical nature of the analyte and the matrix, ICP-MS uses a hard ionization source that destroys proteins into its atoms and measures the elemental signal, which is independent of its chemical environment. As a consequence, ICP-MS turns up as an excellent technique for the screening, mapping and quantification of peptides and proteins in a sample through elemental detection (any element but C, H, N, or O) once they have been previously separated by chromatography. In this time, great efforts have been put in developing instrumentation and new methodologies that enable a better, more efficient, and more useful analysis of proteins with ICP-MS. Moreover, quantitative capabilities but lack of molecular information of ICP has led to a synergic relationship both with identifying capabilities of ESI-MS, or the use of protein-specific antibodies carrying an elemental label. JOURNAL SIGNIFICANCE: We are delighted to participate in this special issue and have the chance to congratulate Journal of Proteomics for its 10th Anniversary, and wish for many further successful anniversaries. During this last decade, Journal of Proteomics has been a clear promotor of works integrating ICP-MS for proteomics analysis. In fact, already in 2009, a review was published by invitation of the editor in chief focused on the established and potential role of ICP-MS in different areas of the proteomics analysis at the time: "The emerging role of ICP-MS in proteomics" [1]. Even though ICP-MS is not fully known or acknowledged in the proteomics world yet, its impact was significant as demonstrated by the really high interest in such publication (over 150 citations). Since then, several excellent papers relating to ICP-MS applications in proteomics have been published in this journal. Following the trend, we expect through this personal view of the current standing of ICP-MS in proteomics to enlighten the readers of Journal of Proteomics with a vision of the full present and future potential of ICP-MS in proteomics.