Dear Colleagues,

The analytical mass spectrometry applies irreplaceable approaches to chemical analysis, thus becoming a gold standard of the analytical practice, due to its superior instrumental features and performances. The method shows ultra-high accuracy, reliability, precision, reproducibility, selectivity, sensitivity, and specificity, together with the capability of low- and high-molecular weight analyses as well as very low concentration limits (attomole and fmol) of detection and quantitation of analytes, among other advantages of the mass spectrometric instrumentation. Mass spectrometric methods, among others, contribute crucially in developing clinical precision medicine, due to the requested, compulsory, high-analytical standards of implemented omics protocols. Mass spectrometric application fields include analytical and environmental chemistry, clinical diagnostics, laboratory medicine, petroleum chemistry, biochemistry, medicinal chemistry, pharmaceutical drug design, pharmacy, forensic chemistry and investigations for forensic medico-legal purposes, toxicology, nuclear forensics, food and agricultural science and technology, geology, archaeology, and more. Omics-methods for molecular identification, annotation, and quantification are used in metabolomics, (neuro)-proteomics, lipidomics, food-omics, steroid-omics, glycomics, pesticide analysis and control, genomics, DNA adduct-omics, transcriptomics, lignomics, interactomics, doping control, petrol-omics, isotomics, among others. Clinical trans-omics integrates clinical phenomena with mass spectrometric multi-omics approaches. The ultra-high precision and reliability of omics-protocols determine their implementation into clinical practice. The method performances should be traceable to significantly higher-order analytical standards, defining uncertainty via the criteria of statistics and chemometrics. Mass spectrometry is capable of determining molecular sequences and modifications. It addresses crucial questions on biological processes in vivo as well as provides the knowledge on the relation between molecular structure and biological function, both in vitro and in vivo. Mass spectrometric methods also utilise the techniques of isotope labelling analytes and H/D exchange, thus yielding the complete data on the structural consequences of biomacromolecules and the activation biochemical reactions of enzymes. This knowledge also significantly develops the field of biochemistry. Mass spectrometric tools also involve the imaging technique for mapping biologically active compounds in tissues. This thematic Second Edition of the Special Issue focuses on the field of analytical mass spectrometry, particularly, the field of biochemistry. While describing mass spectrometric ionization approaches, hard-ionization methods should be highlighted, for instance, inductively coupled plasma-mass spectrometry, which has been regarded as a method of choice for simultaneously quantifying the trace amounts of isotope ions of elements in biological fluids. Its protocols have also been routinely implemented in clinical laboratories.

As the former edition of the Special Issue, the Second Edition introduces the reader to the innovations and applications of soft- and hard-ionization mass spectrometric methods to comprehensively understand biochemical transformations in environmental, food, and biological samples.

Please, consider webpage:

[https://www.mdpi.com/journal/ijms/special_issues/N8Z7YF1DE2].

Yours sincerely,

Dr. Bojidarka Ivanova Guest Editor