Computerized Assisted Tools to Extract the Information From Datasets Obtained by Analytical Separation Techniques Hyphenated With Mass Spectrometry

Abstract

Mass spectrometry (MS) is an analytical technique where ions are separated in a vacuum under the influence on an applied magnetic field, electrical field or both, and according to their mass-to-charge (m/z) ratio. Mass spectrometers consist of three components, each one associated to a fundamental step in mass spectrometry analysis: an ion source, which produces ions from compounds present in the sample; a mass analyzer, which separates the ions based on their m/z; and a detector, which measures the quantity of ions at each m/z values. A chemical entering the instrument will generate a pattern of ions whose type and intensity are characteristic of the chemical, the ionization mode and the instrument settings. Hard ionization modes refer to ionization techniques that will fragment the molecules into smaller ions, whereas soft ionization modes will aim to preserve the integrity of most parent species and will generate fewer ions. The choice of the fragmentation mode depends on the matrices, application and type of analytes. Information obtained from both ionization modes are often complementary and many modern instruments now allow tandem modes. Once samples are ionized, precursor ions of a specific m/z are selected (MS1) and then fragmented (MS2) to generate product ions for detection. The selection-fragmentation-detection sequence can be further extended (MSn).