Mass Spectrometry
Mass spectrometry (MS) is a powerful analytical technique that identifies compounds in a sample by measuring their mass-to-charge (m/z) ratios. The method works by determining the molecular weight of a compound and analyzing the isotopic abundance of its elements. In mass spectrometry, the sample is ionized into gaseous ions, which are then separated and identified based on their mass-to-charge ratios and relative abundances. This allows for the precise identification and structural characterization of a wide range of compounds, making MS an indispensable tool in fields such as chemistry, biology, and pharmaceuticals.
Overview
Mass Spectrometry Overview
Today, mass spectrometry is a well-established detection method that offers a multitude of benefits, such as selectivity, sensitivity, and multi-sample analysis. It can be coupled to various chromatographic techniques, such as liquid chromatography, thin layer chromatography, gas chromatography, or inductively coupled plasma. Mass spectrometry is widely used across many research fields and industries, including the pharmaceutical and food industries, health clinics, clinical research labs, and forensic and environmental testing labs.
How Does Mass Spectrometry Work?
A mass spectrometer works by converting individual molecules into ions and then analyzing the relative abundance of the generated ions. In the ion chamber of a mass spectrometer, each individual molecule is ionized to form a molecular ion, having one electron less than the parent molecule. Molecular ions, or ‘radical cations’, then undergo fragmentation into ions which, in turn, are further fragmented, and so on. From one complex sample, a mass spectrometer generates many ions. The ions are then accelerated in an electromagnetic field and separated based on their mass-to-charge (m/z) ratios. The instrument’s detector records the ions in proportion to their relative abundance and generates a mass spectrum of the molecule.
Applications of Mass Spectrometry
Due to the sensitivity of mass spectrometry, it is widely used to measure very low molecular weights at extremely low concentrations, below nanograms per milliliter (ng/mL). The ability to couple mass spectrometry to other separation techniques such as capillary electrophoresis, GC, and HPLC makes it a versatile analytical tool for the simultaneous separation and identification of analytes.
Typical applications of mass spectrometry include:
- Analysis of amino acid sequences of proteins and peptides
- Evaluation of impurities during drug development
- Purity assessment of active pharmaceutical ingredients
- Routine analysis of illegal drugs in urine, blood, and hair
- Detection of hereditary disorders of amino acid, fatty acid, and organic biosynthesis