Mass Spectrometry

Mass spectrometry is a very useful method for the determination of the structure of organic compounds although the technique has not yet been widely employed in this field. Of particular interest is the high sensitivity of the instrument, making possible the use of very small amounts of sample, and the information obtainable regarding the size of the molecule and position of the groups therein. 

Mass spectrometry is a analytical method used to quantify known materials, to determine unknown compounds within a sample, and to demonstrate the structure and chemical properties of different molecules. The complete process involves in the conversion of the sample into gaseous ions, with or without fragmentation, which are then characterized by their mass to charge ratios and relative abundances. Mass spectrometry technique basically studies the effect of ionizing energy on molecules. It depends upon chemical reactions in the gas phase in which sample molecules are consumed during the formation of ionic and neutral species.Mass spectrometry is  a powerful technique with a variable uses in biology, chemistry, and physics, but also in clinical medicine and even space exploration. It is used to determine the molecular weight of compounds by separating molecular ions on the basis of their mass and charge.

The use of Mass Spectrometry in the pharmaceutical region associated with the Drug Discovery and Development process is rich and varied. Many of the initial efforts were associated with online high performance liquid chromatography-mass spectrometry in drug  metabolism, pharmacokinetic and pharmacodynamics studies. There have been numerous innovative efforts to apply various mass spectrometric techniques in early drug discovery, preclinical and clinical development, as well as in Phase 0 studies using Accelerator Mass Spectrometry. Today there is a re-evaluation and refocusing on how to efficiently adopt, adapt and use modern Mass Spectrometry instrumentation in the Drug Discovery and Development process.

Spectroscopy is the study of the interactions between matter and electromagnetic radiation. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, by a prism. Later the concept was expanded greatly to include any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is often represented by an emission spectrum, a plot of the response of interest as a function of wavelength or frequency.

Clinical Laboratories utilizes the Mass spectrometry technology for disease screening, diagnosis of disease and metabolic disorders, identifying drug toxicity and poisoning, monitoring of drug therapy and determine advanced biomarkers. Therapeutic monitoring of immunosuppressant drugs using MS is well established. Liquid chromatography-mass spectrometry has become the standard for assay of steroid hormones for diagnosis of endocrine disorders. Vitamin D analysis by Liquid chromatography-mass spectrometry is widely used in the clinical laboratory today. Whereas immunoassays are unable to distinguish between 25-hydroxy vitamins D2 and D3, the Liquid chromatography-mass spectrometry methodologies are able to measure these levels separately so the contribution of each to the total can be determined. The capability of measuring thyroid hormones by tandem Mass spectrometry was developed recently and this has overcome the issues associated with immunoassays. Triple quadrupole MS/MS is the preferred methodology for toxicology screening and for toxic drug quantitation. In newborn and prenatal screening programs, electrospray tandem Mass spectrometry has made possible identification of inborn errors in metabolism or genetic defects so that preventive and medical intervention can be implemented promptly to relieve or treat. The intensive research into metabolomics, the assessment of endogenous metabolites as new disease biomarkers, is another promising applications of MS, which has been demonstrated to be very well suited to discovery and clinical application of metabolite profiles . Another area of increasing interest is the use of automated MALDI-TOF MS for rapid identification of microorganisms in clinical microbiology laboratories.

Capillary electrophoresis–mass spectrometry (CE-MS) is an analytical chemistry procedure formed by the combination of the liquid separation process of capillary electrophoresis with mass spectrometry. CE-MS combines advantages of both CE and MS to provide high separation efficiency and molecular mass information in a single analysis. It has high resolving power and sensitivity, requires minimal volume and can analyze at high speed. Ions are typically formed by electrospray ionization, but they can also be formed by matrix-assisted laser desorption/ionization or other ionization techniques. It has applications in basic research in proteomics and quantitative analysis of biomolecules as well as in clinical medicine.

Liquid chromatography-Mass spectrometry is a analytical chemistry process that mixes the physical separation capabilities of liquid action with the mass analysis capabilities of mass analysis. Liquid chromatography-Mass spectrometry  may be a powerful technique used for several applications that has terribly high sensitivity and property. Usually its application is destined towards the overall detection and potential identification of chemicals within the presence of alternative chemicals. LC-MS system is used for quick and mass directed purification of natural-products extracts and new molecular entities which are necessary to food, pharmaceutical, agrochemical and alternative industries.

Gas chromatography–mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, fire investigation, environmental analysis, explosives investigation, and identification of unknown samples, including that of material samples obtained from planet Mars during probe missions as early as the 1970s. GC-MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification.

Tandem mass spectrometry explains various steps of mass selection or analysis, usually separated by some form of fragmentation. In a tandem mass spectrometer, ions are formed in the ion source and separated by mass-to-charge ratio in the first stage of mass spectrometry (MS1). Ions of a particular mass-to-charge ratio (precursor ions) are selected and fragment ions (product ions) are created by collision-induced dissociation, ion-molecule reaction, photo dissociation, or other process. The resulting ions are then separated and detected in a second stage of mass spectrometry (MS2). There are different methods for fragmenting molecules for tandem MS, including electron capture dissociation (ECD), collision-induced dissociation (CID), blackbody infrared irradiative dissociation (BIRD) and infrared multi photon dissociation (IRMPD).

Mass Spectrometry (MS) is a popular technique for environmental analysis because of its ability to carry out sensitive qualitative and quantitative analysis.

A number of developments, particularly in the analyzers used to separate ions based on their mass-to-charge ratio, make it increasingly useful for environmental analysis. Analyzers vary depending on their mass measurement accuracy, resolving power, acquisition speed and linearity. Analyzers like time-of-flight and orbit rap have been investigated for environmental applications.

Tandem MS using hybrid analyzers is further improving MS by using two rounds of mass analysis. It lends itself to environmental analysis because it is useful for analyzing analytes in complex mixtures, or with high sample matrix background. It has been used in pesticide analysis to identify compounds like nitro phenols, which are readily water soluble and can run-off into river water and make their way into drinking water supplies.

Protein mass spectrometry refers to the uses of mass spectrometry to the study of proteins. Mass spectrometry is an important method for the accurate mass determination and characterization of proteins, and a variety of methods and instrumentations have been developed for its many uses. Its applications include the identification of proteins and their post-translational modifications, the elucidation of protein complexes, their subunits and functional interactions, as well as the global measurement of proteins in proteomics. It can also be used to localize proteins to the various organelles, and determine the interactions between different proteins as well as with membrane lipids. The two primary methods used for the ionization of protein in mass spectrometry are electrospray ionization (ESI) and matrix-assisted laser desorption/ionization.

There are many types of ionization techniques are used in mass spectrometry methods. The classic methods that most chemists are familiar with are electron impact (EI) and Fast Atom Bombardment (FAB). These techniques are not used much with modern mass spectrometry except EI for environmental work using GC-MS. Electrospray ionization (ESI) - ESI is the ionization technique that has become the most popular ionization technique. The electrospray is created by putting a high voltage on a flow of liquid at atmospheric pressure, sometimes this is assisted by a concurrent flow of gas. Atmospheric Pressure Chemical Ionization (APCI) - APCI is a method that is typically done using a similar source as ESI, but instead of putting a voltage on the Electrospray Tandem Mass Spectrometry Newborn Screening itself, the voltage is placed on a needle that creates a corona discharge at atmospheric pressures. Matrix Assisted Laser Electrophoresis is a technique of ionization in which the sample is bombarded with a laser. The sample is typically mixed with a matrix that absorbs the radiation biophysics and transfer a proton to the sample Gas-Phase Ionization.

A Mass Spectrometer generates multiple ions from the sample under investigation, it then separates them according to their specific mass-to-charge ratio (m/z), and then records the relative abundance of each ion type. The instrument consists of three major components. Ion Source, Analyzer, Detector System. A Mass Spectrometer should always perform the following processes:

Produce ions from the sample in the ionization source Separate these ions according to their mass-to-charge ratio in the mass analyzer          Eventually, fragment the selected ions and analyze the fragments in a second analyzer Detect the ions emerging from the last analyzer and measure their abundance with the detector that converts the ions into electrical signals Process the signals from the detector that are transmitted to the computer and control the instrument using feedback

Mass spectrometry in forensic analysis is a technology provides a powerful tool for forensic studies. For forensic researchers investigating their samples for unknown compounds, drug metabolites, chemicals or hazards, novel psychoactive substances that have never been previously detected or characterized. The role of mass spectroscopy in forensic science may be characterized as either molecular or elemental analysis. comparatively little volatile nonionic molecules found in a very sort of forensic samples may be analyzed with electron and chemical ionization of single-stage mass analyzers that give relative molecular mass and structural data. Non-polar and polar molecules and their metabolites habitually found in biological matrices along with alternative analytes of forensic interest may be determined by using electrospray.

Mass spectrometry in medicine is the most important area to study for the development of medicines. Mass spectrometry is an analytic technique widely used many laboratories for the development of laboratory medicine. Various types of mass spectrometers are used in order to get improvements in assay performance that is occurring rapidly in areas such as toxicology, endocrinology, and biochemical genetics. Mass spectrometry is a diagnostic system with high specificity and developing vicinity in research facility prescription. Different sorts of mass spectrometers are being utilized as a part of an expanding number of clinical research facilities around the globe. Mass spectrometry has contributed altogether to the development of restorative science in late decades, especially in connection to medication advancement, in-vitro diagnostics, dietary and natural drug.

Imaging Mass Spectrometry is a technology that combines most advanced analytical techniques for the analysis of biological molecules with spatial fidelity. An effective approach for imaging biological specimens in this way utilizes Matrix-Assisted Laser Desorption Ionization Mass Spectrometry. The mass-to-charge ratio  of the ions are measured using a Mass Spectrometer over an ordered array of ablated spots. Imaging Mass spectrum analysis (IMS) encompasses a spread of techniques that change the chemical imaging of analytes from atoms and little molecules to intact proteins directly from biological tissues. Imaging Mass Spectrometry is remodeling specific areas in research project with its distinctive combination of chemical and biological information. Innovations in instrumentation and imaging protocols can create this approach at several stages of the drug discovery method, as well as medical target screening and evaluating the distribution of drug and drug metabolites in cells and tissues.

Analytical Chemistry is the science of obtaining, processing, and communicating information about the composition and structure of matter. Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter.  In practice separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes. Qualitative analysis identifies analytes, while Quantitative analysis determines the numerical amount or concentration. Analytical chemistry consists of classical, wet chemical methods and modern, instrumental methods. Classical qualitative methods use separations such as precipitation, extraction and distillation. Identification may be based on differences in color, odor, melting point, boiling point, radioactivity or reactivity. Classical quantitative analysis uses mass or volume changes to quantify amount. Instrumental methods may be used to separate samples using Ehromatography, Electrophoresis or field flow fractionation. Then Qualitative and Quantitative analysis can be performed, often with the same instrument and may use light interaction, heat interaction, electric fields or magnetic fields . Often the same instrument can separate, identify and quantify an analyte. Analytical chemistry is also focused on improvements in experimental design, chemo metrics, and the creation of new measurement tools. Analytical chemistry has broad applications to forensics, medicine, science and engineering.