Chromatography and Mass Spectroscopy

Chromatography and Mass Spectroscopy:

Chromatography is widely perceived as an essential analytical tool due to its sensitivity and effectiveness in separating and identifying various mixtures of components. It has numerous applications in chemical and biological fields. The method is a technique for separating and analyzing components (solutes) of a mixture according to the relative amounts of compounds distributed between a moving fluid (mobile phase) and a stationary phase. The separation of compounds will happened by allowing a solution or mixture to seep through an adsorbent. The mobile phase in Chromatography may be either a liquid or a gas and based on the mobile phase it could be divided to the following subdivides:

Gas Chromatography (GC)
High Performance Liquid Chromatography (HPLC)

Mass Spectroscopy:

The Mass Spectroscopy is an analytical method which is based on separation of ionic fragments of a component according to mass-to-charge ratios (m/z) in an electric or magnetic field.
In these systems the analyte is passed through an ionic source where a component is changed to ionic fragments by bombarding molecules with a stream of electrons under extremely low pressure. The stream of ionic fragments that differ in mass are accelerated into an electric or magnetic field which is used to change fragments paths. The detect measures the intensity of the each ionic beam and produce a pattern (mass spectrum). This spectrum can be stored in a computer to be compared with entries in a mass spectrum library and identify the target. Mass Spectroscopy is a very specific identifying technique specially when coupled with Gas or Liquid chromatography.


Gas Chromatography (GC):

Gas Chromatography is one of the most important quantitative and qualitative analytical tools in chemistry because of its simplicity, sensitivity and effectiveness in separating and identifying various mixtures of components.
In this technique samples (usually liquid mixtures) are vaporized and introduced into a moving gas stream such as helium, hydrogen, and nitrogen known as the “carrier gas”. The flowing gas transports the gaseous solute into a separation column. The components of the sample are separated based on the degree of interaction with stationary phases inside the column. The components are washed out the column by carrier gas and measure by a detector.
GC has diverse applications in different fields includes biological, chemistry, environmental sciences and widely used in industries. GC is the core tool to analyze complex mixtures of hydrocarbons in petroleum industries which plays an important role in Iran as an energy superpower in the world.

High Performance Liquid Chromatograph (HPLC):

Liquid chromatography (LC) is common technique to separate mixtures of components by using of a liquid mobile phase. The most popular category of liquid chromatography is high-performance liquid chromatography (HPLC). The method employs a mobile phase, usually a solvent (or a mix of solvents which is forced through a tightly packed column by use of a pump. Sample is injected into the column and transports by the high pressurized solvent flow to a detector. The separation is based on swiping velocities of analytes in the column that are affected by the degree of interaction of each compounds with the stationary phase in column. The detector is placed at the end of the column and monitors separated components.

Gas Chromatography/Mass Spectrometry (GC/MS):

The Gas Chromatography/Mass Spectrometry (GC/MS) instrument separate compounds of chemical mixtures in the GC part and analyze each compound emerge from the column in the mass part. Identification is based on the pattern provided by separation of ionic fragments of the component according to mass-to-charge ratios (m/z) in an electric or magnetic field and compares this mass spectrum with known entries in a mass spectrum library to find target. The method is one of the most accurate tools for quantitative and qualitative analyzing of samples and has a variety of applications in different fields. e.g.: environmental analysis of volatile organic compounds (VOCs) and pesticides, explosives investigation, hydrocarbon mixtures analyzing, fire investigation, criminal forensics, drug detection and anti-doping analysis in sports, Food, beverage and perfume analysis, identification of unknown samples and so on.

Gas chromatography/tandem mass spectrometry (GC-MS/MS)

The GC-MS/MS is using a second phase of mass fragmentation which provides the opportunity of obtaining more detailed information about unknown samples and enables to analyze more complex compounds faster than a GC, MS, or GC/MS.

The GC-MS/MS is also suitable for quantitating low levels of a compound in front of a high matrix background.

Liquid Chromatography/Mass Spectrometry (LC/MS):

The LC/MS system is coupling of liquid chromatography and mass spectrometry which may be used to provide information about the molecular weight, structure, identity and quantity of a specific component in a sample matrix. Combination of LC with amazing separating power with supreme detection of mass spectrometry makes the technique one of the desirable analyzing tools. LC/MS is quite new developed method which had a great influence on protein and peptide biochemistry.

Liquid Chromatography /tandem mass spectrometry (LC-MS/MS)

The main characteristics of LC-MS/MS technology are high selectivity, sensitivity, and throughput which cause growingly use of technique in the clinical laboratories. The LC-MS/MS system added a second phase of mass fragmentation. This enable user to program the detector and select certain ions to fragment which help to eliminate high matrix backgrounds effects. the is an important technique study purity and impurity profiles in drugs , pharmacokinetic studies, metabolites identification in the plasma and urine, doping analysis, toxicological studies and so on.