Sequencing with mass spectrometry

Mass spectrometry can be used for the determination of DNA sequence. Matrix laser desorption ionization time of MALDI-TOF MS has been studied as an alternative method for visualizing gel electrophoresis, the DNA fragments or especially flight mass spectrometry. In this method, DNA fragments generated in chain termination sequencing reaction were compared by not the mass size. Mass of each nucleotide are different from each other, the difference is detected by mass spectrometry. It can be detected by MS than by gel electrophoresis easily through one base mutation in the fragment. The MALDI-TOF MS, the DNA sequences indirect method based on the MS by the conversion easily, as can be the RNA of the first, may be used to detect differences in RNA fragments scientists more.

There is particular interest to researchers crimes higher resolution to resolve DNA fragments by the method of MS-based, they can in order to identify an individual, and decides to search the nucleotide polymorphism in a sample of human DNA possible. The forensic investigator, you might want to prefer the mitochondrial DNA of continuity applications and research higher stability than often, greatly reduced these samples. Sequencing method based MS were used to compare the sequence of the mitochondrial DNA samples from human bones found in mass graves soldiers WWII database and FBI.

Sequencing with mass spectrometryMethod chain and early termination of TOF MS showed reads of base pairs up to 100. As sequencing alone chain termination, not able to exceed the average read size and DNA sequencing of the MS-based researchers may not be suitable for projects Denoboshiken large. The Even so, a recent study, short sequence reads, and has benefited from mass spectrometry in order to compare the single nucleotide polymorphism in the pathogenic strain of streptococcus.

Mass spectrometry (MS) is an analytical technique that generated the (single array) Mass spectrum of the molecule, including samples of materials. Is used to determine the elemental composition of the sample mass and molecular particles, spectra were elucidation of the chemical structure of the compound and other molecules, such as peptides. Mass spectrometry operates by chemical compound that generates ions by measuring the mass-to-charge ratios and their molecular fragments or charged molecules.

In a typical procedure, the MS, the sample may be solid, liquid or a gas is ionized. Ions are separated according to their mass to cost ratio. Ions are detected by the detection mechanism of charged particles. Result of the signal processing is shown as spectrum of the relative amount of ions as a function of the mass ratio of the cost. It is possible to identify the combined masses of the characteristic fragmentation table or the identified molecules or atoms. Detector ion source and mass analyzer: mass spectrometer comprises three components.

I will convert a portion of the sample to the ion in the ionizer. A technique of ion species ways depending (solid, liquid, gaseous) phase in the efficiency and sample various mechanisms ionization unknown. Evacuation system removes ions from the sample was trajected through the detector and mass analyzer on the next. The difference of the mass of the fragments allows mass analysis to sort the mass ion their to cost ratio. By measuring the value of the index number, the detector provides data for the calculation of the abundance of each ion present. Further detector Some provide spatial information, such as multi-channel plate.

Mass spectrometry, has a goal of both qualitative and quantitative. That it determines the identification of unknown compounds, the isotopic composition of elements in the molecule and to determine the structure of the compounds according to the picture contains them. Other applications, contains the (neutral in a vacuum and the chemical nature of the ions) to study the basis of gas-phase ion chemistry or to determine the amount of the compound in the sample quantitative. MS is now using a very common in research laboratories biological properties physical, chemical or various compounds.

Mass analyzer, an electric field is created between the bars 4 parallel Alternatively, oscillating erratically, or stabilize the trajectory of ions passing through a radio frequency (RF) a quadrupole field quadrupole uses. Only ions passed through the system at any point within a certain range the mass / charge ratio, but a wide range of values ​​of M / Z of the sample quickly to individual hop series change in the potential of the bar continuously or made possible. Mass analyzer, a point called acts as a mass selective filter, ion trap quadrupole closely, instead of passing the ions are not trapped, it is because it is designed to collect those trapped quadrupole as a transmission quadrupole associated with the ion trap quadrupole linear especially Except.

In a general embodiment of the transmission, it is a quadrupole of triple quadrupole mass spectrometer. The first four acting as a filter for transmitting the table four “three”, the input of a specific collision compositions possible successive stages 3 and the ion, ions are divided into fragments electrode Fourth Weight It is composed of a quadrupole. It acts as a mass filter to transmit the fragment ion detector quadrupole third particular. If you have been made to repeat cycle quickly through a set of configuration of the mass filter quadrupole, you can record the full spectrum. Similarly, it is possible to be executed by the type of different scanning properties of tandem mass spectrometry of four triple 4