Talk:Mass spectrometry/Archive 1

Archive 1

Archive 2

Russian version

Would someone be so kind as to translate and incorporate the information in the vastly larger Russian version of this article? --Ardonik 08:15, Jul 21, 2004 (UTC)

Well, check out the following link--it's a fairly 'functionalist' translation, that gives you a sense of the russion version: http://www.systranbox.com/systran/box?systran_lp=ru_en&systran_id=SystranSoft-en&systran_url=http://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D1%81%D1%81-%D1%81%D0%BF%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D0%BC%D0%B5%D1%82%D1%80%D0%B8%D1%8F&systran_f=1090404300

While it is longer, it's a bit chatty. I don't think it's vastly superior, oddly. I wrote an article once that I can add a few things from in the future.

--Jvraba 08:49, 21 Jul 2004 (UTC)

• Thanks. (Wikimedia can't handle your URL, so anyone wishing to see the site will have to copy and paste it.) That's really painful reading, and I suspect it would be even if it were translated perfectly. But you have to start somewhere. --Ardonik 10:11, Jul 21, 2004 (UTC)

• Here's a better translation than the link above, because I involved a scientific dictionary --Jvraba 18:14, 21 Jul 2004 (UTC)

English "Translation" of the Russian Version

Mass spectrometry Material from Vikipedii - free encyclopedia.

Mass spectrometry is a physical method, based on the mass measurement of charged particles in a material. It has been used for the analysis of different substances for more than 50 years.

This method, today routine used in thousands of laboratories and enterprises of peace, has in its basis the fundamental knowledge of nature of substance and uses the basic physical principles of phenomena. It was before dismantled, why to whom this method was necessary, briefly (how this is possible) and simply let us pause at how it is realized.

Naturally, the instruments, which are used in this method, mass spectrometers or mass-spectrometric detectors are called. These instruments deal concerning the material substance, which as is known, it consists of the smallest particles - molecules and the atoms. Mass spectrometers install that this for the molecules (i.e., they compose their what atoms, which their moleklyarnaya mass, such as the structure of their arrangement) and that this for the atoms (i.e., them изотопный состав). An essential difference in the mass spectrometry from other analytical physico chemical methods lies in the fact that optical, X-ray and some other methods detect emission either energy absorption by molecules or by atoms, and mass spectrometry deals concerning very particles of substance. Mass spectrometry it is measured their mass, is more accurate mass-ratio to the charge. Are used the laws of the motion of the charged particles of the material in the magnetic or the electrical it fell for this. Mass-spectrum - this is simple the sorting of the charged particles throughout their masses (more precise to the mass ratios to the charge).

Consequently, of the first, that must it made so that it would obtain the mass-spectrum, would convert neutral molecules and atoms, which compose any organic or inorganic matter, into the charged particles - ions. This process is called ionization and in different ways is achieved for the organic and inorganic matter.

In the organic matter of molecule are the determinate structures, formed by atoms. Nature and man created the truly neischislimoye variety of organic compounds. And we today umeyem practically everything of them converted into the ions.

Ionization

The oldest and most widely used in the contemporary mass spectrometry method of the ionization of the molecules of organic compounds - this the so-called electron collision (Ъ, in English EI - Electron Impact). So that would ionize the organic matter of it necessarily first from the condensed phase (liquid, solid body) would transfer by any means into the gas phase, for example, it heated (this, of course, it did not not necessarily make with the gases). Then, them necessarily introduced in the so-called source of the ions, where they undergo the bombardment with the electron beam, which possible obtained heating, for example, the metallic ribbon (cathode). Possible placed substance in the condensed phase into the source of ions and it there evaporated. Electrons - lungs in comparison with the molecules the negatively charged particles - colliding with molecules pull out from the electron shells electrons and convert molecules into the ions. In this case the molecules frequently are pulled down to the charged fragments by the mechanism specific for each connection. Specifically, as a result of this process in the final analysis mass-spectrum is received - you remember, the collection of rassortirovanykh throughout the masses ions - carrying information about the structure of molecule and, frequently, so characteristic for the defined organic compound, that it is called "it is fingerprint", i.e., this individual as figure on the fingers of man. All this must it occurred in the vacuum, otherwise electrons too rapidly zaryadyat the molecules, which compose the components of air, and the ions, which were formed from that connection, which interests us, too rapidly again tyuey prevratyatsya into the neutral molecules.

Another method of ionization - this is the ionization in ionomolecular reactions, called the chemical ionization (CHI, THE CI - Chemical Ionization). With this method the source of ions is filled up with any gas (for example, by methane, by isobutane, by ammonia), which ionizuyetsya all by the same electron collision, and the molecule of the interesting us substance, falling into the source they are converted into the ions due to vzamodeystviya with the already located there charged ion- reagents or with the "slow" electrons. This ionization in the gas phase is "soft", i.e., the formed ions are not pulled down to the small fragments, but they rather remain large pieces either only less than initial molecule or even it is larger it due to the connection of other ions. This method gives less than the information about how the structure of molecule is arranged, then with its aid its molecular weight more easily was determined.

Unfortunately, very many organic matter impossibly it evaporated without the decomposition, i.e., it transferred into the gas phase. But this it is meant, that them cannot it ionized with electron collision. But among such substances almost everything which composes the living tissue (proteins, DNA, etc.), physiologically active materials, polymers, i.e., all that which is today of special interest. Mass spectrometry did not stand on the spot and last years was developed the special methods of the ionization of such organic compounds. Today are used, in essence, two of them - ionization into the the elektrospreye (ESI) or its subtype - chemical ionization for the atmospheric pressure, and also ionization by laser desorption with the assistance of matrix (MALDI). In the first case the liquid (interesting us connections with the solvent) escapes under the pressure from the narrow capillary with the enormous speed and directly in this jet from the shells of molecules electrons are torn away, converting them into the ions. In method MALDI laser beam pulls out from the surface of target, to which it is substituted model with the specially selected matrix, ions.

Until now we described the methods, used for the ionization of relatively "myakikh" connections, that compose organic material. "soft" it means that so that it would transfer the molecules of organic matter into the ions they were necessary to relatively low energy. For the ionization of inorganic materials (metals, alloys, the rocks so forth.) the use of other methods is required. Of energies of atomic bond in the solid tele- much more and considerably more rigid methods necessarily used so that it would tear these connections and ions were obtained. Many methods of ionization was tested and today only several of them adapt in the analytical mass-spectral practice.

First method, most common, ionization in the so-called inductively connected plasma. The inductively connected plasma (ISP [SINGLE-OWNER COMPANY], ICP) it is formed inside the burner, in which burns, usually, argon. Argon, generally speaking, non-burning gas; therefore so that it would force it it would burn in it they pump into energy, placing the burner into the induction coil. When atoms and molecules fall into the plasma of argon burner, they immediately are converted into the ions. So that it would introduce the atoms and the molecules of the material into their plasma interesting they usually dissolve in the water and pulverize into the plasma in the form by the smallest it weighed. Another method lies in the fact that would convert substance into the gas. For example, this they will make with the aid of the powerful laser beam, which burns out crater in the piece of material substituted under it, converting its small part to the gaseous state (laser ablation).

Another method - this the so-called thermoionization or surface ionization. The analyzing substance it is applied to the delay from the refractory metal, on which is passed the current, which heats it to the high temperature. The substituted substance it is evaporated and is ionized due to the high temperature. This method usually is used in изотопной масс-спектрометрии.

Other two methods can it adapted for the ionization of the materials conducting current. These are spark ionization and ionization in the glow discharge. Without stopping on the details of these methods, let us say only that in the first due to the difference of potentials between kosochkom of the investigated material and by another electrode breaks through the spark, which pulls out from the surface of target ions, but the secondly it is occurred also the very, but due to the so-called glow discharge, ignited between the piece of the conducting material and the electrode in an atmosphere of inert gas, find under the very low pressure (the same argon in the majority of the cases).

Must it noted for those, who yet not osoznal of this, that beginning from the ionic source and to the detector the mass spectrometer is vacuum device. Sufficiently high vacuum ensures the free motion of ions inside the mass spectrometer, and ions it is simply scattered with its absence and they recombine (tyuey prevratyatsya back into the uncharged particles).

Mass analyzers

Thus, we received ions. Since these are the charged particles, we can with the aid of the electric field it extended them from that region, where they were formed. Now, begins the second stage of the masses of spectrometric analysis - sorting of ions throughout the masses (more precise according to the mass ratio to the charge, or m/z), strictly that which giv name to this method. This it is occurred in that part of the mass spectrometer, which is called "mass analyzer".

All mass analyzers use physical laws of the motion of the charged particles. Historically by the first mass analyzer, which is remained unsurpassed according to its characteristics and today, byl magnet. The trajectory of the charged particles in the magnetic it fell it is bent according to physical laws, and radius of curvature is dependent on the mass of particles. Specifically, this is used for the mass analysis of ions. , so that it would increase разрешение, on the way of ions was installed even the electrostatic analyzer. Magnetic mass spectrometers have high resolution and can it was used with all forms of ionization.

In spite of the significant advantages of the contemporary magnetic mass analyzers over rest (record sensitivity, the uniqueness of identification, large working mass range), they possess two basic "deficiencies" - these instruments large both according to the sizes and on the cost. , where cannot it managed without them, by them there is no alternative (organic analysis with the high resolution, analysis изотопных соотношений, high-precision element analysis), but in the contemporary peace there are thousands of analytical applications of a mass spectrometry, for many of them godyatsya the instruments also of smaller caliber.

Scientists in the long period searched for alternative to magnet as the mass analyzer. First of the success of dobilsya the professor of the Stanford university Robert Finnigan, who built in 1967 the first commercial chromate-mass- spectrometer with the quadrupole analyzer. Quadrupole is four rods, to which in pairs in the opposite polarity is fed the specific combination constant and radio-frequency alternating voltage. The ions, which fly in parallel to the axis of these rods, fall into the hyperbolic it fell and it, depending on the relationship of their mass (as always, m/z) and frequency, they are passed by this I will fall or they are not passed further. The creation of quadrupole mass analyzers sufficed by revolution in the mass spectrometry. Magnetic mass spectrometers require the use of high voltages (thousand of volts), but quadrupole no, and this simplifies its construction, the smaller dimensions of vacuum part simplify the system of the creation of vacuum. Mass spectrometers decreased in the sizes, they became more simply in the operation and, that most important, is considerably cheaper, which opened the possibility used this analytical method to many thousands of users. (look also TRACE MS, Automass)

Further development of quadrupole analyzers led to the creation of the "ion trap". One pair of rods was twisted into the ring, and the second pair became ball-shaped cups. Now the combination of radio-frequency and constant stresses, applied to the electrodes of the ion trap, sufficed it allowed it retained ions inside it or it ejected from it. The first ion traps, released by firm Finnigan in 1983, lost even ionic source. The ionization of molecules sufficed it was carried out directly inside the trap. Subsequently, true, from this they refused, having again carry ouied the place, where are created ions, beyond the limits of the ion trap, which proved to be more winning (illustration). First, external with respect to the mass analyzer, ionic source is guaranteed the absence of the samokhimicheskoy ionization, which leads to the distortion of the mass-spectra of electron collision, and in the second place, will make instrument much more universal - possible it analyzed the negative ions, which are formed with dissociative capture of electrons, classical direct introduction possible was used and so forth mass spectrometers on the base of the ion trap with the internal source of ions at present continue he was let out by firm Varian, which acquired license for this mass-spectrometric detector in Finnigan in 1991.

Use of the ion traps giv pulse to the development of the systems of tandem mass spectrometry or MS/MS. MS/MS - this when mass analyzers erect consecutively after each other. Why this was required? Let us suppose we imeyem the matter concerning the complex organic molecule (for example, biochemists they almost always deal concerning similar) and after breaking it into the fragments, we nevertheless not imeyem are sufficient inofrmatsii about its structure. From the ions divided in the first mass analyzer possible it selected those, which are for us of interest, such as means forced they it was pulled down to the smaller fragments and it again sorted out that which was received, throughout the masses. This will be made in the second mass analyzer. In the case of using the magnetic and quadrupole mass analyzers this means that to us necessarily it erected their after each other into the line. But indeed those, who deal with the analysis of complex molecules, encountered with the fact that both two and three sequential mass analyzers sometimes it is not sufficient so that it would decipher their structure. Here here ion trap proved to be right on target. As we already spoke in the ion trap possible it retained the ions, which are of interest, and rest "rejected" from it. The ions left in the trap possible it subjected to disintegration (by manager of fragmentation), registered they, those, which are of interest, left in the trap, it rejected rest, subjected to fragmentation, registered and so forth in instrument LCQ DECA so possible entered 10 times and thus we imeyem system MSY0, in chromate-mass- spectrometer POLARISQ - 5 times (system MSSHCH). But here mass spectrometer MAT 900 XP- ladder or MAT 95 XP- ladder has a double focusing during the first stage (magnet and electrostatic sector) and a trap on the second and can rabotati' as MSYY. Another mass spectrometer TSQ Quantum is "classical" MS/MS by system - two quadrupole analyzers stand consecutively after each other (between them one more, but this is not mass analyzer, but the "camera of collisions").

In reality, today's progress v протеомике in many respects is obliged to the tandem systems LCQ, and from other side, the enormous need of this rapidly developing branch of science stimulates the rapid developments of new instruments and methods of the analysis of biomolecules. Today in this region by the most advanced and extended method of the analysis of stal 2dlc-esi-ms/ms, i.e., two-dimensional micro-column highly effective liquid chromatography- ionization into the the elektrospreye - tandem mass spectrometry, and by the most extended instrument - LCQ (Advantage or DECA XP).

Let us return, however, to other types of mass analyzers. Is one additional type of mass analyzer, as if combined of those two previously described - magnetic and ion trap. This the so-called mass analyzer of ion-cyclotron resonance with the Fourier transform. In this analyzer the ions fly into the strong magnetic it fell and they are revolved there along the cyclic orbits (as in the cyclotron, the particle accelerator). This mass analyzer possesses the definite advantages: has very high resolution, the range of the measured masses is very wide, can it analyzed the ions, obtained by all methods. However, for its work it requires strong magnetic field, and it is meant, the use of an enormous magnet with superconductive solenoydom, pm! - - systran dnt_.block open - >.dderzhivayemym at a very low temperature (liquid helium, approximately - 2"0oS). An example of this mass spectrometer is NewStar.

Recently ever greater popularity acquired "overflight time" (Time Of Flight, TOF) mass analyzers. We previously said that the ions are sorted throughout the masses due to laws governing the motion of the charged particles in it fell (magnetic or electrostatic). And this it is not entirely related to the overflight time analyzers, since in them, exactly, the ions are moved in bespolevom space. Ions from the source are accelerated with electrical I will fall, acquiring sufficiently high kinetic energy, and they depart into the bespolevoye space. At the entrance into this space all ions have identical kinetic energy, and if it recalled by all known formlulu, which expresses the value of the kinetic energy through the mass and speed (E=.mv2/2), then, obviously, depending on mass ions will be it moved with the different speeds and, sootvestvenno, they will reach the detector, located at the end of their pipe it flew in the different time. After registering them and after measuring time, possible it calculated their mass. All processes, about which we here speak tyuey proiskhodyat for the millionth it add by pouringed second. I.e., this mass analyzer very "rapid". On the basis of this mass analyzer possible built very rapid (and чувствительный) mass spectrometer, which can it proved to be very winning, especially with the analysis of the organic matter, which are the mixture of the enormous number of individual connections (for example, oil). An example of this instrument is GC/TOF MS TEMPUS. However, earlier analysts used another advantage of this method - with this analyzer was much more simply obtained very wide mass range, i.e., with its aid the masses of very large molecules easily were measured. This is important for many studies, concentrated on the enormous molecules (with masses of ten and hundreds of thousands of atomic units). But the most suitable method of ionization is that described above MALDI. (look MALDI TOF DYNAMO).

We described the processes of obtaining of ions, sorting to their masses (mass analysis), now to us it remained them anything to pomeryat'. Measuring a mass of ions (m/z) and their quantity on each mass (intensity), we will receive the mass-spectrum, which can, for example, it looked like this shown on the pictures.

Detector

Thus, the last element of the simplified mass spectrometer described by us, is the detector of the charged particles. The first mass spectrometers used as the detector photographic plate. Now are used the dynode secondary-electron multipliers, in which the ion, falling on the first dynode, knocks out from it electron beam, which in turn, falling on the following dynode, knock out of it an even larger quantity of electrons and so forth the different version - fotoumnozhiteliregistriruyushchiye the glow, which appears with the ion bombardment of phosphor. Furthermore, are used microchannel multipliers, systems of the type of diode matrices and collectors, which gather all ions, which fell into this point of space (Faraday's collectors). The interested reader can it turned to the details of the detection of ions into the specialized literature, we not budem stopped at this in more detail.

What there are the mass spectrometers

Thus, mass spectrometers are used for the analysis of organic compounds and inorganic.

Organic matter in the majority of the cases are multicomponent it compounded individual components. For example, it is shown that it smelled fried hen they compose 400 components (i.e., 400 individual organic compounds). Task analysts lies in the fact that it would determine how many components they compose organic matter, it learned what this of the component (it identified them) and it learned how much each connection it was contained in it compounded. Ideal the combination with the mass spectrometry is хроматографии for this. Gassing chromatography as is cannot better for combination with the ionic source of mass spectrometer with the ionization by electron collision or the chemical ionization, since in the column of the chromatograph of connection already tyuey nakhodyatsya in the gas phase. The instruments, in which mass-spectrometric detector is combined with the gas chromatograph, are called chromate-mass- spectrometers.

Many organic compounds impossibly it divided into the components with the aid of gas chromatography, but it is possible with the aid of the liquid chromatography. For the combination of liquid chromatography with the mass spectrometry today use the sources of ionization into the the elektrospreye (ESI) and chemical ionization with atmospheric pressure (APCI), and the combination of liquid chromatographs with the mass spectrometers is called ZHKH/MS or LC/MS on English. Camye the powerful systems for the organic analysis, claimed of contemporary proteomikoy, stroyatsya on the basis of superconducting coil electromagnet and work according to the principle of ion-cyclotron resonance. They also nosyat name FT/MS, since in them is used the Fourier transform of signal.

Most of all they are used for the analysis of element composition масс-спектрометры с индуктивно-связанной плазмой. With the aid of this instrument they determine of what atoms comprised substance. The same method of analysis can it showed isotopic composition. But best anything was measured isotopic composition with the aid of the specialized isotopic instruments.

However, before passing to instruments for measuring the isotopic composition, briefly let us pause at what are isotopes.

Natural and artificial isotopy

Atoms it is consisted of nucleus and electron shells. The properties of atoms are determined by the fact, how many protons (the positively charged elementnarnykh particles) it is contained nucleus. Nucleus besides the protons it is contained and neutrons. Nature was ordered so that with an equal quantity of protons the nucleus can it contained a different quantity of neutrons. Atoms with an identical quantity of protons in the nucleus, but with a different quantity of neutrons differ in the mass to one or several atomic mass units (amu.) and they are called isotopes. The majorities of elements have the specific collection of stable isotopes. Radioactive isotopes are not stable and are decomposed with the formation of stable isotopes. Natural isotope abundance for each element is known. Some elements in prirorde are mono-isotopic, i.e., 100 % for natural prevalence it is to one isotope (for example, Al, Sc, Y, Rh, Nb, etc.), and others have many stable isotopes (S, Ca, Ge, Ru, Pd, Cd, Sn, Xe, Nd, Sa, etc.). In the technological activity the people learned it changed the isotopic composition of elements for the purpose of obtaining any specific properties of materials (for example, U235 it has a capability for spontaneous chain reaction can it was used as the fuel for the atomic power plants or the A-bomb) or use of isotopic markers (for example, in medicine).

Since the masses of isotopes differ, and mass spectrometry it is measured mass, naturally, this method is become most convenient for determining the isotopic composition. At the same time information by the isotopic composition helps it identified organic compounds it allows it gave answers to many questions nachianaya from the determination it increased species for geology and ending with the determination of the falsification of many products and establishment of the place of the origin of goods and raw material.

Mass spectrometers for the isotopic analysis

Mass spectrometers for determining the isotopic composition must it was very precise. For the analysis of the isotopic composition of light elements (carbon, hydrogen, oxygen sulfur, nitrogen so forth.) ionization by electron collision is used. In this case godyatsya all methods of the introduction of gas phase as in the organic mass spectrometers (DELTAPlus, DELTAPlus XL and MAT2SHCHE).

For the analysis of the isotopes of more heavy elements is used the thermoionization (TRITON TI) or ionization in the inductively connected plasma (NEPTUN, ELEMENT2).

In practice magnetic mass analyzers are used in all types of isotopic mass spectrometers.

Characteristics of mass spectrometers and mass-spectrometric detectors

The most important technical characteristics of mass spectrometers are sensitivity, dynamic range, permission, speed.

Rate of scanning. Mass analyzer, as we showed above, passes ions with the specific relationship of mass and charge in the specific time. So that would analyze all ions it it must it would scan, i.e., the parameters of its field must for the zadanyy time interval it passed all values, necessary for the transmission to the detector of all ions interesting. This skrost' of unwinding field is called rate of scanning and must it was as much as possible (respectively, the time of scanning must it was as less as possible), since the mass spectrometer must it had time it measured signal in short time, for example in the time of the output of chromatographic peak, which can it was 1 second. Magnet is the slowest mass analyzer, the minimum time of its scanning without the special loss of sensitivity comprises it add by pouringed second (MAT 95XP). Quadrupole mass analyzer can it turned spectrum for the tenth it add by pouringed second (TSQ 7000, TRACE DSQ), and the ion trap is still more rapid (POLARIS, LCQADVANTAGE, LCQDECA). But the most rapid mass analyzer is overflight time (TEMPUS). It is capable were written mass-spectra with a velocity of 40,000 per second!

Razresheniye.Naglyadno permission (resolution) possible defined as the possibility of analyzer it divided ions with the adjacent masses or, in other words, was determined the precise mass of ion. For the magnetic mass analyzers, for which peak separation of mass-spectrum it is not dependent on the masses of ions, permission is value equal to M/DM. this value, as a rule, it is determined from 10 % heights of peak. So for example, permission 1000 means that peaks with masses of 100.0 amu. and 100.1 amu are separated from each other, i.e., they are not superimposed up to 10 % heights. For analyzers, whose peak separation changes in the working mass range (the greater the mass, the less the distance), such as quadrupole analyzers, the ion traps, overflight time analyzers, storogo speaking, permission makes another sense the permission, defined as M/DM in this case it kharayeterizuyet specific mass. Makes sense were characterized these mass analyzers in the width of peaks, the value, which is remained constant in entire mass range this width of peaks, usually, it was measured to their 50 % heights. The width of peak on the half-height equal to 1 is not bad index and means that for such instruments this mass analyzer is capable it distinguished the nominal masses, which are differed by one practically in entire its operating range. By nominal mass or mass number is called near to the precise mass of ion integer in the scale of the atomic units of mass. For example, the mass of ion of hydrogen N+ is equal to 1.00787 amu, and its mass number to equal 1. But such mass analyzers, which, in essence, measure the nominal masses, they call the analyzers of poor resolution. We wrote "in essence", because today there are such mass analyzers, which formally otnosyatsya to those being low-resolving, but in reality such no longer appear high technology, first of all quite progressive-minded developer Thermo Finnigan, it already today proposed for the market for analytical equipment the high-resolution quadrupole instruments. So for example, newest TSQQuantum easily works with the width of the peak of mass-spectrum on the half-height 0.1 amu. The knowing people can it objected: "but this width of peak possible was obtained on each quadrupole mass spectrometer!" And they will be right really each quadrupole possible built thus far it evened permissions. But which proizoydet in this case with the signal? Upon transfer from the width of peak on the half-height in 1 amu. to 0.1 amu the value of signal on all quadrupoles upadet practically to two orders in the value. But not on TSQQuantum, on it it is decreased in all to two and one-half of times. The ion traps in the narrow mass range can it worked as the mass spectrometers of high resolution, ensuring, as a minimum, the separation of the peaks, which be distant on 1/4 amu behind each other. Double-focusing mass spectrometers (magnetic and electrostatic), ion-cyclotron resonance - instruments of average or high resolution. Permissions into several thousand also possible attained with the use of overflight time mass analyzers.

Permission is tightly connected with another important characteristic - the accuracy of the measurement of mass. Illustrated the value of this characteristic possible on I will stand an example. The masses of the molecular ions of nitrogen and mono-oxide of carbon () are 28.00615 amu. and 27.99491 amu, respectively (both they are characterized by one mass number 28). These ions will be it was recorded by mass spectrometer separately with permission 2500, and the precise value of mass will give answer - which of the gases is recorded. The measurement of precise mass is accessible on the instruments with the double focusing and on the tandem quadrupole mass spectrometer TSQQuantum.

Dynamic range. If we analyze the mixture, which contains 99.99 % of one connection or any element and 0.01% any mixed, we must it was assured that we correctly determine both that and, etc. , so that it would be confident in the determination of components in this example, necessarily had the range of linearity into 4 orders. Contemporary mass spectrometers for the organic analysis are characterized by dynamic range into 5-6 orders, and mass spectrometers for the element analysis of 9-10 orders. Dynamic range into 10 orders means that the admixture in was opened it wakes visible even when it is 10 milligrams to 10 tons.

Sensitivity. This is one of the most important characteristics of mass spectrometers. Sensitivity this the value, which shows what quantity of substance necessarily it introduced into the mass spectrometer so that it possible it would be it would detect. For simplicity budem were examined the parameter connected with the sensitivity - the minimum determining quantity of substance, or the detection threshold. The typical value of the threshold of detection of a good chromate-mass- spectrometer, used for the analysis of organic compounds, is 1 picogram with the introduction of 1 microliters of liquid. Give let us present to itself that this similar. If we collect by special shpritsom 1 microliter of liquid (one millionth fraction of liter) and I will let out it to the leaf of clean white paper, then with its examination into the magnifier we will see speck, equal according to the sizes it followed from the prick by thin needle. Now let us visualize that we threw 1 gram of substance (for example, one tablet of aspirin) into 1000 tons of water (for example, into this nemalen'kiy pond with a length of 50 meters, with a width of 10 meters and with a depth of 2 meters). Thoroughly peremeshayem water in the pond, let us collect by shpritsom 1 microliter of this water and zakolem into the chromate-mass- spectrometer. As a result of analysis we will receive the mass-spectrum, which we smozhem compared with the library spectrum and the method it was fingerprint it was convinced of the fact that this is the actually acetylsalicylic acid, otherwise called aspirin.

The limit of the detection of inorganic substances, for example, by the method ICP/MS (ELEMENT2) is still below. Here pond already wakes malovat for the preparation of solution with the concentration, which corresponds to the limit of detection. The limit of detection for ELEMENT2 on the row of metals is 1 ppq (one portion to the quadrillion). This it is meant, that the sensitivity of instrument it is sufficient so that would detect 1 kilogram of metal (for example, it would mercurate, lead so forth.) dissolved in dissolved in lake Baykal for its mixing and complete dissolution)!

In the mass spectrometry of isotopes, for example, sufficient 1000 molecules of the dioxide of carbon (SO2, carbon dioxide) so that would be obtained the signal of carbon. So that it would demonstrate, with what accuracy and isotopic sensitivities isotopic mass spectrometry deals, let us resort to the following allegory. I will assume to one thousand completely identical apples, each of which are weighed 100 grams, are come 11 apples, which weigh to 8 % more, i.e., 108 grams. All these apples are assembled in one bag. This example sootvestvuyet to the relationship of the isotopes of carbon in nature - to 1000 atoms of y2S are fallen 11 atoms of yeS. Isotopic mass spectrometry it is measured relationship, i.e., it is capable it distinguished not simply these 11 apples, but it found among many bags those, in which of 1000 stogrammovykh apples not 11 by stovos'mi of gram, but 10 or 12. This example is very light for the isotopic mass spectrometry, in reality such instruments as DELTAPlus, DELTA Plus XL and MAT2SHCHE are capable was determined the difference into one isotope (one stovos'migrammovoye apple) among ten million atoms (ten million apples).

The most important characteristic with the analysis of organic compounds - this is sensitivity. In order to dostignut' largest possible sensitivity with an improvement in the signal-to-noise ratio they come running to the detection on the separate selected ions. Gain in the sensitivity and the selectivity in this case colossal, but with the use of instruments of poor resolution is come it brought in it sacrificed another important parameter - authenticity. Indeed if you recorded only one peak of entire characteristic mass-spectrum, by you was still much it worked, so that it would prove that this peak sootvestvuyet precisely to that component, which interests you. But how it did solve this problem? High resolution on the instruments with the double focusing, where possible it attained high it evened authenticities without sacrificing sensitivity, was used. Or was used the tandem mass spectrometry, when each peak, which corresponds to single ion possible confirmed by the mass-spectrum of daughterly ions. Thus, the organic chromate-mass- spectrometer of high resolution with the double focusing is absolute record holder on the sensitivity. Thus, for instance, the certified characteristic MAT 95 xp it is said, that 2,3,7,8-тетрахлоро-п-дибензодиоксин, introduced through the chromatographic column in a quantity of 10 femtograms will give the peak, which is characterized by signal-to-noise ratio = 40: 1. not dostizhimyy not on what other instrument result! According to the characteristic of the combination of sensitivity with the authenticity of the determination of components after the instruments of high resolution go the ion traps. The classical quadrupole instruments of new generation (TRACE DSQ) have the improved characteristics because of a number of the innovations, used in them, for example, to the use of the bent quadrupole preliminary filter, which prevents contact of neutral particles with detector and, therefore, to reduction in noise.

Why the mass spectrometry is necessary

Deep physical laws, foremost scientific and engineering developments, highly technological vacuum systems, high voltages, the best materials, the high quality of their of treatment, sovremenneyshaya moving rapidly numbering and analog electronics and computer technology, inventive software - here from what is complex contemporary mass spectrometer. And for which all this? For the answer to one of the most important questions of universe - from what is folded the material. But this is a question not of high science, but everyday life of man.

For example, the development of new medicines for the rescuing of man from earlier than incurable diseases and the control of the production of medicines, genetic engineering and biochemistry протеомика. Without the mass spectrometry are unthinkable the control over the illegal propagation of narcotic and psychotropic means, the criminological and clinical analysis of toxic preparations, the analysis of explosives.

The explanation of the source of origin is very important for solving the whole series of the questions: for example, the determination of the origin of explosives helps it found terrorists, narcotics - it fought with their propagation and the ways of their traffic overlapped. Economic national safety is more reliable, if customs services can not only it confirmed by analyses in the doubtful cases the country of the origin of goods, but also its sootvestviye to the declared form and to quality. But анализ нефтей и нефтепродуктов it is necessary not only for the optimization of the processes of petroleum refining or to geologists for looked new petroleum fall, but also so that it would determine guilty of the floods petroleum spots in the ocean or on the earth.

In the epoch the "chemicalization of agriculture" by the very important of stal a question about the presence of trace quantities of used chemical means (for example, pesticides) in the foodstuffs. In scanty quantities these substances can it did irreparable damage to human health.

A whole series of technogenic (i.e., not existing in nature, but appeared as a result of industrial human activity) substances they are supers-toxicant (having the toxic, cancerogenic or harmful for human health action in the lowest possible concentrations). An example is well known диоксин.

Existence of nuclear power engineering is unthinkable without the mass spectrometry. With its aid it is determined the degree of the enrichment of the split materials and their cleanliness.

Certainly and medicine it is not managed without mass spectrometry. The isotopic mass spectrometry of carbon atoms it is used for straight medical diagnostics of the infection of man Helicobacter Pylori and is most reliable of all methods of diagnostics.

With difficulty represented the region of the human activity, where the places for mass spectrometry would not be located. Let us be limited simply by the enumeration: biokhimiyaklinicheskaya chemistry, general chemistry and organic chemistry is pharmaceutics, cosmetic perfumery, food industry chemical synthesis, petroleum chemistry and nefteperarabotka environmental monitoring, the production of polymers and plastics medicine and toxicology, criminology dopingovyy control, the inspection of narcotic drugs the control of alcoholic beverages, geochemistry, geology, hydrology petrography, mineralogy geochrony, archaeology, the nuclear industry and power engineering semiconductor industry, metallurgy.

Applications of a mass spectrometry of system V3JX-mass- spectrometer, the Chromate-mass- spectrometers of column for VEZHKH, mass spectrometers for the element and isotopic analysis, liquid chromatography mass spectrometers for the isotopic analysis

--Jvraba 18:14, 21 Jul 2004 (UTC)

Russian mass spectrometrists

Russians really clean English speakers' clock when it comes to mass spectrometry.

Easy to understand version

I thought this would make no sense to a non-chemist, and chemists probably already know how it works, so I added a fairly easy to understand explanation. I think it's worth keeping and expanding.

Page reorganization

This would really benefit from a re-organization. Look at the Wikipedia entry for Quantum Mechanics for an idea of what a good page looks like.

Page is now more organized. Please give input on how to organize even better.

GC-MS vs. GC/MS

Although it may look a bit nitpicking I'ld like to suggest to use the character "/" instead of "-" for the designation of coupled techniques like GC and MS, LC and UV, CE and MS etc. The hyphen is used for a more detailed description, e.g. electrospray-mass spectrometry (ESI-MS), chemical ionization-mass spectromery (CI-MS) or time-of-flight-mass spectrometry (TOF-MS). The slash indicates different analytical techniques, like GC/MS/MS or LC/APCI-MS. This might clarify the used abbreviation and it is common practice among analytical chemists.

As a technical writer, I concur with the author's dash vs. slash comment (above). See the Wikipedia Manual of Style. -mdf

As a mass spectrometrist I use GC-MS for hyphenated technique (more separation) and GC/MS when dissociation is used to get structural information. This implies: (1) it is always MS/MS. (2)in general it is GC/MS with EI source and GC-MS with soft ionization. In any case TOF-MS should be changed to TOFMS or just TOF. I think these are the official IUPAC rules. Kehrli 18:00, 1 April 2006 (UTC)

Definition

I really think the definition is kind of confusing and somewhat misleading. It also leaves out quantitative aspects of mass spectrometry. It could both be simpler and more accurate and more complete. What do you think??

Definition updated. Any input or criticism?

Interpretation

I read the article posted here for Mass spectrometry and use a ESI mass spec, but I am not familiar with the term 'Wilkinson ion'. Could some one please explain what a Wilkinson ion is?

Orbitrap

It was nice to see the addition of the Orbitrap. Could someone expand on this in an Orbitrap article.

Merge with Mass Spectrum????

I disagree. I think the mass spectrum page discusses some important details of a mass spectra that should not be discussed in detail on a subject page such as this (Mass Spectrometry). Mass Spectrometry is a large field and must be addressed in subsections to be most clear and relevant. I would maybe suggest a data types section here breifly touching on and pointing to a larger articles regarding things such as "mass Spectrum", "single ion chromatogram", "mass chromatogram", "Total ion chromatogram", "precursor ion scan", "Contour map", etc. It is not clear to many scientists even that mass spectrometry can produce data other than a mass spectrum.

Don't merge. Mass spectrometry is already too long. There are details in mass spectrum that require a separate page. If anything, mass spectrometer should be exported from mass spectrometry. Kehrli 18:12, 1 April 2006 (UTC)

As someone who works in the industry, I agree with above... The term Mass Spectra or Spectrum should have its own place in the Wiki. The spectra is a result of the technique and as such should be cross referenced. I also agree that Mass Spectrometer should be divided and have we looked to subdivide based on ionization or mass analyzer type? (Ken Weir, Malrboro MA, USA)

Molecules vs. Atoms

The English version of this entry states, "Different molecules have different masses, and this fact is used in a mass spectrometer to determine what molecules are present in a sample." Is mass spectrometry concerned more with atomic masses than molecular masses? I would expect the sentence to read,

"Different atoms have different masses. Atomic mass is what the mass spectrometer measures to determine the atoms present in a sample."

By far most modern mass spectrometry is concerned with molecular compounds rather than atoms. Mass spectrometry of whole proteins (which contain thousands of atoms to form giant molecular compounds) is not uncommon today. The nobel prize in chemistry was given for the technologies that enabled large biomolecule mass spectrometry (read electrospray and MALDI for more info). The earliest forms of mass spectrometry and the ones most often taught at the fundamental level were strictly atomic, however this is the exception and not the rule today. Mass spectrometry is also performed on non-covalent complexes (several compounds that are associated but not attached by a covalent chemical bond) which are clearly not atoms and can be a stretch to call them molecules. Even more problematic are some cases of mass spectrometry of whole living organisms such as virii. For simplicity's sake I think molecule is a general enough term that is simple and clear without being entirely inaccurate. Also note that this is in the "layman's" explanation and is an example. In the definition the term ion is used which is more general, inclusive and correct but is less easily understood especially since it does not include how you get said ions in the first place.

Sort of unrelated but incorrect is that sodium chloride is used as the example molecule where sodium chloride is not a moleclue but an ionic compound and is less molecular than an atom in my mind. I have therefore changed it from molecule to chemical to be both correct, simple and even more inclusive. An atom is clearly a chemical. I have also changed molecular weight to atomic weight since the example used involves sodium and chloride ions which are atomic ions.

Could the m/q vandal please stop

Look if you want to push m/q do it on the mass-to-charge ratio discussion page. I know you probably have an agenda to correct the entire world but please don't try to redefine convention on wikipedia! In the field of mass spectrometry m/z is used except when dealing with physics where m/q is not uncommon but does not refer to the same thing! m/q is the mass to charge ratio in the true sense not in the MS sense. Yes I know there are some efforts to correct all this but reflect it as an effort and not as convention. Push your agenda in a peer reviewed journal and with IUPAC please but not here.--134.9.228.11 23:51, 7 April 2006 (UTC)

Mass Spectrometry / Mass Spectrum / Mass-to-charge Ratio Page Merge Discussion

See Talk:Mass-to-charge_ratio#Recommend_Merging_this_Entry_with_.22Mass_Spectrum.22 for argument in favor of merging mass-to-charge ratio with mass spectrum and against merging mass spectrum with mass spectrometry.

--Kmurray 02:58, 24 April 2006 (UTC)

---

Formatting

I'm not so sure that the reformating of the mass analyzer section was a good idea since the novice reader may not recognize that there are three sections to instrumentation with the mass analyzer section having several subsections. I agree with instrumentation being one super section but there is no sub-sub-section format. Previously we used italics for each mass analyzer subsubsection. Just some thoughts. --Nick Y. 19:31, 8 May 2006 (UTC)

Re: Formatting

I was trying to emulate the cricket page, which was an example in the style manual of dealing with large pages (the "for more details.." template is useful). I agree that the instrumentation subsections (source, analyzer, detector) should be parallel. The source/ionization methods and detectors could be split out in the main page or split into subpages and analyzer parts folded into a short paragraph with more detail in subpage. Many sections are getting big enough to split out into stand-alone articles. It's a good time to think about organization.

--Kmurray 20:45, 8 May 2006 (UTC)

Merge with Mass Spectrum????

I have removed the merge tag as this acticle is really very long. However, I have added modified the Application part and add a link to Mass Spectrum, which will let the readers don't miss anything, anyways. Shrimp wong 03:06, 21 May 2006 (UTC)

Nobel Prize Issue

I have removed the section below, because:

1. it is not quite neutral WP:NPOV
2. it is original research WP:OR
3. it is too irrelevant to take up half of the history section
4. it is already discussed in the matrix-assisted laser desorption/ionization article

" The choice of Tanaka to receive the Nobel Prize for this work over Hillenkamp and Karas is a contentious issue to some people in the field. The two methodologies are remarkably similar yet significantly different. The work of Hillenkamp and Karas is fundamentally the same as the current implementation of matrix-assisted laser desorption/ionization which is now ubiquitous in mass spectrometry. Hillenkamp and Karas also demonstrated exceptionally well the importance of this new technique. The work of Tanaka is similar and even his protein spectrum was published earlier in a poster in Japan, the work of Hillenkamp and Karas specifically was the development of MALDI itself. They worked with aminoacids first and later with proteins publishing several sicentific papers during the MALDI development and a paper showing a protein spectrum the same year of Tanaka. The work of Tanaka on SLD may have never come to prominence or become particularly useful without further improvement. That is why there is controversy about the Nobel 2002 in chemistry. In addition, the German researchers have kept working in the study of the MALDI-ionization process as well in the improvement of the technique. The choice of John Fenn to receive the Nobel Prize is not controversial, however electrospray processes had been studied for most of the twentieth century and the concept of ESI-MS was proposed nearly twenty years earlier by Malcolm Dole. "

#1 fine. #2 is bogus dogma too often used to quash valuable content. #3 I disagree, what's more relevant than the conception of the method? #4 fair enough. --Belg4mit 02:46, 19 October 2006 (UTC)

Nomenclature

I just added the synonym mass spectroscopy, but would like to see something about the different names. I'd never heard the term "mass spectrometry" until today. I imagine spectrometry is used as it's more accurate to say one is measuring the spectrum than looking at it. --Belg4mit 02:37, 19 October 2006 (UTC)

Thanks for your input. It is an ommision that was a real oversight. I think the term needs to be included as a synonym; however, it is generally considered incorrect and is provisionally deprecated by IUPAC. You are essentially right in your reasoning as to why this is so. Spectroscopy by all definitions I have ever seen specifically refers to the interaction of matter with energy. At one point it was light, then electromagnetic radiation, then electrons and phonons etc. Now it is generally energy, energy into or out of a molecular or atomic system. Mass spectrometry does not fundamentally study such processes. It is a measuring technique not unlike a balance. It measures the change in inertia given a force. --Nick Y. 18:58, 19 October 2006 (UTC)

I think the "(incorrect)" designation is itself incorrect. Deprecated is the proper term, fixed accordingly. --Belg4mit 23:38, 1 November 2006 (UTC)

The reference provided deprecates the term because it is fundamentally incorrect. Mass-spec is fundamentally not a form of spectroscopy. Every definition of spectroscopy I have ever seen which is reasonably well accepted specifically excludes mass spectrometry. "Mass Spectrometry Desk Reference (Paperback)by David O. Sparkman" is a less authoritative source that is more emphatic (not avaiable on line). A review of the book here does indicate that the use of the term mass spectroscopy is incorrect. In the book he explains why. The IUPAC document uses this text as a source. The term, however, has a long history of misuse. There is a general concensus that the term is incorrect in the mass spectrometry community. There is continued use of this term primarily is papers where the mass spectrometry is incidental or tangential to the work such as in biology or medical journals. We should recognize its use but it is fundamentally incorrect and officially deprecated by IUPAC for that reason.--Nick Y. 02:01, 2 November 2006 (UTC)

Sensitivity

Great article! Very useful.

One thing that seems missing is discussion of how sensitive these things are and what sample size they need.

I was speculating about the recent Alexander Litvinenko poisoning with Polonium-210 and presuming that one could use a Mass Spectrometer to date the age of the Polonium-210 as it decays to Lead-206 with a half-life of only 138 days. One might thereby deduce on which day the Polonium had been created (it's a synthetic isotope). However the question of how big a sample one might need - and how sensitive the results might be came up and I was unable to find an answer.

SteveBaker 14:01, 6 December 2006 (UTC)

The issue of sensitivity is complicated by all of the different types of samples and molecules and types of mass spectrometry. It is difficult to make broad limit of detection statements because of this. In other words this is definately an expert topic with details that are very specific to any given situation. Your example would contain a complex matrix (blood/tissue) that might completely destroy any hope of a successful analysis for some approaches. However, because you are interested in an element and not a molecules it might be possible to use an inductively coupled plasma source to break all chemical bonds while ionizing resulting in a simple mixture of C,N,O,H,S,P,Fe,Cu etc. and Po ions. There are mass spectrometers that can essentially count individual atomic ions but are not versatile and can cost millions to repurpose to do an outstanding job for this purpose. The question then becomes what the background is like. Since there is background Po out there a single Po ion doesn't mean anything. In all likelyhood they are using somthing less fancy than I am talking about. The issue of isotope ratios is definately being analyzed by MS. They are certainly getting some of the information you are assuming they are however you need to take into account the initial purity etc. How much lead was created by other processes?? The accuracy of the ratio data may also be an issue depending on the MS being used. The short answer to your question is yes it can be done. We have the technology. Most likely they are using slightly less than optimal approaches that get the job done. A few million dollars and a couple years and they could do an even better job.--Nick Y. 20:40, 6 December 2006 (UTC)

Many thanks! That's most illuminating. SteveBaker 23:47, 6 December 2006 (UTC)

SIMS

Regarding the removal of SIMS for the ionization source section: Secondary ionization mass spectrometry consists of two parts that are generally collectively referred to as SIMS. Secondary ionization is always a part of SIMS and does not stand alone. Secondary ionization is a means of ionization and is not related to fragmentation of tandem mass spectrometry and is not "an analysis method to detect fragments of parent compounds". The secondary part come from that the sample is bombarded with heavy ions such as Cs⁺ which then results in ionization of the sample. This is the first ionization process that the sample sees. Chemical ionization also uses ions to ionize the sample but in a totally different way. They are both means of ionizing samples.--Nick Y. 19:57, 12 February 2007 (UTC)

Bainbridge mass spectrometer

Bainbridge mass spectrometer is an orphan article and I'm wondering if it fits into this article. Squids'and'Chips 01:35, 3 March 2007 (UTC)

Actually this article would be most appropriately placed in Sector instrument and particularly in the history section. Kenneth Tompkins Bainbridge was an early mass spectrometry innovator in the 1920's and 30's. His collaborator, Alfred Nier probably contributed more to the development of mass spectrometers over time, carrying on the work for many years later into the 1940's. I can not confirm the exact configuration of the instrument described but it sounds reasonable. I am certain that the instrument was a sector type instrument. Most probably it was a single magnetic sector and probably 180 degree ion path. I am not particularly aware of the term "Bainbridge mass spectrometer" however I have more frequently seen "Bainbridge type mass spectrometer" in historical literature which I take not to be a specific name but a reference to Bainbridge's work and to note the similarity. I also think that if this was a common name at one point it has clearly faded into being lumped in with other sector instruments. A merge and redirect of the current article would be appropriate. As I said above I have not taken the time to verify the contents of teh article but I am answering your question. It goes with Sector instrument.--Nick Y. 22:31, 5 March 2007 (UTC)

I made this move. Also, should Sector instrument be Sector mass spectromer (I think that the latter is more clear). Also, article needs refs. --Kkmurray 22:43, 14 June 2007 (UTC)

References

I think the article is excellent! I think it might even be good enough for FA class as-is. However, there is only one reference for such a lengthy article. I've tried to find references but have not been really successful. Perhaps those who are in a better position can do so? --Rifleman 82 15:53, 5 April 2007 (UTC)

Thanks for the complement (to everyone who contributed). I will try to add some references in the next few days. In line references will be a little hard but maybe I can get some books or specific chapters on specific topics within mass spectrometry to cover whole paragraphs or sections in a semi-inline fashion. I do think there needs to be some clean up before FA nomination but we have covered most of the field pretty thoroughly.--Nick Y. 17:40, 5 April 2007 (UTC)

If you give online references, I can try and turn them inline. I'm a bit worried about the size of the article. Getting somewhat unwieldy. Anyway to summarize and spin off non-core concepts into side articles? --Rifleman 82 17:46, 5 April 2007 (UTC)

There is already many side articles about most of the instrumentation parts. Perhaps there is some that could be pulled from applications. We can work on that. I'm a bit busy today to really do too much, but a good point.--Nick Y. 20:31, 5 April 2007 (UTC)

I have added ~20 references. Maybe some input as to where they are most needed would help.--Nick Y. 21:45, 11 April 2007 (UTC)

I can't get this reference to format correctly due to characters in the doi

1. ^ R. d. L. John (1998). "Mass spectrometry and geochronology". Mass Spectrometry Reviews 17 (2): 97-125. DOI: 10.1002/(SICI)1098-2787(1998)17:2<97::AID-MAS2>3.0.CO;2-J.

--Nick Y. 20:44, 16 April 2007 (UTC)

Damn Wiley. They're the ones with all the problems. I've fixed that one. See the section on "doilabel" in {{cite journal}}, and see {{doi}}. I'll finish the rest tomorrow. Hope this helps. --Rifleman 82 20:55, 16 April 2007 (UTC)

Mass spectrometer types section

This section has some issues. The first four entries are simply types of ion sources and are already covered in the ion sources section. The others are a mishmash of what is not covered elsewhere. GC/MS, LC/MS, IMS/MS and MS/MS used to be in a hyphenated techniques section which seemed appropriate, although not really that meaningful. Accelerator mass spectrometry is really a form of sector instrument although it is different enough and unique enough that we need to cover it somehow. I don't really consider LC/MS to be a type of mass spectrometry. It is just a mass spectrometer with an LC on the front. Still very important. I would groups LC/MS and GC/MS together under chromatography combined with MS. IMS/MS might fit in there too since if you call it other separation techniques combined with MS. AMS might fit under applications? But I really don't know what we should do with it. Tandem mass spectrometry is probably deserving of its own section. On the sources perhaps we need an expanded sources section rather than just a list but it could grow really fast. Or for that matter if we star trying to cover every possible combination of source, analyzer, detector, combined with every sort of up front separation technique. What do you think?--Nick Y. 19:09, 12 June 2007 (UTC)

I was bold and reorganized along the lines of above. Please discuss. Maybe there is a better solution. I am uncertain about keeping the Specific mass spectrometers section due to consistency/possibility of uncontrolled growth.--Nick Y. 19:16, 12 June 2007 (UTC)

I am all for getting rid of the Specific mass spectrometer types section. It's really just some additional applications. The applications section could also use some reorganization. For example 8.4 through 8.9 are biological MS and 8.5 through 8.9 are specifically peptides and proteins. Combining could cut the sub-areas to a half-dozen or so (atomic, bio, imaging, space, environmental). --Kkmurray 15:47, 14 June 2007 (UTC)

I like your ideas regarding the applications section but the way the formatting works on wikipedia does not allow for very clear sub-sub-sections. I think the protein sections need to be lumped together somehow though due to much overlap.--Nick Y. 17:15, 14 June 2007 (UTC)

Yes. Lump and cut. Move non-redundant stuff to appropriate sub-pages (where they exist). This opens a lot of worm cans, but it needs to be done --Kkmurray 22:14, 14 June 2007 (UTC)

Multiple Reaction Monitoring (MRM)

Could someone please describe multiple reaction monitoring and include it on the MS page, or otherwise? All I know is that it is a widely used technique especially in pharmacokinetics, and involves targeting the mass of a small molecule and verifying its presence by the presence of predicted m/z daughter ions. Thanks! 128.187.0.164 16:55, 6 July 2007 (UTC)

Yes it is almost the same as SRM but with several daughter ions being used.--Nick Y. 18:31, 6 July 2007 (UTC)

what to call the new protein MS page

I think we all want to cut and lump the protein applications into a new sub page. But what do we call this page. We can call it protein mass spectrometry which seems to be consistent with some similar types of pages. We could also call it mass spectrometry of proteins which is consistent with other naming conventions. There is a proteomics page but is not the right place for everything here. --Nick Y. 18:29, 6 July 2007 (UTC)

Definitely protein mass spectrometry. That parallels Isotope ratio mass spectrometry,secondary ion mass spectrometry, etc. --Kkmurray 12:56, 8 September 2007 (UTC)

Done.--Nick Y. 18:33, 13 September 2007 (UTC)

Maximum entropy spectral analysis

This article has been requested. Could someone knowledgeable in the field write up a stub? Thanks--Cronholm¹⁴⁴ 10:50, 10 July 2007 (UTC)

Stub started. MOst of the meat is and should remain in principle of maximum entropy.--Nick Y. 18:01, 10 September 2007 (UTC)

why we are doing MS/MS

WHAT IS THE REASON THAT WE ARE DOING MS/MS —Preceding unsigned comment added by 203.187.199.78 (talk) 08:02, 23 September 2007 (UTC)

MS/MS is here: Tandem mass spectrometry. See the references and bibliography for more info. Also see WP:TALK for talk page guidelines. --Kkmurray 23:53, 23 September 2007 (UTC)

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