What is Mass spectrometer: Definition and 62 Discussions

Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are typically presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
A mass spectrum is a plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds.
In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionized, for example by bombarding it with a beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragments) are then separated according to their mass-to-charge ratio, for example by accelerating them and subjecting them to an electric or magnetic field: ions of the same mass-to-charge ratio will undergo the same amount of deflection. The ions are detected by a mechanism capable of detecting charged particles, such as an electron multiplier. Results are displayed as spectra of the signal intensity of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses (e.g. an entire molecule) to the identified masses or through a characteristic fragmentation pattern.

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  1. T

    What I do not understand about mass spectrometers

    I try to do my assignment which is based on mass spectrometer entirely. The mass spectrometer i am working on has these parts below: 1.Accelerator region 2.Velocity selector region 3.Spectrometer The elements i am working on are isotopes of the same element and they all enter the accelerator...
  2. R

    Mass spectrometer with a Lead element

    Summary:: How to load the plates with the Lead element in the spectrometer I have a mass spectrometer with lead element which has an electronic configuration 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^6 4d^10 5s^2 5p^6 4f^14 5d^10 6s^2 6p^2. It has 2 free electron, so the ejected electrons go...
  3. K

    Charges of ions in a mass spectrometer

    Homework Statement In a mass spectrometer, a few 126C ions are deflected with a radius of 12.9 cm. The ions have a speed of 5.67*10^4 m/s when they enter the field. The magnetic field has a strength of 3.2*10^-2 T. The charge of these ions must be ... SOLUTION: We use the formula: i F=qvB =...
  4. Michael Koch

    Wanted: Instructions for Leybold PGA 100 mass spectrometer

    I have a Leybold PGA 100 mass spectrometer, including the instruction manual. The instrument is paired with a gauge head. If either the instrument or the gauge head is exchanged, then an alignment is required. It's mentioned in the instruction manual there exists a supplement, which contains the...
  5. A

    I Scaling up a mass spectrometer

    The essential question is can this tech be scaled up in the vacuum of space to add a substantial tangential acceleration to the orbital velocity vector of a piece of debris such as a speck of paint 1cm^2 in cross section. I am looking to deflect that speck of paint into a container or out of...
  6. M

    Charged Particle in Magnetic field calculation

    Homework Statement Basically having a problem when trying to theoretically calculate the mass of alpha particle in a charged field. r is the unknown radius of curvature m = mass of an alpha particle (6.646 *10^-27 kg) v = velocity of an alpha particle immediatly after decay (1.381 *10^7 m/s)...
  7. moenste

    Speed, force, magnetic flux of an ion?

    Homework Statement The diagram shows a mass spectrometer used for measuring the masses of isotopes. It consists of an ion generator and accelerator, a velocity selector and an ion separator, all in a vacuum. In one experiment, tin ions, each of which carries a charge of +1.6 * 10-19 C, are...
  8. R

    Mass spectrometer problem -- Need help

    Homework Statement A mass spectrometer is constructed using a velocity selector constructed using a parallel plate capacacitor in a uniform magnetic field Bin. The electric field in the selector is 1003.9 V/m and the magnetic field in that portion of the spectrometer is Bin = 0.998 T. The...
  9. Oribe Yasuna

    Circular Motion in a Simple Mass Spectrometer

    Homework Statement In the simple mass spectrometer shown in the figure below, positive ions are generated in the ion source. They are released, traveling at very low speed, into the region between two accelerating plates between which there is a potential difference ΔV. In the shaded region...
  10. Elvis 123456789

    Distance between Isotopes in a mass spec

    Homework Statement Suppose the electric field between the plates P and P' in the mass spectrometer in following figure is 1.89×104V/m and the magnetic field in both regions is 0.668 T. If the source contains the three isotopes of krypton, 82Kr,84Kr, and 86Kr, and the ions are singly charged...
  11. A

    Mass Spectrometer - Find Radial Separation of 58Ni+ & 60Ni+

    Homework Statement In a mass spectrometer, singly charged 58Ni+ (mass, m= 9.26 × 10-26 kg), and 60Ni+ (mass, m= 9.58 × 10-26 kg) ions pass through a velocity selector (with crossed electric and magnetic fields, E = 2 × 105 N/C and B=3000 G) and then enter a chamber of uniform magnetic field B...
  12. K

    I with an old VGA Smart-IQ+ Mass spectrometer

    I work at a university and we recently had an XPS donated with a mass spec attachment. It is an older instrument that we would love to get working due to the high resolution detector and in situ reduction chamber. We are having issues getting the mass spec to communicate with the gassworks...
  13. carlphysics30

    TOF (mass spectrometer) Analyzer Question

    Homework Statement An unknown hydrocarbon ion required 9.415*10^-6 seconds to travel through the 0.250 T magnetic field of a mass spectrometer with a radius of curvature of 14.1 cm. Since the magnetic chamber is shaped like a 'D' it only travels half way around the circle. a. find the speed...
  14. C

    Mass-to-Charge Ratio of an Ion in Mass Spectrometer

    Homework Statement Consider fields of 1.4e5 N/C and 2.7 T within a velocity selector. If the charge then exits and encounters a field of 1.4 T and radius of 2.4 mm within the mass spectrometer, what would be the mass to charge ratio of this ion? Homework Equations v = E/B m = qrB/V[/B] q =...
  15. E

    How Do Ions Achieve Their Velocity in a Mass Spectrometer?

    Homework Statement The whole problem statement is a bit involved, but it starts with a figure illustrating a mass spectrometer. You have the chamber the gas you want to study is pumped into, and an anode and cathode. An electron beam ionizes the gas, and the ions are accelerated towards the...
  16. mesa

    In a mass spectrometer what mediates the acceleration?

    R=mv/qB describes the radius of a charged particle moving through a static Bf with the acceleration directed radially inward. The cross product is used to calculate the Force that results in this acceleration. Why does the cross product work?
  17. M

    Finding the speed of a proton in a mass spectrometer

    Homework Statement A mass spectrometer uses either a magnetic field or an electric field to deflect charged particles. A proton starts from rest a plate P. The Speed of the proton as it passes through the hole in plate Q is? V= 10000 V Mass of a proton = 1.67x10^-27 Charge of a proton...
  18. L

    Archived Time estimation - mass spectrometer

    Hi everyone Homework Statement I want to separate isotopes of uranium with some kind of a mass spectrometer. The isotopes are Mass numbers 95 Atom numbers 235 and 238 Question: How long does it take to extract 1kg of the 235 isotope if I have a ray of charged ions (charge = e) when the...
  19. P

    With what speed does the ion enter the magnetic field in a mass spectrometer?

    Homework Statement A mass spectrometer has a potential difference of 120 V applied to its accelerator plates. It is accelerating a positively charged ion that has a mass of 2.32 x 10^-26 kg. the ion then is directed into a uniform magnetic field of 0.17 T. The magnetic field is perpendicular...
  20. J

    Quadrupole TOF mass spectrometer axial frequency question

    Hi I have been searching the relevant literature but I cannot find if an ion traveling through a quadruple TOF MS will obtain an axial motion and frequency as a result? and will this axial motion induce a corresponding frequency on the HV rods that could be measured with the right filter...
  21. J

    Mass spectrometer - no deflection

    Homework Statement In one type of mass spectrometer the ions are passed through a velocity selector. This is a pair of parallel plates 2.5 cm apart. A pd of 140 V is applied to create an electric field. A magnetic field is also applied so as to give a force in the direction opposite to the...
  22. A

    Mass Spectrometer Formula question

    Homework Statement In the velocity selector region of a mass spectrometer, an electric field of 2.34 × 10^3 N/C is perpendicular to a magnetic field, B = 1.56 × 10^-2 T. Abeam of positive ions (q = +e) then enters a region with the same B field, but no E field. If the ions are detected at a...
  23. A

    Mass Spectrometry: How Do Different Masses Have Same Velocity?

    When different masses are accelerated by the same potential,the lighter mass should move with a greater velocity than that of the heavier one. But, how in the velocity selector in the Bainbridge mass spectrometer, different masses(isotopes) come out with same velocity?
  24. A

    Magnetic Field Mass Spectrometer Calculations

    Here's a practice diploma question I found on the internet, this isn't homework. I'm studying, I just need help on how to do this type of question. http://www.paulway.com/physics30/p30dips/p30jan2002.pdf (Page 11 Numerical Response #5) Answer: 4.80x10^-3 Homework Statement In the magnetic...
  25. S

    Does Centripetal Acceleration Increase Kinetic Energy in a Mass Spectrometer?

    I understand that in a mass spectrometer, a particle will first pass through an accelerometer to pick up speed (presumably starting from rest). Let's say you have an electron starting from rest being passed through a difference of 1000V, it should have a kinetic energy of 1000eV right before...
  26. W

    Bainbridge's mass spectrometer problem

    [b]1. Homework Statement Bainbridge's mass spectrometer, shown in Fig. 28-58 (look to this link for image- http://www.cramster.com/answers-apr-08/physics/solution-posted-correctly-bainbridges-mass-spectrometer-shown-fig-28-58-separat_226944.aspx) , separates ionshaving the same velocity. The...
  27. X

    Magnesium ion entering a mass spectrometer. find r

    Homework Statement A magnesium ion (Mg 2+) traveling at 60000 m/s enters a mass spectrometer with a magnetic field intensity of 800T. Calculate the radius of deflection forthe magnesium ion. 800T = |B| 24.31g/mol = m 60000 m/s = v 1.66* 10^-27= Atomic mass unit r=? Homework Equations r=...
  28. F

    Atomic Mass in a Mass Spectrometer

    Homework Statement Natural carbon consists of two different isotopes. The isotopes have different masses, which is due to different numbers of neutrons in the nucleus; however, the number of protons is the same, and subsequently, the chemical properties are the same. The most abundant isotope...
  29. B

    Discover the Relationship Between Mass and Charge in a Mass Spectrometer

    Edit: Sorry I just realized this should be in Introductory Physics. Can a moderator could please move it? Homework Statement Show that in a mass spectrometer, the mass to charge ratio, m/q is equal to: m/q = (B2r2)/(2\DeltaV) Homework Equations F = qvBsin\theta The Attempt at a Solution...
  30. P

    Mass Spectrometry Homework: Separating Uranium Ions

    Homework Statement A certain commercial mass spectrometer is used to separate uranium ions of mass 3.92 multiplied by 10-25 kg and charge 3.20 multiplied by 10-19 C from related species. The ions are accelerated through a potential difference of 110 kV and then pass into a uniform magnetic...
  31. T

    Electrical Can a Cathode Ray Tube be Used to Build a DIY Mass Spectrometer?

    I'm wondering if it would be plausible to use a cathode ray tube (crt) style monitor to build my own mass spectrometer. Unfortunately, commercial models are prohibitively expensive, but if I had plans or at least a good idea of how to build one, I have the nagging feeling I could. My idea is as...
  32. J

    Mass of Atom in a Mass Spectrometer

    Homework Statement A mass spectrometer yields the following data for a beam of doubly ionized atoms of a single element. B = 8.0*10^-2 T q = 2(1.60*10^-19 C) r = 0.077 m V = 156 V I am asked to solve for Mass (m) in kg. Homework Equations q/m=((2V)/((B^2)*(r^2))) I am only...
  33. M

    Solving Mass Spectrometer Homework Problem with 90SR+ Isotope

    Homework Statement I'm having problem with a couple parts of this problem. I know how to work it (I think), but I'm consistently off by a couple orders of magnitude off the answer provided by the professor. I've already found that the isotope 90SR+ needs to be given a speed of...
  34. J

    Is Understanding Mass Spectrometer Operation Essential for Proper Calibration?

    Is it necessary to know the procedure of operation of a mass spectrometer in order to select the correct calibration standards? The mass spectrometer will be used to determine the isotopic composition in a gas.
  35. M

    How Does the New Mass Spectrometer Work?

    Hi I've attached the circuit as a word document, along with the question. I was not sure about the answers given, which I have copied below: Between plates field is uniform Acceleration is constant Energy gained = 2000e where does 2000 come from, isn't it 4? All ions have same F or same...
  36. H

    Bainbridge Mass Spectrometer - Finding the mass of ions

    In a particular spectrometer, doubly ionised C (atomic no. 6 mass no. 12) and singly ionised Li (atomic no. 3 mass no. 6) atoms are detected. The ratio of the path radii is 1.00252, the Li having the larger value. The fields are constant. a)Find the mass of the lithium ion. Okay so i...
  37. C

    Mass spectrometer conceptual question

    Homework Statement It's not really a book problem, just a question I encountered in my reading. For a mass spectrometer, if r = mv / qb, then r is directly proportional to mass and inversely proportional to charge. However, my reading says that the higher the mass, the less deflection. I...
  38. C

    Magnetic field and Bainbridge mass spectrometer

    Homework Statement The electric field between the plates of the velocity selector in a Bainbridge mass spectrometer is 1.05 105 V/m, and the magnetic field in both regions is 0.520 T. A stream of singly charged selenium ions moves in a circular path with a radius of 31.0 cm in the magnetic...
  39. R

    Finding the mass of an atom - bainbridge mass spectrometer question

    Q. In a particular spectrometer, doubly ionised \stackrel{12}{6}C and singly ionised \stackrel{6}{3}Li atoms are detected. The ratio of the path radii is 1.00252, the Li having the larger value. The fields are constant. Find the mass of of the lithium atom. I can only think of the equation...
  40. L

    Mass Spectrometer: Separating Ions & Calculating Energy

    If I was given that a mass spectrometer was used to separate ions of mass 3.92x10^-25 kg and charge 3.20x10^-19 C from other ions and the ions were accelerated through a potential difference of 80 kV and then sent into a uniform magnetic field, where they were bent in a path of radius 0.60 m and...
  41. K

    How Does Magnetic Field Strength Affect Ion Trajectory in a Mass Spectrometer?

    A mass spectrometer, sketched below, is a device used to separate different ions. Such ions with a well-defined velocity Vo enter through a slit into a region of uniform magnetic field B, where they follow a semicircular path until they strike the detector slit above the entry slit. The distance...
  42. R

    Is a Homemade Quadrupole Mass Spectrometer Possible?

    Hi, I'm a french (old) amateur scientist developping an homemade TOF mass spectrometer and I'll be pleased to know other amateur realizations in this area. I've found an homemade TEM on the web, and that's all. If someone has already tried to built such a device or know a site where I can...
  43. L

    The Function of the Ceramic Disk in an HP 5971A Mass GC-MS

    Not sure where exactly this should go, as it's a hardware question rather than a homework problem or question about the theory behind it, so, sorry if it's the wrong place. But, I've been working on getting an old HP 5971A mass GC-MS up and running over the past semester, and there's a part...
  44. V

    Understanding Circular Motion: The Importance of F=(mv^2)/r in Mass Spectrometry

    I managed to do part a) of the question but got stuck on b). Why use F=(mv^2)/r for circular motion? And even if I use this equation, how do I find r, the radius? Thank you PV
  45. U

    How Do You Calculate Spatial Separation in a Mass Spectrometer?

    Can anyone help with this problem, I have tried it a number of ways and can not get the correct answer, thanks in advance. Two isotopes of carbon, carbon-12 and carbon-13, have masses of 19.93 10-27 kg and 21.59 10-27 kg, respectively. These two isotopes are singly ionized (+e) and each is...
  46. M

    How Does a Mass Spectrometer Calculate the Path of Protein Fragments?

    Homework Statement A mass spectrometer is designed to separate protein fragments. The fragments are ionized by removing a single electron and then enter a 0.80 T uniform magnetic field at a speed of 2.3*10^5 m/s If a fragment has a mass that is 85 times the mass of the proton, what will be...
  47. W

    How can the charge of an ion be determined using the equation F = qv x B?

    Homework Statement The problem can be found here; http://www.physics.uprm.edu/~mark/courses/FISI3172_I2007/PracticeExamIII.pdf Homework Equations Ok, ok. I made some reaserch, and I found that the; radius of an ion orbit on a mass spectrometer = mv / qB where m = mass, v =...
  48. T

    What is the radius of a charged ion in a magnetic field?

    Homework Statement A singly charged positive ion has a mass of 2.50 x 10^-26kg. After being accelerated through a potential difference of 250 V, the ion enters a magnetic field of 0.500 T, in a direction perpendicular to the field. Homework Equations Calculate the radius of the path of...
  49. T

    How Does a Mass Spectrometer Calculate Ion Path Radius?

    Homework Statement Consider the mass spectrometer shown schematically in Figure 19.30 (don't have a scanner so I can't put the picture). The electric field between the plates of the velocity selector is 950 V/m, and the magnetic fields in both the velocity selector and the defelection chamber...