After a compound is introduced to the mass spectrometer, the sample is bombarded with a beam of high energy electrons. After this, ...Group of answer choicesThe sample forms a radical cation. This molecular ion has a mass-to-charge ratio identical to the molecular weight of the initial compound.The molecular ion is not detected by mass spectrometry.The molecular ion fragments into pieces, yielding other radical cations that are detected by mass spectrometry.The amount of energy absorbed by the beam of high energy electrons is detected and reported by the mass spectrometer.Both A and C.

Explain important application of mass spectrometry. Discuss the limitation of Mass spectrometry.

In a mass spectrometer, a compound is first vaporized and converted into ions, which are then separated and detected. The most common ionization technique involves _____________________________________.Select answer from the options belowUsing a strong magnetic field to remove an electronbombarding the compound with high-energy electronsheating the compound to extreme temperaturesbombarding the compound with high-energy neutronsSave for LaterSubmit Answer

In mass spectrometry, a sample's molecules are ionized in a vacuum and then exposed to a uniform electric field created by a high voltage plate in the acceleration chamber.  The electric field accelerates the ions until they arrive at the next section of the device, designated as the separation chamber.  In this section, the drifting ions are sorted by their mass-to-charge ratio (m/q).The separation chamber in a time-of-flight mass spectrometer (TOF-MS) is linear and has no electric or magnetic fields.  The ions travel at a constant velocity through the chamber until they reach the detector.  The time it takes for an ion to reach the detector depends on its m/q ratio.Figure 1  Time-of-flight mass spectrometerA magnetic sector mass spectrometer (MS-MS) has a curved separation chamber in which a magnetic field is applied.  The magnetic field exerts a centripetal force on drifting ions, bending their trajectories into curved paths.  The radius of the curvature depends on the ion's m/q.Figure 2  Magnetic sector mass spectrometerThe centripetal force F acting on a particle can be determined from its mass m, its velocity v, and the radius r of its curved path:𝐹=𝑚𝑣2𝑟Equation 1 Question 43Which of the following best describes the high voltage plate if it accelerates positive ions away from it?A.It is positively charged, and its electric field lines point away from it.B.It is positively charged, and its electric field lines point toward it.C.It is negatively charged, and its electric field lines point away from it.D.It is negatively charged, and its electric field lines point toward it.

Electrospray ionization mass spectrometry (ESI-MS) employs a soft ionization technique that, unlike traditional ionization via electron bombardment, results in little to no fragmentation of target molecules.  During electron bombardment, electrons collide with the analyte and cause the molecule to lose an electron whereas during ESI-MS, ions are produced by passing the analyte solution through an electrospray needle that has a potential difference applied with respect to a counterelectrode.  This leads to the formation of charged droplets, which are repelled from the needle toward the counterelectrode and mass spectrometer, as shown in Figure 1.Figure 1  ESI-MS ionization mechanismDuring the droplet's flight, the solvent is evaporated off analyte molecules.  Ionization occurs through the protonation of basic sites on target molecules.  Reaction 1 shows the number of protons n added to molecule M.M → (M + nH)n+Reaction 1Researchers used ESI-MS to quantify the formation of four pyridyloxobutyl-DNA (POB-DNA) adducts, shown in Figure 2.  POB-DNA adduct formation involves highly mutagenic pyridyloxobutylating agents, which are formed from cytochrome P450–mediated hydroxylation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), an abundant N-nitrosamine carcinogen found in cigarette smoke.  Adducts were produced in vitro by treating samples of calf thymus DNA with NNK.  The DNA adducts were then separated by reversed-phase high-performance liquid chromatography (RP-HPLC) and analyzed via ESI-MS.Figure 2  Molecular structure of POB-DNA adductsAdapted from Lao, Y., Villalta, P.W., Sturla, S.J., Wang, M., & Hecht, S.S. (2006). Quantitation of pyridyloxobutyl DNA adducts of tobacco-specific nitrosamines in rat tissue DNA by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Chemical Research in Toxicology, 19(5), 674–682. Question 3For the RP-HPLC separation of the POB-DNA adducts, which of the following would most likely be used as the mobile and stationary phases, respectively?A.Water and silicaB.Hexane and C-18 alkyl hydrocarbonC.Water and C-18 alkyl hydrocarbonD.Hexane and silica

explain how a mass spectrometer is used to measure molecular mass. are there any limits to its use for molecular mass determination?