132 + Interview Questions in Mass Spectrometer in Analytical Instrumentation Page 1 InterviewSolution

1.	Mass spectrometers are used to determine which of the following?(a) Composition in sample(b) Concentration of elements in sample(c) Relative mass of atoms(d) Properties of sampleI have been asked this question during an interview.The question is from Principle of operation of Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT option is (C) Relative mass of atoms The best EXPLANATION: Mass spectrometers are used to determine the relative mass of atoms and molecules. Aston made the instrument more ACCURATE.

Discussion

2.	In a mass spectrometer, the ion currents are measured using which of the following?(a) Scintillation counter(b) Ion counter(c) Electrometer tube(d) Electric fieldsI had been asked this question by my school teacher while I was bunking the class.The query is from Principle of operation of Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT option is (c) Electrometer tube The best I can EXPLAIN: The ion currents are MEASURED using a sensitive electrometer tube. The ions reaching the collecting plate are measured.

Discussion

3.	The alternating voltage rf voltage is applied to which of the following?(a) All grids(b) Central grid(c) Alternate grids(d) None of the gridsThis question was posed to me in exam.This interesting question is from Radiofrequency Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (B) Central grid Explanation: The alternating VOLTAGE rf voltage is APPLIED to the central grid. All the other grids are KEPT at ground potential.

Discussion

4.	The resolution of the Bennet tube can be improved by using which of the following?(a) Sine wave rf signal(b) Square wave rf signal(c) Triangular wave rf signal(d) Random signalThe question was posed to me in examination.The doubt is from Radiofrequency Mass Spectrometer topic in division Mass Spectrometer of Analytical Instrumentation
Answer» The correct choice is (b) SQUARE wave RF signal The EXPLANATION is: The resolution of the Bennet tube can be improved by using square wave rf signal. USUALLY, SINUSOIDAL wave signal is used.

Discussion

5.	Which of the following detectors can be used for ions with short life time?(a) Faraday cup collector(b) Photographic plates(c) Micro-channel plate(d) Electron multiplier transducerThis question was addressed to me in examination.This intriguing question comes from Ion Transducers topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» Correct OPTION is (B) Photographic plates The explanation is: Photographic plates can be used for IONS with short life time. This is because they integrate the ion SIGNAL over a period of time.

Discussion

6.	All ions with the same number of charges will have __________(a) Same kinetic energy(b) Different kinetic energies(c) Same mass(d) Different massI have been asked this question in an online interview.The origin of the question is Tandem Mass Spectroscopy topic in section Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT choice is (a) Same KINETIC ENERGY For explanation: All IONS with the same number of charges will have the same kinetic energy. It is assumed that all ions have a single CHARGE.

Discussion

7.	The electric sector field is not subject to hysteresis.(a) True(b) FalseI have been asked this question in an international level competition.My doubt stems from Magnetic Deflection Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Right choice is (a) True The explanation is: The ELECTRIC SECTOR FIELD is not subject to hysteresis. Hence, the relationship between MASS to charge ratio and ACCELERATING voltage is linear.

Discussion

8.	Who invented mass spectrometers?(a) J.J Thompson(b) Goldstein(c) Nikola Tesla(d) AstonI got this question in quiz.The query is from Principle of operation of Mass Spectrometer topic in section Mass Spectrometer of Analytical Instrumentation
Answer» Correct choice is (a) J.J Thompson For EXPLANATION: J.J Thompson introduced mass SPECTROMETERS. Aston modified the INSTRUMENT to make it more ACCURATE.

Discussion

9.	The evacuated tube is also known as which of the following?(a) Pulse tube(b) Detector tube(c) Drift tube(d) Acceleration tubeI got this question during a job interview.I want to ask this question from Time of Flight Mass Spectrometer topic in section Mass Spectrometer of Analytical Instrumentation
Answer» The correct choice is (C) Drift tube The best explanation: The EVACUATED tube is also KNOWN as a drift tube. The electrons move from SOURCE to DETECTOR through the tube.

Discussion

10.	Nier-Johnson geometry involves a deflection of which of the following radians in a radial electrostatic field analyser?(a) Π(b) Π/2(c) Π/3(d) Π/4The question was asked during an interview.This is a very interesting question from Magnetic Deflection Mass Spectrometer in division Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (b) Π/2 Explanation: Nier-Johnson geometry involves a DEFLECTION of Π/2 RADIANS in a radial ELECTROSTATIC field analyser. A magnetic deflection of Π/3 radians follows the analyser.

Discussion

11.	Which of the following is not an advantage of mass spectrometer?(a) Simple(b) Rugged(c) High sensitivity(d) Unlimited mass rangeThe question was asked by my school teacher while I was bunking the class.The query is from Time of Flight Mass Spectrometer topic in division Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (c) High SENSITIVITY To explain I would SAY: TIME of flight mass spectrometers have limited sensitivity and RESOLUTION. They are simple and RUGGED.

Discussion

12.	The DC ion accelerating voltage is swept from _________(a) 0 to 50 V(b) 50 to 100 V(c) 200 to 300 V(d) 50 to 250 VI have been asked this question at a job interview.Question is from Radiofrequency Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» The correct answer is (d) 50 to 250 V For explanation I would SAY: The DC ion ACCELERATING VOLTAGE is swept from 50 to 250 V. This is done twice per second.

Discussion

13.	In Bennet spectrometer, the rf voltage has a fixed frequency.(a) True(b) FalseThis question was addressed to me in class test.This key question is from Radiofrequency Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation
Answer» Right CHOICE is (a) True To elaborate: In BENNET SPECTROMETER, the rf voltage has a fixed frequency. It is MODULATED at 10 percent at 1KHZ.

Discussion

14.	The resolving power of Bennet type spectrometer is primarily based on which of the following?(a) Distance between detector and reflectron(b) Difference between the individual rf accelerating stages(c) Length of the drift tube(d) Laser beam usedThis question was posed to me in an online interview.My query is from Radiofrequency Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» RIGHT choice is (B) Difference between the individual rf accelerating stages Easiest explanation: The resolving POWER of BENNET type spectrometer is primarily based on the difference between the individual rf accelerating stages.

Discussion

15.	Which of the following is not the feature of Bennet type spectrometer?(a) Lightweight(b) Simple(c) Absence of spurious lines(d) Moderate resolutionThe question was posed to me during a job interview.My question is based upon Radiofrequency Mass Spectrometer in division Mass Spectrometer of Analytical Instrumentation
Answer» Correct CHOICE is (c) Absence of spurious lines For EXPLANATION: Absence of spurious lines is not a feature of Bennet type SPECTROMETER. Spurious lines can be REDUCED by ADDING new features.

Discussion

16.	Which of the following is the type of separator used in commercial GC-MS systems?(a) Jet type molecular separator(b) Porous tube(c) Teflon tube(d) Flow type separatorThe question was posed to me in examination.Question is from Gas Chromatograph- Mass Spectrometer topic in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Right ANSWER is (a) JET type molecular separator Explanation: Jet type molecular separator is the type of separator used in commercial GC-MS SYSTEMS. Other methods are porous tube and TEFLON tube.

Discussion

17.	Which of the following is the most accurate method of determination of elemental composition?(a) Spectroscopy(b) Isotope dilution(c) Isobar dilution(d) ChromatographyThe question was asked at a job interview.The origin of the question is Inductively Coupled Plasma Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Correct choice is (b) Isotope dilution Best EXPLANATION: The most ACCURATE method of DETERMINATION of ELEMENTAL composition is isotope dilution. It permits the calculation of the concentration of an element.

Discussion

18.	Which of the following is the most commonly used interface?(a) Nebulizer(b) Chopper(c) Filter(d) Vapourising chamberThis question was addressed to me by my college professor while I was bunking the class.Asked question is from Liquid Chromatograph- Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» RIGHT choice is (a) NEBULIZER To EXPLAIN: Nebulizer is the most commonly used interface. The nebulizer gas and the make-up gas are INTRODUCED coaxially into the HEATED nebulization region.

Discussion

19.	The final MS/MS spectrum consists only of product ions from the selected precursor.(a) True(b) FalseI have been asked this question in an online quiz.I need to ask this question from Tandem Mass Spectroscopy in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct answer is (a) True Easiest explanation: The FINAL MS/MS spectrum consists only of product ions from the SELECTED precursor. The CHEMICAL BACKGROUND and other mixture components are ABSENT.

Discussion

20.	Which of the following is placed just before the detector in a radiofrequency mass spectrometer?(a) Ion source(b) Potential energy selector(c) Ionisation chamber(d) ReflectronI had been asked this question in an interview.I'd like to ask this question from Radiofrequency Mass Spectrometer topic in section Mass Spectrometer of Analytical Instrumentation
Answer» Correct option is (b) POTENTIAL energy SELECTOR The EXPLANATION: A potential energy selector is placed before the detector. It balances out the energy of the ION BEAM.

Discussion

21.	Which of the following components need to be added in order to increase the resolution?(a) Ion source(b) Detector(c) Magnetic sector(d) Electric sectorThis question was posed to me in an online quiz.I'm obligated to ask this question of Magnetic Deflection Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT answer is (d) Electric sector Easiest explanation: Electric sector needs to be ADDED in order to INCREASE the resolution. This compensates for the decrease in resolution due to varying VELOCITIES.

Discussion

22.	ICP spectrometer is a sequential multi-element analyser that has scan times less than ____ for one sweep.(a) 10ms(b) 20ms(c) 50ms(d) 100msI had been asked this question in quiz.Origin of the question is Inductively Coupled Plasma Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct CHOICE is (b) 20ms To explain I WOULD say: ICP spectrometer is a sequential multi-element analyser that has SCAN times LESS than 20ms for one sweep. Quadrupole mass analyser gives a better unit mass resolution.

Discussion

23.	The ions are passed into the high vacuum analyser through which of the following?(a) Orifice(b) Nozzle(c) Nebulizer(d) Venturi tubeThe question was posed to me in an internship interview.My enquiry is from Liquid Chromatograph- Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct choice is (a) Orifice For explanation: The ions are SENT into the high VACUUM ANALYSER through an orifice. It is then mass ANALYSED.

Discussion

24.	A magnetic sector alone can be used as a mass spectrometer, with roughly _____ resolution.(a) Low(b) High(c) Unit(d) InfiniteI had been asked this question in class test.I'm obligated to ask this question of Tandem Mass Spectroscopy topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» RIGHT OPTION is (c) Unit The best I can explain: A magnetic sector alone can be USED as a mass spectrometer, with roughly unit resolution. Early work on MS/MS was done with reverse-geometry double focussing mass spectrometer.

Discussion

25.	Cold tray is provided for liquid N2 or CO2 but is used only for extremely small samples.(a) True(b) FalseI got this question in an interview.I need to ask this question from Gas Chromatograph- Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct answer is (a) True Best explanation: Cold tray is provided for liquid N2 or CO2. It is USED only for MASS spectral ANALYSIS of very SMALL samples.

Discussion

26.	Which of the following filters are used in tandem spectrometer?(a) Quadrupole mass filter(b) Low energy filter(c) High energy filter(d) Time of flight mass filterThe question was asked in an interview for internship.The question is from Tandem Mass Spectroscopy in section Mass Spectrometer of Analytical Instrumentation
Answer» The correct CHOICE is (a) QUADRUPOLE MASS FILTER Best explanation: A tandem mass spectrometer has a quadrupole mass filter. The filter is followed by an analyser.

Discussion

27.	In glow discharge ion source, the sample is atomised by which of the following process?(a) Evaporation(b) Sputtering(c) Heating(d) AnnealingI had been asked this question in a national level competition.This intriguing question comes from Components of Mass Spectrometer topic in division Mass Spectrometer of Analytical Instrumentation
Answer» CORRECT option is (b) Sputtering To elaborate: In glow discharge ion source, the sample is atomised by the PROCESS of sputtering. It not only atomizes the sample but ALSO provides means by which these atoms are IONIZED.

Discussion

28.	GC- MS has been developed for which of the following systems?(a) Packed column(b) Open tubular column(c) Capillary column(d) Porous layer columnThis question was addressed to me during an internship interview.My question is based upon Gas Chromatograph- Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT option is (a) Packed column Best EXPLANATION: GC- MS has been developed for packed column system. These ALLOW for analyte molecules to be dynamically extracted from the carrier gas stream.

Discussion

29.	In cases where differentiation is required between very similar substances, which of the following techniques making use of quadrupole principle is preferred?(a) Evaporation mass spectrometry(b) Pyrolysis mass spectrometry(c) Plasma mass spectrometry(d) Trapped ion mass spectrometryI had been asked this question in class test.I'm obligated to ask this question of Quadrupole Mass Spectrometer in division Mass Spectrometer of Analytical Instrumentation
Answer» Right CHOICE is (b) PYROLYSIS mass SPECTROMETRY Explanation: In cases where differentiation is required between very similar substances, pyrolysis mass spectrometry is USED. The sample is USUALLY solid or involatile liquid in this case.

Discussion

30.	Which of the following problems occur when combining gas chromatography and mass spectroscopy?(a) Difference in operating pressures(b) Reduction in sensitivity(c) Direct identification is not possible(d) It does not permit direct introduction of the effluentI have been asked this question in an interview for job.I want to ask this question from Gas Chromatograph- Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (a) Difference in OPERATING pressures The explanation: The problem that occurs when combining gas chromatography and mass SPECTROSCOPY is the difference in operating pressures. The pressure at the exit of the GC column is ATMOSPHERIC.

Discussion

31.	Introduction of total HPLC effluent into MS is feasible.(a) True(b) FalseThis question was posed to me in an international level competition.My question is taken from Liquid Chromatograph- Mass Spectrometer topic in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Correct answer is (B) False Easy explanation: Introduction of total HPLC effluent into MS is not feasible. The simplest method is the introduction of liquid from LC to the MS ION source REGION.

Discussion

32.	Gas burden from conventional LC flow rates is which of the following?(a) 1ml/min of water produces 1.2 l/mm of gas(b) 1ml/min of water produces 2.4 l/mm of gas(c) 2ml/min of water produces 3.2 l/mm of gas(d) 1ml/min of water produces 4.2 l/mm of gasI got this question by my college director while I was bunking the class.The question is from Liquid Chromatograph- Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (a) 1ml/min of water PRODUCES 1.2 l/mm of gas Easiest explanation: In LC-mass SPECTROMETRY, 1ml/min of water produces 1.2 l/mm of gas. This is the gas burden that CONVENTIONAL FLOW rates produced.

Discussion

33.	Tandem mass spectroscopy combines which of the following devices?(a) Mass spectrometer and gas-solid chromatograph(b) Mass spectrometer and gas-liquid chromatograph(c) Mass spectrometer and gas chromatograph(d) Mass spectrometer and mass spectrometerThe question was asked in quiz.The doubt is from Tandem Mass Spectroscopy in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct CHOICE is (d) MASS SPECTROMETER and mass spectrometer Explanation: Tandem mass spectroscopy combines two mass SPECTROMETERS. It is REPRESENTED as MS/MS.

Discussion

34.	B/E scan is which of the following scans?(a) Product ion scan(b) Precursor ion scan(c) Mass scan(d) Charge scanThe question was asked during an interview.This interesting question is from Tandem Mass Spectroscopy topic in section Mass Spectrometer of Analytical Instrumentation
Answer» The CORRECT choice is (a) PRODUCT ion scan Easy explanation: B/E ratio can be CHOSEN to SELECT ions with a given velocity. It is a product ion scan.

Discussion

35.	Which of the following is located in the region between two analysers?(a) Nebuliser(b) Collision cell(c) Filter(d) Vacuum chamberThe question was asked in an online interview.I would like to ask this question from Tandem Mass Spectroscopy in chapter Mass Spectrometer of Analytical Instrumentation
Answer» The correct choice is (b) Collision CELL The explanation: Collision cell is located in the region between two ANALYSERS. LOW energy parent IONS are mass ANALYSED.

Discussion

36.	Given below is the block diagram of mass spectrometer. Identify the unmarked component.(a) Inlet system(b) Ionisation chamber(c) Vacuum system(d) Ion transducerThis question was posed to me during an interview for a job.The doubt is from Components of Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» Correct choice is (d) Ion transducer The BEST EXPLANATION: The unmarked COMPONENT is ion transducer. It will give current at the output at its output side when ions are PRESENT on the INPUT side.

Discussion

37.	The carrier gas with low molecular weight would diffuse at a higher rate than the higher molecular weight sample.(a) True(b) FalseI have been asked this question in homework.Question is taken from Gas Chromatograph- Mass Spectrometer topic in division Mass Spectrometer of Analytical Instrumentation
Answer» The correct choice is (a) True Easy EXPLANATION: The carrier gas with low molecular weight would DIFFUSE at a HIGHER rate than the higher molecular weight sample. The carrier gas would diffuse away from the LINE of flow.

Discussion

38.	Which of the following are true about dynodes used in discrete dynode electron multiplier?(a) The dynodes are all kept at same voltage(b) Successive dynodes are held at lower potential(c) Successive dynodes are held at higher potential(d) All dynodes are held at very low potentialThis question was addressed to me during an online interview.I'm obligated to ask this question of Ion Transducers in division Mass Spectrometer of Analytical Instrumentation
Answer» Correct option is (c) SUCCESSIVE dynodes are HELD at higher potential The best I can explain: In discrete dynode ELECTRON multiplier, successive dynodes are held at higher potential. Dynodes are metal PLATES with COPPER or beryllium surfaces.

Discussion

39.	In which of the following detectors, the collector is placed in an inclined manner?(a) Faraday cup collector(b) Channeltron(c) Micro-channel plate(d) Electron multiplier transducerI got this question by my college professor while I was bunking the class.The doubt is from Ion Transducers in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct answer is (a) FARADAY cup collector Easiest EXPLANATION: The collector is PLACED in an inclined manner in a faraday cup collector. This is to REFLECT the ions away from the ENTRANCE of the cup.

Discussion

40.	Which of the following is true about time of flight analyser spectrometers?(a) Lighter particles arrive at the detector earlier(b) Heavier particle arrive at the detector earlier(c) Lighter and heavier particles arrive together at the detector(d) Lighter particles do not reach the detectorI have been asked this question in final exam.This key question is from Time of Flight Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Right option is (a) LIGHTER particles ARRIVE at the detector earlier To explain: Lighter particles arrive at the detector earlier than the HEAVIER particles. The time difference is used to SEPARATE the electrons according to their mass.

Discussion

41.	Which of the following leads to the limitation of resolution?(a) All ions do not have same energy(b) All ions do not have same charge(c) All ions are not of the same size(d) All ions do not have the same chargeThis question was posed to me during an online interview.This intriguing question originated from Magnetic Deflection Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» Correct option is (a) All IONS do not have same energy Easy explanation: The RESOLUTION is LIMITED as all ions do not have the same energy. Hence, the ions would not have the same velocity.

Discussion

42.	Which of the following is an ion optic device in which ions pass through a mirror and their flight is reversed?(a) Reversal device(b) Reflectron(c) Mirror arrangement(d) Separation chamberThe question was asked in an online quiz.This intriguing question originated from Time of Flight Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» RIGHT choice is (B) Reflectron To explain I would SAY: Reflectron is an ion optic device in which ions pass through a MIRROR and their flight is reversed. It is used in time of flight mass SPECTROMETER.

Discussion

43.	Which of the following is the disadvantage of using three stage tubes?(a) Reduced resolution(b) Bulky construction(c) Complex(d) HeavyThe question was posed to me in an interview for internship.I'm obligated to ask this question of Radiofrequency Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation
Answer» RIGHT CHOICE is (a) REDUCED resolution The explanation: The spurious lines can be reduced to a minimum by using three stage tubes. This results in reduced resolving POWER.

Discussion

44.	Which of the following is used to cool the ion source?(a) Liquid sodium shield(b) Liquid nitrogen shield(c) Water(d) FreonI had been asked this question in unit test.This interesting question is from Quadrupole Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Correct choice is (b) LIQUID nitrogen SHIELD Explanation: Liquid nitrogen cooled shield is USED to cool the ion source. It REDUCES source contamination.

Discussion

45.	Which of the following are not the characteristics of an electron multiplier transducer?(a) Rugged(b) Reliable(c) Microsecond of response time required(d) High current gainThis question was posed to me in an interview for job.Question is taken from Ion Transducers in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Correct ANSWER is (c) Microsecond of RESPONSE TIME required To explain: Electron multiplier TRANSDUCER requires the only nanosecond of response time. It provides a high CURRENT gain.

Discussion

46.	In tandem spectroscopy, the first stage sepatation device is a mass spectrometer.(a) True(b) FalseThis question was addressed to me in an international level competition.I need to ask this question from Tandem Mass Spectroscopy in chapter Mass Spectrometer of Analytical Instrumentation
Answer» Correct choice is (a) True Explanation: In TANDEM SPECTROSCOPY, the FIRST STAGE sepatation DEVICE is a mass spectrometer. It is represented as MS/MS.

Discussion

47.	Which of the following ions pass through the slit and reach the collecting plate?(a) Negative ions of all masses(b) Positive ions of all masses(c) Negative ions of specific mass(d) Positive ions of specific massThis question was addressed to me in a job interview.This is a very interesting question from Principle of operation of Mass Spectrometer in division Mass Spectrometer of Analytical Instrumentation
Answer» Right answer is (d) Positive IONS of specific mass Easiest EXPLANATION: Positive ions of specific mass PASS through the slit and reach the collecting plate. These ions are MEASURED.

Discussion

48.	Which of the following is normally done to convert the sample into the gaseous state?(a) Sample is pressurized(b) Chemical reactions are made to occur(c) Sample is heated(d) Sample is cooledThe question was posed to me during an interview.The query is from Components of Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» Correct option is (c) SAMPLE is HEATED The explanation: The sample must always be in the gaseous state. Hence, the liquid sample must be heated before INTRODUCING them into the IONIZATION chamber.

Discussion

49.	Direct focussing is obtained by deflecting the ion beam along a _________ trajectory through the magnetic field.(a) 120^o(b) 150^o(c) 190^o(d) 180^oI have been asked this question in an online interview.My doubt is from Magnetic Deflection Mass Spectrometer in section Mass Spectrometer of Analytical Instrumentation
Answer» Correct CHOICE is (d) 180^o Explanation: DIRECT focussing is OBTAINED by DEFLECTING the ion beam along a 180^o trajectory through a magnetic field. The gap between the poles must be large enough to CONTAIN the ion source.

Discussion

50.	Mattauch-Herzog geometry involves a deflection of which of the following radians in a radial electrostatic field analyser?(a) √2Π(b) Π/2(c) Π/3√4(d) Π/4√2I got this question at a job interview.I'm obligated to ask this question of Magnetic Deflection Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation
Answer» The correct answer is (d) Π/4√2 The explanation: Mattauch-Herzog geometry involves a DEFLECTION of Π/4√2 radians in a RADIAL ELECTROSTATIC field ANALYSER. It is followed by a MAGNETIC deflection of Π/2 radians.

Discussion

Explore topic-wise InterviewSolutions in .

The electric sector field is not subject to hysteresis.(a) True(b) FalseI have been asked this question in an international level competition.My doubt stems from Magnetic Deflection Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation

Who invented mass spectrometers?(a) J.J Thompson(b) Goldstein(c) Nikola Tesla(d) AstonI got this question in quiz.The query is from Principle of operation of Mass Spectrometer topic in section Mass Spectrometer of Analytical Instrumentation

The evacuated tube is also known as which of the following?(a) Pulse tube(b) Detector tube(c) Drift tube(d) Acceleration tubeI got this question during a job interview.I want to ask this question from Time of Flight Mass Spectrometer topic in section Mass Spectrometer of Analytical Instrumentation

The DC ion accelerating voltage is swept from _________(a) 0 to 50 V(b) 50 to 100 V(c) 200 to 300 V(d) 50 to 250 VI have been asked this question at a job interview.Question is from Radiofrequency Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation

In Bennet spectrometer, the rf voltage has a fixed frequency.(a) True(b) FalseThis question was addressed to me in class test.This key question is from Radiofrequency Mass Spectrometer in portion Mass Spectrometer of Analytical Instrumentation

The final MS/MS spectrum consists only of product ions from the selected precursor.(a) True(b) FalseI have been asked this question in an online quiz.I need to ask this question from Tandem Mass Spectroscopy in portion Mass Spectrometer of Analytical Instrumentation

A magnetic sector alone can be used as a mass spectrometer, with roughly _____ resolution.(a) Low(b) High(c) Unit(d) InfiniteI had been asked this question in class test.I'm obligated to ask this question of Tandem Mass Spectroscopy topic in portion Mass Spectrometer of Analytical Instrumentation

Cold tray is provided for liquid N2 or CO2 but is used only for extremely small samples.(a) True(b) FalseI got this question in an interview.I need to ask this question from Gas Chromatograph- Mass Spectrometer topic in portion Mass Spectrometer of Analytical Instrumentation

Introduction of total HPLC effluent into MS is feasible.(a) True(b) FalseThis question was posed to me in an international level competition.My question is taken from Liquid Chromatograph- Mass Spectrometer topic in chapter Mass Spectrometer of Analytical Instrumentation

B/E scan is which of the following scans?(a) Product ion scan(b) Precursor ion scan(c) Mass scan(d) Charge scanThe question was asked during an interview.This interesting question is from Tandem Mass Spectroscopy topic in section Mass Spectrometer of Analytical Instrumentation

Which of the following is located in the region between two analysers?(a) Nebuliser(b) Collision cell(c) Filter(d) Vacuum chamberThe question was asked in an online interview.I would like to ask this question from Tandem Mass Spectroscopy in chapter Mass Spectrometer of Analytical Instrumentation

The carrier gas with low molecular weight would diffuse at a higher rate than the higher molecular weight sample.(a) True(b) FalseI have been asked this question in homework.Question is taken from Gas Chromatograph- Mass Spectrometer topic in division Mass Spectrometer of Analytical Instrumentation

Which of the following is used to cool the ion source?(a) Liquid sodium shield(b) Liquid nitrogen shield(c) Water(d) FreonI had been asked this question in unit test.This interesting question is from Quadrupole Mass Spectrometer in chapter Mass Spectrometer of Analytical Instrumentation

In tandem spectroscopy, the first stage sepatation device is a mass spectrometer.(a) True(b) FalseThis question was addressed to me in an international level competition.I need to ask this question from Tandem Mass Spectroscopy in chapter Mass Spectrometer of Analytical Instrumentation