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Chemistry exam 3- practice questions 2024/2024
Chemistry exam 3- practice questions Chemistry exam 3- practice questions Chemistry exam 3- practice questions
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Chemistry exam 3- practice questionsIn chromatography, analyte flows in the ___ phase. It is separated by interaction with the ___ phase.
The resulting plot of signal vs time, which is a series of peaks, is called a ___
A. Mobile, stationary, chromatogram
B. Stationary, mobile, chromatogram
C. GC, HPLC, chromatogram - ANS A. Mobile, stationary, chromatogram
What's are the 4 main components of a chromatography system?
A. Mobile phase, injector, column, detector
B. Lines, waste, mixer, oven, column
C. Centrifuge, spectrometer, cylinder, column - ANS A. Mobile phase, injector, column, detector
True or false
Liquid chromatography is used for analytes that are volatile by derivatization. Gas chromatography is for
any analyte, whether volatile or not - ANS False
Gas is for volatiles, liquid is for anything
Detectors for GC are ___, while detectors for LC are ___
A. MS and FID; UV, QQQ, and QTOF
B. UV, QQQ, QTOF; MS and FID
C. Conductivity, UV, pH; UV, QQQ, and QTOF - ANS A. MS and FID; UV, QQQ, and QTOF
In this detector, analyte from column is mixed with air and hydrogen is burned. The burning creates
charged particles (ions) that flow between the 2 electrodes creating circuit. What is the name of this
detector?
A. MS
,B. QQQ
C. FID
D. QTOF - ANS C. FID
In this detector, the analyte is bombarded by electrons, then breaks into charged fragments. A fragment
of a specific m/z makes it throught the 4 parallel rods to the detector while other fragments hit the rods.
As voltage of the rods are varies different m/z are let through and detected. What is the name of this
detector?
A. El quadrupole MS
B. QQQ
C. QTOF - ANS A. El quadrupole MS
A sequence of voltages is applied to the mass spectrometer rods, and at each voltage, a fragment passes
through the filter and hits the detector. The name of the poor of abundance for each m/z is called a:
A. Chromatogram
B. Mass spectrum
C. El
D. FID - ANS B. Mass spectrum
True or false
Mass spectra are like a fingerprint. Every compound has a unique one - ANS True
Which mode of GCMS operation has more sensitivity and why?
A. SIM. More time at each m/z
B. Full scan. More time at each m/z
C. SIM. Less time at each m/z - ANS A. SIM. More time at each m/z
, True or false
In a TOF analyzer, a fragment of low mass reaches the detector first - ANS True
In GCMS when we know what analytes we are measuring use ___ mode. When we do not know what
analytes are in the sample we use ___ mode. SIM allows greater sensitivity than scan.
A. Scan; SIM
B. SIM; scan - ANS B. SIM; scan
In this detector, the first quadrupole selects one molecular ion through. In the second quadrupole, CID
occurs and the molecular ion is fragmented. In the third quadrupole, a specific fragment is allowed
through the detector. Used for confirmations by LC. What is the name of this detector
A. El quadrupole Ms
b. QQQ
C. QTOF - ANS B. QQQ
True or false
In single reaction monitoring by QQQ, we monitor one precursor and one fragment. In multiple reaction
monitoring, we monitor a group of SRMs. LC QQQ typically sed fro confirmation of nonvolatile drugs of
abuse. - ANS True
In this detector, there is a data acquisition mode called MSE where the collision energy varies between
low anf high settings. In the low setting, the protracted molecules are detected. In the high setting, the
fragments are recorded. This is used for true comprehensive drug screens.
A. El quadrupole MS
B. QQQ
C. QTOF - ANS C. QTOF
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