front 1 A plasma sample is hemolyzed and turbid. What
is required to
perform a sample blank in order
to correct the measurement for
the intrinsic
absorbance of the sample when performing
a
spectrophotometric assay?
A. Substitute deionized water
for the sample
B. Dilute the sample 1:2 with a standard
of
known concentration
C. Substitute saline for the
reagent
D. Use a larger volume of the sample | back 1 C. Substitute saline for the reagent |
front 2 Which instrument requires a highly regulated
DC power
supply?
A. A spectrophotometer with a barrier layer cell
B.
A colorimeter with multilayer interference
filters
C. A
spectrophotometer with a photomultiplier
tube
D. A
densitometer with a photodiode detector | back 2 C. A spectrophotometer with a photomultiplier
tube |
front 3 Which statement regarding reflectometry is true?
A. The relation
between reflectance density and
concentration is linear
B.
Single-point calibration can be used to
determine
concentration
C. 100% reflectance is set with an
opaque film
called a white reference
D. The diode array is
the photodetector of choice | back 3 C. 100% reflectance is set with an opaque film
called a white reference |
front 4 Bichromatic measurement of absorbance can
correct for
interfering substances if:
A. The contribution of the interferent
to absorbance
is the same at both wavelengths
B. Both
wavelengths pass through the sample
simultaneously
C. The
side band is a harmonic of the primary
wavelength
D. The
chromogen has the same absorbance at both
wavelengths | back 4 A. The contribution of the interferent to absorbance
is the same
at both wavelengths |
front 5 Which instrument requires a primary and
secondary
monochromator?
A. Spectrophotometer
B. Atomic absorption
spectrophotometer
C. Fluorometer
D. Nephelometer | |
front 6 Which of the following statements about
fluorometry is
accurate?
A. Fluorometry is less sensitive
than
spectrophotometry
B. Fluorometry is less specific
than
spectrophotometry
C. Unsaturated cyclic molecules are
often
fluorescent
D. Fluorescence is directly proportional to
temperature | back 6 C. Unsaturated cyclic molecules are often
fluorescent |
front 7 Which of the following components is not needed
in a
chemiluminescent immunoassay analyzer?
A. Source lamp
B.
Monochromator
C. Photodetector
D. Wash station | |
front 8 Which substance is used to generate the light
signal in
electrochemiluminescence?
A. Acridinium
B. Luminol
C.
Dioxetane phosphate
D. Ruthenium | |
front 9 Light scattering when the wavelength is greater
than 10 times
the particle diameter is described by:
A. Rayleigh’s law
B.
The Beer–Lambert law
C. Mie’s law
D. The Rayleigh–Debye law | |
front 10 Which statement regarding nephelometry is true?
A. Nephelometry
is less sensitive than absorption
spectrophotometry
B.
Nephelometry follows Beer’s law
C. The optical design is
identical to a turbidimeter
except that a HeNe laser light source
is used
D. The detector response is directly proportional to
concentration | back 10 D. The detector response is directly proportional to
concentration |
front 11 The purpose of the nebulizer in an atomic
absorption
spectrophotometer that uses
a flame is to:
A. Convert ions
to atoms
B. Cause ejection of an outer shell electron
C.
Reduce evaporation of the sample
D. Burn off organic impurities | |
front 12 A flameless atomic absorption spectrophotometer
dehydrates and
atomizes a sample using:
A. A graphite capillary furnace
B.
An electron gun
C. A thermoelectric semiconductor
D. A
thermospray platform | back 12 A. A graphite capillary furnace |
front 13 When measuring lead in whole blood using atomic
absorption
spectrophotometry, what reagent is
required to obtain the needed
sensitivity and
precision?
A. Lanthanum
B.
Lithium
C. Triton X-100
D. Chloride | |
front 14 Interference in atomic absorption
spectrophotometry caused by
differences
in viscosity is called:
A. Absorption
interference
B. Matrix effect
C. Ionization
interference
D. Quenching | |
front 15 All of the following are required when
measuring magnesium by
atomic absorption
spectrophotometry except:
A. A hollow
cathode lamp with a magnesium
cathode
B. A chopper to
prevent optical interference from
magnesium emission
C. A
monochromator to isolate the magnesium
emission line at 285
nm
D. A 285-nm reference beam to correct for
background absorption | back 15 D. A 285-nm reference beam to correct for
background absorption |
front 16 When measuring calcium by atomic absorption
spectrophotometry,
which is required?
A. An organic extraction reagent to
deconjugate
calcium from protein
B. An internal
standard
C. A magnesium chelator
D. Lanthanum oxide to
chelate phosphates | back 16 D. Lanthanum oxide to chelate phosphates |
front 17 Select the equation describing the potential that
develops at
the surface of an ion-selective
electrode.
A. van Deemter
equation
B. van Slyke equation
C. Nernst equation
D.
Henderson–Hasselbalch equation | |
front 18 The reference potential of a silver–silver chloride
electrode is
determined by the:
A. Concentration of the potassium chloride
filling
solution
B. Surface area of the electrode
C.
Activity of total anion in the paste covering
the
electrode
D. The concentration of silver in the paste
covering
the electrode | back 18 A. Concentration of the potassium chloride filling
solution |
front 19 The term RT/nF in the Nernst equation
defines the:
A.
Potential at the ion-selective membrane
B. Slope of the
electrode
C. Decomposition potential
D. Isopotential point
of the electrode | back 19 B. Slope of the electrode |
front 20 The ion-selective membrane used to measure
potassium is made
of:
A. High-borosilicate glass membrane
B. Polyvinyl
chloride dioctylphenyl phosphonate
ion exchanger
C.
Valinomycin gel
D. Calomel | |
front 21 The response of a sodium electrode to a 10-fold
increase in
sodium concentration should be:
A. A 10-fold drop in
potential
B. An increase in potential of approximately 60
mV
C. An increase in potential of approximately 10 mV
D. A
decrease in potential of approximately 10 mV | back 21 B. An increase in potential of approximately 60 mV |
front 22 The response of a sodium electrode to a 10-fold
increase in
sodium concentration should be:
A. A 10-fold drop in
potential
B. An increase in potential of approximately 60
mV
C. An increase in potential of approximately 10 mV
D. A
decrease in potential of approximately 10 mV | back 22 B. An increase in potential of approximately 60 mV |
front 23 Which of the electrodes below is a current producing (amperometric)
rather than a voltage-producing (potentiometric) electrode?
A.
Clark electrode
B. Severinghaus electrode
C. pH
electrode
D. Ionized calcium electrode | |
front 24 Which of the following would cause a “response”
error from an
ion-selective electrode for sodium
when measuring serum but not
the calibrator?
A. Interference from other electrolytes
B.
Protein coating the ion-selective membrane
C. An overrange in
sodium concentration
D. Protein binding to sodium ions | back 24 B. Protein coating the ion-selective membrane |
front 25 In polarography, the voltage needed to cause
depolarization of
the cathode is called the:
A. Half-wave potential
B.
Isopotential point
C. Decomposition potential
D.
Polarization potential | |
front 26 Persistent noise from an ion-selective electrode is
most often
caused by:
A. Contamination of sample
B. Blocked junction at
the salt bridge
C. Overrange from high concentration
D.
Improper calibration | back 26 B. Blocked junction at the salt bridge |
front 27 Which element is reduced at the cathode of a
Clark polarographic
electrode?
A. Silver
B. Oxygen
C. Chloride
D. Potassium | |
front 28 Which of the following statements accurately
characterizes the
coulometric titration of chloride?
A. The indicator electrodes
generate voltage
B. Constant current must be present across
the
generator electrodes
C. Silver ions are formed at the
generator cathode
D. Chloride concentration is inversely
proportional
to titration time | back 28 B. Constant current must be present across the
generator electrodes |
front 29 In the coulometric chloride titration:
A. Acetic acid in the
titrating solution furnishes
the counter ion for
reduction
B. The endpoint is detected by amperometry
C. The
titrating reagent contains a phosphate buffer
to keep pH
constant
D. Nitric acid (HNO3 | back 29 B. The endpoint is detected by amperometry |
front 30 Which of the following compounds can interfere
with the
coulometric chloride assay?
A. Bromide
B. Ascorbate
C.
Acetoacetate
D. Nitrate | |
front 31 All of the following compounds contribute to the
osmolality of
plasma except:
A. Lipids
B. Creatinine
C. Drug
metabolites
D. Glucose | |
front 32 One mole per kilogram H2O of any solute will
cause all of the
following except:
A. Lower the freezing point by 1.86°C
B.
Raise vapor pressure by 0.3 mm Hg
C. Raise the boiling point by
0.52°C
D. Raise osmotic pressure by 22.4 atm | back 32 B. Raise vapor pressure by 0.3 mm Hg |
front 33 What component of a freezing point osmometer
measures the sample
temperature?
A. Thermistor
B. Thermocouple
C.
Capacitor
D. Electrode | |
front 34 What type of measuring circuit is used in a
freezing point
osmometer?
A. Electrometer
B. Potentiometer
C.
Wheatstone bridge
D. Thermal conductivity bridge | |
front 35 What type of detector is used in high-performance
liquid
chromatography with electrochemical
detection (HPLC–ECD)?
A.
Calomel electrode
B. Conductivity electrode
C. Glassy carbon
electrode
D. Polarographic electrode | back 35 C. Glassy carbon electrode |
front 36 In gas chromatography, the elution order of
volatiles is usually
based upon the:
A. Boiling point
B. Molecular size
C.
Carbon content
D. Polarity | |
front 37 Select the chemical that is used in most HPLC
procedures to
decrease solvent polarity.
A. Hexane
B. Nonane
C.
Chloroform
D. Acetonitrile | |
front 38 In thin-layer chromatography (TLC), the distance
the solute
migrates divided by the distance the
solvent migrates is
the:
A. tR
B. Kd
C. Rf
D. pK | |
front 39 Which reagent is used in thin-layer
chromatography (TLC) to
extract cocaine
metabolites from urine?
A. Acid and sodium
chloride
B. Alkali and organic solvent
C. Chloroform and
sodium acetate
D. Neutral solution of ethyl acetate | back 39 B. Alkali and organic solvent |
front 40 What is the purpose of an internal standard in
HPLC and GC
methods?
A. To compensate for variation in extraction
and
injection
B. To correct for background
absorbance
C. To compensate for changes in flow rate
D. To
correct for coelution of solutes | back 40 A. To compensate for variation in extraction and
injection |
front 41 What is the confirmatory method for measuring
drugs of
abuse?
A. HPLC
B. Enzyme-multiplied immunoassay
technique
(EMIT)
C. Gas chromatography with mass
spectroscopy
(GC-MS)
D. TLC | back 41 C. Gas chromatography with mass spectroscopy
(GC-MS) |
front 42 What component is used in a GC-MS but not used
in an
LC-MS?
A. Electron source
B. Mass filter
C.
Detector
D. Vacuum | |
front 43 In addition to velocity, what variable is also
needed to
calculate the relative centrifugal force
(g force) of a
centrifuge?
A. Head radius
B. Angular velocity
coefficient
C. Diameter of the centrifuge tube
D. Ambient
temperature in degrees Centigrade | back 43 B. Angular velocity coefficient |
front 44 In addition to velocity, what variable is also
needed to
calculate the relative centrifugal force
(g force) of a
centrifuge?
A. Head radius
B. Angular velocity
coefficient
C. Diameter of the centrifuge tube
D. Ambient
temperature in degrees Centigrade | |
front 45 When calibrating a semiautomatic pipet that has
a fixed delivery
of 10.0 μL using a gravimetric
method, what should be the average
weight of
deionized water transferred?
A. 10.0 μg
B.
100.0 μg
C. 1.0 mg
D. 10.0 mg | |
front 46 Which of the following contributes the most to
the serum total
CO2?
A. PCO2
B. dCO2
C. HCO3
D. Carbonium ion | |
| back 47 Emission of light by molecules in excited states produced by chemical reactions |
| back 48 Study of the relationship of electrical potential and chemical changes |
| back 49 Emission of light by a substance after absorption of electromagnetic
radiation of a shorter wavelength |
| back 50 Chromatographic technique used to separate mixtures of compounds that
are volatile or can be made volatile |
front 51 High-performance liquid chromatography | back 51 Chromatographic technique that uses high pressure and controlled
temperature for fast separations of molecules in a mixture |
| back 52 Electrodes that measure electrical potential produced by the activity
of free ions. Each type is designed to be sensitive toward one type of ion |
| back 53 Technique used to measure the solute concentration of a solution
using one of the four colligative properties, which change in
proportion to osmotic pressure |