Instrumental Analysis questions with verified
answers
Accuracy Ans✓✓✓ = mean - known value / known value x 100
Advantages of a furnace over a flame in atomic absorption Ans✓✓✓ A
smaller sample amount is required
Higher sensitivity because the atomized sample is in the optical path
longer
Advantages of AA Ans✓✓✓ Detection limits in low ppm to high ppb
range
Narrow bandwidths = little overlap in spectra, allowing for detection of
many elements at once
Atomic absorption Ans✓✓✓ The atomized sample in the flame absorbs
a portion of the radiation emitted from the source, which is composed
of same element being analyzed. The amount of radiation passing
through flame unabsorbed by analyte is measured.
Atomic emission Ans✓✓✓ Atoms are thermally promoted to the
excited state by collisions in the plasma. As they return to a low energy
state, they emit photons. No excitation source outside of the plasma
(like a lamp) is required.
, Atomic fluorescence Ans✓✓✓ Sample atomized in flame. A laser
promotors atoms in flame to an excited state. As atoms return to
ground stat, they fluoresce.
Atomic spectroscopy requires background correction to.... Ans✓✓✓
Distinguish analyte signal from absorption, emission, and optical
scattering of sample matrix, flame, plasma, or furnace
Boltzmann distribution Ans✓✓✓ Describes the population ratio of
different states at thermal equilibrium
Calibration check Ans✓✓✓ Analysis of solutions formulated to contain
known concentrations of analyte
Calibration check Ans✓✓✓ Using a set of standards with known values
to ensure your calibration curve is acceptable. These samples should be
prepared using standards that are independent from the standards in
which the calibration curve was made from
Detection limit Ans✓✓✓ Limit of detection=3 x's the standard
deviation
Dynamic range Ans✓✓✓ Concentration interval over which there is a
measurable response to a change in analyte concentration
answers
Accuracy Ans✓✓✓ = mean - known value / known value x 100
Advantages of a furnace over a flame in atomic absorption Ans✓✓✓ A
smaller sample amount is required
Higher sensitivity because the atomized sample is in the optical path
longer
Advantages of AA Ans✓✓✓ Detection limits in low ppm to high ppb
range
Narrow bandwidths = little overlap in spectra, allowing for detection of
many elements at once
Atomic absorption Ans✓✓✓ The atomized sample in the flame absorbs
a portion of the radiation emitted from the source, which is composed
of same element being analyzed. The amount of radiation passing
through flame unabsorbed by analyte is measured.
Atomic emission Ans✓✓✓ Atoms are thermally promoted to the
excited state by collisions in the plasma. As they return to a low energy
state, they emit photons. No excitation source outside of the plasma
(like a lamp) is required.
, Atomic fluorescence Ans✓✓✓ Sample atomized in flame. A laser
promotors atoms in flame to an excited state. As atoms return to
ground stat, they fluoresce.
Atomic spectroscopy requires background correction to.... Ans✓✓✓
Distinguish analyte signal from absorption, emission, and optical
scattering of sample matrix, flame, plasma, or furnace
Boltzmann distribution Ans✓✓✓ Describes the population ratio of
different states at thermal equilibrium
Calibration check Ans✓✓✓ Analysis of solutions formulated to contain
known concentrations of analyte
Calibration check Ans✓✓✓ Using a set of standards with known values
to ensure your calibration curve is acceptable. These samples should be
prepared using standards that are independent from the standards in
which the calibration curve was made from
Detection limit Ans✓✓✓ Limit of detection=3 x's the standard
deviation
Dynamic range Ans✓✓✓ Concentration interval over which there is a
measurable response to a change in analyte concentration
