ACS INSTRUMENTAL ANALYSIS Exam 2026|2027 Advanced Practice
Questions and Answers with Complete A+ Solutions 100% Correct!!!
Calculations for Raman Stokes and anti-stokes lines, Raleigh scattering and Raman
scattering - Correct Answer --Rayleigh scattering -same frequency
E = hν
- Raman scattering -changes in frequency
- Stokes lines: E = hν - ΔE
- Anti-Stokes lines: E = hν +ΔE
Appropriate sources/materials used in various instrumentation - Correct Answer -
Signal to noise calculations - Correct Answer -
Beer's law theory and calculations - Correct Answer -A = a·b·c
A =ε·b·c
Transmittance T = P/Po
• Percent Transmittance %T =(P/Po)x100%
1|Page
,• Absorbance A = -logT = -log(P/Po)
Mass spec hard vs. soft ionization sources (examples of each, how are they different?) -
Correct Answer -Hard:
-EI
-
Soft:
-electrospray
-MALDI
-chemical
Mass spec instruments, advantages for quadrupole, TOF, etc. - Correct Answer -
Theory behind MALDI - Correct Answer --used for high-boiling materials
-usually produces monovalent ions
-dissolve target analyte in solution containing crystal forming cmpd; droplets of solution are
deposited on a metal plate and solvent is allowed to evaporate, leaving analyte trapped in
crystalline matrix
2|Page
,Atomic emission/ ICP theory, deviations to Beers law - Correct Answer -
Precision, sensitivity trade-offs with GFAA, flame, ICP? - Correct Answer -
Stokes shift theory for fluorescence - Correct Answer -
Common detectors for Raman - Correct Answer -
Beer's law extension to mixtures of compounds - Correct Answer -
Comparison in sensitivity of absorbance vs. fluorescence methods - Correct Answer -The
sensitivity of a spectrophotometer is often inadequate at low sample concentrations.
Researchers may need to concentrate their sample, adding additional steps and time to
their workflow.
The sensitivity of fluorescence detection is approximately 1,000 times greater than
absorption spectrophotometric methods. This leads to greater limits of detection, while
3|Page
, potentially using less sample material. This is important especially when working with
precious or limited-quantity materials.
Groove density and focal length considerations for resolution - Correct Answer -The
resolving power of a grating is the product of the diffracted
order in which it is used and the number of grooves illuminated
by the incident radiation. It can also be expressed in terms of
grating width, groove spacing, and diffracted angles. Resolving
power is a property of the grating, and therefore, unlike
resolution, it is not dependent on the optical and mechanical
characteristics of the system in which it is used.
The resolution of an optical system, usually determined by
examination of closely spaced absorption or emission lines for
adherence to the Rayleigh criteria (R = λ/Δλ), depends not only on
the grating resolving power but also on focal length, slit size, f
number, the optical quality of all components, and system
alignment. The resolution of an optical system is usually much less
than the resolving power of the grating.
A grating with a large angular dispersion can
produce good resolution in a compact optical system. Angular
dispersion is the slope of the curve given by λ = f(θ).
4|Page
Questions and Answers with Complete A+ Solutions 100% Correct!!!
Calculations for Raman Stokes and anti-stokes lines, Raleigh scattering and Raman
scattering - Correct Answer --Rayleigh scattering -same frequency
E = hν
- Raman scattering -changes in frequency
- Stokes lines: E = hν - ΔE
- Anti-Stokes lines: E = hν +ΔE
Appropriate sources/materials used in various instrumentation - Correct Answer -
Signal to noise calculations - Correct Answer -
Beer's law theory and calculations - Correct Answer -A = a·b·c
A =ε·b·c
Transmittance T = P/Po
• Percent Transmittance %T =(P/Po)x100%
1|Page
,• Absorbance A = -logT = -log(P/Po)
Mass spec hard vs. soft ionization sources (examples of each, how are they different?) -
Correct Answer -Hard:
-EI
-
Soft:
-electrospray
-MALDI
-chemical
Mass spec instruments, advantages for quadrupole, TOF, etc. - Correct Answer -
Theory behind MALDI - Correct Answer --used for high-boiling materials
-usually produces monovalent ions
-dissolve target analyte in solution containing crystal forming cmpd; droplets of solution are
deposited on a metal plate and solvent is allowed to evaporate, leaving analyte trapped in
crystalline matrix
2|Page
,Atomic emission/ ICP theory, deviations to Beers law - Correct Answer -
Precision, sensitivity trade-offs with GFAA, flame, ICP? - Correct Answer -
Stokes shift theory for fluorescence - Correct Answer -
Common detectors for Raman - Correct Answer -
Beer's law extension to mixtures of compounds - Correct Answer -
Comparison in sensitivity of absorbance vs. fluorescence methods - Correct Answer -The
sensitivity of a spectrophotometer is often inadequate at low sample concentrations.
Researchers may need to concentrate their sample, adding additional steps and time to
their workflow.
The sensitivity of fluorescence detection is approximately 1,000 times greater than
absorption spectrophotometric methods. This leads to greater limits of detection, while
3|Page
, potentially using less sample material. This is important especially when working with
precious or limited-quantity materials.
Groove density and focal length considerations for resolution - Correct Answer -The
resolving power of a grating is the product of the diffracted
order in which it is used and the number of grooves illuminated
by the incident radiation. It can also be expressed in terms of
grating width, groove spacing, and diffracted angles. Resolving
power is a property of the grating, and therefore, unlike
resolution, it is not dependent on the optical and mechanical
characteristics of the system in which it is used.
The resolution of an optical system, usually determined by
examination of closely spaced absorption or emission lines for
adherence to the Rayleigh criteria (R = λ/Δλ), depends not only on
the grating resolving power but also on focal length, slit size, f
number, the optical quality of all components, and system
alignment. The resolution of an optical system is usually much less
than the resolving power of the grating.
A grating with a large angular dispersion can
produce good resolution in a compact optical system. Angular
dispersion is the slope of the curve given by λ = f(θ).
4|Page
