INSTRUMENTAL ANALYSIS ACS
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what are the difference between calibration sensitivity and analytical sensitivity -
ANSWERcalibration sensitivity is the slope of a calibration curve at the concentration of
interest while analytical sensitivity is a response to the noise ratio
how to calculate calibration sensitivity - ANSWERy=mx+b (m is the calibration
sensitivity)
graph concentration vs mean analytical signal
how to find the analytical sensitivity - ANSWERAs (concentation) = calibration
sensitivity/SD [ ]
how to find the coefficient of variation for the mean of each of the replicate sets -
ANSWERCV = SD/Average x 100
how to find the detection limit for method? - ANSWER3.3*SD(blank)/calibration
sensitivity
voltage in a series - ANSWERVt = Vc + Vb + Va
Voltage in a parallel circuit - ANSWER1/Veff = 1/Va + 1/Vb
Capacitance in a series - ANSWER1/Ceff = 1/Ca + 1/Cb
capacitance equals - ANSWERQ/V
if a spectrum is the result of a single scan while another is the result of multiple scans,
how man individual spectra were summed to increase S/N from 4.2 to 43?
a) formula?
b) answer - ANSWERa) (S/N)a = sqrt(n) (S/N)b
b) 105
what type of noise can be reduced by decreasing the temperature of a measurement -
ANSWERthermal noise
what type of noise can be reduced by decreasing the frequency used for the
measurement - ANSWERflicker noise
what type of noise can be reduced by decreasing the bandwidth of the measurement -
ANSWERenvironmental noise
, What would be an appropriate source and detector to determine the emission lines for
lithium from 200 to 780 nm? - ANSWERflame and photo multiplier tube (PMT)
you've been asked to measure the UV absorbance of a sample containing poly cyclic
aromatic hydrocarbons, a byproduct of the incomplete combustion of organic matter.
What would be an appropriate material for the sample container? - ANSWERfused silica
or quartz
which of the following changes will result in a decreased effective bandwidth?
a) increasing the number of blazes in the monochromatic grating
b) switching from a short-pass filter to a long-pass filter
c) increasing sample concentration
d) decreasing the amount of stray light - ANSWERa
what would be the distance between blazes for a grating where the first order diffraction
line for 600 nm light is reflected at 10 degrees and the angle of incidence light is 45
degrees?
a) formula
b) answer - ANSWERa) n(wavelength) = distance*(sin(i)+sin(r))
b) 680 nm
which of the following would be considered a discontinuous wavelength selector?
a) quartz prism
b) Czerny-Turner Grating (monochormator)
c)interference filter
d)glass prism - ANSWERc
which characteristics are desirable for a radiation transducer?
a) high sensitivity to short wavelength light
b) low S/N ratio
c) consistent high output when not illuminated
d) constant response over large wavelength range
e) all of the above - ANSWERd
what is the appropriate process for atomization for AAS and AES? (3 steps) -
ANSWERdesolvation, vaporization, atomization
the doppler effect is one reason for line broadening in atomic spectroscopy. What is the
effect on a measured signal? - ANSWERmovement of excited atoms toward the
detector causes a shortening in the wavelength of the emitted light
it is better to select an excitation source for AAS with ____bandwidth - ANSWERsmaller
what is the general layout for AES? - ANSWERsample --> source --> wavelength
selector --> detector
FINAL PREP 100% VERIFIED
what are the difference between calibration sensitivity and analytical sensitivity -
ANSWERcalibration sensitivity is the slope of a calibration curve at the concentration of
interest while analytical sensitivity is a response to the noise ratio
how to calculate calibration sensitivity - ANSWERy=mx+b (m is the calibration
sensitivity)
graph concentration vs mean analytical signal
how to find the analytical sensitivity - ANSWERAs (concentation) = calibration
sensitivity/SD [ ]
how to find the coefficient of variation for the mean of each of the replicate sets -
ANSWERCV = SD/Average x 100
how to find the detection limit for method? - ANSWER3.3*SD(blank)/calibration
sensitivity
voltage in a series - ANSWERVt = Vc + Vb + Va
Voltage in a parallel circuit - ANSWER1/Veff = 1/Va + 1/Vb
Capacitance in a series - ANSWER1/Ceff = 1/Ca + 1/Cb
capacitance equals - ANSWERQ/V
if a spectrum is the result of a single scan while another is the result of multiple scans,
how man individual spectra were summed to increase S/N from 4.2 to 43?
a) formula?
b) answer - ANSWERa) (S/N)a = sqrt(n) (S/N)b
b) 105
what type of noise can be reduced by decreasing the temperature of a measurement -
ANSWERthermal noise
what type of noise can be reduced by decreasing the frequency used for the
measurement - ANSWERflicker noise
what type of noise can be reduced by decreasing the bandwidth of the measurement -
ANSWERenvironmental noise
, What would be an appropriate source and detector to determine the emission lines for
lithium from 200 to 780 nm? - ANSWERflame and photo multiplier tube (PMT)
you've been asked to measure the UV absorbance of a sample containing poly cyclic
aromatic hydrocarbons, a byproduct of the incomplete combustion of organic matter.
What would be an appropriate material for the sample container? - ANSWERfused silica
or quartz
which of the following changes will result in a decreased effective bandwidth?
a) increasing the number of blazes in the monochromatic grating
b) switching from a short-pass filter to a long-pass filter
c) increasing sample concentration
d) decreasing the amount of stray light - ANSWERa
what would be the distance between blazes for a grating where the first order diffraction
line for 600 nm light is reflected at 10 degrees and the angle of incidence light is 45
degrees?
a) formula
b) answer - ANSWERa) n(wavelength) = distance*(sin(i)+sin(r))
b) 680 nm
which of the following would be considered a discontinuous wavelength selector?
a) quartz prism
b) Czerny-Turner Grating (monochormator)
c)interference filter
d)glass prism - ANSWERc
which characteristics are desirable for a radiation transducer?
a) high sensitivity to short wavelength light
b) low S/N ratio
c) consistent high output when not illuminated
d) constant response over large wavelength range
e) all of the above - ANSWERd
what is the appropriate process for atomization for AAS and AES? (3 steps) -
ANSWERdesolvation, vaporization, atomization
the doppler effect is one reason for line broadening in atomic spectroscopy. What is the
effect on a measured signal? - ANSWERmovement of excited atoms toward the
detector causes a shortening in the wavelength of the emitted light
it is better to select an excitation source for AAS with ____bandwidth - ANSWERsmaller
what is the general layout for AES? - ANSWERsample --> source --> wavelength
selector --> detector
