Instrumental Analysis ACS Final Prep questions
with verified answers
5 characteristics of absorption measurements that make it amenable to
quantitative measurements in nearly every field Ans✓✓✓ easy sample
prep
selective
linear response to concentration
sensitive
non-destructive
absorbance from transmittance Ans✓✓✓ A= -log(T)
Capacitance equals Ans✓✓✓ Q/V
Capacitance in a series Ans✓✓✓ 1/C = 1/Ca + 1/Cb
Conventional spectrophotometers Ans✓✓✓ Use mechanical methods
(rotation of a grating) to scan the spectrum. An entire spectrum
requires several minutes to procure. Multichannel instruments have
the advantage of speed and long-term reliability.
Conventional spectrophotometers can be of higher resolution and have
lower stray light characteristics
, Describe how increasing the rod length would affect the ion separation
for a quadrupole Ans✓✓✓ increases the resolution.
The longer the rod, the more time to allow ions with a close but not
exact target to get off track
Desirable characteristics for a radiation transducer? Ans✓✓✓ Constant
response over large wavelength range
Detection range for ion trap Ans✓✓✓ Less than 20,000 g/mol
Detection range for single quadrupole Ans✓✓✓ 1500 to 3000 g/mol
Detection range for TOF Ans✓✓✓ 50000 g/mol
Detection range for triple quadrupole Ans✓✓✓ 1500 to 3000 g/mol
determining resolution from t and W Ans✓✓✓
Doppler effect on a measured signal Ans✓✓✓ movement of excited
atoms toward the detector causes a shortening in the wavelength of
the emitted light
with verified answers
5 characteristics of absorption measurements that make it amenable to
quantitative measurements in nearly every field Ans✓✓✓ easy sample
prep
selective
linear response to concentration
sensitive
non-destructive
absorbance from transmittance Ans✓✓✓ A= -log(T)
Capacitance equals Ans✓✓✓ Q/V
Capacitance in a series Ans✓✓✓ 1/C = 1/Ca + 1/Cb
Conventional spectrophotometers Ans✓✓✓ Use mechanical methods
(rotation of a grating) to scan the spectrum. An entire spectrum
requires several minutes to procure. Multichannel instruments have
the advantage of speed and long-term reliability.
Conventional spectrophotometers can be of higher resolution and have
lower stray light characteristics
, Describe how increasing the rod length would affect the ion separation
for a quadrupole Ans✓✓✓ increases the resolution.
The longer the rod, the more time to allow ions with a close but not
exact target to get off track
Desirable characteristics for a radiation transducer? Ans✓✓✓ Constant
response over large wavelength range
Detection range for ion trap Ans✓✓✓ Less than 20,000 g/mol
Detection range for single quadrupole Ans✓✓✓ 1500 to 3000 g/mol
Detection range for TOF Ans✓✓✓ 50000 g/mol
Detection range for triple quadrupole Ans✓✓✓ 1500 to 3000 g/mol
determining resolution from t and W Ans✓✓✓
Doppler effect on a measured signal Ans✓✓✓ movement of excited
atoms toward the detector causes a shortening in the wavelength of
the emitted light
