BLD 313 EXAM 3 QUESTIONS AND ANSWERS WITH COMPLETE
SOLUTIONS GRADED A++
Qualitative Data
Presence or Absence: positive or negative
Description of physical characteristics and the example
Semi-quantitative data
An estimate of concentration
Based on an arbitrary scale
ex: 1+ ; 0-5
Quantitative Data
Based on measurement
Concentration based on a change of some signal
Produces a value with units
Signal
We convert signal to concentration:
Concentration is determined by relating change in signal to a scale
Monitored Signals
Light based, electronic based, physical characteristics
Light based
Change in intensity
*Absorbance
,*Fluorescence
*Chemiluminescence
*Scatter
*More
Electronic based
Voltage
Current
Resistance
Physical characteristics
Temperature
Freezing point / boiling point
Vapor pressure
Change in rate of signal generation
Change in signal per unit of time
Signal on y axis
Time on x
Slope = change in rate of signal generation
Change of signal frequency
Signal repetition rate
# of signals per minute
Change in duration of signal
How long each signal is expressed
Factors that affect response / concentration relationship
, Noise, drift/shift, artifactual output
Noise
Fluctuations in output from a property of electronic system
-Effect of the fluctuation depends on the ratio of signal to noise (on a separate card)
Drift and Shift
Drift: Signal baseline creep up / down
-Upward drift: Overestimate the concentration
-Downward drift: underestimate the concentration
Shift: Signal baseline shift up / down
Signal to noise ratio
Low signal may be hidden by high noise. Lower noise will allow to detect small signal.
High signal with low noise is the best condition
Noise width: affects reportable significant figures
Artifactual output
non reproducible output from the property of electronic system. (Peak of the signal and
time graph)
Analytical Range
Standard curve must be within analytical range.
Upper limit of linearity
-Neat Data (graphic method)
SOLUTIONS GRADED A++
Qualitative Data
Presence or Absence: positive or negative
Description of physical characteristics and the example
Semi-quantitative data
An estimate of concentration
Based on an arbitrary scale
ex: 1+ ; 0-5
Quantitative Data
Based on measurement
Concentration based on a change of some signal
Produces a value with units
Signal
We convert signal to concentration:
Concentration is determined by relating change in signal to a scale
Monitored Signals
Light based, electronic based, physical characteristics
Light based
Change in intensity
*Absorbance
,*Fluorescence
*Chemiluminescence
*Scatter
*More
Electronic based
Voltage
Current
Resistance
Physical characteristics
Temperature
Freezing point / boiling point
Vapor pressure
Change in rate of signal generation
Change in signal per unit of time
Signal on y axis
Time on x
Slope = change in rate of signal generation
Change of signal frequency
Signal repetition rate
# of signals per minute
Change in duration of signal
How long each signal is expressed
Factors that affect response / concentration relationship
, Noise, drift/shift, artifactual output
Noise
Fluctuations in output from a property of electronic system
-Effect of the fluctuation depends on the ratio of signal to noise (on a separate card)
Drift and Shift
Drift: Signal baseline creep up / down
-Upward drift: Overestimate the concentration
-Downward drift: underestimate the concentration
Shift: Signal baseline shift up / down
Signal to noise ratio
Low signal may be hidden by high noise. Lower noise will allow to detect small signal.
High signal with low noise is the best condition
Noise width: affects reportable significant figures
Artifactual output
non reproducible output from the property of electronic system. (Peak of the signal and
time graph)
Analytical Range
Standard curve must be within analytical range.
Upper limit of linearity
-Neat Data (graphic method)
