Instrumental Analysis Exam 2026
Questions and Answers
transducer - Correct answer-A device that converts energy from one form to
another-- electrical energy to non electrical
processor - Correct answer-processes signal
readout - Correct answer-converts signals to something understandable by the
human observer
External calibration - Correct answer-Calibration procedure where a series of
external standard samples are prepared separately from the analytical sample; used
when there are no interference effects from matrix components in the analytical
sample; calibration is accomplished by measuring an analytical property, e.g.
absorbance, as a function of analyte concentration in a series of external standards;
calibration curve is then used to predict concentration of unknown.
standard addition - Correct answer-A technique in which an analytical signal due to
an unknown is first measured. Then a known quantity of analyte is added, and the
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,increase in signal is recorded. From the response, it is possible to calculate what
quantity of analyte was in the unknown.
spiking- adding known increments to sample aliquots containing identical volumes
internal standard - Correct answer-A known quantity of a compound other than
analyte added to a solution containing an unknown quantity of analyte. The
concentration of analyte is then measured relative to that of the internal standard.
most accurate method
internal standard guidelines - Correct answer-I.S. similar signal response with
analyte
I.S. known to be absent from the sample
I.S. not affect signal intensity of the analyte
precision - Correct answer-a measure of how close a series of measurements are to
one another
-absolute std, relative srd. coefficient of variation, variance-
bias - Correct answer-systematic error of an analytic method
absolute sys error, rel sys error
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
, sensitivity - Correct answer-ability to discriminate between small differences
calibration sensitivity, analytical sensitivity
detection limit - Correct answer-minimum concentration or mass of analyte that
can be detected at a known confidence level
blank plus 3xSTD of the blank
dynamic range - Correct answer-concentration LOQ to LOL
selectivity - Correct answer-degree to which the method is free from interference
by other species contained in the sample matrix
coefficient of selectivity
LOD - Correct answer-Limit of Detection- smallest amount detected
LOQ - Correct answer-Limit of quantification- smallest amount quantifiable
LOL - Correct answer-limit of linearity- limit that it is linear
Chemical Noise - Correct answer-Random signal fluctuations that result from a
variety of uncontrollable variables, e.g. temperature, pressure, humidity, vibrations,
etc.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
Questions and Answers
transducer - Correct answer-A device that converts energy from one form to
another-- electrical energy to non electrical
processor - Correct answer-processes signal
readout - Correct answer-converts signals to something understandable by the
human observer
External calibration - Correct answer-Calibration procedure where a series of
external standard samples are prepared separately from the analytical sample; used
when there are no interference effects from matrix components in the analytical
sample; calibration is accomplished by measuring an analytical property, e.g.
absorbance, as a function of analyte concentration in a series of external standards;
calibration curve is then used to predict concentration of unknown.
standard addition - Correct answer-A technique in which an analytical signal due to
an unknown is first measured. Then a known quantity of analyte is added, and the
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,increase in signal is recorded. From the response, it is possible to calculate what
quantity of analyte was in the unknown.
spiking- adding known increments to sample aliquots containing identical volumes
internal standard - Correct answer-A known quantity of a compound other than
analyte added to a solution containing an unknown quantity of analyte. The
concentration of analyte is then measured relative to that of the internal standard.
most accurate method
internal standard guidelines - Correct answer-I.S. similar signal response with
analyte
I.S. known to be absent from the sample
I.S. not affect signal intensity of the analyte
precision - Correct answer-a measure of how close a series of measurements are to
one another
-absolute std, relative srd. coefficient of variation, variance-
bias - Correct answer-systematic error of an analytic method
absolute sys error, rel sys error
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
, sensitivity - Correct answer-ability to discriminate between small differences
calibration sensitivity, analytical sensitivity
detection limit - Correct answer-minimum concentration or mass of analyte that
can be detected at a known confidence level
blank plus 3xSTD of the blank
dynamic range - Correct answer-concentration LOQ to LOL
selectivity - Correct answer-degree to which the method is free from interference
by other species contained in the sample matrix
coefficient of selectivity
LOD - Correct answer-Limit of Detection- smallest amount detected
LOQ - Correct answer-Limit of quantification- smallest amount quantifiable
LOL - Correct answer-limit of linearity- limit that it is linear
Chemical Noise - Correct answer-Random signal fluctuations that result from a
variety of uncontrollable variables, e.g. temperature, pressure, humidity, vibrations,
etc.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
