Signal and Noise Analysis in an Undergraduate Instrumental Analysis Laboratory

Understanding the difference between signal and noise
in a measurement
is fundamental to analytical chemists. The typical instruments found
in an undergraduate chemistry department can be used to teach this
concept, as well as signal averaging, by giving students hands-on
experience with measurements and data processing. This work presents
an undergraduate laboratory module (homework and experiment) that
provides specific instructions for using gas chromatographs, fluorometers,
a nuclear magnetic resonance spectrometer, an atomic absorption spectrophotometer,
and an infrared spectrometer to collect replicate measurements and
a framework for calculating the noise level, baseline, signal level,
signal-to-noise ratio (SNR), and the signal thresholds for the limits
of detection and quantitation (LOD and LOQ). With these figures of
merit, students can graphically visualize the relationship between
these parameters and the measured data. Also instructive is the graphical
comparison between a single measurement and an ensemble averaged measurement
where the baseline noise is visibly attenuated.