Atomic Absorption SpectrometerVarian SpectrAA Model 220FS
The InstrumentThe instrument consists of:A flameLamps to produce
the correct wavelength of lightA detectorA system to aspirate
solutions into the flameA computer to control the experiment
The InstrumentOn the left is the flame (behind the grid) and the
spectrometer. The two bottles contain water used for flushing the
tubing and for diluting solutions that are too concentrated. The
round object is a pump.On the right is a cabinet containing the
lamps shown on a later slide.The flame, like all large burners, is
vented at the top.
The Lamps
From bottom to top, the lamps are for Mg, Ca, K, and a
combination of Fe, Co, Ni, Mn, Cu, and Cr. Each element uses a
specific wavelength of light.
The Flame The flame is with only water being aspirated.The two
holes, left and right, are where the light beam enters and leaves
after passing through the flame.The dark place at the top is a
stain from the heat of the flame.
The InstrumentCurrent spectrometers use a PC Computer to control
the experment.There needs to be standards (solutions of known
concentration) to calibrate the instrument.The experiment must be
setup in the program controlling the experiment withIons to be
analyzedConcentration of the standardsNumber of points to be
measuredWavelength of lightLamp Position
Measurement - Standards A set of standards ready to be aspirated
into the flame. This instrument automatically dilutes the
solution.
Aspiration of the Solution Being Measured A sample of maple
syrup ready to be aspirated into the flame.
The PC Screen The solution being measured has an absorbance of
0.068 which corresponds to a concentration of 10.2 ppm
Colors Produced by Different IonsThe following slides show the
colors of different ions in the flame. The differences in intensity
of the colors is, in part, due to differences in concentration.
The Calcium Flame The calcium flame is red. This is intensely
red because the calcium content is high.
The Copper Flame
The Potassium Flame
The Manganese Flame
The Cobalt Flame
ResultsThe computer stores the data which can be printed.The
experiment can be set up to show the calibration curve and the
concentrations on the screen. To get reliable concentrations, the
program must be told what fitting algorithm to use. As can be seen
on the screen shown previously, the calibration data are not linear
in that instance.
