Elizabethtown College Department of Chemistry
Last Updated by KK 1/09
8.
Enter the appropriate information into the Users’ Log found in the drawer below the instrument.
Be certain to record any unusual observations or changes that you make to the instrument.
FOR FLAME MEASUREMENTS:
9.
On the computer, select and launch the AA WinLab Analyst Software. The software will initialize
and establish communication with the spectrometer. If the initialization step includes a verification
that the furnace is on (
i.e.
, you are the first to use the flame set-up after the instrument has been
used in graphite furnace mode), you will need to exit the Checking Connections box and select
Flame on the Technique menu bar.
10.
When prompted, select “Use the basic system procedure for…” and choose the setup designated by
your instructor. Alternatively, you may develop your own setup by consulting the appropriate
section in the instrument manual.
11.
If necessary,
a.
align the lamp according to the procedures outlined in the
AA Winlab Software
Guide for Atomic Absorption Spectroscopy
, Section 3-3.
b.
adjust the burner height as described in the
AAnalyst 100/300 Atomic Absorption
Spectrometer Hardware Guide for Atomic Absorption Spectroscopy
, Section 4-74.
12.
Consult the literature and/or the methods manuals to determine the appropriate gas mixture for
measurement of your metal ion analyte.
a.
Turn on the air supply and adjust the outlet pressure to 60 psi or that which you
determined from the literature.
b.
Turn on the acetylene supply and adjust the outlet pressure to 13-14 psi or that
which you determined from the literature.
13.
Double check that you know the location of the fire extinguisher, and then select Flame from the
Toolbar, and light the burner. Close the flame control window, and make certain that the Print Log
has been selected.
14.
Measure Blank, Standards, and Sample(s)
a.
Aspirate a blank solution (solvent matrix with no analyte), and select Analyze
Blank. NOTE: When you remove the aspiration tube from a solution, insert it
quickly into the next solution to prevent significant gas build-up in the tube.
b.
Aspirate a standard solution beginning with the least concentrated. When the
reading stabilizes, select Analyze Standard. Record the absorbance in your
notebook. Repeat this step with each of your standard solutions in order of
increasing concentration.
c.
Aspirate your sample solution(s), and select Analyze Sample when the absorbance
reading stabilizes. Verify that the absorbance for your sample falls between the
readings for your standards. If it is too high, you will wish to dilute and re-measure
the sample. If it is too low but within the detection limits of the instrument, you will
wish to prepare and measure standard solutions of lower concentration.
d.
Aspirate the blank solution again, and record the reading in your notebook. A value
that differs significantly from zero is problematic and will require your attention.
e.
Record all measured absorbances in your notebook.
