TIME KEEPER .. Naila Machado
TASK KEEPER .. Navy Ros
SCRIBE Kipum Lee
PRESENTER .. .... Marcus Frohm
Date: May, 2001
Abstract:
The AAnalyst 100 (AA100) can be used as an absorption spectrometer
or a flame emission spectrometer without lamps, in which the instrument
measures ion concentrations based on the light emitted upon vaporizing
a sample in the flame. This project involved learning to use the AA100
in the emission mode, and determining its sensitivity (precision and accuracy),
in absorption and emission mode for K and Na. The emission sensitivities
for Na and K were compared with absorption sensitivities and it was determined
that there is no significant difference in sensitivities. For K in
absorption mode, the standard percent deviations for the two test sample
trials were ± 4.01% and ± 3.40%, and in the emission mode,
± 1.41% and ± 0.92%. For Na in the absorption mode,
the standard percent deviations for the two test sample trials were ±
3.83% and ± 3.09%, but values were not found in the emission mode
because no linear range was found. For K in the absorption mode,
the percent error for the two test sample trials were 2.71% and 4.00%,
and in the emission mode, the percent errors were 3.00% and 3.55%.
For Na in the absorption mode, the percent error for the two test sample
trials were 2.00% and 3.71%, but percent error values were not found in
the emission mode because no linear range was found. Since there
were no standard percent deviation and percent error values determined
for Na in the emission mode, comparisons of absorption and emission must
be solely based on the tests done for K. The standard percent deviations
and percent errors calculated for K showed that there was no significant
difference between absorption and emission mode at the 95% confidence intervals
for the respective linear ranges of concentration. The principal accomplishment
of this experiment was finding the optimal settings for K and Na in the
emission mode. Knowing the optimal settings allows the user a great
deal of versatility with the AA100 in emission mode. The optimal
setting for the nebulizer was determined to be 1 turn for both K and Na
in emission mode. The optimal settings for K for the vertical adjustment
knob, horizontal adjustment knob and fuel-to-oxidant ratio were determined
to be 12.5 clockwise turns, 4 clockwise turns, and 2.25, respectively.
The optimal settings for Na for the vertical adjustment knob, horizontal
adjustment knob and fuel-to-oxidant ratio were determined to be 15 clockwise
turns, 2.75 clockwise turns and 2, respectively. All values in the
emission mode linear testing were recorded with the machine at the optimal
settings.