Lab 7- ICP and AA
Intro: The AA, or atomic absorption, is perfect for analyzing metals, specifically in the ppm
range. The AA in our lab uses an air/acetylene flame. The ICP, or inductively coupled plasma,
uses the same technique as the AA, but instead uses plasma, and can run several samples at once.
Purpose: To become familiar with both the ICP and the AA, and learn the pros and cons of both
instruments.
Procedure:
Day one: Create calibration curves using zinc and copper samples.
Day two: Continue making a calibration curve for the second metal on the AA.
AA method:
Turn on acetylene and compressed air
Open winlab32
Turn on lamps, and allow them 15 minutes to warm up
Choose instrumental settings according to SOP
Turn on flame and analyze metal sample
ICP method:
Turn on cooling system and exhaust vent. Let run for 15 minutes
Turn on argon gas
Click on ICP expert program
Set up parameters according to SOP
Allow plasma torch to heat up for 10-15 minutes
Run your samples
AA data:
Atomic Absorption Information for Zinc (Zn) Standard Samples
Standard
Mean Absorbance
Theoretical
Actual
Sample ID
(Abs)
Concentration
Concentration
(#)
(ppm)
(ppm)
Blank
1
2
3
4
5
0.0000
0.0124
0.0202
1.1338
1.7094
1.7244
0 (ppm)
10 (ppm)
20 (ppm)
30 (ppm)
40 (ppm)
50 (ppm)
Equation of The Line
y = 0.04236x – 0.29233
r = 0.926966
6.901 (ppm)
7.195 (ppm)
7.377 (ppm)
33.666 (ppm)
47.254 (ppm)
47.608 (ppm)
Atomic Absorption Information for Copper (cu) Standard Samples
Standard
Mean Absorbance
Theoretical
Actual
Sample ID
(Abs)
Concentration
Concentration
(#)
(ppm)
(ppm)
Blank
1
2
3
4
5
0.0000
0.3711
0.7989
1.1057
1.3738
1.5867
0 (ppm)
10 (ppm)
20 (ppm)
30 (ppm)
40 (ppm)
50 (ppm)
Equation of The Line
y = 0.03214x + 0.06926
Correlation Coefficient
r = 0.992798
-2.155 (ppm)
9.393 (ppm)
22.704 (ppm)
32.250 (ppm)
40.592 (ppm)
47.216 (ppm)
Atomic Absorption Information for Copper (cu) Unknown Samples
Standard
Mean Absorbance
Theoretical
Actual
Sample ID
(Abs)
Concentration
Concentration
(#)
(ppm)
(ppm)
1
---2.106 (ppm)
2
---2.111 (ppm)
3
---2.111 (ppm)
Atomic Absorption Information for Zinc (Zn) Unknown Samples
Standard
Mean
Theoretical
Actual
Sample ID
Absorbance
Concentration
Concentration
(#)
(Abs)
(ppm)
(ppm)
1
2
3
----
----
1.217 (ppm)
1.214 (ppm)
1.214 (ppm)
ICP data:
Standard Sample Data Output From The ICP
For Zinc (Zn) and Copper (Cu)
Metal Type
Copper 1
Copper 2
Copper 3
Copper 4
Copper 5
Zinc 1
Zinc 2
Zinc 3
Theoretical Concentration
10 (ppm)
20 (ppm)
30 (ppm)
40 (ppm)
50 (ppm)
10 (ppm)
20 (ppm)
30 (ppm)
Actual Concentration
9.4249
18.353
29.734
35.736
51.841
9.8685
18.8660
30.3460
Zinc 4
Zinc 5
40 (ppm)
50 (ppm)
Equation of the Line
y = 6277.14x + 191.561
r = 0.999354
y = 5531.5x + 127.893
r = 0.994133
39.383
-------
(Zn)
(Cu)
Concentration of Zinc and Copper in the Unknown Samples
Unknown Sample ID
Metal Analysis
Concentration
Bathroom Water
Zinc/Copper
0.009857/0.020924
Lab Water
Zinc/Copper
0.041252/0.057655
Fountain Water
Zinc/Copper
0.119710/0.110210
Conclusion:
Our zinc and copper calibration curves on the AA were successful, since the correlation
coefficients were fairly high. We obtained 0.992798 for copper, and 0.926966 for zinc. We had
to rerun out initial analysis for zinc, because the concentrations were too close. We’re pretty sure
we accidentally made two samples of the same concentration. For the water samples, we used
bathroom (1) lab (2) and fountain water (3). All the water samples contained about 1.2ppm of
zinc, which is common for tap water. However, we received negative numbers for copper, which
we can assume means there is no copper present, or there was some sort of error. Other elements
or filtering agents present in the water may have manipulated these results. Our results from the
ICP were much more accurate. The correlation coefficients for both elements were around .99.
We used the same types of water in the ICP as we did in the AA, but got different results. Zinc
was found in concentrations of 0.009857, 0.041252, and 0.119710. We also got positive results
for copper present in the water, indicating that the AA analysis was incorrect. In the end, it seems
that the ICP is the better instrument. It quantifies more accurately, and can run multiple metals at
once, while the AA is less accurate and can only run one metal at a time.