Introduction:
For this lab it is our goal to fully understand and be able to use the Atomic Absorption
Spectroscopy (AA) and the Inductively Coupled Plasma Optical Emission Spectroscopy (ICP).
We will accomplish these goals by researching it and running test with it and resolving any
problems that we encounter and learn as we go. By doing these things we will become experts on
these instruments.
Atomic Absorption Spectroscopy is used to analyze the amount of absorption of light by free
atoms. In order to determine the concentration of the atoms, the absorption of light must be
determined, to determine the absorption the atoms must be vaporized by a flame and the atoms
absorb the visible light. In this case the atoms being looked at are metals. Atoms have their own
distinct pattern of wavelengths at which they absorb energy. The AA uses air/acetylene and the
temperature of the flame ranges from 2100-2400°C.
The ICP uses a similar method to that the AA uses. The main difference is that the ICP uses
plasma which is 3-4x the temperature of the AA flame. The ICP uses three concentric quartz
tubes that stream the flow of argon gas. The argon gas creates a discharge which heats up the
plasma. This discharge comes from a radio frequency generator. The plasma can reach a high of
1000K. The plasma picks up the sample which was broken up into droplets due to the argon gas.
This then can be quantified and results gathered.
Objective:
To compare and determine the amount of copper and zinc between surrounding lab water and the
nearby water fountain.
Method: (suggested)
Atomic Absorption Spectroscopy
1. Work with the AA and create standards of copper and zinc. Use a 100mL volumetric
2.
3.
4.
5.
flask to make a 1, 10, 20, 30, 40 ppm of copper and zinc.
Obtain samples of water and put them in 300mL beakers.
a. Obtained water from
i. Organic Chem lab
ii. General Chem lab
iii. Water fountain
iv. Instrumental Chem lab
Run the copper through the AA and then after the zinc. Copper and zinc cannot be tested
for at the same time and must be done separately.
Create a calibration curve for copper and zinc
Record results and put into notebook
ICP
Known concentrations copper and zinc in ppm
1, 10, 20, 30, 40
Can be run during the same time
Unknown copper and zinc concentrations collected in a 250 mL or 300mL beaker
1) Instrumental lab water
2) Organic lab water
3) Gen chem lab water
4) Water fountain outside boys bathroom
Once the calibration curve is known these unknowns concentrations can be figured out for zinc
and copper.
Method: (actual)
Day One:
1.
2.
3.
4.
Read operating procedures and manuals for ICP
Create five standards of copper and zinc at 5, 10, 20, 30, and 40 ppm and put in beakers
Run simulation on computer software and get familiar with software
Collect samples of water for Instrumental Lab, Organic Lab, General Chem Lab, and the
water fountain nearby
Day Two:
1.
2.
3.
4.
Make sure samples and standards are ready to be run
Run standards and samples through ICP for both copper and zinc
Record results and get calibration curve
Print out results
Day Three:
1.
2.
3.
4.
5.
6.
Read operating procedures and manuals for AA
Reuse previously made standards and solutions
Become familiar with the AA software
Run standards and samples through AA for copper and then zinc (order doesn’t matter)
Record results and get calibration curve
Print out results
Day Four:
1. Remake standards at 5, 8, 10, 13, and 15 ppm zinc and copper because previous
concentrations were too high for ICP
2. Rerun standards and samples for ICP for copper and zinc
3. Record results and get calibration curve
4. Print out results
ICP Standard Operating Procedure:
1) Turning on the ICP
a. The cooling unit should be on for ten minutes; this is left of the ICP and is a box.
To turn it on the switch is on the back of the cooling unit.
i. Make sure the unit has cooling liquid in it.
b. Flip the levers on the bottom right of the ICP and make sure that the tubes
attached to them do not twist. Otherwise the flow will be changed.
c. Turn on the argon gas for around 5-10 minutes. This is accomplished by turning
the dial on the argon tank in the gas cylinder room. The dial is on top of the tank
and is to be turned counter clockwise. Also turn the valve so that it is
perpendicular to the tubing (located behind tank). On the left of the instrument
table there is a valve labeled argon gas turn that so it is also parallel with the
tubing.
d. Finally turn on the ICP. You should have a blank in the probe so that the bulb
does not burn out. This should be done at all times you’re not running a sample.
2) Software startup
a. Turn on the computer and click on ICP expert.
b. Click on the button that resembles a lock with electricity in the middle of the top
page, this will turn on the plasma. If you can’t find it there are pictures of the
icon in the ICP log book in the drawer. This should be heated for 15 minutes.
3) Method
a. On the main index window select worksheet.
b. On the load dialog worksheet box select new. You will then have a choice for
either quantitative or time resolved scan, this experiment uses quantitative. Save
the worksheet
c. Open the method editor; this is done by clicking on the box with the hand that
seems to be writing on paper. This should open the elements page.
d. To select the elements you will be looking for (zinc and copper) hold control and
click on the elements. They will then be highlighted blue
e. Click on the standards tab and edit the number of calibration standards. In the
experiment 5 are being used. Select the units of measurement you will be using.
Keep the correlation coefficient the same. Save and exit from file menu
4) Analysis
a. Once the flame has been on for 10 -15 minutes click on the sequence tab under
the worksheet window and make sure the source is set to manual.
b. Click the icon that looks like a wand and a magic hat; this is the sequence editor
icon. Enter the number of samples in the sample field count, on the samples and
calibration page. Click on begin with calibrations and select include a blank,
then click confirm.
c. On the sequence page, select the sequence parameters icon, and choose stop for
the calibration failure option. Click okay to exit and yes to confirm selections.
d. Click the analysis tab and confirm all samples are selected, if not click the tube
cell in top left corner.
e. Click on play icon and follow instructions. If an error message pops up that says
“maximum error exceeded”, just click okay and run your samples
f. After your data is collected place a blank into probe.
g. On data chart, click on the diagonal line to get calibration graph. Print if you
want, the data should print automatically.
5) Turning off ICP
a. To turn off the plasmid press the lock with the electricity button or the F4 key
b. Turn off computer program
c. Turn off argon gas at bench top and in the gas cylinder room. Turn clockwise and
valve on wall and bench top should perpendicular.
d. Turn off ICP
e. After 15 minutes turn off coolant and take out blank.
AA Standard Operating Procedure:
1. Turning of the AA
a. Make sure the exhaust fan is turned on (it should always be on)
b. Then turn on the AA cooling system, which is to left of the AA
c. Then turn on the AA, the power button is on the front left of the machine
d. Then go to the gas room and turn on the air and the acetylene
e. Open the gas valves for air and the acetylene on the left of the AA
f. Make sure the lamps for the specific elements you are looking for are installed
(zinc and copper were already)
2. Open the WinLab 32 software on the desktop of the computer
a. System check will appear for the flame, spectrometer, and the auto sampler
b. Then click the Lamps button at the top left of the screen. A window will open and
turn on the element you are searching for clicking on the on/off button and then
highlight the row of the element. When the light is green, the lamp is turned on.
Wait ten minutes for the lamp to warm up fully and when it is finished close the
window.
3. Create a Method
a. Click the “Wrkspc” button in the menu bar at the top. When a window pops up,
click the “AUTO.flm” or “MAN.flm”. Four new windows will then appear on the
screen.
b. Then click the “File” menu button and click “New” and the “Method”. Then
select the element you are going to be running for this experiment and click the
checkbox for “Recommended Values”.
c. A “Method Editor Window” will then appear. Click the “Spectrometer” tab, and
make sure the appropriate element is chosen. Do not change any of the other
settings.
d. Click the “Calibration” tab. Click the “Equations and Units” tab on the side of the
window. Select the equation of the line you want to use for your experiment (We
used linear through zero). Enter the concentrations (ppm) for your samples and
standards. Click the “Standard Concentrations” tab on the side of the window.
Enter the names of your standards and samples and the concentrations of your
standards in the appropriate places (Do not fill in the A/S column; it will be filled
in by the computer with your results). Close the window
4. Turning on the flame
a. Check to make sure the flame is safe to light by looking at the “Safety Interlocks”
box. Green check means it is safe and a red x means it is not safe and will not
light.
b. Once it is safe to light, click the ignite flame button and the top middle of the
screen. (If it does not light, try again and if it continues to not work, check the
gases being used)
5. Run Standards and Samples
a. Look at the “Manual Analysis Control” screen
b. Place the tube in your blank (distilled water) and click “Analyze Blank”. (When
the green light goes out the sample is done being analyzed)
c. After the blank then run your standards the same way but in the Standard part of
the “Manual Analysis Control” screen
d. After the standards then your samples the same way but in the Sample part of the
“Manual Analysis Control” screen
6. AA Shut-down
a. Flush the probe with deionized water
b. Turn off the flame
c. Turn off the lamp
d. Close the air and acetylene valves at the bench next to the AA
e. Turn off the air and the acetylene in the gas storage room
f. Bleed the gases by clicking on the “Bleed Gases” button in the “Flame Control
Panel”
g. Close the software entirely
h. Turn off the AA
i. Turn off the AA cooling system
Data:
ICP Standard Concentrations for Zinc and Copper
Copper
Intensity (c/s)
200000
Y intercept= -24613+ 14160
R2= .9335
150000
Zinc
100000
Y intercept= -23948 + 12890
R2= .9689
50000
0
0
5
10
15
20
Concentration (ppm)
Concentration
5.
8.
10.
13.
15.
Sample
Instrumental
Organic
General Chem
Water Fountain
Standard Concentrations
Copper Intensity
Zinc Intensity
18652.
43367.
32971.
56595.
74762.
87164.
83727.
129375.
100966.
151985.
ICP Results for Samples
Concentration
Copper
X
67.639
X
707.42
X
90.534
X
412.62
Zinc
103.07
5724.8
202.5
255.02
AA Copper Standard Concentrations
Intensity (c/s)
1.5
Y intercept = .08562 + .03218
1.0
R2= .9943
0.5
0.0
0
10
20
30
40
50
Concentration (ppm)
Concentration
Standard Concentrations
Copper Intensity
5.
10.
20.
30.
40.
Sample
Instrumental
Organic
General Chem
Water Fountain
Zinc Intensity
0.20180
0.39230
0.71940
1.00910
1.24900
AA Results for Samples
Concentration
Copper
X
.3477
X
.346
X
.3458
X
.3458
Calculations:
Calculation of standards:
M1V1=M2V2
1000V=5*100
V=.5
1000V=10*100
N/A
N/A
N/A
N/A
N/A
Zinc
N/A
N/A
N/A
N/A
V=1
1000V=20*100
V=2
1000V=30*100
V=3
1000V=40*100
V=4
New Standards:
M1V1=M2V2
1000V=5*100
V=.5
1000V=8*100
V=.8
1000V=10*100
V=1
1000V=13*100
V=1.3
1000V=15*100
V=1.5
ICP
Copper Samples:
Instrumental Lab
Y= 14160x-24163
67.639=14160x-24163
X= 1.711
Organic Lab
Y= 14160x-24163
707.42=14160x-24163
X=1.756
General Chem Lab
Y= 14160x-24163
90.534=14160x-24163
X=1.713
Water Fountain
Y= 14160x-24163
412.62=14160x-24163
X=1.736
Zinc Samples:
Instrumental Lab
Y= 12890x-23948
103.07=12890x-23948
X= 1.866
Organic Lab
Y= 12890x-23948
5724.8=12890x-23948
X= 2.302
General Chem Lab
Y= 12890x-23948
202.5=12890x-23948
X= 1.874
Water Fountain
Y= 12890x-23948
255.02=12890x-23948
X= 1.878
AA
Copper Samples:
Instrumental Lab
Y=.08562x + .03218
.3477=.08562x + .03218
X=3.685
Organic Lab
Y=.08562x + .03218
.346=.08562x + .03218
X=3.665
General Chem Lab
Y=.08562x + .03218
.3458=.08562x + .03218
X=3.663
Water Fountain
Y=.08562x + .03218
.3458=.08562x + .03218
X=3.663
Zinc Samples:
We were not able to calculate the zinc concentration because our standards were too high and if
done next time, should be made smaller.
Conclusion:
Our results for the ICP came out nicely and we received good R2 values. For zinc we got R2=
.9689 and for copper we got R2= .9335. This shows that the ICP was running properly. The
results could have been better since the ICP is a very precise machine. Our results for the AA
came out differently compared to the ICP. When we used the AA, we did not get any zinc results
and our copper results were not the best. We tried different ppm for the ICP because we had
enough time and the lower the ppm, the better the results turned out. If we had more time we
would have run the AA again for both copper and zinc in order to get the best and the most
accurate results. Our standards for the AA for some copper and zinc were too high and caused
out calibration curve to suffer greatly.