The Determination of water Soluble Ionic
Species (Cl-, NO3-, and SO42-) in Airborne
Particulates by Ion Chromatography
1. Introduction
1.1 Objective
Determinate the concentration of certain soluble species in aerosol particles by using
Ion Chromatography.
2. Experimental& Result
2.1 Experimental Condition
Temperature (outside): 29℃[1]
Table 1. Ion chromatography Parameters
Flow Rate
1.0 mL/min
Column Information
Dionex IonPac AS11 Hydroxide-Selective Anion-Exchange Column
Auto-Suppressor
Dionex Anion Self-Regenerating Suppressor (ASRS)
Injection Volume
10.0μL
2.2 Data and Data Treatment
2.2.1 For ClCl- stock solution = 100.0 ppm
Table 2. Information of ClName
Volume of Cl- stock/ mL
Final [Cl-]/ ppm
Area of Peak/ μs*min
Standard 1
0.25
1.005
0.1648
Standard 2
0.50
2.01
0.3247
Standard 3
0.75
3.015
0.4727
Standard 4
1.00
4.02
0.6727
Standard 5
1.25
5.025
0.7889
Sample
-
-
0.2466
Area of peak
Calibration Curve of Cl0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
y = 0,1588x + 0,0059
R² = 0,9954
Ряд1
Линейная (Ряд1)
0
2
4
6
Calibration Curve of Cl- /ppm
Figure 1. Calibration Curve of Cl-
The regression equation of Cl- is:
Y = 0.158X + 0.005 𝑅 2 = 0.995
The concentration of Cl- sample is:
0.2466 − 0.005
[𝐶𝑙 − ] =
= 1.529 𝑝𝑝𝑚
0.158
2.2.2 For NO3NO3- stock solution = 200.0 ppm
Table 3. Information of NO3Name
Volume of NO3- stock/ mL
Final [NO3-]/ ppm
Area of Peak/ μs*min
Standard 1
0.25
2.002
0.1858
Standard 2
0.50
4.004
0.3614
Standard 3
0.75
6.006
0.5388
Standard 4
1.00
8.008
0.6971
Standard 5
1.25
10.01
0.6667
Sample
-
-
0.3428
Calibration Curve of NO30,8
0,7
Area of peak
0,6
0,5
y = 0,0855x + 0,0179
R² = 0,9993
Ряд1
0,4
0,3
Линейная (Ряд1)
0,2
0,1
0
0
2
4
6
8
10
Concentration of NO3- /ppm
Figure 2. Calibration Curve of NO3-
The regression equation of NO3- is:
Y = 0.085X + 0.017 𝑅 2 = 0.999
The concentration of NO3- sample is:
0.3428 − 0.017
[𝑁𝑂3− ] =
= 3.833 𝑝𝑝𝑚
0.085
2.2.3 For SO42SO42- stock solution = 200.0 ppm
Table 4. Information of SO42Name
Volume of SO42- stock/ mL
Final [SO42-]/ ppm
Area of Peak/ μs*min
Standard 1
0.25
2.006
0.2215
Standard 2
0.50
4.012
0.4591
Standard 3
0.75
6.018
0.6576
Standard 4
1.00
8.024
0.8376
Standard 5
1.25
10.03
0.8802
Sample
-
-
0.6457
Area of peak
Calibration Curve of SO420,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
y = 0,102x + 0,0322
R² = 0,996
Ряд1
0
2
4
6
8
10
Concentration of SO42- /ppm
Figure 3. Calibration Curve of SO42-
The regression equation of SO42- is:
Y = 0.102X + 0.032 𝑅 2 = 0.996
The concentration of SO42- sample is:
0.6457 − 0.032
[𝑆𝑂42− ] =
= 6.017 𝑝𝑝𝑚
0.102
Because the 5th data is obviously inaccurate in NO- and SO42- curve, they are rejected.
2.2.4 Concentration Sheet
Table 5. The Concentration of Cl-, NO3-, SO42Species
Cl-
NO3-
SO42-
Concentration/ ppm
1.529
3.833
6.017
2.2.5 Determine the concentration of water-soluble ionic species in airborne
particulates (μg/m3).
Wlt =
Total wt. of sample loaded filter paper (g)
3.914
Wl =
Wt. of sample loaded filter paper used for extraction (g)
0.9980
H=
Sampling time (hr)
24
Flt =
Total volume flow through the filter paper (m3) per day
2343
𝐶 × 𝑉 𝑊𝑙𝑡
×
𝐹𝑙𝑡
𝑊𝑙
C: the concentration of soluble species determined before;
V: the volume of sample(100ml)
1.529 𝜇𝑔⁄𝑚𝐿 × 100𝑚𝐿 3.914𝑔
𝐶𝐶𝑙− =
×
= 0.255 𝜇𝑔⁄𝑚3
2343𝑚3
0.9980𝑔
3.833 𝜇𝑔⁄𝑚𝐿 × 100𝑚𝐿 3.914𝑔
𝐶𝑁𝑂3− =
×
= 0.640 𝜇𝑔⁄𝑚3
3
2343𝑚
0.9980𝑔
6.017 𝜇𝑔⁄𝑚𝐿 × 100𝑚𝐿 3.914𝑔
𝐶𝑆𝑂42− =
×
= 1.005 𝜇𝑔⁄𝑚3
2343𝑚3
0.9980𝑔
conc. =
3. Discussion
3.1 Problems & Questions
1. Discussion the advantage(s) of using auto-suppressor in Ion Chromatography.
It can help to reduce background noise.
Thepeak of analyte will become better.
Reduce the background conductance of the eluent.[2]
2. If there are peaks remaining un-resolved, how could we change the mobile
phase to solve the problem.
Change the flow rate of mobile phase.
Change the polarity of mobile phase.
4. Conclusion
The Concentration of Cl-, NO3-, SO42- in water soluble sample:
Species
Cl-
NO3-
SO42-
Concentration/ ppm
1.529
3.833
6.017
The Concentration of Cl-, NO3-, SO42- in airborne particulates
Species
Cl-
NO3-
SO42-
Concentration/μg/m3
0.255
0.640
1.005
Therelatively high concentration of NO3-, SO42- may cause the acidity increases in
atmosohere.
5. References
[1] Hong Kong Observatory. Daily Extract of Meteorological Observations ,
September 2017.http://gb.weather.gov.hk/cis/dailyExtract_uc.htm?y=2017&m=09
[2] http://www.ppkao.com/tiku/shiti/642872.html