A brand new method of analyzing organic contaminants in tailings pond waters! Miniaturizable, high-voltage, high potential. The oil sands industry will benefit from this. Capillary electrophoresis-electrospray ionization-mass spectrometry technology for the analysis of naphthenic acids fraction compounds in oil sands process-affected waters. Technical, peer-reviewed description of the optimized method: https://doi.org/10.1016/j.jes.2016.06.019

1. Capillary electrophoresis-mass
spectrometry technology for the
analysis of naphthenic acid fraction
compounds in oil sands process
waters
M.S. MacLennan, C. Tie, K.M. Peru,
J.V. Headley, D.D.Y. Chen
1

2. Contents
• Instrumentation setup
• Sample preparation
• Three “modes of attack” for NAs
• Results workup
2

3. Flow-through Microvial Interface
for CE-ESI-MS
Maxwell, E. J.; Zhong, X.; Zhang, H.; van Zeijl, N.; Chen, D. D. Y. Electrophoresis 2010, 31, 1130–1137.
3

4. EDC-NHS Derivatization(s) of
naphthenic acids
4
Hermanson, G. T. Bioconjugate Techniques; 2nd ed.; Elsevier Inc., 2008; p. 1323.

5. 5

6. Three modes of attack
Capillary Zone
Electrophoresis
Field Amplified
Sample
Injection
Polarity
Switching
Nonaqueous
capillary
electrophoresis
Weak
pH/solubility
junction
6

7. Capillary Zone Electrophoresis (CZE)
• All three derivatization mixtures
• Capillary 50 μm i.d., coated with PEI(+)
• Small sample plug injected hydrodynamically
(0.5 psi, 10 sec)
• Sandwiched between buffer (50% MeOH, 2%
HCOOH)
• Separation voltage -30 kV
7

8. EDC derivatization of NAs
8

9. EDC-NHS derivatization of NAs
9

10. 10
EDC-Sulfo-NHS derivatization of NAs

11. 11
C10
Z=0,-2
C11
Z=0,-2,-4
C12
Z=0,-2,-4
C13
Z=0,-2,-4
C14
Z=0,-2,-4
C15
Z=0,-2,-4
C16
Z=0,-2,-4

12. 12

13. 13

14. Field-Amplified Sample Injection (FASI)
• Short plug of water introduced into the
capillary (0.5 psi 10 sec)
• Sample injected by applied voltage of +10 kV
for 2 seconds
• Electrophoretic separation carried out as per
usual
14
Chien, R.-L.; Burgi, D. J. Chromatogr. 1991, 559, 141–152.

15. 15
Field-Amplified Sample Injection (FASI)
EDC EDC-NHS EDC-Sulfo-NHS

16. 16

17. A.
B.
C.
D.
E.
E.
17

18. 1.460
1.457
1.461
1.504
1.514
1.524
4
10
14
18
45 amu

19. A.
B.
C.
D.
E.
E.
19

20. 20

21. Field Amplified Sample Injection with
Polarity Switching (FASI-PSw)
• Begin with FASI
• Separate with -30 kV
• At ~8.3 minutes, switch voltage to +30 kV and
separate for 4 minutes
• Switch polarity to -30 kV for 4 minutes
• Decrease time to switch
• 3 switches in total
21
Chien, R.-L.; Burgi, D. S. J. Chromatogr. A 1991, 559, 153–161.

22. 22

23. S
EOF (+ESI)-MS
23
Weak pH/solubility gradient
Britz-McKibbin, P.; Chen, D. D. Anal. Chem. 2000, 72, 1242–1252.
50% MeOH
2% Formic acid
48% water
90% MeOH
10% Formic acid
0% water

24. 24
0.00E+00
1.00E+07
2.00E+07
3.00E+07
4.00E+07
5.00E+07
6.00E+07
7.00E+07
8.00E+07
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
TotalIonCountforPeakofInterest
Carbon number
Structural distribution for naphthenic acids in Sigma-Aldrich
Technical mixture
Z=0 Z=-2 Z=-4 Z=-6 Z=-8

25. 0
20000000
40000000
60000000
80000000
100000000
120000000
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Structural distribution for naphthenic acids
in Sigma-Aldrich Technical mixture
Z=0 Z=-2 Z=-4 Z=-6 Z=-8
25

26. Preliminary Conclusions
• Three derivatizations produce generally the
same results
• Multivariate “design of experiment” and
response surfaces for system optimization
• Nonaqueous CE underivatized NAs
• Analysis of native OSPW sample
26

27. Acknowledgements
27
Walter C. Sumner
Memorial Foundation
G
C
D

28. Software
• OpenMS
• MSConvert
• R Statistical software
• Gaussian03W
• Marvin Sketch (ChemAxon)
• PyMOL
28

29. IDEAS
• Kanamori polymer to adsorb hydrophobic
species directly from wastewater; direct DESI
(MeOH) of marshmallow fragment
• Chemometric analysis using alternate buffer
compositions and pH.
29

30. Summary of Theoretical Preamble
• 3° amine is protonated in acidic media
• Carboxamide moiety is more electrophilic
• Upon protonation:
– 3° ammonium twists toward carboxamide
– 3° ammonium bond lengths
increase suggesting a
possible neutral fragment
loss of 45 amu
30

31. 31
Nominal Mass
Probable structure (based on
m/z−𝟏𝟏𝟕
𝟏𝟒
+ 𝟏)
484 (Z=0) 27 carbon naphthenic acid
468 (Z=0) 26 carbon naphthenic acid
456 (Z=0,-2,-4) 25 carbon naphthenic acid
399 (Z=0,-2,-4) 21 carbon naphthenic acid
383 (Z=0,-2) 20 carbon naphthenic acid
369 (Z=0,-2,-4,-6) 19 carbon naphthenic acid
351 (Z=0,-2,-4,-6,-8) 18 carbon naphthenic acid
342 (Z=0,-2,-4,-6) 17 carbon naphthenic acid
328 (Z=0,-2,-4,-6) 16 carbon naphthenic acid
314 (Z=0,-2,-4,-6) 15 carbon naphthenic acid
299 (Z=0,-2,-4) 14 carbon naphthenic acid
285 (Z=0,-2,-4) 13 carbon naphthenic acid
271 (Z=0,-2,-4) 12 carbon naphthenic acid
257 (Z=0,-2,-4) 11 carbon naphthenic acid
244 (Z=0,-2) 10 carbon naphthenic acid
229 (Z=0) 9 carbon naphthenic acid
213 7 carbon naphthenic acid, one ring
129* Common fragment

32. 25.3 °
twist
41.7 °
twist
11 °
twist
4.215 Å
2.224 Å
4.055 Å
32

33. 33
HOMO
LUMO
B3LYP 6-31G(d)