1. Naphthenic acids research
Matthew S. MacLennan
Chen Lab Group Meeting
March 03, 2014

2. Outline
• What are Naphthenic acids
again?
• What Cai has tried
• What I have tried
• What I plan to try

3. Concept of Naphthenic acids
Rogers, V. V; Liber, K.; MacKinnon, M. D. Chemosphere 2002, 48, 519–527.
Headley, J. V.; McMartin, D. W. J. Environ. Sci. Heal. Part A 2004, 39, 1989–2010.

4. Headley, J. V. et al.
J. Environ. Sci. Health. A. Tox. Hazard.
Subst. Environ. Eng. 2013, 48, 1145–
1163.
R = alkyl group
X = COOH, R, OH, Sox, Nox, SH
Y = C, S, N
Note: ring structures may not be
fully saturated.

5. I have forgotten what naphthenic acids
were...
• Oil sands process (affected) water (OSPW)
• Acidified with H2SO4 to pH 2-2.5
• Extracted into organic phase (DCM, EtOAc,
hexanes) and dried to form film
• Film reconstituted in solvent of choice for
further preprocessing
• = Naphthenic acids fraction compounds
(NAFCs)

6. What Cai has tried
• Acidify native sample
• Extract into EtOAc (dry sample)
• Perform NHS-EDC derivatization in DMSO
• Inject reaction mixture into CE-MS with 1%
HCOOH/50% MeOH acidic buffer
• (PrO)3Si(PEI) coated capillary for EOF

7. EDC-NHS coupling
R
O
O H
EDC-NHS
R
O
NH
N
CH3
CH3
N
CH3
CH3
NH2
DMSO
OH2

8. EDC-NHS coupling
http://www.piercenet.com/instructions/2160650.pdf

9. Sample chromatogram

10. What I have tried
• Sample induced transient isotachophoresis
(tITP) of aqueous derivatized CNLR OSPW (vial
5)
• tITP of aqueous derivatized Syn OSPW (vial 4)

11. Aqueous EDC-Sulfo-NHS coupling
R
O
O H
EDC, Sulfo-NHS
R
O
NH
N
CH3
CH3
N
CH3
CH3
NH2
buffered H2O, pH ~ 7.5
OH2

12. Aqueous EDC-Sulfo-NHS coupling
http://www.piercenet.com/instructions/2160650.pdf

13. Acidified derivatized Syn OSPW

14. Acidified derivatized Syn OSPW

16. Scan 505 – Suspect peak

17. Scan 505; m/z 100-400

18. Scan 505; m/z 450-700

19. Scan 505; m/z 700-1000

20. Acidified derivatized CNLR OSPW
tITP injection

22. Scan 506 – Suspect peak

23. Scan 506; m/z 150-1400
1093.7
1125.2
1125.9
1138.9
1140.9
1153.5
157.7
169.7
201.7
250.8
268.4
280.0
283.6
290.1
295.8
305.4
536.3
551.3
560.6
575.7
589.5
604.2
804.5
828.5
842.7
856.6
872.0
886.7

24. What I plan to try
• Activation of NAs with NHS or Sulfo-NHS (UV
active); Dry-stable
• Fischer esterification with MeOH-HCl; CE-ESI-
MS
– Commonly used derivatization in lipidomics
– Good for fragmentation