Using GCxGC to study evaporation and water washing after the

1
Using GCxGC to study evaporation and water
washing after the Bouchard 120 oil spill
Chris Reddy Dept. of Marine Chemistry and
Geochemistry Woods Hole Oceanographic
Institution, Woods Hole, MA
2
Bouchard 120 oil spill

• On April 27, 2003, the tugboat Evening Tide was
  towing the unmanned fuel barge, Bouchard 120 with
  a 1000-foot cable approaching Buzzards Bay from
  the south.
• The barge contained 4.1 million gallons of No. 6
  ("Bunker C") fuel oil and ran aground near the
  entrance to Buzzards Bay.
• The barge was en route from Philadelphia to the
  Mirant Power Generating facility in Sandwich, MA.
  
• 400,000 liters of fuel spilled. (Exxon Valdez
  spilled 40 million liters of crude oil).

3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
No. 6 fuel oil Background

• Petroleum is a complex mixture of organic
  compounds, which can have different toxicities
  and long-term fates.
• No. 6 fuel oils are often used in marine diesels
  or industrial power applications.
• Prepared from the residuum and cut with a
  lighter petroleum product.
• Can vary dramatically in composition.

7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
1-D gas chromatography (GC)
Bouchard 120 oil, original composition
Bouchard 120 oil, 4 months weathered
C24
FID intensity
C21
C27
C18
C30
C16
C10
C35
C13
Retention time (minutes)
13
1-D gas chromatography (GC)
Bouchard 120 oil, original composition
Bouchard 120 oil, 4 months weathered
Where did material go? ?Evaporation or water
washing
FID intensity
retention time (minutes)
14
Comprehensive two-dimensional GC (GCxGC)

• Technology capable of separating hundreds to
  thousands more compounds in complex mixtures.
• Retention indices can provide physical and
  chemical properties (water solubility, vapor
  pressure, etc).

15
Loop Jet Modulator
Cold Jet
Hot Jet
Delay Loop
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
Unresolved Complex Mixture
UCM
carbon number
volatility separation
heart-cut
21
Second-Dimension Separation
alkanes
cycloalkanes
one-ring aromatics
two-ring aromatics
multi-ring aromatics
0
15
10
5
20
Time (s)
polarity separation
22
Unresolved Complex Mixture
UCM
carbon number
comprehensive heart-cutting
23
Comprehensive Second-Dimension Separations
24
Comprehensive Second-Dimension Separations
25
Comprehensive Second-Dimension Separations
26
Comprehensive Second-Dimension Separations
27
Comprehensive Second-Dimension Separations
28
Comprehensive Second-Dimension Separations
First Dimension
Second Dimension
29
Bouchard 120 Cargo 6 Fuel Oil Bunker C
6
5
C1-phenanthrenes
C2-phenanthrenes
C3-phenanthrenes
naphthalene
4
C1-naphthalenes
C2-naphthalenes
C3-naphthalenes
3
17a(H),21ß(H)-hopane
2
1
pristane
phytane
n-alkanes
0
60
10
20
30
40
50
70
80
30
Bouchard 120 Cargo 6 Fuel Oil Bunker C
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
31
Nyes Neck Surf Zone 6-May-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
32
Nyes Neck Surf Zone 13-May-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
33
Nyes Neck Surf Zone 6-June-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
34
Nyes Neck Surf Zone 16-June-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
35
Nyes Neck Surf Zone 3-July-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
36
Nyes Neck Surf Zone 30-July-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
37
Nyes Neck Surf Zone 13-August-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
38
Nyes Neck Surf Zone 9-September-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
39
Nyes Neck Surf Zone 6-November-2003
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
40
Bouchard 120 Cargo 6 Fuel Oil Bunker C
6
5
4
3
Time (seconds)
2
1
0
60
10
20
30
40
50
70
80
Time (minutes)
41
Bouchard 120 Cargo 6 Fuel Oil Bunker C
6
These compounds were mainly lost due to
evaporation (lost the front end).
5
4
3
Time (seconds)
2
These compounds were biodegraded.
1
0
60
10
20
30
40
50
70
80
Time (minutes)
42
20
Bouchard 120 Oil Spill May 9, 2003
18
16
14
12
Time (seconds)
10
8
6
4
2
0
20
30
40
50
60
70
80
90
100
110
Time (minutes)
43
20
Bouchard 120 Oil Spill Nov. 23, 2003
18
16
14
12
Time (seconds)
10
8
6
4
2
0
20
30
40
50
60
70
80
90
100
110
Time (minutes)
44
20
Bouchard 120 Oil Spill Difference
Chromatogram May 9, minus Nov. 23,
18
16
14
12
Time (seconds)
10
8
6
4
2
0
20
30
40
50
60
70
80
90
100
110
Time (minutes)
45
Bouchard 120 Oil Spill May 9, 2003
46
Bouchard 120 Oil Spill Nov. 23, 2003
47
Difference Chromatogram May 9, 2003 minus Nov.
23, 2003
48
Physical properties from GCGC

• Use first and second dimension retention times to
  estimate vapor pressure and water solubility,
  respectively.
• Apply this information to all compounds in GCxGC
  images.
• Model processes with every compound.

49
Why could GCxGC give us special insights into oil
weathering?
Information about electrostatic and induced
electrostatic (polar) solute-solvent interactions
??
Iso-T Range of T Polar stationary phase
Information about cavitation, VdW (nonpolar)
solute-solvent interactions
Ramping T Nonpolar stationary phase
??
Hypothesis
environmental partitioning properties vapor
pressureaqueous solubility octanol-water
partition coefficient
environmental behaviors evaporation
rates water-washing rates ecotoxicity
?1, ?2
50
GCxGC chromatogram of a standards-amended diesel
fuel
Second dimension retention time (sec)
n-alkyl benzenes
n-alkyl cyclohexanes
C12
C14
C16
n-alkanes
C10
C24
First dimension retention time (min)
51
Transformation of 2-D retention indices into
physical properties
(Arey, Nelson, Xu, Reddy, Anal. Chem. 2005)
Vapor pressure
Aqueous solubility
r2 0.99 std dev 0.21
r2 0.96 std dev 0.26
calculated log PL
calculated log Cw
measured log PL Pa
measured log Cw mol/L
log Cw -0.0177I1 0.0133I2 - 2.00
log PL -0.00464I1 6.81
We can also estimate air-water partition
coefficient octanol-water partition
coefficient enthalpy of vaporization molecular
weight
52
Contour plot of hydrocarbon volatility and water
solubility overlaid onto the GCxGC chromatogram
of Bouchard 120 oil
decreasing solubility
Second dimension retention time (sec)
2nd dimensionretention time (sec)
decreasing volatility
1st dimension retention time (min)
First dimension retention time (min)
53
Projections of volatility and water solubility
onto GCxGC chromatograms
Bouchard 120 raw chomatogram
FID Intensity
FID Intensity
Second dimension retention time (sec)
Second dimension retention time (sec)
First dimension retention time (min)
First dimension retention time (min)
map of volatility
map of water solubility
more
volatile
less soluble
more
evaporation weathering path
soluble
water-washing weathering path
less volatile
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)
57
80 20
51 to air 49 to water
31 69
58
Acknowledgements

• This work is a joint effort of Bob Nelson, Sam
  Arey, Li Xu, and me (WHOI).