Approaches to quantify the
biogenic interference on
Petroleum hydrocarbon
levels
Chris Swyngedouw
Remtech 2007
Outline
GC/FID hydrocarbon analysis
Silica gel treatment
Approaches to quantify the
biogenic interference
slide number 2
Gas Chromatography
slide number 3
Hydrocarbon Analysis
Developed to provide quantitative information. Example
- for regulatory decisions
CCME method provides some characterization –
hydrocarbon ranges.
Information about composition of the hydrocarbon is not
provided.
Methods are not capable of distinguishing between
materials with similar properties.
slide number 4
Organic compounds detected by
GC/FID
Volatile aromatics (BTEX)
Polyaromatic hydrocarbons (PAHs)
Alkylated PAHs
Hetero PAHs (S and N)
Waxes and Asphalthenes
Organic acids (fatty acids)
slide number 5
Farm soil
slide number 6
Plant material
slide number 7
Biogenic Hydrocarbons
Odd carbon-numbered n-alkanes are much
abundant than even carbon- numbered nalkanes in the C21- C33 range.
Note absence of UCM;
Presence of "biogenic cluster" in the GC.
slide number 8
Peat- extracted
slide number 9
CCME
Summary of Tier I Levels (mg/kg) for surface soil.
Land Use
Agricultural
Soil Texture
Coarse-grained
Fine-grained
Residential/ Coarse-grained
Parkland
Fine-grained
Commercial Coarse-grained
Fine-grained
Industrial
Coarse-grained
Fine-grained
Fraction 1
C6-C10
2007
old
30
130
210(170) 260(180)
30
30
210(170) 260(180)
320(240) 310(300)
320(170) 660(180)
320(240) 310(300)
320(170) 660(180)
Fraction 2
C10-C16
2007
old
150
450(90)
150
900(250)
150
150(90)
150
900(250)
260
760(90)
260(230) 1500(250)
260
760(90)
260(230) 1500(250
Values in brackets for fractions 1 and 2 considers additional potable groundwater protection
For complete levels, consult Tables in the Technical Supplement Document
slide number 10
Fraction 3
C16-C34
2007
old
300
400
1300
800
300
400
1300
800
1700
1700
2500
2500
1700
1700
2500
2500
Fraction 4
C34+
Old/new
2800
5600
2800
5600
3300
6600
3300
6600
Interference with CCME fractions
F2
slide number 11
F3
F4
Soxhlet (CCME)
20-30 gm (CCME ≥ 5 gm)
Mix with drying agent
16-24 hr. Soxhlet with Hexane / Acetone
Cleanup
Concentrate
Assess
slide number 12
Soxhlets
slide number 13
Rotatory evaporator
slide number 14
Concentrated Soxhlet extracts
slide number 15
Silica gel cleanup
slide number 16
GC vials
slide number 17
High temp GC/FIDs
slide number 18
C10-C60 Assessment
2.5e4
Sig. 1 in C:\HPCHEM\...\035F0101.D
12
| .
CARBON NUMBER
16
20 24 28 32 36 40 44 48 52 56 60
. . | . . . | . . . | . . . | . .. | . . . | . . . | .. . | .. .| . ..| ...|...|
F3
F4
F2
F4HTGC
5000
0
slide number 19
Time (min.)
20
Pure Canola Oil
.
Sig. 1 in C:\HPCHEM\...\014F0201.D
12
|
CARBON NUMBER
16
20
24 28 32 36 40 44 48 52 56 60
. . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . .. | . .. | . .. |
3.0e5
0
0
slide number 20
Time (min.)
20
Canola and crude oil
12
|
.
Sig. 1 in C:\HPCHEM\...\018F0101.D
2.2e5
CARBON NUMBER
16
20
24 28
32
36 40 44 48 52 56 60
. . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . .. |
0
0
slide number 21
Time (min.)
20
Canola oil Removal
CARBON NUMBER
16
20
24
28
32
36
40 44 48 52 56 60
. . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . .. |
.
0
0
Time (min.)
.
CARBON NUMBER
16
20
24
28
32
36
40 44 48 52 56 60
. . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . .. |
.
CARBON NUMBER
16
20
24 28
32
36 40 44 48 52 56 60
. . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . .. | .. . |
0
Time (min.)
2.2e5
12
|
.
.
20
Sig. 1 in C:\HPCHEM\...\015F0101.D
12
|
12
|
0
20
Sig. 1 in C:\HPCHEM\...\016F0101.D
2.2e5
2.2e5
Sig. 1 in C:\HPCHEM\...\017F0101.D
12
|
Sig. 1 in C:\HPCHEM\...\018F0101.D
2.2e5
CARBON NUMBER
16
20
24
28
32
36
40
44 48 52 56 60
. | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . . .| . .. |
0
0
0
0
slide number 22
Time (min.)
20
Time (min.)
20
Silica gel treatment
Losses with each treatment
fraction
% Change
Before/after
batch
F2
16 %
F3
13 %
C34-C50 1 %
C50+
30%
slide number 23
Natural Interferences - Peat
F2
slide number 24
F3
F4
Biodiesel waste water
slide number 25
Biogenic material
Biogenic interference and silica gel Cleanup
Tundra peat
False positives
slide number 26
Conceptual Model
TEH = TPH + TOM
TPH = TEH - TOM
TEH from CCME fractions F2 - F4
TOM from ?
TPH is then the true petroleum hydrocarbons
slide number 27
TOM Approaches
Blanks
Chromatographic separation
GC/MS
Standard additions
TOC + silica gel
slide number 28
Blank Subtraction
Run 1: blank/amendments
Run 2: sample
Result: TPH = sample - blank
slide number 29
Peat + diesel
slide number 30
Coal in this sample
slide number 31
Coal
slide number 32
extracted wood
slide number 33
Example - coal
TOC = TC – TIC (carbonates)
TOC =? TOM (LOI)
slide number 34
GC/MS ?
slide number 35
Use of GC/MS
% plant material – PHC
Gasoline + plant material
Ratios
Still a chromatographic guess.
slide number 36
GC/MS
Soil + plant material + asphalt
MOG 2800 mg/kg
TOC 3.55%
On GC/MS no PHC detected
On high temp GC mostly C40+
MS would not detect this
slide number 37
Plant material + asphalt
slide number 38
Asphalt + peat
Sig. 1 in C:\HPCHEM\...\057F0201.D
CARBON NUMBER
12
2.5e4
|
16
.
.
.
|
20
24
28
32
36
40
44
48
52
56
60
. . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . .| . . .| . . .|
5000
0
slide number 39
Time (min.)
20
Peat
Peat + PHC
no SG done
Subtract blank peat
No blank, do extr.HC before and after SG
2 silica gel treatments
slide number 40
Fresh crude and peat
slide number 41
standard additions
40
a re a
30
20
10
0
-4
-2
0
2
TEH result
slide number 42
4
6
8
Standard addition experiments
Eg % wood by volume
Works in theory, problem with real samples
(normalization)
TOC before and after extraction
Bulk density, moisture
Need relationship between BD and TOC
slide number 43
Combination approach
Extract sample as per PHC method
Analyzed for TOC and PHC before and after
SG cleanup
Results used for CTGM interpretation only
Presence of biogenic interference
Biogenic chromatographic fingerprint
Effectiveness of SG cleanup
slide number 44
Some further considerations
Difference between TOC and LOI
The need for marker compounds
Ratio marker compound/total amendments
Surrogates for F2 – F4
Reverse surrogate for SG treatment.
slide number 45