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
slide number 3 Gas Chromatography
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
slide number 6 Farm soil
slide number 7 Plant material
Biogenic Hydrocarbons Odd carbon-numbered n-alkanes are much abundant than even carbon- numbered n- alkanes in the C21- C33 range. Note absence of UCM; Presence of "biogenic cluster" in the GC. slide number 8
slide number 9 Peat- extracted
CCME Summary of Tier I Levels (mg/kg) for surface soil. Land Use Soil Texture Fraction 1 C6-C10 Fraction 2 C10-C16 Fraction 3 C16-C34 Fraction 4 C34+ 2007 old 2007 old 2007 old Old/new Agricultural Coarse-grained 30 130 150 450(90) 300 400 2800 Fine-grained 210(170) 260(180) 150 900(250) 1300 800 5600 Residential/ Coarse-grained 30 30 150 150(90) 300 400 2800 Parkland Fine-grained 210(170) 260(180) 150 900(250) 1300 800 5600 Commercial Coarse-grained 320(240) 310(300) 260 760(90) 1700 1700 3300 Fine-grained 320(170) 660(180) 260(230) 1500(250) 2500 2500 6600 Industrial Coarse-grained 320(240) 310(300) 260 760(90) 1700 1700 3300 Fine-grained 320(170) 660(180) 260(230) 1500(250 2500 2500 6600 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
Interference with CCME fractions F2 F3 F4 slide number 11
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
slide number 13 Soxhlets
slide number 14 Rotatory evaporator
slide number 15 Concentrated Soxhlet extracts
slide number 16 Silica gel cleanup
slide number 17 GC vials
slide number 18 High temp GC/FIDs
C10-C60 C60 Assessment 2.5e4 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48525660.................................... F3 F4 F2 F4HTGC Sig. 1 in C:\HPCHEM\...\035F0101.D 5000 0 20 Time (min.) slide number 19
Pure Canola Oil 3.0e5 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\014F0201.D slide number 20 0 0 20 Time (min.)
2.2e5 Canola and crude oil CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\018F0101.D slide number 21 0 0 20 Time (min.)
Canola oil Removal 2.2e5 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\018F0101.D 2.2e5 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\017F0101.D 0 0 20 Time (min.) 0 0 20 Time (min.) 2.2e5 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\016F0101.D 2.2e5 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\015F0101.D 0 0 20 Time (min.) 0 0 20 Time (min.) slide number 22
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 F3 F4 slide number 24
slide number 25 Biodiesel waste water
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
slide number 30 Peat + diesel
slide number 31 Coal in this sample
slide number 32 Coal
slide number 33 extracted wood
Example - coal TOC = TC TIC (carbonates) TOC =? TOM (LOI) slide number 34
slide number 35 GC/MS?
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
slide number 38 Plant material + asphalt
Asphalt + peat 2.5e4 CARBON NUMBER 12 16 20 24 28 32 36 40 44 48 52 56 60.................................... Sig. 1 in C:\HPCHEM\...\057F0201.D 5000 0 20 Time (min.) slide number 39
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
slide number 41 Fresh crude and peat
standard additions 40 30 area 20 10 0-4 -2 0 2 4 6 8 TEH result slide number 42
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