1. ENVIRONMENTAL ANALYSIS I. Solid Phase Extraction
oil & grease –
EPA method 1664

2. O & G : Summary Definitions Liquid / Liquid Extraction methods
Solid Phase Extraction methods
Optimizing SPE: Special O&G Tube

3. Definitions The Samples Surface and Saline Waters
Industrial and Domestic Aqueous Wastes
Waste Water Sludge

4. Definitions (cont.) The Analytes HEM: n-Hexane Extractable Material
TPH (or SGT-HEM): Total Petroleum Hydrocarbons = Silica Gel Treated HEM (HEMs not adsorbed by silica gel)
Examples: non-volatile hydrocarbons, waxes, soaps, vegetable oils, animal fats, greases.

5. L / L Extraction Solvent: CCl4 Hungarian Standard MSZ 260/22-74
Solvent: Freon-113
ASTM Method 413.1
Montreal Protocol on Substances that Deplete the Ozone Layer  phase out the use of CFCs
Solvent: n-Hexane
EPA Method 1664

6. L / L Extraction of O & G Na2SO4 Drying Evaporation Purge Silica Gel
pH ~2
Silica Gel
Treatment
Weigh
Re-dissolve
Evaporation
Purge
Weigh

7. Features of Method 1664 The solvent (n-Hexane) is lighter than water
repouring the water means more labour
Four QA/QC samples per analytical batch
- blank - blank spike
- matrix spike - ms duplicate
Solvent-related matrix interferences
see Table (next slide)

8. EPA CFC Replacement Study

9. EPA 1664 Criteria
EPA 1664: Performance-Based Method

10. Why SPE? Reduce solvent usage Eliminate emulsion problem
Reduce handling
Readily amenable to automation

11. O & G on ISOLUTE TPH Sample: #2 Fuel Oil HCl to pH=2,
1. Sample pre-treatment
2. Column solvation
3. Column pre-equilibrium
4. Sample application
5. Interference elution
6. Analyte elution
HCl to pH=2,
MeOH wetting agent
10 mL MeOH
10 mL water
One liter in 1/2 hour
10 mL water, 15 min N2
2 x 3 mL THF/nC6 1:1

12. Petroleum Hydrocarbon Recoveries: ISOLUTE TPH
Conc
% rec
Std
mg/L
vs std
Avg
Dev 90 94
20.0
104 93 89 5 88 92
120.0 2

13. EPA Represention of O & G Fractions
Formerly: #2 Fuel Oil or Wesson Oil
Currently: Hexadecane - non-polar...
Stearic Acid - polar fraction C H ( C H ) C H 3 2 1 4 3 O C H ( C H ) C 3 2 1 6 O H

14. Selective Elution Polar vs. Non-Polar Fractions
First: Non-polar solvent  Non-polar interactions
Second: Mixed solvent  Polar and Non polar interactions

15. Selective Elution (cont.)
Stearic Acid
Hexadecane
Hexane
Hexane / THF
+ Stearic Acid

16. Recoveries from Selective Elution
20 ppm spike
(90% C16, 10% stearic acid)
Hexadecane (TPH) %
Stearic Acid %

17. Extraction of EPA 1664 Standards at High Concentrations
Stearic acid spike precipitates from solution
Plugging of sample lines and extraction cartridges
Low recoveries

18. Building a TPH / Total O & G Column
Frits
Polyester
Depth Filter
Large Particle
Special Phase
Std. Particle
Silica

19. Polyester Depth Filter
Oil and Grease: Distributes grease to prevent frit and cartridge plugging
Particulates: Distributes solids to prevent packing from plugging

20. Loading Rate with Depth Filter
Avg Loading Time, min: 34
Loading Rate, mL/min : 30
(n = 7)

21. O & G on ISOLUTE O & G HCl to pH=2, MeOH wetting agent
(sample temperature?)
1. Sample pre-treatment
2. Column solvation
3. Column pre-equilibrium
4. Sample application
5. Interference elution
6. Analyte elution
10 mL MeOH
10 mL water, pH 2
1/2 liter in min
10 mL water, 30 min N2
1st: 3 mL Hexane
2nd: 3 mL THF/nC6 1:1

22. Impact of Various Factors
Elution solvent: Hexane / THF
Wetting Agent: 1% Methanol
Sorbents: 1/2 g or 1 g ISOLUTE O&G
Bottle wash: 20 mL Acetone + 80 mL water

23. Recoveries for TPH / Total O&G
Spike, mg/L
Recovery, %
%Recovery
Total O & G
120
Hexadecane: 92
Stearic Acid:
104 98 60 94 96 95 24 88
102 12 87
100