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

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Presentation on theme: "ENVIRONMENTAL ANALYSIS I. Solid Phase Extraction oil & grease – EPA method 1664."— Presentation transcript:

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

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

4 DefinitionsDefinitions The Samples Surface and Saline Waters Industrial and Domestic Aqueous Wastes Waste Water Sludge

5 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.

6 Solvent: CCl 4 Hungarian Standard MSZ 260/22-74 Solvent: Freon-113 ASTM Method Montreal Protocol on Substances that Deplete the Ozone Layer phase out the use of CFCs Solvent: n-Hexane EPA Method 1664 L / L Extraction

7 L / L Extraction of O & G EvaporationPurge WeighRe-dissolve Silica Gel Treatment EvaporationPurgeWeigh Na 2 SO 4 Drying pH ~2

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

9 EPA CFC Replacement Study

10 EPA 1664 Criteria EPA 1664: Performance-Based Method

11 Why SPE? v Reduce solvent usage v Eliminate emulsion problem v Reduce handling v Readily amenable to automation

12 O & G on ISOLUTE TPH Sample: #2 Fuel Oil 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 N 2 2 x 3 mL THF/nC6 1:1

13 Petroleum Hydrocarbon Recoveries: ISOLUTE TPH Conc% recStd mg/L vs stdAvgDev

14 EPA Represention of O & G Fractions Formerly: #2 Fuel Oil or Wesson Oil Currently: Hexadecane - non-polar... Stearic Acid - polar fraction Stearic Acid - polar fraction CH 3 (CH 2 ) 14 CH 3 CH 3 (CH 2 ) 16 C O OH

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

16 Selective Elution (cont.)

17 Recoveries from Selective Elution 20 ppm spike (90% C16, 10% stearic acid) Hexadecane (TPH) 96% Stearic Acid 113%

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

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

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

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

22 O & G on ISOLUTE O & G 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 (sample temperature?) 10 mL MeOH 10 mL water, pH 2 1/2 liter in min 10 mL water, 30 min N 2 1st: 3 mL Hexane 2nd: 3 mL THF/nC6 1:1

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

24 Recoveries for TPH / Total O&G Spike, mg/LRecovery, % %Recovery Total O & G 120 Hexadecane:92 Stearic Acid: Hexadecane: 94 Stearic Acid: Hexadecane:88 Stearic Acid: Hexadecane:87 Stearic Acid:


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