1. Alexandria Pavkovich Jason Thomas Trent Sprenkle
Complete Fractionation of Extractable Petroleum Hydrocarbons Using Newly Developed EPH SPE Cartridges
Alexandria Pavkovich
Jason Thomas
Trent Sprenkle

2. Outline Background EPA Method Requirements Background and Recovery
PAHs in Used Motor Oil

3. What is EPH? Extractable Petroleum Hydrocarbons
Means to separate Aliphatic and Aromatic compounds
Clean up step for environmental samples
Typical cartridge format for MA and NJ methods: 5g irregular silica gel fritted in 25 mL syringe tube

4. Importance of EPH: Multiple states follow EPH Methods
MA, NJDEP, Texas, WA, Atlantic RBCA
Used to assess impact of environmental samples
Separates target aliphatic components from target aromatic components
Allows separation of EPA priority 16 PAHs
Higher proportion of aromatics have more hazardous designation relative to samples consisting of primarily aliphatic hydrocarbons

5. How does a EPH cartridge work?
Normal Phase
Dried Silica Gel (Activated) is Polar
Non-polar compounds will elute first
Hexane pulls off non-polar aliphatic compounds
Dichloromethane pulls off more polar aromatic compounds
Compared to Hexane, DCM is moderately polar

6. EPH Method Requirements:
MA EPH Method
40 – 140% Recovery for Analytes and Surrogates
< 5% Breakthrough for Naphthalene and 2- Methylnaphthalene
NJ EPH Method
Based off MA EPH Method
Requires monitoring of additional analytes
Texas EPH Method
Uses Pentane instead of Hexane
60 – 140% Recovery for Analytes, 70 – 130% Recovery for Surrogates
< 10 – 20% Crossover

7. Extractable Background
< 30 ng of background contamination on-column
8.2 ppm
11.5 ppm
5ppm
min 5
7.5 10
12.5 15
17.5 20
22.5 25
Aliphatic Fraction
14.2 ppm
13.1 ppm
5ppm
min 5
7.5 10
12.5 15
17.5 20
22.5 25
Aromatic Fraction
ng on-column = ppm

8. Analyte Separation
Aliphatic
Aromatic

9. Recovery – MA and NJDEP EPH Cartridge: Reference Standards:
Resprep EPH Fractionation SPE Cartridge – Restek Cat #
Reference Standards:
MA Fractionation Surrogate Spike Mix – Restek Cat # 31480
MA Surrogate Spike Mix – Restek Cat # 31479
NJDEP Aliphatic Calibration Standard – Restek Cat # 30544
NJDEP Aromatic Calibration Standard – Restek Cat # 30545
Naphthalene Standard – Restek Cat # 31280
2-Methylnaphthalene Standard – Restek Cat # 31285

10. Recovery – MA and NJDEP Sample Preparation: Analysis:
Condition Cartridge with 15 mL Hexane
Addition of 1 mL of Sample
Elute with 19 mL of Hexane (Aliphatic Fraction), followed by 20 mL of dichloromethane (Aromatic Fraction)
Concentration to a final volume of 1 mL
Analysis:
Agilent 7890 GC-FID
Column: Rxi-5Sil MS – 30m x 0.32mm x 0.25µm – Restek Cat # 13624
Oven Program: 40°C (1.5 min.) → → 350°C (7 6°C/min
Injection temperature: 300°C; Injection volume: 1.0 μL, Carrier: Helium, constant 3 mL/min.
Injection mode: splitless, purge flow: 50 1min.
Detector Temp: 350°C

11. Average of 3 Replicates of 3 Different Lots @ 35 ppm
Recovery – MA and NJDEP
Average of 3 Replicates of 3 Different 35 ppm
40 – 140% Analyte Recovery

12. Recovery – Texas EPH Cartridge: Reference Standards:
Resprep EPH Fractionation SPE Cartridge – Restek Cat # 25859
Reference Standards:
MA EPH Surrogate Spike Mix – Restek Cat # 31479
1-Chlorooctane – Restek Cat # 30084
8270 Calibration Mix #5, Revised – Restek Cat # 31995
BTEX Standard – Restek Cat # 30213
TNRCC 1006 Retention Time Marker Mix – Restek Cat #
Custom 1,2,3-Trimethylbenzene and Benzo(e)pyrene Mix

13. Recovery – Texas Sample Preparation: Analysis:
Condition Cartridge with 15 mL Pentane
Addition of 1 mL of Sample
Elute with 40 mL of Pentane (Aliphatic Fraction), followed by 20 mL of Dichloromethane (Aromatic Fraction)
Concentration to a final volume of 1 mL
Analysis:
Agilent 7890 GC-FID
Column: Rxi-5Sil MS – 30m x 0.25mm x 0.25µm – Restek Cat # 13623
Oven Program: 35°C (4 min.) → → 4°C/min →
Injection temperature: 300°C; Injection volume: 1.0 μL, Carrier: He, constant flow 2 mL/min
Inj. mode: pulsed splitless, 30 psi until 0.5 min, 75 mL/min at 0.6 min
Detector Temp: 330°C

14. 60 – 140% Analyte Recovery 70 – 130% Surrogate Recovery
Recovery – Texas
Average (n = 5ppm
60 – 140% Analyte Recovery 70 – 130% Surrogate Recovery

15. Matrix Overview: Motor oil loading at a range of concentrations
Evaluation of breakthrough of Naphthalene and 2- Methylnaphthalene
Breakthrough of used motor oil samples at 20 mg/mL
PAH levels
A great fractionation is possible with clean samples, but what happens when the silica is loaded with a lot of hydrocarbons in a real sample, or even worse, with a very dirty sample. Does the activity of the silica decrease to the point where separation is affected?

16. Cartridge Loading Capacity
MADEP recommends maximum of 25 mg/mL
Saturation of silica could lead to breakthrough of early eluting aromatics
The separation is typically one of a delicate balance as it is without additional encumbrances
Complex matrices
A range of concentrations of motor oil were prepared
Breakthrough of naphthalene and 2- methylnaphthalene monitored in hexane fraction

17. Sample Preparation – Loading Capacity
5W/20 conventional motor oil was diluted into hexane to produce each target concentration
Each sample was spiked with naphthalene and 2- methylnaphthalene at 10 ppm
Surrogates 1-chlorooctadecane, o-Terphenyl and fractionation surrogates, 2-bromonaphthlene and 2-fluorobiphenyl, were spiked at 20 ppm
6 levels of motor oil were prepared in hexane
5 mg/mL to 100 mg/mL

18. Sample Preparation – Loading Capacity
Condition Cartridge with 15 mL Hexane
Addition of 1 mL of Sample
Elute with 19 mL of Hexane (Aliphatic Fraction), followed by 20 mL of dichloromethane (Aromatic Fraction)
Concentration to a final volume of 1 mL
Analysis:
Agilent 7890 GC-FID
Column: Rxi-5Sil MS – 30m x 0.32mm x 0.25µm – Restek Cat # 13624
Oven Program: 40°C (1.5 min.) → → 350°C (7 6°C/min
Injection temperature: 300°C; Injection volume: 1.0 μL, Carrier: Helium, constant 3 mL/min.
Injection mode: splitless, purge flow: 50 1min.
Detector Temp: 350°C

19. Sample Preparation – Loading Capacity
Samples of motor oil in hexane solution at 5 – 100 ppm. Note slight color as you get to the more concentrated. Jar of motor oil used to create samples.

20. Loading Capacity Results (100 mg/mL)
naphthalene
2-methylnaphthalene
Blue trace – aromatic fraction
Red trace – aliphatic fraction
This is a demonstration that loading an oil sample with a 100 mg/ml concentration (4 x max recommended) resulted in no breakthrough into the aromatic fraction (the blue trace) not zoom of naph and 2MN.

21. PAHs in Used Motor Oil
PAH is a result of incomplete combustion produced by internal combustion engines
Can accumulate in motor oil through blow-by
Would be expected in higher concentrations with increasing engine age and mileage
Older technology and declining engine performance produce more PAH
Deterioration of compression rings due to age and wear from high mileage increases blow-by
Diesel vehicles produce more PAH during combustion
Blow-by is the condition where high pressure gases from the combustion/compression process leak past the piston and into the crankcase.

22. PAHs in Used Motor Oil
Because of PAH content (as well as metals and other contaminants) used motor oil is more of a concern than new oil
Wrecking yards, storage tanks
Why the interest in PAHs being in used motor oil? PAHs as well as heavy metals are much more toxic than saturated hydrocarbons. Examples of places expected to have/be sources of used motor oil. Photo illustrates new motor oil versus very dark colored used oil

23. PAHs in Used Motor Oil
Samples were collected from vehicles with a range of ages and mileage

24. PAHs in Used Motor Oil
Samples were collected from vehicles with a range of ages and mileage 1B 2B 4B 6B 7B 8B
Although all the samples of used oil looked very dark, once diluted to 20 mg/mL, there were obvious differences. Does this represent different levels of PAH’s. These id’s are carried through the presentation so you can get an idea of what the samples looked like.

25. PAHs in Used Motor Oil
Extent of migration of color band during elution
Sample Loading
After Extraction
Photo 1 shows color differences in samples again at the start. Photo 2 shows bulk of color is held behind illustrating cleanup capacity of dirt/junk.

26. PAHs in Used Motor Oil (Breakthrough)
naphthalene
2-methylnaphthalene
1 chlorooctadecane surr.
This is an overlay of the aliphatic fraction from two samples (2B and 4B) with the highest level of light PAH’s and were used to illustrate the fractionation capacity of samples with a dirty matrix. Napht and 2Mnaph are pointed out here as the highest PAHs and so also serve as the breakthrough check. The box indicates the area of interest that will be focused on in next slides.

27. PAHs in Used Motor Oil (Breakthrough-Aromatic Fraction)
Naphthalene
2-Methylnaphthalene
10 ppm std.
Sample 2B
Sample 4B
5 ppm std.
This is a close up of the same two samples 2B and 4B showing an overlay of the aromatic fractions compared to a 5 and 10 ppm standard to give an idea of PAH concentration

28. PAHs in Used Motor Oil (Breakthrough-Aliphatic Fraction)
Naphthalene
2-Methylnaphthalene
Sample 2B DCM
Sample 4B DCM
Sample 2B hex
Sample 4B hex
Overlay of the aliphatic and aromatic versions of samples 2B and 4B showing no breakthrough. Small peaks in aliphatic do not match, besides naphtha breakthrough allows precedes 2 M napht, so if RTs were off, the naphtha peak would be the larger of the two.

29. PAHs in Used Motor Oil (Heavier PAHs)
Benzo(a)anthracene and chrysene
Phenanthrene and anthracene
fluoranthene and anthracene
dibenzo(a,h)anthracene and benzo(g,h,i)perylene
This is 2B & 4B aromatic fraction overlaid with 5 ppm standard showing presence of other PAHs at lower levels than the light PAHs Blue and red are 2B and 4B and green is the standard. Qualitative screening to show that there are heavier PAHs in samples. 2B and 4B had the highest amount of PAHs of all samples analyzed.

30. PAHs in Used Motor Oil (Diesel compared to gasoline powered vehicle)
surrogates
Blue and red are 2B and 4B again and green is now 6B (motor oil from a diesel pickup) showing no PAHs at the low end. Also, none of all the other peaks found in the gasoline powered vehicles. This indicates PAHs are not coming (at least the vast majority) from blowby, but notice the similarity of the front end of these cgrams to weathered gasoline. Minimal PAHs in oil pulled from Diesel engine for lighter PAHs whereas the oil pulled from a gas engine samples contain the lighter PAHs.

31. Likely Source of Lighter PAHs in Used Motor Oil (Diluted gasoline sample)
Naphthalene
2-methylnaphthalene
Overlay of 2B and 4B (blue & red) with diluted gasoline sample (green) note good match in the zoomed area. Lighter parts of the gasoline are driven off by the heat of the engine. This strongly suggests that the lighter PAHs observed in the motor oil is a result of gasoline washing down the sides of the cylinder into the cranckcase. Naph and 2-Methylnaph are in gas standard and since we see these in oil from a gas engine, we can conclude that this is a result of unburned gas making its way into the motor oil.

32. Conclusions
A method specific Silica gel cartridge provides excellent fractionation and cleanup properties even under heavy loading and with complex matrices
PAHs were found in used motor oil samples but not necessarily correlated to vehicle age and mileage
Likely reason for lack of correlation is that lighter PAHs are likely a result of concentrated gasoline in the oil rather than from blow-by

33. Questions? Alexandria Pavkovich – alexandria.pavkovich@restek.com
Jason Thomas –
Trent Sprenkle – restek.com