1. H&P Mobile GeoChemistry Escondido, CA
TO-15 or not TO-15?
That is the question.
James Picker, Ph.D.
H&P Mobile GeoChemistry Escondido, CA

2. H&P Mobile GeoChemistry Escondido, CA
Objective
Compare/Contrast
EPA Method 8260B vs. EPA Method TO-15/TO-14A
Used for the analysis of VOCs in soil vapor (gas) to measure health risk
H&P Mobile GeoChemistry Escondido, CA

3. H&P Mobile GeoChemistry Escondido, CA
Perceived (advertised?) Difference OR
H&P Mobile GeoChemistry Escondido, CA

4. H&P Mobile GeoChemistry Escondido, CA
Actual difference OR
H&P Mobile GeoChemistry Escondido, CA

5. H&P Mobile GeoChemistry Escondido, CA
Summary EPA 8260 vs. TO-15/14A
Data Reduction
GC/MS System
Sample Preparation
SAME
IDENTICAL
SLIGHTLY DIFFERENT
H&P Mobile GeoChemistry Escondido, CA

6. H&P Mobile GeoChemistry Escondido, CA
Similarities
GC/MS Method (SCAN or SIM)
GC with FSCC (20-60m X mm id)
LRMS (quadrupole, ion trap, TOF)
*Concentration of compounds on multiadsorbent trap*
Uses Internal Standards/Surrogate(s) for accuracy/QC
Multipoint Calibration ICAL, linearity checks, Daily CCV
Varying sample size permitted
Quant by RFs
H&P Mobile GeoChemistry Escondido, CA

7. H&P Mobile GeoChemistry Escondido, CA
Differences
Standards and Sample Preparation
EPA 8260B (modified)
*Standards in liquid (MeOH)*
Purge and trap
Purged from headspace and H2O using He or dry purging
Water management
Desorption direct to GC/MS
EPA TO-15/14A
*Standards in Air (N2)*
Vacuum (or Pressure) flow and Trap
pulled from cylinder, using pump or pressure
Desorption to cryofocus or directly to GC/MS.
H&P Mobile GeoChemistry Escondido, CA

8. Standards in Water or Air-
H&P Mobile GeoChemistry Escondido, CA

9. Compounds Analyzed equally well by EPA 8260 or TO-15
BTEX, Trimethylbenzenes, Freons
PCE, TCE, vinyl chloride, DCEs, 1,2- DCPE, 1,1,1,2- TCA
1,1,1-TCA,
H&P Mobile GeoChemistry Escondido, CA

10. Compounds Analyzed with a slight high bias by EPA 8260 versus TO-15
MTBE, other oxygenates
1,1,2,2-TCA, 1,2- DCA, 1,1,2-TCA
Naphthalene
rest of common 8260 list
H&P Mobile GeoChemistry Escondido, CA

11. Compounds Analyzed with a high bias by EPA 8260 versus TO-15
Ethanol, TBA
1,4 Dioxane
Acetone & other ketones
Any water soluble low volatility compound
H&P Mobile GeoChemistry Escondido, CA

12. H&P Mobile GeoChemistry Escondido, CA
Differences II
Calibration and Range
EPA 8260B (modified)
“Typical” Calibration 500 – ug/m3 ( ppbv for benzene)
MDLs 100 ug/m3 (31 ppbv benzene)
For 8260 SIM 10 ug/m3 (3 ppbv benzene
EPA TO-15/14A
“Typical” Calibration ug/m3 benzene (1-40 ppbv)
MDLs 0.3 ug/m3 benzene( 0.1ppbv)
For TO-15 SIM 0.03 ug/m3 benzene (0.01ppbv)
H&P Mobile GeoChemistry Escondido, CA

13. Calibration Range MDL to highest standard assumes 20 cc sample
Normal Range
8260 SCAN
Extended by dilution
8260 SIM
TO-15/14A SCAN
TO-15/14A SIM
ug/m3
H&P Mobile GeoChemistry Escondido, CA

14. Fail Levels TCE @ subslab TCE @ 5’bgs
EPA R9
CA-EPA
8260 SCAN
8260 SIM
TO-15/14A SCAN
TO-15/14A SIM
ug/m3
H&P Mobile GeoChemistry Escondido, CA

15. Fail Levels Benzene @ subslab Benzene @ 5’bgs
CA EPA
EPA R9
8260 SCAN
8260 SIM
TO-15/14A SCAN
TO-15/14A SIM
ug/m3
H&P Mobile GeoChemistry Escondido, CA

16. Project BL 4FEB05 results in ug/L
Sample
TO-15
PCE
8260
TCE
c12DCE
t12DCE
F-113
SV1
128 88 42 31
<1
1.6
1.1
SV2
399
280
134
100
4.4
3.7
1.7
1.4
3.4
2.7
SV3 95 46 40
SV4
541
330 75 60
SV5
169
110 70 65
1.5
3.1
SV6
234
150
138
3.6
3.2
4.8
4.1
SV7
108 54 25 17
2.1
SV8
250
120 74
4.7
3.5
9.9
AVG
%Diff. 52 28 13 19
Average % Diff across all compounds = 38%
H&P Mobile GeoChemistry Escondido, CA

17. Project MC 1FEB05 results in ppbv
Sample
TO-15
PCE
8260
TCE
c12DCE
111TCA
F-113
SG1
190
250
<16
<25 32 NA
SG3 59 83
110 93 40 36
SG8
<14 64
540
370
SG12
1300
910 91 65
360
261
SG13 29 98 81 28
<20
H&P Mobile GeoChemistry Escondido, CA

18. H&P Mobile GeoChemistry Escondido, CA
Conclusions
For most vapor intrusion compounds of interest, methods yield identical results
For more water soluble compounds 8260 is within factor of 2. Fine for VI calculations
A few compounds may require TO method. Some compounds may require 8260 method
On-site analysis assists in decision making, regulatory QA requirements and assurance of tracer compound integrity
H&P Mobile GeoChemistry Escondido, CA

19. H&P Mobile GeoChemistry Escondido, CA
Recommendations
Choose either or a combination of methods, depending on compounds and DLs required
Select on-site analysis for decision making, regulatory QA requirements (assurance of tracer compound integrity, purge volume testing, etc.)
Do onsite TO-15 where levels are low
Do onsite 8260 where levels are moderate to high
Follow with offsite TO-15 for Quality Assurance
H&P Mobile GeoChemistry Escondido, CA

20. H&P Mobile GeoChemistry Escondido, CA

21. H&P Mobile GeoChemistry Escondido, CA

22. H&P’s Solutions Option 1 – Where 8260B Meets Project DQOs:
On-site, full QC 8260B fulfilling DTSC/LA-RWQCB requirements with off-site TO-15 confirmation on a sub-set of samples.
Option 2 – Where TO-14/15 is required to meet Project DQOs:
On-site screening-level 8260B of all samples with of-site analysis of ALL samples by TO-15.
Option 3 – For larger projects with lower DLs:
On site TO-15
All Options:
Fulfill all DTSC soil gas advisory requirements
Allow on-site analysis for leak/tracer compound test
Guarantee sample integrity
Provide real-time data for real-time decisions

23. James Picker, Ph.D. 148 Vinewood Street
Escondido, CA 92029
(800)