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1. Solid Phase Extraction Issues
TRC September 2007

2. Solid Phase Extraction (SPE)
 Provides a means for preconcentrating water
phase organics to allow lower detection limits
without logistically intimidating sample sizes
(~20L equivalent per analyte type- PCBs,
PAHs, etc)
 May show some artifacts of incomplete
recovery, depending on a number of factors,
e.g. DOC, sample size, collection speed

3. RMP Collection Methodology
 100L sample, pumped at 1.5L/min by Infiltrex
300 through wound glass filter (nominal 1um
pore) and columns (2x70g) of XAD2 resin.
 Most recent cruise increased volume pumped
through filter to increase PBDE signal relative
to blanks (no change in pumping speed)

4. Infiltrex vs Whole Water
 4L whole water
sample vs 100L
Infiltrex
particulate (filter)
+ dissolved
(XAD2)
2003 PCB 100L vs 4L
y = 1.5875x + 0.046
R2
= 0.9916
0
2
4
6
8
10
12
0 2 4 6 8 10 12
100 L results (pg/L)
4
L
results
(pg/L)
BG30

5. 2004
2004 PCB 100L vs 4L
y = 1.1164x - 0.615
R2
= 0.9309
y = 0.5856x + 0.432
R2
= 0.9754
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60 70
100L results (pg/L)
4L
results
(pg/L)
SB026W
SPB010W

6. 2005
2005 PCB 100L vs 4L
y = 1.2096x + 0.0227
R
2
= 0.9891
y = 0.7442x + 0.1428
R2
= 0.9925
0
5
10
15
20
25
30
35
40
45
50
0 10 20 30 40 50
100 L results (pg/L)
4
L
results
(pg/L)
SB036W
CB015W

7. Bias Trend?
site year
max
PCB
(100L) slope SS DOC
BG30 2003 6 1.59 23.5 1606
CB015 2005 10 1.21 3.8 1014
SPB010 2004 22 1.12 34.5 1650
SB036 2005 40 0.74 9.0 2463
SB026 2004 65 0.59 18.0 1870

8. Bias Trend?
 Does not track TSS (SSC)
 4L (liquid-liquid) solvent extraction recovery
high for low organics (=totPCBs)
– 100L short contact time = lower recovery?
 100L solid phase extraction high(er) for high
organics samples
– 4L solvent volume = limited equilibrium?

9. Alternatives
 Switch to liquid-liquid extraction
– Likely accurate for low organics
– Underestimate for high concentrations
– PCB/PBDE, PAH, OCP, OPP, backup = 4L x 5
bottles/site x 22 sites = 110 bottles, 440L to ship
 Status quo 100L SPE- (preferred?)
– Maintain awareness of tendencies
– Considered minimum concentrations
– More accurate for high concentration samples