Introduction to a 2-step analysis for persistent organic

Report
Introduction to a 2-step
analysis for persistent organic
pollutants
Peggy Krahn
National Oceanic and Atmospheric
Administration
National Marine Fisheries Service
Peggy Krahn directs the National
Marine Fisheries Environmental
Conservation Division
Laboratory in Seattle
Peggy gave us a tour of the 2-step
process she uses to look for
persistent organic pollutants.
If you have downloaded
RealPlayer you can listen to Peggy’s
tour when you click on her picture.
We’ve also included brief text
descriptions.
The reason for a 2-step process is
to start looking for contaminants
with a less expensive approach.
If the first “rapid analysis” stage
shows that there are contaminants,
then the second stage can provide
more complete information.
Let’s start with the rapid analysis
step.
Parts of Rapid Analysis
Tissue
extraction
with solvent
Sample
precleanup
Automated
Instrumental
Analysis
PDA
HPLC
Autosampler
Cosmosil
PYE column
Chromatogram
10
PDA Detector
Compounds the rapid analysis
step can identify and measure
these contaminants

Pesticides: HCB,
o,p’-DDT, p,p’-DDT,
o,p’-DDD, p,p’DDD,p,p’-DDE
 Specific
types of
PCBs (“congeners”)
77, 101*, 105, 110, 114,
118, 126, 128, 138, 153,
156, 157, 169, 170/190,
180, 189, 200, total PCBs
The first step is to get rid of the water in the sample
and mix it with gasoline-like solvents.
The next step is to separate the solids from the
liquids. You do this with a centrifuge that spins
the mixture very rapidly. Before using the
centrifuge, you have to make sure it is
balanced. Otherwise it will walk off the table
with your sample!
The centrifuge itself is behind Darr’s arm.
There is now too much solvent in the
sample. Darr here is boiling the solvents
off under a hood that keeps the fumes
away from her.
The black
band in the
glass column
is the natural
materials
being
captured,
allowing the
contaminants
to go through
to the bottle
at the bottom
Next, Darr is using a column to
separate natural materials in the
sample from the contaminants
Back to the hood to
boil off solvents
These are the actual
instruments that measure
the contaminants
The computer calculates a graph
with peaks that show amounts of
specific contaminants measured
by the instruments in the previous
slide
Analyses of NIST whale blubber
control material by rapid analysis
ng/g, wet wt
Selected
CB Congeners
105
118
138
153
156
180
Sample wt (g)
Rapid Analysis
n= 99
90 ± 19
247 ± 34
500 ± 78
823 ± 111
29 ± 4
495 ± 69
0.26 ± 0.04
† = coeluting CB congeners 163, 164
NIST
(published)
88.9 ± 13
267 ± 25
664 ± 8†
870 ± 9
38 ± 1
483 ± 9
2–3
Parts of Detailed Analysis
Tissue
extraction
with solvent
Sample
precleanup
Automated Instrumental Analysis
HPLC
GC/MS
MSD
Chromatogram
10
Contaminants measured in
detailed analysis

Pesticides: HCB, a-HCH,
ß-HCH, lindane, aldrin,
dieldrin, endosulfan I & II
& sulfate, HPE, heptaclor,
heptaclor epoxide,
oxychlordane,g-chlordane,
a-chlordane, transnonachlor, cis-nonachlor,
o,p’-DDT, p,p’-DDT, o,p’DDD, p,p’-DDD,o,p’-DDE,
p,p’-DDE
 PCBs: 17, 18, 28, 31, 33,
44, 49, 52, 66, 70, 74, 82,
87, 95, 99, 101/90, 105, 110,
118, 128, 138/163/164, 149,
151, 153/132, 156, 158,
170/190, 171, 177, 180, 183,
187/159/182, 191, 194, 195,
199, 205, 206, 208, 209
Toxaphenes
 PAHs

A marine mammal
blubber sample (1-2 g) is
weighed.
The sample is ground for 5
minutes
Balancing the sample for the
centrifuge to separate the
solid from the liquid
Pouring the liquid off through a
column to take out the natural
materials and leave the
contaminants in the liquid
Brown jars with all
the liquid
Tubes of liquid being
heated to boil off the extra
liquid
The High Performance Liquid
Chromatograph (HPLC) to get rid
of the rest of the lipids (fats)
We use this column filled with
sand with a coating on it to
separate the lipids from the
contaminants
We boil off solvent again.
Then we go further by
putting it in the vial and
use nitrogen gas get rid
of more solvent. Then we
can see contaminant
peaks on the instrument.
A chromotgram from the Mass
Spectrometer showing great detail
Jenny (like her blue hair?) and Doug
figured out a way to quickly transfer
data from the Mass Spec to a computer
database
Comparison of Results of Detailed
Analysis to NIST whale blubber
Standard Reference Material
ng/g, wet wt
Selected
Analytes
HCB
a-chlordane
p,p’-DDE
105
118
153/132
156
170/190
Sample wt (g)
GC/MS
NIST
(certified)
29.6 ± 1.3
50.0 ± 7.3
526 ± 33
27.0 ± 1.6
77.4 ± 3.2
236 ± 11
11.4 ± 0.9
41.2 ± 4.8
32.9 ± 1.7
46.9 ± 2.8
445 ± 37
30.1 ± 2.3
74.6 ± 5.1
213 ± 19
10.3 ± 1.1
40.6 ± 2.6
~ 1.5
2–3
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