Recent Advances in Sample Preparation for
Accelerated Solvent Extraction
SM Rahmat Ullah, Kannan Srinivasan, and Chris Pohl
Thermo Fisher Scientific, Sunnyvale, CA, USA
Overview
Methods
Purpose: To demonstrate the utility of a new moisture absorbing polymer as a drying
agent for extraction applications.
Polymer used
Methods: Moisture absorption capacity of a new polymer was studied. The in-cell
moisture removal was performed in an extraction setup in an accelerated solvent
extraction instrument at high temperature and pressure. Analytes in the extract were
measured by high-pressure liquid chromatography (HPLC) and gas chromatography
(GC).
Results: The moisture absorbing polymer and the diatomaceous earth can remove
moisture when mixed with wet sample for in-cell, in-line extraction method. An addition of
a small amount of polymer in the collection bottle can also result in complete water
removal from the collected extract.
Introduction
Analyses of organic pollutants are becoming increasingly important, and often with the
need to isolate and analyze trace organic compounds from a variety of matrices such as
soil, sediment, fruits, and vegetables. In this regard, sample pretreatment constitutes an
important step prior to analysis. The purpose of the sample pretreatment step is to
selectively isolate or concentrate the analytes of interest from matrix components and
present a sample suited for routine analysis by established analytical techniques such as
gas chromatography or high-pressure liquid chromatography. Typical sample
pretreatment steps include techniques such as solid phase extraction, liquid-liquid
extraction, solid-liquid extraction, dilution, evaporation, distillation and the like.
Accelerated solvent extraction is a technique used for extracting the analytes of interest
from a solid, semisolid or liquid sample by performing extraction using an organic solvent
at elevated temperature and pressure. The elevated pressure also elevates the boiling
temperature of the solvent, thereby allowing faster extraction to be conducted at relatively
higher temperatures. The benefit of a relatively high temperature extraction is primarily
speed; thus the extraction process is significantly faster than traditional methods such as
Soxhlet extraction.
In some samples containing moisture or water such as soil samples or food samples
(fruits, vegetables, etc.) an additional step may be needed either before the extraction to
remove the moisture from the samples or post extraction to remove the moisture from the
extracted solvent (containing the extracted analytes). Sample drying can be accomplished
in several ways such as air drying and oven drying prior to extraction. However, these
approaches are not suited when analyzing volatile or semivolatile components as they
would be removed from the sample prior to extraction or analysis.
Another common method for moisture removal is by using salts such as sodium sulfate,
calcium chloride, magnesium sulfate, calcium sulfate and the like. These salts tend to
associate to water molecules to form hydrated salts. Sodium sulfate for example tends to
clump together when water is present.
Sodium sulfate is not suitable for in-cell moisture removal and accelerated solvent
extraction. Sodium sulfate can dissolve in hot solvent to a certain extent and can
precipitate downstream in some instances clogging the outlet frit, tubes and valves.
Moreover, sodium sulfate becomes an aggregate hard lump upon water absorption and is
not easy to process during sample preparation for in-cell moisture removal and extraction
(1).
Polymers have been used for moisture removal such polymers have been designated
super absorbent polymers (2). The most common polymer is the sodium salt of
polyacrylic acid. Although this polymer removes water by absorbing it into the polymer
matrix, the water absorbing capacity decreases as the ionic strength increases. Another
limitation of the polymer is poor water absorbing property under high temperature
conditions. Yet another limitation of this polymer is that it becomes a hard plug inside the
extraction cell (1). The present research solves these issues.
Here, the authors synthesized a water absorbent polymer comprising a copolymer of a
basic monomer and an acidic monomer. This combination is suitable for moisture removal
under high ionic strength conditions. Results shown here also demonstrate that when the
polymer is mixed with diatomaceous earth (DE) the water removal efficiency increases
significantly. Different formats of using the polymer such as in-cell, in-vial and a
combination of the two are discussed.
2 Recent Advances in Sample Preparation for Accelerated Solvent Extraction
A proprietary moisture absorbing po
Sample preparation
Sample containing moisture was us
polymer or the polymer was combin
Dionex™ ASE™ extraction cell for t
Accelerated Solvent Extraction syste
Extraction using the Dionex ASE
Sample extraction at high temperatu
350 Accelerated Solvent Extractor s
Dionex ASE 350 extraction condition
Pressure: 1500 psi
Temperature: 100 ⁰C- 150 ⁰C
Static time: 5-10 min
Cycles: 1-3
Flush: 10-75%
Purge: 120 sec
Solvent: Hexane or 1/1 Acetone/Dic
Measurement of moisture remova
Known amounts of water were spike
measure the water removal capacity
solvent. Similarly, water removal cap
temperature for comparison purpose
Water removal capacity of polyme
The water removal capacity of the p
water present in the cell without any
Liquid chromatography
A P680 pump, PDA-100 photodiode
used for chromatographic separatio
Chromatography Data System softw
column was a Thermo Scientific ™
flow rate was 1.0 mL/min. Separatio
mM acetic acid/ammonium acetate
B changed from 25% to 70% over 1
Gas Chromatography
A GC with Flame Ionization Detecto
hydrocarbon (PAH). The Chromeleo
.The separation column was a Therm
The helium carrier gas flow rate wa
min), 25 °C/min to 140 °C , then 10
a new moisture absorbing polymer as a drying
ty of a new polymer was studied. The in-cell
extraction setup in an accelerated solvent
ure and pressure. Analytes in the extract were
matography (HPLC) and gas chromatography
mer and the diatomaceous earth can remove
for in-cell, in-line extraction method. An addition of
ction bottle can also result in complete water
oming increasingly important, and often with the
nic compounds from a variety of matrices such as
In this regard, sample pretreatment constitutes an
urpose of the sample pretreatment step is to
nalytes of interest from matrix components and
alysis by established analytical techniques such as
liquid chromatography. Typical sample
such as solid phase extraction, liquid-liquid
on, evaporation, distillation and the like.
hnique used for extracting the analytes of interest
e by performing extraction using an organic solvent
The elevated pressure also elevates the boiling
owing faster extraction to be conducted at relatively
elatively high temperature extraction is primarily
ignificantly faster than traditional methods such as
or water such as soil samples or food samples
tep may be needed either before the extraction to
or post extraction to remove the moisture from the
cted analytes). Sample drying can be accomplished
oven drying prior to extraction. However, these
zing volatile or semivolatile components as they
or to extraction or analysis.
removal is by using salts such as sodium sulfate,
calcium sulfate and the like. These salts tend to
ydrated salts. Sodium sulfate for example tends to
l moisture removal and accelerated solvent
e in hot solvent to a certain extent and can
ces clogging the outlet frit, tubes and valves.
aggregate hard lump upon water absorption and is
paration for in-cell moisture removal and extraction
removal such polymers have been designated
st common polymer is the sodium salt of
removes water by absorbing it into the polymer
ecreases as the ionic strength increases. Another
absorbing property under high temperature
s polymer is that it becomes a hard plug inside the
ch solves these issues.
absorbent polymer comprising a copolymer of a
er. This combination is suitable for moisture removal
esults shown here also demonstrate that when the
arth (DE) the water removal efficiency increases
the polymer such as in-cell, in-vial and a
Methods
Results
Polymer used
Moisture absorbing capability
A proprietary moisture absorbing polymer was used here.
The amount of moisture absorbing po
absorbing one gram of water at room
Sample preparation
Sample containing moisture was used or a spiked sample with water was added to the
polymer or the polymer was combined with DE and loaded into the Thermo Scientific™
Dionex™ ASE™ extraction cell for the extraction using the Thermo Scientific Dionex ASE
Accelerated Solvent Extraction system.
Extraction using the Dionex ASE 350 System
Sample extraction at high temperature and pressure was performed using Dionex ASE
350 Accelerated Solvent Extractor system.
Dionex ASE 350 extraction conditions:
The moisture removal formats
a) In-cell (in-line) moisture removal:
The moisture absorbing polymer can
in-cell moisture removal and extractio
moisture removal the polymer is used
Dispersant for ASE. The ASE Prep DE
accelerated solvent extraction, therefo
customer’s current practices.
b) In-vial (off-line) moisture removal:
The amount of moisture absorbing po
of water at room temperature. A simp
(proportional to the amount of water p
complete water removal from the extr
needed is 4 g to absorb one gram of
polymer in an aliquot basis.
Pressure: 1500 psi
Temperature: 100 ⁰C- 150 ⁰C
Static time: 5-10 min
Cycles: 1-3
Flush: 10-75%
Purge: 120 sec
Solvent: Hexane or 1/1 Acetone/Dichloromethane
Measurement of moisture removal capacity at room temperature
Known amounts of water were spiked as the sample and was mixed with the polymer to
measure the water removal capacity at room temperature in the presence of organic
solvent. Similarly, water removal capacity of sodium sulfate was measured at room
temperature for comparison purposes.
c) Combination Mode:
In this mode, the in-cell moisture rem
removal (off line). If some breakthroug
addition of a small amount of polymer
moisture removal. In fact a small amo
there would be no moisture present in
for samples with unknown moisture c
Water removal capacity of polymer and polymer-DE
The water removal capacity of the polymer was measured as the maximum amount of
water present in the cell without any breakthrough of the water into the collection bottle.
Liquid chromatography
A P680 pump, PDA-100 photodiode array detector and a chromatographic oven were
used for chromatographic separation. Thermo Scientific™ Dionex™ Chromeleon™ 6.8
Chromatography Data System software was used for data acquisition. The separation
column was a Thermo Scientific ™ Acclaim ™ Polar Advantage C16 5µm 4.6 x 150 mm,
flow rate was 1.0 mL/min. Separation was based on gradient elution of A comprising 25
mM acetic acid/ammonium acetate and B comprising of acetonitrile where composition of
B changed from 25% to 70% over 17.5 min. Detection wavelength was 280 nm.
Gas Chromatography
A GC with Flame Ionization Detector (FID) was used for the analysis of polyaromatic
hydrocarbon (PAH). The Chromeleon 6.8 CDS software was used for data acquisition
.The separation column was a Thermo Scientific ™ TR-5MS 30 m x 0.25 mm x 0.25 5µm.
The helium carrier gas flow rate was 1.5 mL/min. The temperature profile was 65 °C (1
min), 25 °C/min to 140 °C , then 10 °C/min to 290 °C. The run time was 40 minutes.
In-cell moisture removal
A combination of polymer and DE (1:1
Dionex ASE 350 system at various ex
used as the extraction solvent. Result
efficiency dropped as the temperature
was still feasible even at 150 °C. The
agent required for a given sample wit
sediments, fruits and vegetable with r
temperature.
Table 1. In-cell water removal capa
temperatures and cell sizes using t
Accelerated
solvent
extraction
temperature,
⁰C
Total water
present in the
cell, g
100
5.05
125
2.54
150
2.15
100
10.05
125
5.05
150
2.09
100
15.15
125
8.14
150
2.14
Thermo Scientific Poster Note • PN70546_E 03/13S 3
Results
Analyte recovery for in-cell moist
Analyte recovery from the extraction
phenols, two anilines and a neutral a
presence of 8 g of the polymer and a
mL standard solution in acetonitrile a
was then extracted using the Dionex
dichloromethane: acetone solvent a
was evaporated to 10 mL under nitro
µg/mL for a 10 mL extract.
Moisture absorbing capability
mer was used here.
or a spiked sample with water was added to the
with DE and loaded into the Thermo Scientific™
extraction using the Thermo Scientific Dionex ASE
.
0 System
and pressure was performed using Dionex ASE
em.
The amount of moisture absorbing polymer needed is approximately 0.20 g for
absorbing one gram of water at room temperature.
The moisture removal formats
a) In-cell (in-line) moisture removal:
The moisture absorbing polymer can remove moisture when mixed with wet sample for
in-cell moisture removal and extraction. For improved flow characteristics and improved
moisture removal the polymer is used in conjunction with Diatomaceous Earth (DE)
Dispersant for ASE. The ASE Prep DE is normally used with the sample when pursuing
accelerated solvent extraction, therefore adding the polymer to this setup maintains the
customer’s current practices.
b) In-vial (off-line) moisture removal:
The amount of moisture absorbing polymer needed is 0.20 g for absorbing one gram
of water at room temperature. A simple addition of a small amount of polymer
(proportional to the amount of water present) in the collection bottle can result in
complete water removal from the extract. In comparison the amount of sodium sulfate
needed is 4 g to absorb one gram of water. Further there is no need to add the
polymer in an aliquot basis.
romethane
apacity at room temperature
as the sample and was mixed with the polymer to
t room temperature in the presence of organic
city of sodium sulfate was measured at room
ray detector and a chromatographic oven were
Thermo Scientific™ Dionex™ Chromeleon™ 6.8
e was used for data acquisition. The separation
claim ™ Polar Advantage C16 5µm 4.6 x 150 mm,
was based on gradient elution of A comprising 25
d B comprising of acetonitrile where composition of
5 min. Detection wavelength was 280 nm.
FID) was used for the analysis of polyaromatic
6.8 CDS software was used for data acquisition
Scientific ™ TR-5MS 30 m x 0.25 mm x 0.25 5µm.
1.5 mL/min. The temperature profile was 65 °C (1
/min to 290 °C. The run time was 40 minutes.
Analyte recovery for in-vial moisture
using the same concentration level o
water (5 mL) was spiked into the 10
polymer or by sodium sulfate. The re
recoveries were obtained for moistu
sulfate.
Table 2. Recovery of analytes.
Analytes
c) Combination Mode:
In this mode, the in-cell moisture removal (in-line) is followed by in-vial moisture
removal (off line). If some breakthrough of water is observed in the extract then
addition of a small amount of polymer in the collection bottle can result in complete
moisture removal. In fact a small amount in the collection vessel always ensures that
there would be no moisture present in the samples. This mode is particularly useful
for samples with unknown moisture content.
and polymer-DE
mer was measured as the maximum amount of
eakthrough of the water into the collection bottle.
The 10 mL extract was analyzed usi
above experiment are shown in Tab
acceptable performance of the polym
acceptance criteria of ± 30% as per
there is no detrimental effect of usin
analytes.
Total
level
10 m
1
2, 4-Dinitrophenol
3
2
Phenol
3
A combination of polymer and DE (1:1) was tested for in-cell water removal using a
Dionex ASE 350 system at various extraction temperatures and cell sizes. Hexane was
used as the extraction solvent. Results are shown below in Table 1. The water removal
efficiency dropped as the temperature increased, nevertheless practical water removal
was still feasible even at 150 °C. The data provides guideline on the amount of drying
agent required for a given sample with a known range of water content such as
sediments, fruits and vegetable with respect to a chosen cell size and extraction
temperature.
3
P-Toluidine
3
4
4-Nitrophenol
3
5
2-Chlorophenol
3
6
4-Ethylaniline
3
7
4-Chloroaniline
3
8
2-Nitrophenol
3
Table 1. In-cell water removal capacity of the polymer-DE at different
temperatures and cell sizes using the Dionex ASE 350 system.
9
2, 4Dichlorophenol
3
10
2, 4, 6Trichlorophenol
3
In-cell moisture removal
Accelerated
solvent
extraction
temperature,
⁰C
Total water
present in the
cell, g
Drying agent
(Polymer and
DE)
Cell size, mL
Water
observed in
the collection
bottle, g
100
5.05
2 g each
34
No
125
2.54
2 g each
34
No
150
2.15
2 g each
34
No
100
10.05
4 g each
66
No
125
5.05
4g each
66
No
150
2.09
4 g each
66
No
100
15.15
6 g each
100
No
125
8.14
6 g each
100
No
150
2.14
6 g each
100
No
4 Recent Advances in Sample Preparation for Accelerated Solvent Extraction
Polyaromatic hydrocarbon (PAH) re
cell (in-line) moisture removal and e
clean soil sample was spiked with P
30% moisture) by adding water. The
polymer and DE and loaded into a 3
using the Dionex ASE 350 instrume
acetone) at an extraction temperatu
under nitrogen stream at 40⁰C. The
final extract volume of 1 mL.
The extract was analyzed using a G
experiment are shown in Table 3. A
it was still deemed acceptable base
Method 8270. The extraction condit
these two PAHs, naphthalene and a
Analyte recovery for in-cell moisture removal and in-vial moisture removal
Analyte recovery from the extraction using the polymer was studied using a mixture of
phenols, two anilines and a neutral analyte. An in-cell extraction was pursued in the
presence of 8 g of the polymer and a spike with a standard solution that contained 1.5
mL standard solution in acetonitrile and 8.5 mL of water. The spiked polymer sample
was then extracted using the Dionex ASE 350 instrument and a 1:1 ratio of
dichloromethane: acetone solvent at an extraction temperature of 100⁰ C. The extract
was evaporated to 10 mL under nitrogen stream at 40⁰C. The spike level was 30
µg/mL for a 10 mL extract.
mer needed is approximately 0.20 g for
mperature.
move moisture when mixed with wet sample for
For improved flow characteristics and improved
conjunction with Diatomaceous Earth (DE)
s normally used with the sample when pursuing
e adding the polymer to this setup maintains the
mer needed is 0.20 g for absorbing one gram
addition of a small amount of polymer
sent) in the collection bottle can result in
t. In comparison the amount of sodium sulfate
ter. Further there is no need to add the
The 10 mL extract was analyzed using an HPLC instrument The results from the
above experiment are shown in Table 2. The per cent recovery data showed
acceptable performance of the polymer for these test analytes based on an
acceptance criteria of ± 30% as per EPA Method 8270. Moreover, it also indicates that
there is no detrimental effect of using this polymer for in-cell extraction for these test
analytes.
Analyte recovery for in-vial moisture removal at room temperature was also studied
using the same concentration level of analytes in a 10 mL solvent. A known amount of
water (5 mL) was spiked into the 10 mL solvent. The water was removed either by the
polymer or by sodium sulfate. The results are shown in Table 2. Comparable
recoveries were obtained for moisture removal by the polymer compared to sodium
sulfate.
Table 2. Recovery of analytes.
Analytes
al (in-line) is followed by in-vial moisture
of water is observed in the extract then
the collection bottle can result in complete
nt in the collection vessel always ensures that
he samples. This mode is particularly useful
tent.
was tested for in-cell water removal using a
action temperatures and cell sizes. Hexane was
are shown below in Table 1. The water removal
ncreased, nevertheless practical water removal
ata provides guideline on the amount of drying
a known range of water content such as
pect to a chosen cell size and extraction
y of the polymer-DE at different
e Dionex ASE 350 system.
ying agent
olymer and
E)
Cell size, mL
Water
observed in
the collection
bottle, g
2 g each
34
No
2 g each
34
No
2 g each
34
No
4 g each
66
No
4g each
66
No
4 g each
66
No
6 g each
100
No
6 g each
100
No
6 g each
100
No
Total spike
level in
10 mL
In-cell
moisture
removal by
the
polymer
In-vial
moisture
removal by
the
polymer
In-vial
moisture
removal by
the sodium
sulfate
µg
% recovery
% recovery
% recovery
1
2, 4-Dinitrophenol
300
81.01
82.96
86.79
2
Phenol
300
89.99
88.58
88.41
3
P-Toluidine
300
86.72
95.03
93.88
4
4-Nitrophenol
300
96.05
90.96
88.93
5
2-Chlorophenol
300
92.33
87.45
87.16
6
4-Ethylaniline
300
92.82
89.47
88.02
7
4-Chloroaniline
300
94.44
88.39
87.51
8
2-Nitrophenol
300
93.83
92.64
87.39
9
2, 4Dichlorophenol
300
97.50
93.25
89.58
10
2, 4, 6Trichlorophenol
300
97.51
95.20
91.02
Polyaromatic hydrocarbon (PAH) recovery from spiked soil sample was pursued for incell (in-line) moisture removal and extraction in the Dionex ASE 350 system. A 5 g
clean soil sample was spiked with PAHs and then the soil was made moist (to about
30% moisture) by adding water. The spiked wet soil sample was mixed with 4 g of 1:1
polymer and DE and loaded into a 34 mL ASE cell. The soil sample was then extracted
using the Dionex ASE 350 instrument by solvent (1:1 ratio of dichloromethane:
acetone) at an extraction temperature of 100⁰ C. The extract was evaporated to 1 mL
under nitrogen stream at 40⁰C. The spike level was calculated as 20 µg/mL for the
final extract volume of 1 mL.
The extract was analyzed using a GC instrument with FID. The results from the above
experiment are shown in Table 3. Although two compounds showed a lower recovery,
it was still deemed acceptable based on the acceptance criteria of ± 30% as per EPA
Method 8270. The extraction condition yet to optimize to increase the recovery of
these two PAHs, naphthalene and acenaphthylene.
Table 3. PAH recovery by using GCAnalytes
1
Naphthalene
2
Acenapththyene
3
Acenaphthylene
4
Phenanthrene
5
Anthracene
6
Fluoranthene
7
Pyrene
8
Benzo(a)anthracene
9
Chrysene
10
Benzo(b)fluoranthene
11
Benzo(k)fluoranthene
12
Benzo(a)pyrene
13
Indeno((1,2,3,c,d)pyrene
14
Dibenzo(a,h)anthracene
15
Benzo(g,h,i)perylene
Analyte recovery for in-vial (off-line) mo
using the same solvent, 1:1 dichlorome
PAHs. A known amount of water was a
The water was removed either by the p
evaporated to 1 mL under nitrogen stre
final extract volume of 1 mL. The resul
were obtained for in-vial moisture remo
Therefore, the usefulness of the polym
table.
Conclusion

The utility of a new polymer for r
from a collected extract is shown

The new polymer is designed to
intended for in-cell (in-line) mois
and a combination of both in-cel

The unique formulation of the po
extraction conditions and is not a
polymer is a free-flowing white g
ASE Prep DE and used for the m
polymer can be easily removed f
high-temperature extractions are

The polymer overcomes the limi
removal and extraction.

Investigations are underway to e
moisture/water containing sampl
References
1. Burford, M. D., Hawthorne, S. B.
line supercritical fluid extraction,
2. Determination of Acephate and M
Polymer, Analytical Communicat
Thermo Fisher Scientific Inc. All rights reserved
subsidiaries.
This information is not intended to encourage use
property rights of others.
PO70546_E 03/12S
Thermo Scientific Poster Note • PN70546_E 03/13S 5
e removal and in-vial moisture removal
sing the polymer was studied using a mixture of
alyte. An in-cell extraction was pursued in the
pike with a standard solution that contained 1.5
d 8.5 mL of water. The spiked polymer sample
SE 350 instrument and a 1:1 ratio of
n extraction temperature of 100⁰ C. The extract
en stream at 40⁰C. The spike level was 30
an HPLC instrument The results from the
2. The per cent recovery data showed
r for these test analytes based on an
A Method 8270. Moreover, it also indicates that
his polymer for in-cell extraction for these test
moval at room temperature was also studied
analytes in a 10 mL solvent. A known amount of
L solvent. The water was removed either by the
lts are shown in Table 2. Comparable
removal by the polymer compared to sodium
ike
In-cell
moisture
removal by
the
polymer
In-vial
moisture
removal by
the
polymer
In-vial
moisture
removal by
the sodium
sulfate
% recovery
% recovery
% recovery
81.01
82.96
86.79
89.99
88.58
88.41
86.72
95.03
93.88
96.05
90.96
88.93
92.33
87.45
87.16
92.82
89.47
88.02
94.44
88.39
87.51
93.83
92.64
87.39
97.50
93.25
89.58
97.51
95.20
91.02
very from spiked soil sample was pursued for inaction in the Dionex ASE 350 system. A 5 g
Hs and then the soil was made moist (to about
piked wet soil sample was mixed with 4 g of 1:1
mL ASE cell. The soil sample was then extracted
by solvent (1:1 ratio of dichloromethane:
of 100⁰ C. The extract was evaporated to 1 mL
pike level was calculated as 20 µg/mL for the
instrument with FID. The results from the above
ough two compounds showed a lower recovery,
on the acceptance criteria of ± 30% as per EPA
yet to optimize to increase the recovery of
naphthylene.
Table 3. PAH recovery by using GC-FID.
Analytes
In-cell moisture
removal by the
polymer-DE
In-vial moisture
removal by the
polymer
In-vial moisture
removal by the
sodium sulfate
% recovery
% recovery
% recovery
1
Naphthalene
77.8
100.8
96.2
2
Acenapththyene
93.9
99.3
97.5
3
Acenaphthylene
74.5
97.0
95.7
4
Phenanthrene
100.7
103.1
98.6
5
Anthracene
103.1
103.3
99.8
6
Fluoranthene
102.3
110.1
101.0
7
Pyrene
98.8
109.4
100.6
8
Benzo(a)anthracene
96.8
116.4
108.1
9
Chrysene
93.3
117.3
104.0
10
Benzo(b)fluoranthene
96.2
120.3
103.7
106.4
11
Benzo(k)fluoranthene
97.2
119.2
12
Benzo(a)pyrene
85.3
118.0
106.0
13
Indeno((1,2,3,c,d)pyrene
98.1
112.1
105.5
14
Dibenzo(a,h)anthracene
109.7
110.9
105.1
15
Benzo(g,h,i)perylene
105.9
112.5
107.3
Analyte recovery for in-vial (off-line) moisture removal at room temperature was studied
using the same solvent, 1:1 dichloromethane: acetone. A 40 mL solvent was spiked with
PAHs. A known amount of water was added to the spiked solvent acting as an extract.
The water was removed either by the polymer or by the sodium sulfate. The extract was
evaporated to 1 mL under nitrogen stream at 40⁰C. The spike level was 20 µg/mL for the
final extract volume of 1 mL. The results are shown in Table 3. Comparable recoveries
were obtained for in-vial moisture removal by the polymer compared to sodium sulfate.
Therefore, the usefulness of the polymer as drying agent was evident from the above
table.
Conclusion

The utility of a new polymer for removing moisture from wet samples as well as
from a collected extract is shown here.

The new polymer is designed to work with accelerated solvent extraction and is
intended for in-cell (in-line) moisture removal, in-vial (off line) moisture removal
and a combination of both in-cell and in-vial.

The unique formulation of the polymer allows moisture removal under ASE
extraction conditions and is not affected by the sample ionic strength. The
polymer is a free-flowing white granular material that can be easily mixed with
ASE Prep DE and used for the moisture removal applications. Additionally the
polymer can be easily removed from the Dionex ASE extraction cell after the
high-temperature extractions are complete.

The polymer overcomes the limitation of sodium sulfate for in-cell moisture
removal and extraction.

Investigations are underway to expand the applicability of this polymer to other
moisture/water containing samples.
References
1. Burford, M. D., Hawthorne, S. B., Miller, D. J. Evaluation of drying agents for offline supercritical fluid extraction, J. Chromatography A, 1993, 657, 413-427.
2. Determination of Acephate and Methamidophos in Foods Using Super-absorbent
Polymer, Analytical Communications, 1997, 34, 253-256.
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