Determination of Dioctylsulfosuccinate (DOSS) in Oysters ... - Dionex

Determination of Dioctylsulfosuccinate
(DOSS) in Oysters Using Single Quadrupole
Mass Spectrometry
Jonathan R. Beck, 1 Marcus Miller, 2 Leo Jinyuan Wang, 2 and William C. Schnute, 2
1
Thermo Fisher Scientific, San Jose, CA; 2 Thermo Fisher Scientific, Sunnyvale, CA, USA

Overview
A simplified method for extraction of sodium dioctylsulfosuccinate (DOSS) from oysters
is demonstrated in this work. Previous methods employed extraction protocols based on
QuEChERS methods. 1 Here, a Thermo Scientific Dionex ASE 350 Accelerated Solvent
Extractor allowed single-step extraction using a mixture of water and acetonitrile to achieve
high extraction effi ciencies. The extract was filtered and then diluted to a fi nal concentration
within the valid calibration range established. Use of standards in deionized water
demonstrated linear response across three orders of magnitude and provided the basis for
determination of DOSS concentrations in oyster extracts and salt water samples. In addition to
linear response, high recoveries and low carryover were demonstrated. The Thermo Scientifi c
MSQ Plus Mass Detector (single quadrupole) provided the sensitivity and selectivity when
coupled with HPLC chromatography. The complete extraction and analysis proved to be
rugged, and it was possible to identify the target analyte even at very low concentrations and in
complex biological matrices.
Introduction
During the Deepwater Horizon disaster, over 1.8 million gallons of dispersants were used
in the Gulf of Mexico. 2 The primary dispersant used was COREXIT ® 9500 (Nalco Co.,
Naperville, IL) along with small amounts of COREXIT 9527. Both these proprietary mixtures
contain DOSS as the major component. 3 DOSS has low volatility and a potential to persist
in the environment, and there is concern that COREXIT component substances have a
potential to bioconcentrate. 4 Analysis for DOSS serves as a useful marker to assess the
presence and persistence of these dispersants. This study was undertaken to identify a rapid
extraction technique and subsequent analysis that would allow for the identifi cation and
quantitation of DOSS.
Methods
Instrumentation
Extraction
Dionex ASE 350
Chromatography
Thermo Scientifi c Dionex UltiMate 3000 LC
LPG-3000 Series Low-Gradient Pump
FLM-3100 Flow Manager
WPS-3000 Autosampler
MSQ Plus Mass Detector (single quadrupole)
AXP-MS Auxiliary Pump
Thermo Scientifi c Dionex Chromeleon 6.8 SR10 Chromatography Data System software
Chromatographic Condit
(3 µm, 120 A, 2.1 mm ×
Mobile Phase: Solvent A = Water + 0.1
Solvent B = Acetonitrile
HPLC System
Column: Thermo Scientifi c Accla
Gradient Time (min) % B
0 45
3 45
6 95
9 95
9.01 45
12 45
Flow Rate: 0.45 mL/min
Inj. Volume: 25 µL (full loop)
Temperature: 40 °C
Mass Spectrometer Parameters for
ESI, negative ion
SIM scan, 421.1 m/z with 0.7 m/z span
N 2
pressure: 80 psi
Probe Temperature: 400 °C
Needle Voltage: 2 kV
Cone Voltage: 70 V
A divert valve was plumbed after the co
compounds to be directed away from th
analyte of interest. A flow rate of 0.1 mL
low-volume mixing tee prior to the mas
the mass spectrometer during eluent d
dry out.
Divert Valve:
Time (min) Position
0 To Waste
3.0 To Mass
6.5 To Waste
FIGURE 1. Schematic of the HPLC-m
Extraction Conditions
The oyster emulsion (prepared as described in Chemicals and Reagents section) was
maintained at 4 °C until just prior to extraction. To prepare the extraction vessels, a clean glass
fiber filter (P/N: 068092) was placed on the bottom of the 10 mL stainless steel extraction
vessel and the bottom cap was screwed in place. The extraction vessel was then loaded with
1g of diatomaceous earth (ASE prep DE−CAS 68855-54-9, P/N: 062819) that was ground
with a mortar and pestle. A 1 mL aliquot of oyster emulsion was loaded on top of the DE. The
remaining space in the extraction vessel was fi lled with DE, a second glass fi ber filter was
placed on the top of the vessel, and the top cap was screwed in place. For spiked samples, an
aliquot of DOSS was added directly to the oyster emulsion prior to fi lling the cell with DE.
A
B
Ultimate 3000 Pump 1
450 µL/min
Si
The extraction vessels were loaded in the top carousel of the ASE 350 instrument, and 60 mL
glass collection vials were weighed then placed in the bottom carousel. The extraction mode
used was standard, with an oven temperature of 100 °C, extraction pressure of 1000 psi, and
a static cycle time of 5 minutes for a single cycle followed by a rinse volume of 60% and a gas
purge of the vessel for 90 seconds. The extraction solvent used was 1:1 acetonitrile/water.
Between samples, a 5 mL rinse of of solvent was used to minimize carry-over.
Following extraction, the collection vessels were weighed and the difference from tared weight
noted for use in calculating the concentration factor for each sample analyzed.
Data System
Chemicals and Reagents:
DOSS was purchased from Sigma-Ald
structure is shown below.
FIGURE 2. Chemical structure for DO
LPN 2 3019
Determination of Dioctylsulfosuccinate (DOSS) in Oysters Using Single Quadrupole Mass Spectrometry

SS) from oysters
protocols based on
ccelerated Solvent
acetonitrile to achieve
o a fi nal concentration
onized water
provided the basis for
er samples. In addition to
d. The Thermo Scientifi c
y and selectivity when
alysis proved to be
low concentrations and in
ispersants were used
9500 (Nalco Co.,
ese proprietary mixtures
d a potential to persist
substances have a
arker to assess the
ertaken to identify a rapid
he identifi cation and
ata System software
nts section) was
ion vessels, a clean glass
less steel extraction
el was then loaded with
819) that was ground
d on top of the DE. The
glass fi ber filter was
. For spiked samples, an
ing the cell with DE.
0 instrument, and 60 mL
l. The extraction mode
ressure of 1000 psi, and
olume of 60% and a gas
1:1 acetonitrile/water.
rry-over.
erence from tared weight
nalyzed.
Chromatographic Conditions
HPLC System
Column: Thermo Scientifi c Acclaim 120 C18 column
(3 µm, 120 A, 2.1 mm × 150 mm)
Mobile Phase: Solvent A = Water + 0.1% Formic Acid
Solvent B = Acetonitrile + 0.1% Formic Acid
Gradient Time (min) % B
0 45
3 45
6 95
9 95
9.01 45
12 45
Flow Rate: 0.45 mL/min
Inj. Volume: 25 µL (full loop)
Temperature: 40 °C
Mass Spectrometer Parameters for DOSS:
ESI, negative ion
SIM scan, 421.1 m/z with 0.7 m/z span, dwell time: 0.8 second
N 2
pressure: 80 psi
Probe Temperature: 400 °C
Needle Voltage: 2 kV
Cone Voltage: 70 V
A divert valve was plumbed after the column to allow the eluent and other background
compounds to be directed away from the mass spectrometer before and after the elution of the
analyte of interest. A flow rate of 0.1 mL/min of 1:1 water and acetonitrile was added using a
low-volume mixing tee prior to the mass spectrometer. This provided a steady stream of fl uid to
the mass spectrometer during eluent diversion to ensure the needle and spray interface did not
dry out.
Divert Valve:
Time (min) Position
0 To Waste
3.0 To Mass Spectrometer
6.5 To Waste
FIGURE 1. Schematic of the HPLC-mass spectrometer system used here.
A
B
Ultimate 3000 Pump 1
450 µL/min
Data System
Signal
Chemicals and Reagents:
DOSS was purchased from Sigma-Aldrich (CAS 577-11-7, Aldrich: 323586). The chemical
structure is shown below.
FIGURE 2. Chemical structure for DOSS.
HPLC Column
MSQ Plus
Divert Valve
Waste
Acetonitrile
Micro Tee
AXP Pump
1:1 Acetonitrile/water
27788
Acetonitrile was obtained from Burdick
water was produced by a Millipore wa
was obtained from Fluka (CAS 64-18-
salt (Instant Ocean Sea Salt, Spectrum
recommendations. A solution of appro
prepared by dissolving 30 g aquarium
A primary stock solution of DOSS was
stock solutions were prepared by dilut
into 50 ppm and 500 ppb concentratio
calibration standards.
Oysters were obtained from a local ma
Willapa Bay, Washington). A food blend
using one 8 oz package of oysters and
emulsion was stored at 4 °C and the bo
sampling. Syringe filters (IC tAcrodisc ®
PALL Scientific P/N 4583T) were used t
Results
Calibration
DOSS standards were prepared in DI w
500 ppb and 1, 2, and 5 ppm. Full loop
125 ng loaded on column (Figure 3). Sa
100, 200, 500 and 1000 ppb. These sam
(CH 3
CN + 0.1% formic acid) to improve
FIGURE 3. Calibration for DOSS in D
55,000
DOSS counts
LOD = 4.6 ppb
Based on 7 replicate
0
0.0 0.5 1.0 1.5 2
Oyster Samples
Oyster emulsion was spiked with DOS
analyzed as unspiked blanks. Three s
Collection vials were weighed before a
All extractions were fi ltered using a sy
acetonitrile and water. This prepared s
at 5 o C to await analysis.
Chromatography
As shown in Figure 4, DOSS was well
acidifi ed solvents to keep the analyte i
organic solvent concentration (45%) a
be washed off the column and diverted
concentration followed that reduced th
and ended at a high organic concentra
the column. This improved method rug
content, or oyster extractions which ar
O
O
O
Na + - O
S
O
O
O
28650
Thermo Scientific Poster Note • LPN3019-01_e 11/11SV
3

ther background
nd after the elution of the
rile was added using a
steady stream of fl uid to
nd spray interface did not
ed here.
Divert Valve
Waste
Acetonitrile
ro Tee
AXP Pump
1:1 Acetonitrile/water
27788
3586). The chemical
Acetonitrile was obtained from Burdick & Jackson (HPLC grade, AH015-4). Deionized (DI)
water was produced by a Millipore water station with 18.2 MΩ.cm resistance. Formic acid
was obtained from Fluka (CAS 64-18-6, Fluka: 06440). Commercially available synthetic sea
salt (Instant Ocean Sea Salt, Spectrum Brands, Inc.) was prepared following manufacturer’s
recommendations. A solution of approximately 3.5% salinity of synthetic sea water (SW) was
prepared by dissolving 30 g aquarium salt into 1 L DI water.
A primary stock solution of DOSS was prepared at 5000 ug/ml (ppm) in DI water. Working
stock solutions were prepared by diluting the primary stock solutions with DI water individually
into 50 ppm and 500 ppb concentrations. These were used to subsequently prepare
calibration standards.
Oysters were obtained from a local market (Fresh Pacific Oysters, Goose Point Oysters brand,
Willapa Bay, Washington). A food blender (Oster ® 10-speed) was run at high setting for 1 min
using one 8 oz package of oysters and their liquor to create a homogeneous emulsion. The
emulsion was stored at 4 °C and the bottle was shaken to resuspend the emulsion before
sampling. Syringe filters (IC tAcrodisc ® 25 mm syringe filter with 0.2 µm Supor [PES] membrane,
PALL Scientific P/N 4583T) were used to remove particulate material from the postextraction fluid.
Results
Calibration
DOSS standards were prepared in DI water at ten concentrations: 5, 10, 20, 50, 100, 200, and
500 ppb and 1, 2, and 5 ppm. Full loop injections of 25 µL yielded a total amount of 125 pg to
125 ng loaded on column (Figure 3). Samples were prepared in synthetic SW and spiked at 50,
100, 200, 500 and 1000 ppb. These samples were diluted 10x with acidified acetonitrile
(CH 3
CN + 0.1% formic acid) to improve linearity of recovery.
FIGURE 3. Calibration for DOSS in DI water.
55,000
DOSS counts
LOD = 4.6 ppb
Based on 7 replicate injections of 20 ppb
Oyster Samples
Oyster emulsion was spiked with DOSS at 2.5, 10, 25, 100, and 250 ppm levels and also
analyzed as unspiked blanks. Three samples at each level were prepared and extracted.
Collection vials were weighed before and after the extraction to calculate the dilution ratio.
All extractions were fi ltered using a syringe fi lter and a 0.1 mL aliquot diluted to 1 mL with 1:1
acetonitrile and water. This prepared sample was then placed in the thermostatted autosampler
at 5 o C to await analysis.
Chromatography
As shown in Figure 4, DOSS was well retained on the C18 column. It was necessary to use
acidifi ed solvents to keep the analyte in its nonionized neutral form during separation. The low
organic solvent concentration (45%) at the beginning of the run allowed the inorganic salts to
be washed off the column and diverted away from the MS. A gradient of increasing organic
concentration followed that reduced the total elution time necessary to recover the analyte,
and ended at a high organic concentration (95%) to wash any strongly retained compounds off
the column. This improved method ruggedness when using SW samples with high inorganic
content, or oyster extractions which are high in both inorganic and organic content.
2,996
-55
-0.002 0.080 0.140 0.250
ppm
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
ppm
28651
DOSS counts
FIGURE 4. Chromatogram comparis
70,000
DOSS Count
0
-10,000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Black: 500ppb in DI
Blue: 100 ppm in Oyster, extracte
Mass Spectrometry (MS)
The aim of the study was to develop a
in oysters and SW samples. The mass
mass-to-charge (m/z) ratio and a selec
The ionization parameters for the anal
followed by needle voltage, and fi nally
in the chromatographic conditions sec
peak shape given the chromatographi
signal accumulation but reduce the nu
narrow chromatographic peaks require
should be noted that optimal paramete
dependent. Therefore, analysts wishin
the parameters described above to de
Method Performance
Calibration over three orders of magni
level showed excellent linear response
detection limit (MDL) was estimated us
replicate injections of a 20 ppb standa
where s is the standard deviation and
calculated MDL was 4.6 ppb. Carryove
analysis of a 100 ppb standard. The re
average value below the MDL. Accura
amount × 100%.
Table 1 summarizes the recovery at va
dilution with acidifi ed acetonitrile. This
clean water and SW.
Table
Actual (ppb)
50
100
200
500
1000
The performance of the extraction effi c
The extract process resulted in a ~20-f
the analyte concentration within the ran
recovered concentrations. The measur
final calculation was made by multiplyi
and the factor of 10x dilution. Thus, fin
volume × 10. The highest measured co
U.S. FDA limit for DOSS in oysters. 5 Th
current limit are easily detected. Shoul
currently shown, the method can be ad
step and still achieve an additional ord
M
28650
4 Determination of Dioctylsulfosuccinate (DOSS) in Oysters Using Single Quadrupole Mass Spectrometry

15-4). Deionized (DI)
istance. Formic acid
available synthetic sea
llowing manufacturer’s
tic sea water (SW) was
) in DI water. Working
with DI water individually
quently prepare
FIGURE 4. Chromatogram comparison
70,000
DOSS - S/N 333.1
DOSS Count
Tab
Actual (ppm) Measured* (ppb) Fin
0 0
2.5 12.8
10 61.3
25 123.4
100 440.8
250 1329.6
* Three extractions at each level, ~200x dilution from original co
†
No peak observed
se Point Oysters brand,
t high setting for 1 min
neous emulsion. The
he emulsion before
Supor [PES] membrane,
m the postextraction fluid.
, 20, 50, 100, 200, and
al amount of 125 pg to
ic SW and spiked at 50,
fied acetonitrile
0.140 0.250
5.0 5.5 6.0
28651
ppm levels and also
ared and extracted.
late the dilution ratio.
diluted to 1 mL with 1:1
hermostatted autosampler
was necessary to use
uring separation. The low
ed the inorganic salts to
t of increasing organic
o recover the analyte,
ly retained compounds off
les with high inorganic
ganic content.
0
-10,000
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11
Minutes
Black: 500ppb in DI
Blue: 100 ppm in Oyster, extracted and ~200x dilution
Mass Spectrometry (MS)
The aim of the study was to develop a selective, sensitive method for direct analysis of DOSS
in oysters and SW samples. The mass spectrometer provides inherent selectivity based on
mass-to-charge (m/z) ratio and a selected ion monitoring (SIM) was chosen for sensitivity.
The ionization parameters for the analyte were optimized starting with varying cone voltage,
followed by needle voltage, and fi nally probe temperature. Optimal parameters are recorded
in the chromatographic conditions section. The scan dwell time was optimized to give good
peak shape given the chromatographic width of the peak. Longer dwell times result in greater
signal accumulation but reduce the number of points across the chromatographic peak. Thus,
narrow chromatographic peaks require shorter dwell times to maintain good peak shape. It
should be noted that optimal parameters for MS analyses are instrument- and compounddependent.
Therefore, analysts wishing to repeat these experiments are advised to evaluate
the parameters described above to determine optimal values for different systems.
Method Performance
Calibration over three orders of magnitude (5 ppb to 5 ppm) with triplicate injections at each
level showed excellent linear response with a correlation coeffi cient of 99.96%. A method
detection limit (MDL) was estimated using the standard deviation obtained from seven
replicate injections of a 20 ppb standard, then calculated using the following equation:
MDL = s (n-1)
× t (99%)
where s is the standard deviation and t is the student’s t at 99% confi dence interval. The
calculated MDL was 4.6 ppb. Carryover was evaluated by analyzing DI water after the
analysis of a 100 ppb standard. The resulting average of three sets of analyses gave an
average value below the MDL. Accuracy was calculated as observed amount/specifi ed
amount × 100%.
Table 1 summarizes the recovery at various concentrations in SW, corrected for a ten-fold
dilution with acidifi ed acetonitrile. This demonstrated that DOSS can be measured in both
clean water and SW.
Table 1. Recovery in Salt Water
Actual (ppb) Measured Recovery (%)
50 67 134
100 100 100
200 232 116
500 464 92.8
1000 1010 101
The performance of the extraction effi ciency was evaluated over two orders of magnitude.
The extract process resulted in a ~20-fold dilution. The extract was diluted ten-fold to bring
the analyte concentration within the range of calibration for the system. Table 2 shows the
recovered concentrations. The measured concentrations are for the diluted extract, while the
final calculation was made by multiplying the measured concentration by the extraction volume
and the factor of 10x dilution. Thus, final concentration = measured concentration × extraction
volume × 10. The highest measured concentration at 250 ppm represents half the current
U.S. FDA limit for DOSS in oysters. 5 The data show that concentrations 100 times below the
current limit are easily detected. Should future requirements specify lower detection limits than
currently shown, the method can be adjusted by reducing or eliminating the extract dilution
step and still achieve an additional order of magnitude in sensitivity.
28652
DOSS stability was evaluated to deter
Oyster emulsion was spiked with 50 p
immediately extracted, fi ltered, and dil
one aliquot was immediately analyzed
days; and the third was stored in a ref
emulsion was prepared, a second and
vessels. In this case extraction was de
room temperature and half under refri
were extracted and prepared using th
the same day they were extracted, alo
that the worst case scenario is allowin
temperature, as this showed the large
the oyster emulsion at cold temperatu
recommended to keep samples cold a
Conclusion
A robust method for analysis of DOSS
oyster matrix was accomplished using
single-step extraction. The Ultimate 3
provided chromatographic separation
analyte selectivity, and the use of the
combination of effi cient extraction and
exceeds the limits of detection set by
References
Tab
Extract
Measured on Day 1
Maintained cold, meas
Room temperature, me
Extract
Maintained cold until ex
Maintained at room tem
1. Lehotay, S. J. Determination of Pes
Partitioning with Magnesium Sulfat
2. RestoreTheGulf.gov, Operations an
restorethegulf.gov/release/2010/12
(Accessed Jun 16, 2011).
3. Nalco Company, COREXIT Ingredi
(Accessed Jun 16, 2011).
4. Nalco Energy Services, L.P. CORE
corexit_9500_uscueg.539287.pdf (
5. FDA Dept. of Health and Human S
Memorandum: Levels of Concern (
downloads/Food/FoodSafety/Produ
(Accessed Jun 16, 2011).
Acrodisc is a registered trademark of Pall Life Sciences Corpora
Oster is a registered trademark of Sunbeam Products.
All other trademarks are the property of Thermo Fisher Scientifi c
This information is not intended to encourage 5use of these produ
Thermo Scientific Poster Note • LPN3019-01_e 11/11SV

Table 2: Oyster Extraction
Actual (ppm) Measured* (ppb) Final Conc. Calculated (ppm) % Recovery Std. Dev. RSD
0 0 0 † † †
2.5 12.8 2.6 104.4 0.4 15
10 61.3 12.6 125.9 0.5 4
25 123.4 25.4 101.8 6.6 26
100 440.8 91.1 91.1 15.1 17
250 1329.6 243.6 97.4 25.4 10
* Three extractions at each level, ~200x dilution from original concentration
†
No peak observed
11
r direct analysis of DOSS
nt selectivity based on
chosen for sensitivity.
th varying cone voltage,
arameters are recorded
optimized to give good
ell times result in greater
matographic peak. Thus,
in good peak shape. It
ent- and compoundare
advised to evaluate
rent systems.
licate injections at each
of 99.96%. A method
tained from seven
llowing equation:
dence interval. The
DI water after the
f analyses gave an
amount/specifi ed
rrected for a ten-fold
be measured in both
ry (%)
.8
28652
orders of magnitude.
iluted ten-fold to bring
. Table 2 shows the
iluted extract, while the
by the extraction volume
oncentration × extraction
ents half the current
ns 100 times below the
ower detection limits than
ng the extract dilution
DOSS stability was evaluated to determine if degradation occurred during sample storage.
Oyster emulsion was spiked with 50 ppm DOSS (Table 3). The first group of samples was
immediately extracted, fi ltered, and diluted. The extract was separated into three aliquots:
one aliquot was immediately analyzed; the second was stored at room temperature for three
days; and the third was stored in a refrigerator for three days. At the same time the first oyster
emulsion was prepared, a second and third batch were prepared and loaded into extraction
vessels. In this case extraction was delayed for three days, with half the vessels stored at
room temperature and half under refrigeration. After this time, the contents of the vessels
were extracted and prepared using the same extraction method. The extracts were analyzed
the same day they were extracted, along with the extracts from day one. The results suggest
that the worst case scenario is allowing the DOSS and oyster emulsion to remain at room
temperature, as this showed the largest loss in recovery. Immediate extraction or maintaining
the oyster emulsion at cold temperatures produced higher recoveries. It is therefore
recommended to keep samples cold and minimize time to analysis.
Conclusion
A robust method for analysis of DOSS has been demonstrated here. Extraction from an
oyster matrix was accomplished using the ASE 350 system, allowing for quick, simple,
single-step extraction. The Ultimate 3000 HPLC system with the Acclaim C18 column
provided chromatographic separation. The MSQ Plus Mass Detector provided molecular ion
analyte selectivity, and the use of the SIM function provided good low-level quantitation. The
combination of effi cient extraction and sensitive detection resulted in a method that easily
exceeds the limits of detection set by the U.S. FDA for allowable limits of DOSS in oysters.
References
Table 3. Degredation Study
Extract Day 1
% Recovery
Measured on Day 1 100.6
Maintained cold, measured on Day 4 83.2
Room temperature, measured on Day 4 89.8
Extract Day 4
Maintained cold until extracted 83
Maintained at room temperature until extracted 63.4
1. Lehotay, S. J. Determination of Pesticide Residues in Foods by Acetonitrile Extraction and
Partitioning with Magnesium Sulfate: Collaborative Study. J. AOAC Int. 2007 90 (2) 485-520.
2. RestoreTheGulf.gov, Operations and Ongoing Response December 1, 2010. http://www.
restorethegulf.gov/release/2010/12/01/operations-and-ongoing-response-december-1-2010
(Accessed Jun 16, 2011).
3. Nalco Company, COREXIT Ingredients. http://www.nalco.com/news-and-events/4297.htm
(Accessed Jun 16, 2011).
4. Nalco Energy Services, L.P. COREXIT 9500 Material Safety Data Sheet. http://lmrk.org/
corexit_9500_uscueg.539287.pdf (Accessed Jun 16, 2011).
5. FDA Dept. of Health and Human Services, Public Health Service. Sep 17, 2010
Memorandum: Levels of Concern (LOC)s for Select Gulf Seafood. http://www.fda.gov/
downloads/Food/FoodSafety/Product-SpecificInformation/Seafood/UCM231697.pdf
(Accessed Jun 16, 2011).
Acrodisc is a registered trademark of Pall Life Sciences Corporation. COREXIT is a registered trademark of Nalco Corporation.
Oster is a registered trademark of Sunbeam Products.
All other trademarks are the property of Thermo Fisher Scientifi c Inc. and its subsidiaries.
This information is not intended to encourage use of these products in any manner that might infringe the intellectual property rights of others.
6 Determination of Dioctylsulfosuccinate (DOSS) in Oysters Using Single Quadrupole Mass Spectrometry

www.thermoscientific.com/dionex
Thermo Scientific Dionex products are
designed, developed, and manufactured
under an ISO 9001 Quality System.
©2011 Thermo Fisher Scientific Inc. All rights reserved. Acrodisc is a registered trademark of Pall Life Sciences Corporation. COREXIT is a registered trademark of Nalco Corporation.
Oster is a registered trademark of Sunbeam Products. All other trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries. Specifications, terms and pricing
are subject to change. Not all products are available in all countries. Please consult your local sales representative for details.
U.S./Canada (847) 295 7500
Brazil (55) 11 3731 5140
Austria (43) 1 616 51 25
Benelux (31) 20 683 9768
(32) 3 353 42 94
Denmark (45) 36 36 90 90
France (33) 1 39 30 01 10
Germany (49) 6126 991 0
Ireland (353) 1 644 0064
Italy (39) 02 51 62 1267
Sweden (46) 8 473 3380
Switzerland (41) 62 205 9966
United Kingdom (44) 1276 691722
Australia (61) 2 9420 5233
China (852) 2428 3282
India (91) 22 2764 2735
Japan (81) 6 6885 1213
Korea (82) 2 2653 2580
Singapore (65) 6289 1190
Taiwan (886) 2 8751 6655