supplemental information for · supplemental information for by steven j. lehotay, lijun han, and...
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Supplemental information for
by Steven J. Lehotay, Lijun Han, and Yelena Sapozhnikova
“Automated mini-column solid-phase extraction cleanup for rapid analysis of chemical contaminants in foods by low-pressure gas chromatography –
tandem mass spectrometry”
USDA Agricultural Research ServiceEastern Regional Research Center
Wyndmoor, Pennsylvania; USA
Contact: [email protected]
Automated Mini-SPE of QuEChERS Reagent Blank ExtractsGC-MS Full Scan m/z 100-500, 1 µL injection including APs
Rgt Blk (no cleanup)
MeCN
200 µL
400 µL
600 µL600 µL
400 µL
200 µL
45 mg MgSO4+PSA+C18+CarbonX 30 mg Z-Sep+C18+CarbonX
Peaks are from Analyte Protectantsand Reagent Co-Extractives,
Not SPE Contaminants!
Water in extracts when MgSO4 not included in SPE yields worse cleanup
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Kale ExtractsGC-MS Full Scan m/z 100-500, 1 µL injection including APs
No Cleanup
MeCN
200 µL
300 µL
500 µL
600 µL
400 µL
Conclusion: Not much cleanup, but 200-300 µL is ok
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Salmon ExtractsGC-MS Full Scan m/z 100-500, 1 µL injection including APs
No Cleanup
MeCN
200 µL
300 µL
500 µL
600 µL
400 µL
Conclusion: Not much cleanup
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Pork ExtractsGC-MS Full Scan m/z 100-500, 1 µL injection including APs
No Cleanup
MeCN
300 µL
500 µL
600 µL
400 µL
Conclusion: Not much cleanup
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Avocado ExtractsGC-MS Full Scan m/z 100-500, 1 µL injection including APs
MeCN
No Cleanup
200 µL
500 µL
600 µL
400 µL
Conclusion: Not much cleanup
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Kale ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
600 µL 500 µL 400 µL 200 µL None300 µL
Chlorophyllsand Xanthophylls
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Salmon ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
600 µL 500 µL 400 µL 200 µL None300 µL
45 mg MgSO4+C18+PSA+CarbonX Mini-SPE of Salmon ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
600 µL 500 µL 400 µL 200 µL None300 µL
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Pork ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
600 µL 500 µL 400 µL 200 µL None300 µL
45 mg MgSO4+C18+PSA+CarbonX Mini-SPE of QuEChERS Pork ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
600 µL 500 µL 400 µL 200 µL None300 µL
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Avocado ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
Chlorophylls
600 µL 500 µL 400 µL 200 µL None300 µL
45 mg MgSO4+C18+PSA+CarbonX Mini-SPE of Avocado ExtractsUV/Vis Absorbance Results
Spectrum of Extract before Cleanup
Ab
sorb
ance
Ab
sorb
ance
Spectrum of 300 µL Cleaned Up Extract
Wavelength (nm)
Chlorophylls
600 µL 500 µL 400 µL 200 µL None300 µL
Comparison of Mini-Cartridges to Remove Chlorophyll
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
100 200 300 400 500 600
%R
emo
ved
bas
ed
on
Ab
sorb
ance
at
68
0 n
m
Added Extract Volume (uL)
ITSP Cleanup of Chlorophyll
Kale 30 mg 3-sorbentsKale 45 mg 4-sorbentsAvocado 30 mg 3-sorbentsAvocado 45 mg 4-sorbents
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS Kale ExtractsChlorophyll Removal and HCB Results vs. Extract Vol. Added
Conclusion: 200 µL extract needed for 80% HCB elution
50%
60%
70%
80%
90%
100%
50%
60%
70%
80%
90%
100%
150 200 250 300 350 400 450 500 550 600 650
%R
em
ove
d b
ased
on
Ab
sorb
ance
at
68
0 n
m
HC
B P
eak
Are
a vs
. Max
Added Extract Volume (µL)
% vs. Max HCB
Chlorophyll removal
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS ExtractsRecovery vs. Extract Vol. Added
50%
60%
70%
80%
90%
100%
110%
120%
150 200 250 300 350 400 450 500 550 600 650
Pea
k ar
ea v
s. t
hat
fo
r 6
00
µL
Added Extract Volume (µL)
Rel. Responses of bifenthrin in ITSP
Kale Salmon
Pork Avocado
Conclusion: most analytes were not retained by the sorbents
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS ExtractsRecovery vs. Extract Vol. Added
Conclusion: 300 µL extract needed for >70% elution of PBDEs
40%
50%
60%
70%
80%
90%
100%
110%
120%
150 200 250 300 350 400 450 500 550 600 650
Pea
k ar
ea v
s. t
hat
fo
r 6
00
µL
Added Extract Volume (µL)
Rel. Responses of BDE 153 in ITSP
Kale Salmon
Pork Avocado
45 mg MgSO4+C18+PSA+CarbonX ITSP of QuEChERS ExtractsRecovery vs. Extract Vol. Added
50%
60%
70%
80%
90%
100%
110%
120%
150 200 250 300 350 400 450 500 550 600 650
Pea
k ar
ea v
s. t
hat
fo
r 6
00
µL
Added Extract Volume (µL)
Rel. Responses of BDE 153 in ITSP
Kale Salmon
Pork Avocado
Conclusion: 300 µL extract needed for >70% elution of PBDEs
30 mg C18+Z-Sep+CarbonX Mini-SPE of QuEChERS ExtractsRecovery vs. Extract Vol. Added
Conclusion: ≥600 µL extract needed for full elution of PAHs
40%
50%
60%
70%
80%
90%
100%
150 200 250 300 350 400 450 500 550 600 650
Pea
k ar
ea v
s. t
hat
fo
r 6
00
µL
Added Extract Volume (µL)
Rel. Responses of 2 PAHs in ITSP
Kale Salmon
Pork Avocado
Rel. responses of benz(a)anthracene+chrysene
45 mg MgSO4+C18+PSA+CarbonX Mini-SPE of QuEChERS ExtractsRecovery vs. Extract Vol. Added
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
150 200 250 300 350 400 450 500 550 600 650
Pea
k ar
ea v
s. t
hat
fo
r 6
00
µL
Added Extract Volume (µL)
Rel. Responses of 2 PAHs in ITSP
Kale Salmon
Pork Avocado
Conclusion: ≥600 µL extract needed for full elution of PAHs
Rel. responses of benz(a)anthracene+chrysene
Relative Recovery Differences for the Analytes in Mini-SPEfor the 300 µL Extract Volumes vs. Avg. 600 µL Result with45 mg mini-cartridge results – 30 mg mini-cartridge results
(n = 12 for 4 matrices)
Conclusion: Similar results using either mini-cartridge
-60%
-40%
-20%
0%
20%
40%
60%
Re
lati
ve R
eco
very
Dif
fere
nce
(4
5 m
g -
30
mg)
Analyte No. from Table 1
Validation ExperimentsDetermine performance results in the use of automated mini-SPE
cleanup in the LPGC-MS/MS analysis of pesticides and other contaminants in QuEChERS extracts of 10 different matrices.
Used mini-cartridgesshowing removal of chlorophyll and othermatrix components
Robotic liquid handler:3 min cleanup step at 2 µL/s+ 5 min for addition of APs and switching/washing syringes
Final extract volumes = 278 ± 5 µL (n = 255) after 50 µL addition of APs (and/MeCN) solution
Injection liner and septa after the 5 day experimentincluding 230 matrix extracts of diverse commodities
A little “dirt” here and there, but the analyte protectantsdid their job and results still looked great from start to finish.
Coumaphos in salmon after 230 injections of QuEChERS matrix extracts using mini-SPENo internal standard needed to still yield R2 = 0.999 calibration curve
Quant. Ion
Qual. Ion
25 ng/mL std in salmon extract
green boxes = atrazine-d5 (IS)black circles = stds in solventblue triangles = matrix-matched stds
10 ng/mL std in kale
quant. ion qual. ion
Methamidophos Results (vs. atrazine-d5 IS) – all 325 analyses combined!
green boxes = atrazine-d5 (IS)black circles = stds in solventblue triangles = matrix-matched stds
25 ng/mL std in orange
quant.ion
qual. ion
Acephate Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in carrot
quant.ion
qual.ion
Omethoate Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in pork
quant.ion
qual.ion
Dicrotophos Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in kiwi
quant.ion
qual.ion
Dimethoate Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
10 ng/mL std in orange
quant.ion
qual.ion
Carbofuran Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
10 ng/mL std in wheat
quant.ion
qual.ion
Diazinon Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in basil
quant.ion
qual.ion
Chlorothalonil Results (vs. atrazine-d5 IS) – all 325 analyses combined!
quant. ion
qual. ion
Chlorothalonil 5 ng/mL calibration standards over the course of 5 days (inj. #)RO = reagent-only; ion ratios within horizontal lines < |±10%| of ref. ratio
Day1
Day2
Day3
Day4
Day5
5) RO-a 12) apple 36) kiwi 59) RO-b
70) RO-a 77) carrot 101) kale 124)RO-b
135)RO-a
142)orange
166)olive 189)
RO-b
200)RO-a
207)wheat 231)
basil254)RO-b
265)RO-a
272)pork
296)salmon
319)RO-b
Matrix contaminationof system from canned black olive extracts slowlydissipated duringsequence, but did not cause instrument or analytical performance problems.
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in black olive
quant.ion
qual.ion
Chlorpyrifos Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in black olive
quant.ion
qual.ion
Cyprodinil Results (vs. atrazine-d5 IS) – all 325 analyses combined!
10 ng/mL in wheat grain
TBECH Results (vs. atrazine-d5) – all 325 analyses combined!
quant.ion qual. ion
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL in salmon
Thiabendazole Results (vs. atrazine-d5) – all 325 analyses combined!
quant.ion
qual. ion
black circles = stds in solventblue triangles = matrix-matched stds
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in kale
quant.ion
qual.ion
Flutriafol Results (vs. atrazine-d5 IS) – all 325 analyses combined!
Imazalil Results (vs. atrazine-d5) – all 325 analyses combined!
quant.ion
qual. ion
5 ng/mL std in apple
Note: imazalil was incurredin orange at 1243 ng/mL
black circles = stds in solventblue triangles = matrix-matched stds
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in apple
quant.ion
qual.ion
Myclobutanil Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in apple
quant.ion
qual.ion
Endosulfan II Results (vs. atrazine-d5 IS) – all 325 analyses combined!
black circles = stds in solventblue triangles = matrix-matched stds
10 ng/mL std in orange
quant.ion
qual.ion
Endosulfan Sulfate Results (vs. atrazine-d5 IS) – all 325 analyses combined!
Endosulfan sulfate 5 ng/mL reagent-only and matrix-matched calibration standards
LOQ ≈2 ng/mL in all matrices; even after 325 injections, including 230 food extracts
black circles = stds in solventblue triangles = matrix-matched stds
5 ng/mL std in basil
quant.ion
qual.ion
Bifenthrin Results (vs. atrazine-d5 IS) – all 325 analyses combined!
Benzo(b+k)fluoranthene (vs. benzo(a)pyrene-d12 IS) – all 325 analyses combined!
quant.ion
qual.ion
5 ng/mL std in wheat grain
IS
black circles = stds in solventblue triangles = matrix-matched stds
10 ng/mL std in orange
quant.ion
qual.ion
atrazine-d5(IS)
a ghost peak occurs in orange 1 injection later
(Es)fenvalerate Results (vs. atrazine-d5 IS) – all 325 analyses combined!
Matrix effects occur at later tR
Dechlorane Plus Results (vs. FBDE 126 IS) – all 325 analyses combined!
quant.ion
qual.ion
5 ng/mL std in wheat grain
IS
black circles = stds in solventblue triangles = matrix-matched stds
0
20
40
60
80
100
120
140
apple kiwi carrot kale orange olive wheat basil pork salmon
Ave
rage
Re
cove
rie
s (%
)
Flame Retardants vs IS wo IS
0
20
40
60
80
100
120
140
apple kiwi carrot kale orange olive wheat basil pork salmon
Ave
rage
Re
cove
rie
s (%
)
Pesticides vs IS wo IS
0
20
40
60
80
100
120
apple kiwi carrot kale orange olive wheat basil pork salmon
Ave
rage
Re
cove
rie
s (%
)
PCBs vs IS wo IS
0
20
40
60
80
100
120
140
apple kiwi carrot kale orange olive wheat basil pork salmon
Ave
rage
Re
cove
rie
s (%
)
PAHs vs IS wo IS
-100
-80
-60
-40
-20
0
20
40
60
80
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15M
E %
(vs
IS)
Flame Retardants Apple
Kiwi
Carrot
Kale
Orange
Olive
Wheat
Basil
Pork
Salmon
-60
-40
-20
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
ME
% (
vs IS
)
PAHs Apple
Kiwi
Carrot
Kale
Orange
Olive
Wheat
Basil
Pork
Salmon
-40
-30
-20
-10
0
10
20
30
40
0 1 2 3 4 5 6 7 8 9 10 11 12 13
ME
% (
vs IS
)
PCBs AppleKiwiCarrotKaleOrangeOliveWheatBasilPorkSalmon
Numbers correspond to
analytes listed in Table 1
PBTTBNPA
naphthalene was ubiquitous