Transcript Presentation - Projects at NFSTC.org

Technology Transition Workshop
DART and Trace Evidence
(a bag of tricks for using DART)
Robert B. Cody
JEOL USA, Inc.
Technology Transition Workshop
Outline
•
•
•
•
•
•
•
•
Use of dopants with DART
SPME, other methods for analyzing volatiles
Derivatization and H/D Exchange
Counterfeit materials
Quantitative analysis
Pyrolysis of polymers, materials
Other DART chemistries
Atmospheric pressure thermal ionization for inorganics
Technology Transition Workshop
Dopants, adducts
• Some compounds don’t form MH+ or [M-H]• Ammonia, NH4OH useful for forming [M+NH4]+
from polar analytes that will not form MH+
– Carbonyls, peroxides
• Chloride, acetate, nitrate useful for forming
anion adducts for compounds that will not
form [M-H]– e.g. [M+Cl]- from explosives like RDX, PETN
Technology Transition Workshop
Dopant addition
NH4OH, MeCl2
on swab
Sample
DART
or liquid in vial with capillary into gas stream…or…
Technology Transition Workshop
Example: Organic acids (e.g. aspirin)
• Should normally be analyzed in negative ion
mode: give abundant [M-H]• Will not normally form [M+H]+
• However, can form [M+H]+ and [M+NH4]+ if
ammonium is present
Technology Transition Workshop
Example: Aspirin
O T C A n a lg e s ic T a b le t
A sp irin
[M + N H 4 ] +
A : U n b ro ke n T a b le t
A ce ta m in o p h e n
[M + H ] +
100%
C a ffe in e
[M + H ] +
#
*
* #
#
*
60
80
100
120
140
160
B : B ro k e n T a b le t
100%
A sp irin
[M + H ] +
180
C a ffe in e
1 9 5 .0 8 8 3 9 4
[M + H ] +
A ce ta m in o p h e n
1 5 2 .0 7 1 3 0 4
[M + H ] +
#
#
200
A sp irin
[M + N H 4 ] +
A sp irin
1 8 1 .0 5 0 4 0 0
[M + H ] +
#
60
80
100
120
140
160
# = a sp irin fra g m e n t io n
* = in a ctive in g re d ie n t o r co a tin g
180
200
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Explosives
Class
Examples
Polarity
Observed
Comments
Aromatic Nitro
TNT, DNT, TNB
Negative
M- , [M-H]-, [M-NO]-
Positive ions less
sensitive
Other nitro, nitroso
EGDN, NG, RDX,
HMX, tetryl,
PETN
Negative
[M+anion]-, e.g. [M+Cl]-, [M+NO2]-,
[M+NO3]-, [M+OAc]-
Positive ions less
sensitive
.
Positive
[M+H]+, [M+NH4]+
Ammonia, keep
temperature
low (< 200
degrees)
Perchlorate
Negative
ClO4-
Hot gas (350
degrees)
Ammonium nitrate
Both
NH4+, NO3-
Hydrogen peroxide
Negative
[M+O2]-
Very sensitive, even
to headspace
vapor
Smokeless powders
Positive
Additives, TNT, DNT, etc.
Fingerprinting
Peroxide
TATP, HMTD
Technology Transition Workshop
Explosives detected on wipe
Name
TNT-H
HMX+Cl
RDX+Cl
PETN+Cl
amino-DNT+Cl
Tetryl+Cl
NG+Cl
PETN-H
Neutral comp.
C7H5N3O6
C4H8N8O8
C3H6N6O6
C5H8N4O12
C7H7N3O4
C7H5N5O8
C3H5N3O9
C5H8N4O12
Meas.
226.0125
331.0164
257.0078
350.9821
232.0149
321.9839
261.9713
315.0101
Calc.
Diff(u)
226.0100 0.0025
331.0154 0.0010
257.0037 0.0041
350.9827 -0.0006
232.0125 0.0024
321.9826 0.0012
261.9714 -0.0001
315.0060 0.0041
Rel. Abund.
100.0000
59.6984
39.5938
14.8834
10.7766
3.8259
2.2762
1.8731
Technology Transition Workshop
Nitroglycerin on an employee’s tie 8
hours after walking through plume from
construction blasting
98
O
NO3
-
O
x 10
N
O
O
55
NO2-
MCl-
N
O
O
O
C3H5O3-
N
O
O
195
199
12
50
100
171
175
179
(m ainlib) Nitroglyc erin
183
187
150
200
m/z
250
191
300
350
203
207
21
Technology Transition Workshop
Volatiles, headspace: some applications
•
•
•
•
•
Arson accelerants
Residual solvent vapors
Odors
Liquors
Residual tear gas ?
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Volatiles, headspace: methods
1. Direct analysis
2. Adsorbant (e.g. Tenax), thermal desorption
3. Solid-phase microextraction
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1. Volatiles, headspace: direct
Diesel fuel standard
50
100
150
200
250
300
350
400
450
m/z
Carpet burned
with diesel
50
100
150
200
250
300
350
400
450
m/z
Burnt carpet
(no accelerant)
Scale x50
50
100
150
200
250
m/z
300
350
400
450
Technology Transition Workshop
Direct analysis of volatiles
• Fast and easy, but may not be best choice in
looking for trace components in presence of
strong interference
– Concentrate the vapor (adsorbent)
– Concentrate and select the sample (SPME)
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2. Volatiles, headspace: trap
Inject sample with gas-tight syringe
Adsorbant in
heatable trap
He
to DART
• Adsorbant, thermal desorption
– Trap vapor on Tenax, heat to desorb and purge with inert gas
– or place sample inside thermal desorption chamber
Technology Transition Workshop
3. Volatiles, headspace: SPME
• Fiber coated with extractive phase (e.g.
PDMS)
• Selective phases
• Compatible with GC/MS, DART, LC/MS
Technology Transition Workshop
SPME/DART Procedure
1. Clean SPME fiber:
heat to 250 degrees C
in inert gas (e.g. GC
injector)
2. Expose SPME fiber to
headspace or liquid solution
for several minutes
3. Hold fiber in DART
gas stream
(250 degrees C)
We have had good success with DVB/Carboxen/PDMS
SPME fibers (Supelco)
Technology Transition Workshop
Prep: SPME/DART Irish whiskey
EtOH dimer Direct: No SPME
93.0900
Rel. Abund.
100
80
60
40
20
0
60
120
180
240
Carboxen/DVB/PDMS SPME Fiber
Et-octanoate
173.1521 Et-decanoate
201.1875
Et-hexanoate
Furfural
Et-dodecanoate
93.0917
Rel. Abund.
100
80
60
40
20
0
60
120
180
m/z
240
Technology Transition Workshop
Derivatization and reactions
• Derivatize to enhance volatility, count and
protect labile groups like OH
– Use rapid derivatization, no further cleanup
• H/D exchange to count exchangeable H’s
– Provides some structural information
– Distinguish some isomers
21 22
hylsilyl)-
Technology Transition Workshop
Polyhydroxy compounds
Derivatization with TMSI/Pyridine
N
Si
Mix, heat, analyze.
N
No purification step
needed.
• Commercially available
R
– 25e.g.
23 24
26 Pierce
27 28 29Tri-Sil-Z
30 31 32 33 34 35 36 37 38
• Simple, rapid silylation reaction. Mix with sample and
heat for a few seconds (heat gun).
• Moisture-tolerant (use excess reagent)
• Count the OH’s. Only reacts with hydroxyl groups.
Unreactive with thiol, amine groups.
Technology Transition Workshop
g-Cyclodextrin
100 %
[g-CD+TMSn+C3H5N2]+
n=22
Rel. Abundance
n=23
n=21
n=19
n=20
C48H80O40
Underivatized
MW 1296.4
8 amyloses
24 hydroxyls
24 TMS’s
n=24
2549 2619 2689 2759 2829 2899 2969 3039 3109 3179
m/z
Technology Transition Workshop
Aminoglycoside antibiotics
[M+TMSn+H]+
See 1 extra (small) TMS
for these compounds
n=7
Neomycin sulfate
C23H46N6O13 . 3H2SO4
n=8
n=6
n=5
950
1000
1050
1100
1150
1200
1250
m/z
Neomycin sulfate: 7 OH’s, see 8 TMS’s
Kanamycin B sulfate: 6 OH’s, see 7 TMS’s
Apramycin sulfate: 6 OH’s, see 7 TMS’s
Technology Transition Workshop
Melamine detected in pet food
by Teresa Vail (University of the Pacific)
6 exchangeable H’s
127.072
100
Melamine
C3H6N6
Rel. Abundance
80
MH+ = 127.073
60
H2N
40
N
N
20
NH2
N
NH2
0
100
150
200
m/z
250
300
350
Technology Transition Workshop
Melamine H/D Exchange
7: [D6-melamine+D]+
Melamine: with D2O
134.1175
6
1
125
2
3 4 5
130
135
140
m/z
Melamine: No D2O MH+
127.0732
C3H6N6
125
130
135
m/z
140
Technology Transition Workshop
BT (Bacillus Thuringensis) Spores
Garden Pest Control
Spore Biomarker
MH+
Dipicolinic acid dimethyl ester
196.0591
100
O
CH3
H3C
Rel. Abundance
O
O
O
50
DART+ / He
Heated with
TMAH
0
150
250
350
m/z
450
550
Technology Transition Workshop
Counterfeit materials
• Presence or absence of critical ingredients
(e.g. active pharmaceutical ingredients)
• Differences in the presence or absence of
trace impurities
Technology Transition Workshop
Genuine and Counterfeit CialisTablets
Courtesy Tony Moffat (U. London Pharmacy)
Tadalafil (Cialis)
Rel. Abund.
Genuine
Other tablet components
100
390.1413
80
60
40
20
0
100
200
300
400
500
m/z
Sildenafil (Viagra)
Rel. Abund.
Counterfeit
475.2073
100
80
60
40
20
0
100
200
300
m/z
400
500
Technology Transition Workshop
Counterfeit Antimalarials
“Yaa-chud” (Combination medicine)
Samples from
Prof. Facundo Fernandez
Georgia Tech
All these and more were analyzed in a single afternoon. Most of the
time was taken up by opening the packages and keeping track of
sample serial numbers.
Technology Transition Workshop
Counterfeit Antimalarials were found to
contain:
•
•
•
•
•
•
•
•
Chlorpheniramine (antihistamine)
Acetaminophen (analgesic)
Chloroquin (older, ineffective antimalarial)
Aspirin (analgesic)
Chloramphenicol (antibacterial)
Pyramethamine/sulfadoxin (ineffective in SE Asia)
Metamizol (analgesic, may cause bone marrow disorders)
Some tablets contained low levels of the active ingredient
(artemisinin), presumably to fool the field tests
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Real (top) vs. Counterfeit Marlboro Brand
Cigarette
Volatile trace components
are different
Nicotine
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DART Quantitation
• Successful for liquid samples
– Internal standard corrects for variations in sample
positioning. Example: GHB in urine
– Possibility for AWC analysis without I.S. ?
– Some fully validated methods completed
• Semiquantitative data obtained from swabs with no
internal standard
• Under investigation for solid samples (tablets).
– Preliminary data promising
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AutoDART: Promazine (Chlorpromazine I.S.)
5 replicates, 7 concentrations, 250 ppb to 250 ppm, CV = 4.5%
60
y = 0.1839x + 0.8363
50
2
R = 0.9941
30
20
10
0
0
50
100
150
200
250
300
ppm
14
12
10
S / IS
S / IS
40
8
6
4
2
0
0
10
20
30
ppm
Linear fit
40
50
60
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IonSense GIST Implementation
Reported BMSS 9/07
Orifice
DART
Tube
Pump
GIST on AccuTOF
Enhanced Ion Collection with Vacuum Pump
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AutoDART + GIST: Lower detection limits
Chlorpromazine (Promazine I.S.)
180
160
Chlorpromazine (AutoDART, alumina) 0.1 to 1000 ppb
140
120
10000
100
Series1
80
y = 1.1297x
R2 = 0.9983
1000
60
40
20
100
S/IS (%)
0
1
2
3
4
5
6
7
8
9
10
10
1
0.1
1
10
100
1000
CV = 5.7%
10 replicates
100 ppb
0.1
ppb
Log/log plot, 6 replicates over 2 day period, 0.1 ppb to 1000 ppb
Technology Transition Workshop
IonSense VapurTM Pro’s and Con’s
• Reduced helium consumption
• Better quantitative reproducibility
• Better detection limits for compounds with high proton
affinities (stable ions in atmosphere). This includes
most drugs and many compounds of forensic interest.
• Poorer detection limits for compounds, with lower
proton affinities e.g. methyl stearate
• Cannot adjust DART chemistry to analyze
hydrocarbons, produce odd-electron ions.
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Another kind of information:
Pattern matching for materials, commercial
products, polymers, adhesives, etc.
• Products are a mixture of components
• Each component adds a detail to a
characteristic “fingerprint” pattern DART mass
spectrum
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Polymers
Polyethylene terephthalate
Nylon 6
poly(caprolactam)
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PittCon Carpet 2006
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PittCon Carpet Polymer = Nylon 6
Match:
Nylon 6
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Material ID: Latex from J&J Band-Aid
•Searchable polymer library
spectrum
100
279.1612
C16H23O4+ 345.3535
C25H45+
277.2906
C20H37+
•All compositions confirmed
by exact masses
413.4145
C30H53+
•C5H8 (isoprene) units
•m/z 279=Dibutyl phthalate
(plasticizer)
481.4807
C35H61+
50
551.5575
619.6162
C40H71+
C45H79+
0
60
110
(p o lym ers) La tex
160
210
260
310
360
410
460
510
560
610
660
710
760
810
Technology Transition Workshop
3 beige paint chips
149
100
227
301
•Different beige paints
give different mass
spectra
50
193
99
255
329
175
369
313
122
449
411
483
511
549 578
610 641
675
0
80
130
180
230
280
330
380
430
(dart_paints) JEOL W2274 (N.E. Tanya Finishes) (ECL Poly/ urac hem )
480
530
580
630
680
•Spectra are reproducible
and a searchable library
can be created
149
100
50
279
175
99
81
123
297
187
337
369
600
411
0
78
128
178
228
278
328
378
(dart_paints) JEOL Beige Ura W 2273 Eastern Chem -Lac Corp
428
478
528
578
635
628
•Polymers and additives
can be identified.
678
114
100
50
549 578
457
83
149
133
203
227
179
263
301
291
327
371
415
459
443
503
549
578
636 663
0
78
128
178
228
278
328
378
(dart_paints) JEOL G reen gray W4322 Eastern Chem -Lac Corp.
428
478
528
578
628
678
Technology Transition Workshop
Condom lubricants
Condom swab
n=7
Acetone anil
n=5
n=9
n=3
*
200
*
*
400
*
*
*
*
m/z 600
*
*
200
200
400
400
m/z
m/z
600
600
*
1000
Post-coital
vaginal swab
Nonoxynol-9
*
*
800
Cholestadiene
*
*
*
*
800
800
1000
1000
Technology Transition Workshop
CS (Tear gas) Detected Directly on Cloth
96
N
189.0209
57
[M+H]+
N
207.0311
Cl
[M+H+H2O]+
18
20
23
26
29
32
(mainlib) 2-Chlorobenzalmalononitrile
35
38
41
44
47
377.0348
50
53
[2M+H]+
100
200
300
m/z
2-Chlorobenzalmalononitrile
CAS # 2698-41-1
Formula: C10H5ClN2
400
500
56
59
62
Technology Transition Workshop
Other DART CI Reagents
Reagent
IE (eV)
P.A. (kJ/mol)
Reagent Ion
Water
12.621
691
H 3 O+
Oxygen
12.0697
421
O2+.
Ammonia
10.070
853.6
NH4+
Nitric oxide
9.2642
531.8
NO+.
Fluorobenzene
9.20
755.9
C6H5F+.
Values from http://webbook.nist.gov
Technology Transition Workshop
Proton transfer is very useful, but it
is not universal
• Won’t work for saturated alkanes and some
other compounds
• Even-electron ions
• Can we produce odd-electron ions and mass
spectra that resemble EI mass spectra?
Technology Transition Workshop
Different DART Chemistries
O2+.
Rel. Abund.
100
80
60
40
20
0
O2+
He DART
Charge Exchange
Rel. Abund.
80
60
40
20
0
Charge exchange
H3O+
15
100
[(H2O)2+H]+
[(H2O)3+H]+
20
25
N2 DART
NO+ APCI
30
NO+.
20
40
45
50
[(H2O)2+
H]+
[NO+NH3+H]+
N2H+
O+
25
55
Addition, charge exchange,
hydride abstraction, oxidation
[(H2O)+NH3+
H]+
NH4+
H3
35
30
35
m/z
40
45
Technology Transition Workshop
Charge-Exchange DART
Oxygen
He* + O2 → O2+. + e- + He
O2+. + S → S+. + O2
O2 +. + S → Fragment+ + O2 + R.
(IE of sample S < 12.07 eV)
Fluorobenzene
He* + C6H5F → C6H5F +. + e- + He
C6H5F +. + S → S+. + C6H5F
C6H5F +. + S → [Fragment]+ + C6H5F + R.
(IE of sample S < 9.2 eV)
Technology Transition Workshop
n-Hexadecane
Normal DART Parameters
85
100
+
[M-H]+ [M-H+O]
Rel. Abund.
80
60
71
40
97
[M-3H+2O]+
241
2
2
5
2
20
1
1
1
1
1
2
4
5
5
1
1
5
6
9
2
1
9
7
3
7
0
75
100
125
150
175
200
m/z
85
Rel. Abund.
250
275
DART O2+. Charge Exchange
100
80
225
71
60
M+.
99
113 127
40
141 155 169
226
1
20
8
3
1
9
7
0
75
100
125
150
175
Rel. Abund.
225
250
275
m/z
100
80
200
Electron ionization
71
60
85
40
99
20
1
1
3
1
2
7
1
4
1
1
5
5
1
6
9
1
8
3
2
1
9
2
6
7
0
75
100
125
150
175
m/z
200
225
250
275
Technology Transition Workshop
Hexadecane : Fragmentation vs. temperature
226
Helium 200 degrees
100
60
225
40
71
85
1
20
9
1
9
1
1
2
4
1
155 169
7
3
1
8
3
1
9
7
2
1
1
0
75
100
125
150
175
200
225
250
275
m/z
85
100
80
Rel. Abund.
Rel. Abund.
80
71
60
Helium 300 degrees
99
113 127
40
141 155 169
226
1
20
8
3
1
9
7
0
75
100
125
150
175
m/z
200
225
250
275
Technology Transition Workshop
92
Cholesterol
[M+H-H2O]+
369.3528
69
Rel. Abund.
100
Normal DART:
Proton Transfer
50
275
[M-H]+
46
385.3437
261
271
281
291
(mainlib ) Cholest-5-en-3-ol (3á)-
0
300
325
350
375
400
HO
301
311
425
369.3529
Rel. Abund.
100
50
Fluorobenzene
Dopant
386.3551
0
300
325
350
375
400
425
369.3542
Rel. Abund.
100
50
M+.
Oxygen
Charge Exchange
386.3558
0
300
325
350
375
m/z
400
425
321
331
341
351
361
371
Technology Transition Workshop
GC-DART: Grob Mix TICs
6
Rel. Abund.
100
Modified DART parameters
Pseudo EI spectra
8
3
50
9
5
1
2
4
12
11
13
10
7
0
10
12
14
16
18
20
22
Time (min.)
1.
2.
3.
4.
5.
6.
7.
1,3-Butanediol
Decane
1-Octanol
Undecane
Nonanal
2,6-Dimethylphenol
2-Ethylhexanoic acid
8.
9.
10.
11.
12.
13.
2,6-Dimethylaniline
Methyl decanoate
Surfynol
Methyl undecenoate
Dicyclohexylamine
Methyl dodecanoate
24
Technology Transition Workshop
GC-DART: Grob Mix TICs
1.
2.
3.
4.
5.
6.
7.
1,3-Butanediol
Decane
1-Octanol
Undecane
Nonanal
2,6-Dimethylphenol
2-Ethylhexanoic acid
8.
9.
10.
11.
12.
13.
6
100
Rel. Abund.
13
8
9
80
2,6-Dimethylaniline
Methyl decanoate
Surfynol
Methyl undecenoate
Dicyclohexylamine
Methyl dodecanoate
Standard DART
parameters
CI spectra
10,11,12
5
60
40
3
1
20
0
3
4
5
6
7
8
9
Time (min.)
10
11
12
13
Technology Transition Workshop
Application of GC-DART: Diesel Fuel
100
TIC
60
40
20
0
4
6
8
10
12
14
Time (min.)
Alkanes
100
80
Rel. Abund.
Rel. Abund.
80
60
40
RIC
m/z 71
20
0
4
6
8
10
Time (min.)
12
14
Technology Transition Workshop
Atmospheric Pressure Thermal
Ionization for Inorganics & Metals
Technology Transition Workshop
Atmospheric Pressure Thermal Ionization
for Inorganics & Metals
• Easy way to add some qualitative inorganic analysis
capabilities to system configured for DART.
• Use hand-held butane torch to heat samples in DART
gas stream.
• High orifice potential breaks up clusters & adducts to
maximize atomic ions.
• Can also use the electrospray source
Technology Transition Workshop
Lead in paint chip
PbOH+224.9787
Orifice 1=20V
PbO2H3+
Rel. Abund.
100
0
100
80
Rel. Abund.
264.9724
50
Pb+
80
140 200 260 320 380 440 500 560 620 680
Pb+
20
207.9744
Orifice 1=90V
60
40
Pb2(OH)3+
Rb+
PbOH+
In+
224.9764
84.9135 114.9051
0
100
150
m/z
200
250
Technology Transition Workshop
Stainless Steel Wire
100
Fe+
55.9349
Rel. Abundance
80
Plunger wire from
PCR Pipette
60
40
20
0
Cu+
Mn+ Ni+
Cr+
50
FeOH+
62.9294
Ga+
60
70
m/z
72.9400
80
Technology Transition Workshop
Thank you!