1 analysis of the isotope patterns of organic sulfur containing compounds ray a. gross, jr
Post on 24-Dec-2015
223 Views
Preview:
TRANSCRIPT
1
Analysis of the Isotope Patterns of Organic Sulfur Containing Compounds
Ray A. Gross, Jr.
2
Outline
• Theoretical Isotope Patterns
• Real Isotope Patterns
• New Method of Determining # S Atoms
3
A/(A + 2) Isotope Ratios
r 30:1 30 (3)28 (92)Silicon
p 500:1 18 (0.2)16 (99.8)Oxygen
q 22:1 34 (4.29)32 (94.93)Sulfur
n 3:1 37 (24)35 (76) Chlorine
m 1:1 81 (49)79 (51) Bromine
Variable
# atoms
Ratio
a/bba Element
4
Bromine Binomial Model for A + 2 Molecular Ion Intensities
• Ratio of 79Br to 81Br = 1:1
• (a + b)m for Brm
• (a + b)1 = 1a + 1b = 1:1
• (a + b)2 = 1a2 + 2ab + 1b2 = 1:2:1
5
Chlorine Binomial Model for A + 2 Molecular Ion Intensities
• Ratio of 35Cl to 37Cl = 3:1
• (3a + b)n for Cln
• (3a + b)1 = 3a + b = 3:1
• (3a + b)2 = 9a2 + 6ab + 1b2 = 9:6:1
6
Sulfur A + 2 Binomial
• Ratio of 32S to 34S = 22:1
• (22a + b)q for Sq
• (22a + b)1 = 22a + 1b = 22:1
• (22a + b)2 = 484a2 + 44ab + 1b2 = 484:44:1
7
SqSulfur Isotope Patterns
Normalized to Highest Mass = 1
(22:1)q
Ratio
M/M + 2
S122 : 1 22
S2484 : 44 : 1 11
S310648 : 1452 : 66 : 1 7.3
S4234256 : 42592 : 2904 : 88 : 1 5.5
S55153632 : 1171280 : 106480 : 4840 : 110 : 1 4.4
S6113379904 : 30921792 : 3513840 : 212960 :
7260 :132 :13.7
8
SqSulfur Isotope Patterns
Normalized to M = 100
(22:1)q
Ratio
M/M + 2
(T)
S1100 : 4.5 22 (2)
S2100 : 9 : 0.2 11 (2)
S3100 : 14 : 0.6 : 0.01 7.3 (2)
S4100 : 18 : 1.2 : 0.03 : 0.0004 5.5 (2/3)
S5100 : 23 : 2.1 : 0.09 : 0.002 : 0.00002 4.4 (2/3)
S6100 : 27: 3 : 0.2 : 0.006 : 0.0001 : 0.0000008 3.7 (2/3)
9
SqRatio
M/M + 2
(T)
Yan Ratio
M/M +2
(T)
S1 22 (2) 22.2 (2)
S2 11 (2) 11.1 (2)
S3 7.3 (2) 7.35 (2)
S4 5.5 (2/3) 5.52 (3)
S5 4.4 (2/3) 4.41 (3)
S6 3.7 (2/3) 3.68 (3)
10
S
M = 134 100.0M + 1 = 135 9.8M + 2 = 136 4.8
M/(M + 2) = 100.0/4.8 = 21 = S1
M = 134 136
11
223.0 100.0 224.0 12.4 225.0 6.0
M = 223
R2 = 17
12
M +1 +2 +3 M +1 +2 +3
100 9.0 (11)100.0 4.5 (22)
S1 S2
C20H42N4O4S1
100.0 8.2 (12) 100 12.9 (7.75)
C20H42N4O4S2
Rel
ativ
e In
ten
sity
Rel
ati
ve In
ten
sit
y
m/z m/z
13
223 100.0224 12.4225 6.0
R2 = 17
S1 = 12-22S2 = 7.75-11
NH2 SO3H
S1
M = 223
14
Intensity Ratios for Real Compounds Containing Sulfur
Number S AtomsSample Size
R2 R4 R24
1 >100 12-23
2 >100 7.7-12
3 47 5.59-7.4
4 12 4.66-5.53 50-71 11-14
5 10 3.68-4.70 31-51 8.5-10.8
6 2 3.69-3.12 21.5-31.5 7.09-8.71
15
CH3(CH2)3SS(CH2)3CH3
178 180
M = 178.0 33.6 M + 2 = 180.0 3.1
33.6/3.1 = 11 = S2
16
Intensity Ratios for Real Compounds Containing Sulfur
Number S Atoms R2 R4 R24
1 12-23
2 7.7-12
3 5.59-7.4
4 4.66-5.53 50-71 11-14
5 3.68-4.70 31-51 8.5-10.8
6 3.69-3.12 21.5-31.5 7.09-8.71
17
SS
S
M = 136.0 100.0 M + 2 = 138.0 13.6
100.0/13.6 = 7 = S3
136 138
18
Intensity Ratios for Real Compounds Containing Sulfur
Number S Atoms R2 R4 R24
1 12-23
2 7.7-12
3 5.59-7.4
4 4.66-5.53 50-71 11-14
5 3.68-4.70 31-51 8.5-10.8
6 3.69-3.12 21.5-31.5 7.09-8.71
19
S S CN(Et)2
S
(Et)2NC
S
M = 296.0 17.9 M + 2 = 298.0 3.4
17.9/3.4 = 5 = S4
296 298
20
Intensity Ratios for Real Compounds Containing Sulfur
Number S Atoms R2 R4 R24
1 12-23
2 7.7-12
3 5.59-7.4
4 4.66-5.53 50-71 11-14
5 3.68-4.70 31-51 8.5-10.8
6 3.69-3.12 21.5-31.5 7.09-8.71
21
332 100.0334 18.9336 1.4
R2 = 5.29; R4 = 71; R24 = 14
S4: R2 = 4.66-5.53 R4 = 50-71 R24 = 11-14
S
NN
SS S
S4
M = 332
22
M = 406
406 4.3408 1.1
R2 = 3.9
S5: R2 = 3.68-4.70
S S
S SC C
O O
S
23
S
S S
SS
S5
224 100.0226 22.2228 2.3
R2 = 4.50, R4 = 44, R24 = 9.7
M = 224
S5: R2 = 3.68-4.70 R4 = 31-51 R24 = 8.5-10.8
24
Conclusion
• The intensity-ratio method is an efficient tool for determining small numbers of sulfur atoms in an unknown from its mass spectrum.
25
Acknowledgments
• SDBS– http://www.aist.go.jp/RIODB/SDBS/cgi-bin/
cre_index.cgi
• NIST– http://physics.nist.gov/PhysRefData/Compositions/
index.html
• Yan– http://www.geocities.com/junhuayan/pattern.htm
top related