Kovats Indices for C2-C13 Hydrocarbons and Selected Oxygenates/Halocarbons
with 100% Dimethylpolysiloxane Columns
by Randall Bramston-Cook, Lotus Consulting
Identification of hydrocarbons in a chromatogram of ambient air or vehicle exhaust is inherently difficult since well over 300
chemical species can be detected, and the most common detector used for measurement - flame ionization - cannot distinguish
any of them other than by retention times. Mass spectrometry helps in picking out specific compounds, but many hydrocarbons
have remarkably similar spectra and subtle differences become difficult to sort out which hydrocarbon matches a library of
standard spectra. Relative retention indices, commonly called Kovats Indices1, help to assign labels to eluting peaks in
samples of ambient air and vehicle exhaust samples, based on elution relative to nearby n-Alkanes. Since most
chromatograms for a wide range of hydrocarbons are generated with temperature programmed conditions, the Kovats Index (KI)
simplifies to:
/
100
100
where n = number of carbon atoms in the smaller n-alkane, N = number of carbon atoms in the larger n-alkane, and tr = retention
time of associated compounds. This compilation of Kovats Indices is generated from 11 different gas chromatographs, 15
different chromatograms from related columns with differing dimensions, and dissimilar temperature programs. Remarkably,
Kovats Indices remain quite consistent. Peak identifications are made from known standard gas mixtures and from mass
spectral interpretations.
Common Name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
R-134a
Propylene
R-12
Isobutane
Isobutylene
n-Butane
2,2-Dimethylpropane
Isopentane
Acetone
R-11
Acrylonitrile
Isopropanol
n-Pentane
Isoprene
n-Propanol
MTBE
Methylethylketone
IUPAC Name
Average
Kovats Index
Standard
Deviation
ETHANES
1,1,1,2-Tetrafluoroethane
Propene
PROPANE
Dichlorodifluoromethane
Propadiene
Propyne
Methylpropane
Methylpropene
But-1-ene
Buta-1,3-diene
Methanol
BUTANE
But-1-ene-3-yne
But-2-yne
trans-But-2-ene
Neopentane
But-1-yne
Acetic Acid
cis-But-2-ene
Butadiyne
But-1,2-diene
3-Methylbut-1-ene
Acetonitrile
Ethanol
Methylbutane
Propanone
Penta-1,4-diene
But-2-yne
Trichlorofluoromethane
Pent-1-ene
Prop-2-enenitrile
2-Methylbut-1-ene
Propan-2-ol
PENTANE
Methylbuta-1,3-diene
trans-Pent-2-ene
3,3-Dimethylbut-1-ene
cis-Pent-2-ene
Carbon Disulfide
2-Methylbut-2-ene
trans-Penta-1,3-diene
2-Ethyl-3-Methylbut-1-ene
3-Methylbuta-1,2-diene
Cyclopenta-1,3-diene
2,2-Dimethylbutane
cis-Penta-1,3-diene
Cyclopentene
4-Methylpent-1-ene
3-Methylpent-1-ene
Propan-1-ol
Cyclopentane
2,3-Dimethylbutane
2,3-Dimethylbut-1-ene
2-Methoxy-2-methylpropane
2-Methylpentane
4-Methyl-trans-pent-2-ene
Butan-2-one
200
248
286
300
318
326
334
359
385
390
394
~395
400
404
409
410
414
417
~418
422
428
441
453
~456
~458
473
~479
480
485
486
488
~491
495
~496
500
504
509
513
515
~517
519
521
523
526
528
533
535
548
553
556
~557
560
563
564
~566
568
571
~573
=0
±7
=0
±5
±2
±4
±2
±1
=0
±1
±2
±2
±3
±2
±4
±2
±2
±2
±1
=0
±1
±1
±1
±1
±2
±2
±5
±3
±2
±3
±2
±2
±2
±1
±3
Number of
Chromatogram
Sources
11
2
7
11
1
2
4
8
1
4
8
3
11
4
1
10
5
3
1
10
2
4
6
2
1
10
2
1
5
1
10
1
5
1
15
13
13
4
13
1
7
1
1
1
1
13
1
7
7
6
1
14
14
1
3
13
4
3
1
Kovats, E. (1958). "Gas-chromatographische Charakterisierung organischer Verbindungen. Teil 1: Retentionsindices aliphatischer Halogenide, Alkohole,
Aldehyde und Ketone". Helv. Chim. Acta 41: 1915–32.; and Nomenclature of Organic Chemistry (3 ed.). London: Butterworths. 1971 (3rd edition combined)
And
[1958 (A: Hydrocarbons, and B: Fundamental Heterocyclic Systems), 1965 (C: Characteristic Groups)]. ISBN 0408701447.
en.wikipedia.org/wiki/Kovats_retention_index.
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
Isobutanol
n-Hexane
Di-isopropylether
Ethyl-t-butylether
n-Butanol
tert-Amylmethylether (TAME)
Isoöctane
n-Heptane
n-Pentanol
Methylbenzene
4-Methyl-cis-pent-2-ene
2-Methylpenta-1,4-diene
3-Methylpentane
2-Methylpent-1-ene
Hex-1-ene
Butan-2-ol
Hexa-1,4-diene
2-Ethylbut-1-ene
HEXANE
Di(1-methylethyl)ether
trans- Hex-3-ene
cis-Hex-3-ene
trans-Hex-2-ene
2-Methylpent-2-ene
2-Methylpent-1-ene
3-Methyl-trans-pent-2-ene
3-Methylcyclopent-1-ene
4,4-Dimethyl-trans-pent-2-ene
3-Methyl-trans-pent-2-ene
cis-Hex-2-ene
4,4-Dimethylpent-1-ene
3-Methyl-cis-pent-2-ene
trans-Hexa-1,3-diene
2,2-Dimethylpentane
Methylcyclopentane
2,3-Dimethylpentane
2,4-Dimethylpentane
2,3,3-Trimethylbut-1-ene
2,2,3-Trimethylbutane
2-Ethoxy-2-methylpropane
3,4-Dimethylpent-1-ene
2,4-Dimethylpent-1-ene
1-Methylcyclopent-1-ene
Benzene
3-Ethylpent-1-ene
3-Methylhex-1-ene
3,3-Dimethylpentane
Butan-1-ol
2,4-Dimethylpent-2-ene
2,4-Dimethylpent-1-ene
Cyclohexane
2-Methyl-trans-hex-3-ene
2-Ethyl-3-methyl-trans-but-1-ene
2-Ethyl-3-methylbutane
4-Methyl-trans-hex-2-ene
2-Methylhexane
2,3-Dimethylpentane
5-Methyl-trans-hex-2-ene
1,1-Dimethylcyclopentane
2-Methoxy-2-methylbutane
Cyclohexene
3-Methylhexane
5-Methylhex-2-ene
3,4-Dimethyl-cis-pent-2-ene
trans-1,3-Dimethylcyclopentane
cis-1,3-Dimethylcyclopentane
3-Ethylpentane
trans-1,2-Dimethylcyclopentane
2,2,4-Trimethylpentane
Hept-1-ene
3-Methyl-trans-hex-3-ene
trans-Hept-3-ene
HEPTANE
cis-Hept-3-ene
2,2,4-Trimethylpent-1-ene
2-Methylhex-2-ene
trans-Hept-2-ene
3-Ethyl-cis-pent-2-ene
3-Methyl-cis-hex-2-ene
2,3-Dimethy-trans-pent-2-ene
cis-Hept-2-ene
3-Methyl-trans-hex-2-ene
2,3-Dimethylpent-2-ene
3-Ethylcyclopent-1-ene
cis-1,2-Dimethylcyclopentane
Methylcyclohexane
1,1,3-Trimethylcyclopentane
2,2-Dimethylhexane
2,4,4-Trimethylpent-2-ene
Ethylcyclopentane
2,5-Dimethylhexane
2,2,3-Trimethylpentane
2,4-Dimethylhexane
1,2,4-Trimethylcyclopentane
3,3-Dimethylhexane
2,4-Dimethylhex-2-ene
1,2,3-Trimethylcyclopentane
2,3,4-Trimethylpentane
Pentan-1-ol
Toluene
574
580
582
588
589
~593
597
599
600
~602
603
604
605
606
607
608
610
611
612
613
614
619
621
623
625
628
631
632
634
~637
639
642
643
649
650
651
653
~654
655
657
658
660
662
663
666
668
669
671
672
673
674
676
679
680
681
684
686
687
689
693
695
698
700
702
703
704
705
708
710
712
714
716
717
718
720
721
722
723
727
731
733
734
735
740
742
746
748
752
~754
756
±1
±1
±3
=0
±1
±1
±0.2
±1
±0.5
±6
±1
±1
±2
±2
±1
±1
±1
±2
±1
±2
±3
±2
±2
±1
±2
±2
±2
±0.2
±1
±1
±2
±1
±1
±1
±1
±1
±0.3
±1
±1
±1
±2
±1
±1
±1
±0.1
=0
±2
±2
±1
±2
±1
±1
±1
±2
±3
±1
±2
±2
±2
±1
±2
±1
±2
±1
±3
±4
2
1
14
5
9
1
1
1
15
1
6
4
6
3
6
4
3
3
2
7
1
6
1
4
14
1
13
3
6
2
3
6
4
14
1
4
6
1
5
1
14
3
3
3
6
11
14
1
3
1
7
14
3
1
8
8
5
4
14
5
5
6
15
1
3
4
6
5
7
3
6
1
1
1
3
14
1
5
5
6
8
1
6
6
6
3
6
14
1
14
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
n-Octane
n-Hexanol
1,3-Dimethylbenzene
1,4-Dimethylbenzene
Vinylbenzene
1,2-Dimethylbenzene
n-Nonane
Isopropylbenzene
α-Pinene
m-Ethyltoluene
p-Ethyltoluene
2,3,3-Trimethylpentane
2,3-Dimethylhexane
2-Methyl-3-ethylpentane
1,1,2-Trimethylcyclopentane
2-Methylheptane
4-Methylheptane
3-Ethyl-3-methylpentane
3,4-Dimethylhexane
3-Methylheptane
3-Ethylhexane
cis-1,3-Dimethylcyclohexane
trans-1,4-Dimethylcyclohexane
1,1-Dimethylcyclohexane
trans-1-Ethyl-2-methylcyclopentane
2,2,5-Trimethylhexane
trans-1-Ethyl-3-methylcyclopentane
cis-1-Ethyl-2-methylcyclopentane
Oct-1-ene
cis-1-Ethyl-3-methylcyclopentane
2,2,4-Trimethylhexane
trans-Oct-4-ene
1,2-Dimethylcyclohexane
OCTANE
trans-Oct-2-ene
trans-1,3-Dimethylcyclohexane
cis-Oct-4-ene
2,4,4-Trimethylhexane
cis-Oct-2-ene
2,3,5-Trimethylhexane
2,2-Dmethylheptane
2,4-Dimethylheptane
cis-1,2-Dimethylcyclohexane
2,6-Dimethylheptane
Propylcyclopentane
Ethylcyclohexane
3,5-Dimethylheptane
Cycloöctene
1,1,3-Trimethylcyclohexane
1,1,4-Trimethylcyclohexane
2,5-Dimethylheptane
Ethylbenzene
Hexan-1-ol
1,3,5-Trimethylcyclohexane
2,3-Dimethylheptane
2-Methyloct-1-ene
2-Methyloct-2-ene
m-Xylene
p-Xylene
4-Ethylheptane
4-Methyloctane
2-Methyloctane
1,2,3-Trimethylcyclohexane
3-Ethylheptane
3-Methyloctane
3,3-Diethylpentane
Stryrene
1,2,4-Trimethylcyclohexane
1,1,2-Trimethylcyclohexane
o-Xylene
2,2,4-Trimethylheptane
cis-1,2,4-Trimethylcyclohexane
1-Ethyl-4-methylcyclohexane
2,2,5-Trimethylheptane
Non-1-ene
(2-Methylpropyl)cyclopentane
trans-7-Methyloct-3-ene
cis-Non-2-ene
trans-Non-3-ene
NONANE
1-Ethyl-1-methylcyclohexane
3,3-Dimethyloctane
trans-1-Ethyl-3-methylcyclohexane
cis-1-Ethyl-3-methylcyclohexane
Cumene
4,4-Dimethyloctane
2,3-Dimethyloctane
2,2-Dimethyloctane
2,5-Dimethyloctane
Benzaldehyde
2,4-Dimethyloctane
2,6-Dimethyloctane
(1s,5s)-2,6,6-Trimethylbicylo[3.1.1]hept-2-ene
Propylbenzene
1-Ethyl-3-methylbenzene
1-Ethyl-4-methylbenzene
1,3,5-Trimethylbenzene
4-Methylnonane
2-Methylnonane
3-Methylnonane
758
761
762
763
767
768
770
772
775
777
778
779
782
783
785
788
790
792
793
795
797
798
800
804
806
808
811
815
818
820
823
827
831
832
833
838
839
841
844
847
852
~853
854
856
858
859
861
862
863
865
868
870
871
872
875
878
881
882
883
884
887
888
890
894
896
897
898
899
900
901
905
911
914
916
920
921
924
929
932
934
936
945
947
954
956
961
964
966
969
±1
±1
±2
±1
±1
±2
±1
±1
±1
±1
±0.4
±0.5
±1
±0.5
±1
±1
±1
=0
±1
±1
±1
±1
±1
±2
±2
±1
±1
±1
±1
±1
±1
±1
±4
±2
±3
±4
±4
±2
±2
±3
±4
±4
±1
±1
±2
±3
±2
=0
±3
±1
±3
±0.5
±3
±3
±2
±2
±2
±1
±3
±3
±3
±1
±1
±1
±3
1
6
1
4
14
7
1
6
14
5
4
4
1
4
6
5
5
5
4
6
6
1
15
1
2
4
6
3
5
4
7
7
6
1
7
7
3
3
3
4
14
1
7
4
1
1
14
13
2
5
5
1
1
7
1
14
2
1
14
5
3
6
7
6
1
1
1
1
15
1
5
3
2
14
3
7
7
7
3
7
6
1
14
13
13
7
7
7
3
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
1.
2.
3.
o-Ethyltoluene
Isobutylbenzene
n-Decane
β-Pinene
Benzocyclopentane
Benzocyclopentadiene
m-Diethylbenzene
p-Diethylbenzene
o-Diethylbenzene
Decalin
n-Undecane
(2,2-Dimethylpropyl)benzene
Benzocyclohexane
Naphthalene
1-Ethyl-2-methylbenzene
(Dimethylethyl)benzene
(1-Methylpropyl)benzene
1,2,4-Trimethylbenzene
1-Methyl-2-propylcyclohexane
(2-Methylpropyl)benzene
Dec-1-ene
DECANE
1-Methyl-3-propylbenzene
1-Methyl-3-(1-methylethyl)benzene
1,2,3-Trimethylbenzene
1-Methyl-4-(1-methylethyl)benzene
6,6-Dimethyl-2-methylenebicylco[3.1.1]heptane
Indane
1-Methyl-2-(1-methylethyl)benzene
1H-Indene
3-Ethylnonane
1,3-Diethylbenzene
1-Methyl-3-propylbenzene
1,4-Diethylbenzene
1-Methyl-4-propylbenzene
1-Ethyl-3,5-dimethylbenzene
Butylbenzene
1,2-Diethylbenzene
1,2,3,4,4a,5,6,7,8,8a-Decahydronaphthalene
1-Methyl-2-propylbenzene
2-Methyldecane
1-Ethyl-2,5-dimethylbenzene
1-Ethyl-2,4-dimethylbenzene
1-Ethyl-3,4-dimethylbenzene
1-Ethyl-2,6-dimethylbenzene
Undec-1-ene
1-Methyl -4-(dimethylethyl)benzene
1-Ethyl-2,3-dimethylbenzene
1-Ethyl-2-(1-methylethyl)benzene
UNDECANE
1-Ethyl-4-(methylethyl)benzene
1-Ethyl-2,3-dimethylbenzene
1,2,4,5-Tetramethylbenzene
1-Butyl-2-methylbenzene
1,2,3,5-Tetramethylbenzene
1-Methyl-4-(dimethylethyl)benzene
1-Methyl-2-(dimethylethyl)benzene
Neopentylbenzene
5-Methylindane
4-Methylindane
1-Ethyl-2-propylbenzene
1-Methyl-2-(2-methylpropyl)benzene
2-Methylindane
1,2,3,4-Tetramethylbenzene
Pentylbenzene
1-Butyl-3-methylbenzene
1,3-Diethyl-4-methylbenzene
2-Methylundecane
1-Butyl-2-methylbenzene
1,2,3,4-Tetrahydronaphthalene
Bicyclo[4.4.0]deca-1,3,5,7,9-pentene
1,3-Dimethyl-5-(dimethylethyl)benzene
1-Butyl-4-ethylbenzene
1,3-Dipropylbenzene
Dodec-1-ene
DODECANE
1,3,5-Triethylbenzene
1-Methyl-4-pentylbenzene
1,2,4-Triethylbenzene
Hexylbenzene
1,2,3,4,5-Pentamethylbenzene
2-Methylnaphthalene
Tridec-1-ene
1-Methylnaphthalene
TRIDECANE
972
977
984
986
993
996
997
1000
1003
1007
1015
1016
1017
1026
1032
1033
1034
1039
1042
1045
1047
1049
1051
1053
1055
1060
1067
1071
1073
1079
1086
1093
1094
1095
1098
1100
1102
1106
1111
1113
1114
1117
1120
1131
1133
1138
1141
1143
1145
1148
1150
1154
1157
1162
1165
1169
1173
1176
1181
1190
1193
1200
1214
1236
1249
1262
1287
1292
1295
1299
1300
±3
±3
±3
±2
±1
=0
±1
±2
±4
±2
±2
±3
±3
±3
±3
±3
±2
±0.5
±3
±2
±1
±1
±2
±2
±4
=0
±2
±2
±2
±0.1
±2
±2
±3
±4
±5
±5
±5
±1
±1
±2
±4
±4
±4
±3
=0
=0
14
4
1
14
1
7
3
15
7
5
13
7
1
7
6
1
1
7
7
12
5
6
3
12
1
6
3
6
6
7
7
1
1
1
1
14
4
1
7
1
6
3
4
3
6
5
1
4
6
5
5
1
3
3
5
1
6
4
1
6
1
8
1
1
1
1
1
1
1
1
7
Listed compound names follow IUPAC protocol (see: en.wikipedia.org/wiki/IUPAC_nomenclature). For example: Isobutane or 2-Methylpropane is
simply Methylpropane, as the methyl group can only be substituted in the second position with propane.
Retention times for Oxygenates, including alcohols and ethers, can vary significantly with differing temperature programs; Kovats indices listed here
are approximations only, and should be used only as rough guidelines for their elution.
o
Suggested column conditions - Column: Varian CP-Sil 5 CB, 60 meters, 0.25 mm ID, 1 micron film thickness; temperature program: -45 C,
o
o
hold for 1.45 minutes, 3.6 C/minute to 210 C, hold for 2.72 minutes; flow: 2.0 ml/minute.
Copyright 2010 Lotus Flower, Inc.
Lotus Consulting
310/569-0128 Fax 714/898-7461
email [email protected]
5781 Campo Walk
Long Beach, California 90803