Rapid Qualitative GC-TOFMS Analysis of Unleaded Gasoline

Transcription

1 Rapid Qualitative GC-TOFMS Analysis of Unleaded Gasoline LECO Corporation; Saint Joseph, Michigan USA Key Words: GC-TOFMS, Petrochemical, Deconvolution 1. Introduction Analyses of petroleum fuels are complicated by the relatively large number of volatile and semivolatile components contained in these mixtures. As a result, GC or GCMS analyses of these mixtures typically take well over two hours. Previous analytical conditions have focused on complete chromatographic resolution of as many individual analytes as possible. While all mass spectrometers offer multi-channel detection capabilities that may be used to identify coeluting analytes, slow spectral acquisition rates and under-developed software algorithms have minimized the impact of MS detectors on faster GC separation times. The LECO Pegasus II GC-TOFMS offers several unique advantages for reducing the time of fuel analyses. The Pegasus II provides acquisition rates of up to 500 full range mass spectra/second to allow accurate definition of the narrowest GC peaks. Fast GC techniques may now be effectively used to reduce separation times without sacrificing data quality. The unique degree of spectral continuity across a chromatographic peak provided by the Pegasus II has allowed the development of several revolutionary software algorithms. The Peak Find algorithm effectively locates the position of all peaks in the chromatogram including multiple components in complex coelutions. The Deconvolution algorithm effectively resolves the mixed mass spectra of the coelution into accurate individual mass spectra for each analyte, including the accurate distribution of signal from masses shared by several components in the coelution. 2. Experimental Conditions The potential benefit of these unique features of the Pegasus II in petroleum fuel analyses were evaluated using an unleaded gasoline sample obtained from a local distributor. The analytical conditions used for the 14 minute analysis of this complex mixture are summarized in Table 1. The resulting total ion chromatogram from the separation is shown in Figure 1 with the peak table (Table 2) indicating the analyte name, its Retention Time (RT), and the accuracy of its library search result versus the NIST spectral database. Table 1. Pegasus II GC-TOFMS Conditions for a 14 minute Analysis of an Unleaded Gasoline Sample. Detector: LECO Corporation Pegasus II Time-of-Flight Mass Spectrometer Transfer Line: 275 o C Source: 210 o C Acquisition Rate: 50 spectra/sec GC: Hewlett Packard 6890* Column: DB-1 20 m x 0.1 mm ID, 0.4 µm phase film Oven: 40 o C for 0.4 min., then to 110 o Cat10 o C/min., then to 260 o Cat 20 o C/min., hold for 1 min. Injector: 225 o C Carrier Gas: Helium, 0.6 ml/min. constant flow Sample: No preparation required. 0.2 µl split (1000:1) injection *HP6890 GC is equipped with fast oven temperature ramp capabilities and a high pressure EPC module. Figure 1: Unleaded Gasoline Total Ion Chromatogram (TIC) 573 Analytes in 14 Minutes. 3. Results The effectiveness of the Peak Find and Deconvolution algorithms to accurately locate and identify analytes in complex coelutions resulting from the rapid separation conditions used in this analysis can be evaluated in Figures 2 and 3. In Figure 2, the positions of all components in a coelution containing five C7 hydrocarbons are accurately located by the Peak Find algorithm. The mass spectra for all five analytes are accurately resolved from one another by the Deconvolution algorithm. Library search results for these mass spectra versus the NIST spectral database are presented in Figure 3. The Deconvolution algorithm not only separates out ions unique to the spectra of each analyte but also successfully assigns the appropriate amount of signal to each analyte spectrum for masses that are shared between multiple analytes in the coelution. In the C7 hydrocarbon coelution (Figure 3), the signal at 55u, 81u, 96u, and 98u is appropriately proportioned between the five analytes by the Deconvolution algorithm. Figure 2. Extracted Ion Profile Chromatogram Showing the Coelution of C7 Hydrocarbons. The markers indicate peak positions as determined by the Pegasus II GC-TOFMS Peak Find algorithm.

2 Delivering the Right Results Table 2. Unleaded Gasoline Peak Table With the and Numbers Resulting From Comparison of the Acquired Spectra to the NIST Mass Spectral Database. Peak Name RT 1 Propane Isobutane Propene, Butyne Butane Acetic acid, 2-propenyl ester Butene Propane, 2, Butene Ethanol Cyclopropane, 1, Butane, Pentene Cyclopropane, 1,2-, cis Pentane ,3-Pentadiene, (Z) Cyclopropane, 1, , trans Pentene, (Z) Butene, ,2-Pentadiene ,3-Butadiene, Penten-1-yne Butane, 2, ,3-Pentadiene, (Z) Pentene, Cyclopropane, 1-ethyl Propane, 2-methoxy Cyclobutane, Butane, 2, Pentane, Butanone Pentane, Pentene, Hexene trans-1,4-hexadiene Cyclopropane, ( Hexane Hexene, (Z) Hexene Pentene, Pentene, 3-, (Z) Cyclopentene, Hexene Pentene, 3-, (Z) Pentene, Butane, 2,2, Cyclopentane, Pentane, 2, Cyclopropane, (1-methylethylidene)- 50 1,3-Cyclopentadiene, Butane, 2,2, ,3-Cyclopentadiene, ,4-Hexadiene, (E,E) Pentene, 3, Pentyne, 4, Peak Name RT 56 1-Pentene, 2, Cyclopentene, Hexene, Benzene Cyclopropane, 1,1,2,2- tetra Thiophene Pentane, 3, Pentene, 3-ethyl Cyclobutene, 3, Cyclohexane ,3-Cyclopentadiene, Azetidine ,5-Dimethylcyclopentene Pentene, 3-ethyl Hexane, Pentane, 2, Hexane, 3-methoxy Cyclopentane, 1, Hexane, ,4-Hexadiene, (Z) Hexene, 5-, (Z) Cyclopentane, 1, Pentane, 3-ethyl Cyclopentane, 1, Cyclopentane, 1, , cis- 81 Butane, 2,2,3,3- tetra Hexene, 3-, (Z) Cyclopentene, 1,2, Heptene Heptane Hexene, 3-, (Z) Heptene Methyl-3-hexene,c&t ,4-Hexadiene, Pentene, 2, ,5-Dimethylcyclopentene Heptene Pentene, 3,4-, (Z)- 94 3,4-Heptadiene Methyl-2-heptyne Cyclopentene, 3-ethyl ,4-Heptadiene Cyclopentane, 1, Cyclohexane, Cyclopentane, 1,1, Cyclopentene, 1,2, ,5-Di1,3- hexadiene Hexane, 2, Cyclopentane, ethyl Hexane, 2, Methyl-1,5-hexadien-3-ol Cyclohexane, methylene

3 Peak Name RT 108 Cyclopentane, 1,2,4-, (1à,2á,4à) Hexane, 3, ,3,6-Heptatriene Methyl-3-heptene Butene, 2, ,4-Hexadiene, 2, Cyclopentane, 1,2, , (1à,2à,3á)- 115 Cyclopentene, 4, Pentane, 2,3, Cyclopentene, 3-ethyl Methyl-3-heptene Heptene, 4-, (E) Toluene Pentane, 2,3, Thiophene, Pentane, 2,3, Methyl-1,4-heptadiene Pentene, 3-ethyl Pentane, 3-ethyl ,5-Dimethylcyclopentene Cyclohexane, 1, Heptane, Cyclohexane, methylene Heptane, Hexene, 2, Hexane, 3, Methyl-3-hexen-2-ol Pentene, 3-ethyl Heptane, Butene, (Z) Hexane, 3-ethyl Pentene Pentane, ,1,3, Tetramethylcyclohexane 142 1, Dimethylcyclohexane,c&t 143 Cyclopentane, 1,2,3-, (1à,2à,3à) Cyclohexane, 1, Heptene, 2-, (E) Heptane, 2, Ethyl-3-hexene Heptane, 3-methylene Octene Cyclohexane, 1, Cyclopentane, 1-ethyl-3-, trans Hexene, 2,5-, (E)- 153 Cyclopentane, 1-ethyl-3-, trans- 154 Cyclopentane, 1-ethyl-2-, cis- 155 Cyclopentene, 1,2, Octene, (E) Heptane, 3-methylene Methyl-1,4-heptadiene Hexane, 2, ,4-Heptadiene, Octene Peak Name RT 162 1à,2á,3à,4á- Tetramethylcyclopentane Cyclohexane, 1, Methyl-1,3-heptadiene (c,t) 165 Heptane, 3, Octene Ethyl methylcyclopentene 168 Cyclopentane, ( Heptene, 2, ,4-Hexadiene, 3-ethyl Hexane, 2,3, Butane, 2-cyclo Pentane, Ethanone, 1-(1, cyclohexen-1-yl) ,3-Di cyclohexene 176 Cyclopentane, 1-ethyl-2-, cis Hexane, 2, ,4-Di cyclohexene Methyl-1,6-heptadien-4- ol Cyclopentane, 1,1,3,3- tetra Heptane, 2, Cyclohexane, 1, Cyclopentane, Pyrazoline, 1-iso Cyclohexane, ethyl Ethyl methylcyclopentene 187 Heptane, 2, ,2-Di1, cyclohexadiene 189 Cyclohexane, 1,1, Cyclooctane, butyl ,3,5, Tetramethylcyclopentene 192 1,1,4-Trimethylcyclohexane cis-4-nonene Cyclohexane, 1-ethyl-2-, cis ,4-Octadiene,c&t Ethylbenzene Thiophene, 3-ethyl Cyclohexane, 1,2,3-, (1à,2á,3à) p-xylene p-xylene Benzene, 1, Octane, Thiophene, 2-ethyl Octane, Thiophene, 2, Nonyne, Methyl-1-heptanol Cyclopentene, Octane, Cyclopentane, ( ,3-Hexadiene, 3-ethyl

4 Delivering the Right Results Peak Name RT 212 Thiophene, 2, Bicyclo[4.2.0]octa-1,3, triene 214 1,6-Heptadiene, 3, Cyclohexane, 1,2, Heptane, 2,2, Benzene, 1, Heptene, 4-ethyl Undecanethiol, Cycloheptanone, 4-, (R)- 221 cis-1-ethyl-3-methylcyclohexane Thiophenecarboxaldehyde cis-4-nonene Ethyl methylcyclohexane (c,t) Nonene Cyclopentanone, (2-227 trans-2-methyl-3-octene Nonane ,3-Hexadiene, 3-ethyl Heptane, 2,5, cis-2-nonene cis-4-nonene Methyl-1,4-heptadiene Nonyne Cyclohexane, 1,2,3-, (1à,2à,3á) Furan, Cyclohexane, 1-ethyl , cis Heptene, 2, Cyclohexane, 1-ethyl , cis- 240 Undecane, Benzene, ( ,5-Octadiene, 7-3- ( Nonane, Heptane, Heptane, 2,3, ,1'-Bicycloheptyl Cyclohexane, 1-propenyl Hexene, 3-ethyl-2, Nonane, Heptane, 3, Pentalene, octahydro Octane, 2, Diisoamylene Cyclohexane, ( Oxirane, (3, Cyclopentane, butyl Nonane, Octane, 3, Cyclohexane, ,4-Diethyl-3-hexene Peak Name RT 261 Heptane, 3-ethyl Benzene, Heptane, 3-ethyl Benzene, 1-ethyl (6Z)-Nonen-1-ol ,2,4-Trimethylbenzene Benzene, 1,2, Benzene, 1-ethyl Octane, 4-ethyl Cyclooctane, ethyl Benzene, 1,2, Nonane, Nonane, ,2,6, Tetramethylheptane 275 Cyclohexane, 1-ethyl-2, Octane, 3-ethyl Benzene, 1,2, Pentanol, Methyl-4-( cyclohexane 280 Cyclohexane, 1-4- (1-methylethylidene) Heptane, 2,2, Octane, Methyl-4-( cyclohexane Nonene, 3-, (E) Octanol, 2, Benzene, 1,2, Cyclohexane, 1-ethyl cis-4-decene Cyclobutane, 1,2-diethyl-, cis ,1'-Bicyclohexyl, , trans Octen-1-ol, 7-3- methylene Ethyl-3-methylheptane Octane, 3, trans-3-decene Benzene, ( Thiophene, 2,3, Benzene, ( Benzeneacetaldehyde, à Cyclohexane, (1-methylbutyl)- 300 Benzeneacetaldehyde, à Tridecane, Cyclopentane, ( Decene, (E) Benzene, 1-2-( Benzene, 1-ethyl Benzene, 1,2, ,2,4-Trimethylbenzene Benzene, 1-2-( Octane, 2,3, Octane, 2,4, Decane, 3, Decane, Phenol,

5 Peak Name RT 314 Cyclohexane, 1-ethyl Benzene, 1-propenyl Benzene, 1-ethenyl Benzene, 1-propenyl Decane, 2,2, Benzene, 1-propynyl Undecene, Cyclopentane, pentyl Cyclopentane, 1,1,3-3-( Benzene, 1,2-diethyl Benzene, Benzene, ( Benzene, Decane, 2,5, Benzene, ( Benzene, ( Benzene, 4-ethyl-1, Decane, 2, Benzene, 1,2-diethyl Nonane, 2, Octene, 2,3, Propyl-1-pentanol Decane, Benzene, Benzene, ( Hexane, 2,2, Pentane, 3-ethyl-2, Decane, Decen-1-ol, (Z) Decane, Decane, 2,5, Benzene, 2-ethyl-1, ,3-Dimethyldecane Benzene, 1-2-( Benzene, 1-butenyl-, (E) Benzene, 4-ethyl-1, Benzene, 1-butenyl-, (E) Octanol, 2, Benzene, 1-2-( Decene, 8-, (E) Cyclopentane, 1,1'-(1, butandiyl)bis- 355 Cyclohexane, Bicyclo[2.2.2]oct-5-en-2- one Undecene, (E) Decane, 3, H-Indene, 2,3-dihydro ,6-360 Benzene, 1-4-( Benzene, (1, dimethylethyl) 362 Benzene, (1, Benzene, (1, Peak Name RT 344 Decane, 2,5, Benzene, 2-ethyl-1, ,3-Dimethyldecane Benzene, 1-2-( Benzene, 1-butenyl-, (E) Benzene, 4-ethyl-1, Benzene, 1-butenyl-, (E) Octanol, 2, Benzene, 1-2-( Decene, 8-, (E) Cyclopentane, 1,1'-(1, butandiyl)bis- 355 Cyclohexane, Bicyclo[2.2.2]oct-5-en-2- one Undecene, (E) Decane, 3, H-Indene, 2,3-dihydro ,6-360 Benzene, 1-4-( Benzene, (1, dimethylethyl) 362 Benzene, (1, Benzene, (1, Undecane Benzene, 4-ethyl-1, H-Indene, 1-ethyl-2, dihydro Benzene, (1, Cyclopentylcyclopentene Benzene, methyl( Benzene, 2, (1-371 Benzene, 1,2,4, tetra 372 Benzene, 1-4-( Benzene, 4-ethyl-1, Bicyclo[4.1.0]hept-4-en-3- ol, 3,7,7-, [1S- (1à,3à,6à)] ,6-Dimethyldecane Benzene, ( Nonane, 3, Benzene, (1, Benzene, 2,4-diethyl Butyl pentyl carbonate H-Indene, 2,3-dihydro ,6-382 Benzene, 1-2-( Benzene, (1, Benzene, (1, H-Indene, 2,3-dihydro- 1, Benzene, 1-butynyl

6 Delivering the Right Results Peak Name RT 387 Benzene, 1-4-( Benzene, 1-2-( Benzene, 1-2-( Benzene, 1,4-diethyl Benzene, (2-methylbutyl) Benzene, (1-methylbutyl) Undecane, Undecane, Benzene, (1, Benzene, 2, (1-397 Naphthalene, 1,2,3, tetrahydro- 398 Benzene, (1, Benzene, 2, (1-400 Benzene, 1-4-( Undecane, Dodecane, Benzene, (1, Undecane, Benzene, (1, Heptane, 3-ethyl Hexen-4-yne, (Z) H-Indene, 1, Heptane, 3, Bicyclo[2.2.2]octane, 2- chloro Benzene, 1-(1-ethylpropyl) Benzene, 2-ethenyl-1,3, Naphthalene H-Indene, 1-methylene H-Indene, 2,3-dihydro ,2-416 Benzo[c]thiophene Benzene, 2-ethenyl-1,3, Benzene, (1, Decanol, 2-ethyl Benzene, (1-ethyl H-Indene, 2,3-dihydro ,3-422 Benzene, 2, (1-423 Benzene, 2,4-diethyl H-Indene, 2,3-dihydro- 1, Undecane ,11-Dodecadiene Benzene, 1-( methylethenyl)-3-(1-428 Benzene, 2, (1-429 Benzene, (1,2, tri 430 Cyclopentane, 1,2-3-( Peak Name RT 431 Benzene, (1, Benzene, 1-2-( ethylpropyl)- 433 Naphthalene, 1,2,3,4- tetrahydro-1, Undecane, 2, Benzene, 2, (1-436 Naphthalene, 1,2,3, tetrahydro Benzene, 2,4-1- ( Undecane, 4, Benzene, 1-(1, di4-ethenyl- 440 Naphthalene, 1,2,3,4- tetrahydro Benzene, (2-methylpentyl) Benzene, (1, Undecane, 2, Benzene, 1,1'-(1,1,3, tetra1,3- propanediyl)bis- 445 Naphthalene, 1,2,3, tetrahydro Benzene, 2, (1-447 Benzene, 1-4-( Benzene, (1, dimethylethyl) 449 Benzene, 1,2, (1-methylethenyl) ,5-Decadiyne, 2, Hexanone, 2, H-Indene, 2,3-dihydro ,1, ,5-Decadiyne, 2, Benzene, (1, Cyclohexane, hexyl Benzene, 2, (1-457 Benzene, 2-ethenyl-1,3, Dodecane, Benzene, ( butenyl) Naphthol, 1,2,3,4- tetrahydro Benzene, hexyl Dodecane, Benzene, 1,2-diethyl-3, Naphthalene, 1,2-dihydro Benzene, 1,4-2- ( Tridecane, Benzene, (1, Benzene, 2-ethenyl-1,3, Naphthalene, 1,2,3, tetrahydro H-Indene, 2,3-dihydro- 1,

7 Peak Name RT 471 Dodecane, Benzene, 1,2-diethyl-4, Benzene, 1, (2-474 Naphthalene, 6-ethyl Octane, 2,3, Butanol, 3, Benzene, hexa Benzene, 1,4-di Naphthalene, 6-ethyl Benzene, 2, ( H-Indene, 2,3-dihydro ,2-482 Naphthalene, 1,2,3, tetrahydro-1,1-483 Naphthalene, 6-ethyl Benzene, 2, (1-485 Benzene, 1-( methylethenyl)-2-(1-486 Naphthalene, 1,2,3,4- tetrahydro Benzocycloheptatriene H-Indene, 1-ethylidene Benzaldehyde, 2,4, ,4-Methanonaphthalen ol,, stereoisomer 491 Naphthalene, 1,2,3, tetrahydro-1,1-492 Benzene, ( cyclohexylethyl)- 493 Benzo[b]thiophene, Decane, 2,5, Cyclopenten-1-ol, phenyl- 496 Benzocycloheptatriene H-Indene, 1-ethylidene Undecane, 3, Benzene, 1,4-di ,4-Di1,2,3, tetrahydronaphthalene 501 Disiloxane, penta2- propenyl Decanol, 2-ethyl Benzene, 1-( methylethenyl)-3-(1-504 Naphthalene, 6-ethyl Cyclohexen-1-amine, 6- (4-methylphenyl)-2,5- diphenyl-, (1à,2à,5à,6á) Benzene, 1,3, Undecane, 2, Naphthalene, 2-ethyl Benzene, [2-1-( methylethyl)propyl] H-Indene, 2,3-dihydro- 1,1,4,7-tetra Peak Name RT 511 Naphthalene, 6-ethyl Cyclohexene-1-ethanol, à-ethenyl-à,3-6- (1-methylethylidene)- 513 Benzene, bis( Naphthalene, 1,2,3, tetrahydro-2,7-515 Benzene, (1,2, tri 516 Naphthalene, 5-ethyl Octanol, 2-butyl Benzene, octadecyl Naphthalene, 1,2,3, tetrahydro-1,1-520 Tridecane, Benzene, 4-(2-butenyl)-1, , (E)- 522 Ethanone, 1-(2,4,6- trimethylphenyl) Benzene, hexyl Naphthalene, 6-ethyl Dodecane, Indan, 1,1,6,7-tetra Methyl-4-Nhexylbenzene Iodo-2-methylnonane Benzene, 1,1'-(1,1,3,3- tetra1,3- propanediyl)bis Naphthalene, 2-ethenyl Naphthalene, 6-ethyl Dodecane, 2,6, Benzo[b]thiophene, 2, Pentadecane Naphthalene, 1-ethyl Naphthalene, 1,2,3,4- tetrahydro-1, Naphthalene, 1-ethyl Octane, 2,4, Decanol, 2-ethyl Naphthalene, 1, Naphthalene, 2, Benzene, 1-(1- methylethenyl)-4-( Naphthalene, 1, Propyltetraline Naphthalene, 2, Naphthalene, 1, Naphthalene, 2, Decane, 2,5, Naphthalene, 1, Tridecane, ,1'-Biphenyl, Naphthalene, [[4-(1,1- dimethylethyl)phenoxy]met hyl] ,1'-Biphenyl, Decane, 6-ethyl

8 Delivering the Right Results Peak Name RT 555 Naphthalene, 2-( Naphthalene, 2-( Naphthalene, 2-( Naphthalene, 2-( Methyl-1-phenylhexa ,3,4-triene 560 Naphthalene, 2-( Naphthalene, 1,4, Naphthalene, 1,3, Naphthalene, 1,4, Naphthalene, 2,3, Naphthalene, 1,4, Naphthalene, 1,4, Naphthalene, 1,4, Undecane, 2, H-Fluorene-9-carboxylic acid 570 Naphthalene, 1,4, Naphthalene, ,1'-Biphenyl, Naphthalene, 1,3,

9 A B C D E Figure 3. Mass Spectra for Coeluting C7 Hydrocarbons as Determined by the Pegasus II GC-TOFMS Deconvolution algorithm. Top: Pegasus II spectrum. Bottom: NIST Library spectrum. A: Peak 88; 2-1,4-hexadiene; 896; 911. B: Peak 89; 2,3-1-pentene; 914; 934. C: Peak 90; 3,5-dimethylcyclopentene; 916; 944. D: Peak 91; 2-heptene; 918; 920. E: Peak 92; 3,4-Di2-pentene; 917; Conclusions The combination of Fast GC techniques (shorter microbore columns and faster temperature program rates), fast mass spectral acquisition rates, and unique Peak Find and spectral Deconvolution algorithms allow accurate analysis of 573 analytes in an unleaded gasoline sample in only 14 minutes using the Pegasus II GC-TOFMS. This represents a 10 fold decrease in data acquisition time. The unique software features also significantly reduce data processing time resulting in an overall decrease of analysis time of well over 1 order of magnitude. LECO Corporation 3000 Lakeview Avenue St. Joseph, MI Phone: Fax: info@leco.com ISO-9001:2000 No. FM LECO is a registered trademark of LECO Corporation. Form No /10-REV LECO Corporation