Analysis of Biomolecules Using Electrospray IonizationâIon-Trap

Chapter 25

Analysis of Biomolecules Using Electrospray Ionization—Ion-Trap Mass Spectrometry and Laser Photodissociation 1

James L. Stephenson, Jr. , Matthew M. Booth, Stephen M. Boué, John R. Eyler, and Richard A. Yost Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611-7200

The technique of photo-induced dissociation (PID) offers several advantages over that of collision-induced dissociation (CID) for structural analysis, including a welldefinedenergy deposition process and no direct competition between ion dissociation and resonance ejection (typically observed in trapping instruments). Comparisons between thecollisionaland photon fragmentation processes forpeptides,oligosaccharides and RNA dimers demonstrate the applicability of PID for structural elucidation of biological molecules. The instrumentation employed consisted of an rf-only octopole for ion injectionof dectrosprayed ions The ring electrode was modified with three mirrors to increase the photoabsorption pathlength for the PID process. The photoabsorption cross sections (IR) for the three compound classes studied followed the order: oligosaccharides (C—Ο—C ether linkage) > RNA dimers (phosphodiester linkage) > peptides (amide linkage). Over the last decade, perhaps the most important advancement in quadrupole ion trap mass spectrometry has been that of tandem mass spectrometry or MS" for the structural elucidation of polyatomic ions. The mostfrequentlyused method for the activation of these ions has been collisional activation or what is customarily called collision-induced dissociation (CID) (/). The major factors contributing to the success of CID experiments in the quadrupole ion trap mass spectrometer (QITMS) include the ability to perform tandem-in-time as opposed to tandem-in-space MS/MS experiments (2), the efficient conversion of parent ions to product ions (typically 10-50%) (3), and most importantly the high collision cross sectional area observed for a typical CID experiment (on the order of e r r e n t address: Oak Ridge National Laboratory, Building 5510, Mail Stop 6365, Oak Ridge, TN 37831-6365

0097-6156/95/0619-0512$20.25/0

© 1996 American Chemical Society

25. STEPHENSON ET AL.

Analysis of Biomolecules

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2

10 to 200 Â ). These advantages arise in part because in the quadrupole ion trap, uniquely amongst tandem mass spectrometers, kinetic energy is imparted to the parent ions between (rather than before) collisions. In this chapter we discuss an alternative to collisional activation for tandem MS experiments, which utilizes the photon-absorption process for the activation of polyatomic ions (produced by electrospray ionization) in the QITMS. Until recently, photo-induced dissociation (PID) or photodissociation has been used almost exclusively in fundamental studies of gas-phase ions in physics and chemistry. Photo-induced dissociation is the next mostfrequentlyused method for activation of polyatomic ions after collisional activation. The range of internal energies present after the photon absorption process are much narrower than those obtained with collisional energy transfer. Therefore, the usefulness of PID for the study of ion structures is greatly enhanced. However, the reduced absorption cross sections observed with photodissociation (10~ Â ) compared to those of collisioninduced dissociation (10 to 200 À ) can Hmh this technique for analytical appUcations. The recent availability of higher powered lasers over a wider range of wavelengths should provide greaterflexibilityfor photodissociation as a routine analytical technique (1,4). In this study, extended irradiation of trapped ions and a multipass optical configuration make PID practical for analytical studies. The process of photodissociation for a positive ion can be described by the following equation: 2

2

2

A*

+

nhv + A* P*+N relaxation dissociation +

(1

)

where A is the ion of interest, η is the number of photons absorbed, h ν is the photon energy, A*" is the excited state, and P* represents the product ion (with loss of neutral N). For photodissociation to occur several prerequisites must be met. The most important criteria include the absorption of photons with energy h v, the existence of excited states above the dissociation threshold, a slow relaxation rate compared to the rate of photon absorption (muttiphoton processes), and dissociation rates which are fast on the time scale of the type of mass spectrometer employed (1,4). The information obtainedfroma photodissociation experiment can address a variety of gas-phase chemistry issues. One of the most important issues is the difference observed infragmentationspectra between ΡΠ) and CID. Since the range of internal energies after the activation step is much narrower in PID, typically the dissociation process proceeds via thefragmentationpathway with the lowest activation energy (especially for visible and infrared wavelengths) (5-7). Ion energy studies by Louris et al. using ultraviolet-visible (UV-Vis) wavelengths demonstrated the higher energy deposition available for the photodissociation process compared to the CID process (e.g. higher m/z 91 to m/z 92 branching ratiosfromthe molecular ion of η-butyl benzene) in the quadrupole ion trap (8). In addition, wavelength-dependent photodissociation spectra can be obtained as long as the internal energy of the excited ion population is above the dissociation threshold for the wavelength of interest. The photodissociation spectrum can then be compared with the vuv absorption spectrum of the neutral molecule, provided that sufficient transition

514

BIOLOGICAL AND BIOTECHNOLOGICAL APPLICATIONS OF ESI-MS

intensity exists between the ground state neutral and the excited state ion. The information obtainedfromthese experiments may constitute as a fingerprint in the détermination of ion structures (6 7). In trapping instruments, photo-induced ionfragmentation(i.e. product ion relative abundances) can be measured as a function of irradiance time. These data can be used effectively to distinguish isomeric ion structures in the gas-phase. Kinetic energy release data can also be used (below 100 mV) to add important ionfragmentationinformation (9). Perhaps some of the more interesting studies utilizing PID and trapping instruments involve ion trajectory studies, or what isfrequentlytermed ion tomography. Several recent studies by Williams et al. have demonstrated the ability of PID in the UV-Vis range to map the instantaneous trajectories of ions stored in the quadrupole ion trap (JO, J J). Analogous studies by Lammert et al. have successfully used ion tomography to characterize the frequency of ion motion as well as the observed "mass shifts" caused by ion population effects in the trap (12), Initial reports of PID combined with ion cyclotron resonance (ICR) mass spectrometryfirstdemonstrated the usefulness of PID as an analytical tool. These early studies using photodissociation for structural studies of biological species in the ICR employed a wide range of wavelengthsfrominfrared (IR) to UV (73-75). Williams et al. reported photodissociation efficiencies on the order of 100% for the peptide alamethicin using 193 nm light when the ions were confined to the beam path. Corresponding CID experiments involved pulsed-gas introduction of collision gas, which makes the MS/MS experiment much more complicated and produces dissociation efficiencies on the order of 15% which is significantly lower than for photodissociation (14). Comparison studies of photodissociation and surface-induced dissociation (SID) of porphyrins in the ICR by Castro et al. yielded higher dissociation efficiencies for the photodissociation process. Longer irradiance times (i.e., with no parent ion selection after thefirstMS/MS step), produced more fragment ions at higher abundances than those obtained with SID. At very long irradiance times (both UV and UV-Vis wavelengths), the newfragmentions produced were at the expense of diagnostically significant ions (75). By combining the technique of electrospray ionization with that of PID for the structural elucidation of biological species, a unique and powerful tool can be developed to solve the more difficult problems faced by the analytical biochemist. Recently, infrared multiple photon dissociation (IRMPD) has been reported in the ICR for photodissociation of biological ions generated by electrospray ionization. Little et al. demonstrated the capability of IRMPD to obtain sequence information for peptides/proteins and oligonucleotides (75). The IRMPD of carbonic anhydrase producedfragmentions similar, but with valuable additions, to fragmentation information obtained by other methods (e.g., CID and SID). Optimization of irradiance times varied widely for peptides/proteins (from 50 to over 300 ms), indicating a greater range of ion stabilities than originally believed from CID data. Irradiance times for oligonucleotides (negative ion mode) were significantly less (e.g., 10-30 ms) than those of the peptide/protein experiments. This could be attributed to the photon resonance of the Ρ—Ο stretchingfrequency.More importantly, IRMPD was shown to have greater selectivity, have less mass discrimination, and could dissociate much more stable ions than the corresponding CID process (73). t

25. STEPHENSON ET AK


515

Here we report the development of a novel electrospray ion injection system combined with continuous wave (cw) and pulsed IR lasers for the analysis of peptides/proteins, carbohydrates, and oligonucleotides. Over the last eight years, ion injection into the quadrupole ion trap has become one of the most popular areas of research in mass spectrometry. Since the original report of ion injec^on using an external electron ionizati^^ (EI) ion source by Louris et al. (16), a myriad of different ion sources have been interfaced with the ion trap. These include but are not limited to El/chemical ionization (CI) (16-18), fast atom bombardment (FAB) (19), particle beam (20), thermospray (27), electrospray (22-26), glow-discharge (27-29), atmospheric pressure (30,31), inductively coupled plasma (ICP) (32), laser desorption (33-37), and super criticalfluid(38) sources. In all the aforementioned literature, evay external ionization source has utilized some form of dc lens system for ion injection into the ion trap. Although a dc lens system may be the simplest to design and constructforan ion injection system, it is not necessarily the easiest and most efficient way to transfer ionsfroman external source to the ion trap analyzer. This is especially true for high pressure ionization sources such as electrospray or atmospheric pressure ionization where a large number of collisions between ionized species and gasphase neutrals can occur, effectively scattering a large portion of the ion signal. Since dc lenses serve only to focus the ion beam and not to "recapture" scattered ions for ion injection, an alternative method which could recapture scattered ions and focus them into appropriate trajectories for ion injection would be desirable. One technique which fulfills this requirement is the rf-only multipole. RF-only multipoles have been used extensively in both analytical and physical mass spectrometry (39,40). The ability of these devices to focus ions in a high pressure environment can be understood by examining the forces exerted on a given ion population as it moves through an rf-only device. As an ion is displacedfromthe center axis of the device, the restoring force acting upon that ion (in an rf-only multipole with 2n electrodes) is proportional to the (n-l)* power of that displacement, where n=2,3, and 4 for a quadrupole, hexapole, and octopole, respectively (41). Therefore, as ions are displacedfromthe center of the rf-only device due to collisions with neutral molecules, the restoring forces recapture the displaced ions and successfully transfer themfroma high pressure region (e.g., electrospray ion source) to a lower pressure region (e.g., ion trap analyzer) with minimal scattering losses. Based on the above discussion, the octopole would be the logical choice for an ion injection device due to the greater restoring forces for the n=4 case. Previously, the rf-only octopole has been used as an ion-molecule reaction cell (42,43), as a collision cell in tandem quadrupole instruments (44), as an ion injection device for triple quadrupole instruments (45), and as a method for determining ion-molecule reaction cross sections and energetics (i.e., translational energy dependence, product branching ratios, collision-cross sections) of ion-molecule reactions (46-49). Other rf-only devices have been designed and used (e.g., hexapoles and quadrupoles) for the aforementioned purposes and have been employed as ion transmission devices (50-53). As mentioned previously, the main reason for the lack of analytical publications on PID is the low photoabsorption cross section (10~ Â ) observed for most organic ions (1). In order to overcome this inherent disadvantage, we have developed a modified ion trap ring electrode which facilitates an increase in the photoabsorption pathlength for the PID experiment. The modified optical arrangement, as originally described by White (54), 2

2

516


increased the optical pathlength and thus the amount of photon absorption obtained in the IR region Thefirstapplication of this technique in mass spectrometry was for the ICR cell as described by Watson et al (55). The White-type cell was used for the study of resonance-enhanced two-laser infrared multiphoton dissociation of gaseous perfluoropropene cations, protonated diglyme cations, gallium hexafluoroacetylacetonate anions and ally! bromide cations (55,56). Note that ion traps such as these offer the opportunity for extended irradiation of trapped ions, helping to overcome the disadvantage of low photodissociation cross sections. For the quadrupole ion trap, the White-type design was constructed by mounting three spherically symmetric concave mirrors in the radial plane of the ring electrode. The gain in PID efficiency obtained with this arrangement was directly related to the eight laser passes across the ring electrode which produced a concurrent increase in the photoabsorption pathlength. A detailed description of the modifiedringelectrode, theoretical considerations (using C0 lasers), and performance characteristics have been published previously (57,58). A brief summary of these results are presented in the experimental section of this chapter. One major advantage of photodissociation (in the quadrupole ion trap) is that the kinetic energy of an ion does not have to be converted into the necessary internal energy to effectfragmentationIn addition, several tuning parameters, including helium buffer gas pressure, ionfrequency,and ion population, can further complicate the single-frequency CID experiment even for an experienced user. Even when broadband excitation techniques are employed to minimize ionfrequencyand population effects, dissociation efficiencies observed are somewhat lower than the corresponding single-frequency experiments and can be significantly lower than photodissociation experiments when a sufficient photoabsorption cross-section exists for the ions of interest. Infigure1 is shown the effect of ion population on the dissociation efficiency of protonated 12-crown-4 ether. Ionization time (shown on the x-axis) is directly proportional to the number of ions in the trap. For the case of the single-frequency CID experiment (where in this example, the tuning parameters were optimized for a low number of ions stored in the ion trap), a significant decrease in photodissociation efficiency was observed as the ionization time was increased and hence the ion population increased. Typically, an increase in ion population results in a shift of the fundamentalfrequencyof ion motion to lowerfrequency,thus resulting in a decrease in dissociation efficiency for the given CID tune parameters (see figure 1) (59). In the case of broadband excitation where a whole range offrequenciesare excited over a given time period, the dissociation efficiency is independent of ion population. However, a decrease is typically observed in dissociation efficiency compared to that of the optimum single-frequency results. When the results of the two CID methods are compared to photodissociation data for the same protonated 12-crown-4 ether, the PID efficiency seen is independent of ion population. However, the overall dissociation efficiency is substantially higher (approximately 100% compared to 65% for the optimum ângle-frequençy tune and 45% for the broadband excitation) than either CID technique (see figure 1). These results can be attributed to two factors: (1) the increased photoabsorption pathlength of the multipass ring electrode, which compensates for the reduced photoabsorption cross-sections of organic species; and (2) the elimination of collisions for transfer of translational energy to 2


1.00-,


517

Photodissociation with an energy of0.240 J

0.80-

g

0.60 -I

Broadband Excitation 200 mV at the Center Frequency (3 kHz Window)

η—ι—ι—ι—ι—J—ι—ι—ι—ι—|—ι—r 15 30 45 Ionization Time in ms Figure 1. Evaluation of the various MS/MS techniques used with the quadrupole ion trap. The dissociation efficiency of photodissociation, single frequency CID, and broadband excitation are plotted versus ionizationtimefor 12-crown-4 ether. The ionizationtimeis directly proportional to the trapped ion population.

Heated Capillary

ESI Tube Lens

Support Rod

Gas Sheath Inlet

Figure 2. Analytica electrospray ionization source equipped with a heated capillary (as modified by Mark Hail at Finnigan MAT, San Jose, CA).

First Differentially Pumped Vacuum Region

LensL3

LensL2

Second Skimmer Cone

First Skimmer Cone

Vacuum Connection

25. STEPHENSON ET AK


519

vibrational energy, where ion stability can cause competition between resonance ejection and CID during an MS/MS experiment. Experimental The electrospray ionization source used with the ESI/ion trap system was a standard Analytica (Analytica Inc., Branford, CT) source equipped with a stainless steel heated capillary (modification performed at Finnigan MAT) as seen infigure2. The purpose of the heated capillary is to help droplet desolvation for the electrospray ionization process. The heated capillary was 0.308" in diameter by 4.580" long with an i.d. of 0.020". Temperature control of the heated capillary was by an Omega 6000 (Omega Engineering, Stamford, CT) series temperature controller with a 220 V output, previously used for controlling the Finnigan MAT ITMS manifold temperature. The 220 V output was stepped down via a transformer to 24 V (< 2 amp output current). Typical operating temperatures were in the 170° to 215 C range. For this temperature range, little if any thermal degradation or inducedfragmentationof the [M+iiH] * (where n=l, 2, 3...) ion(s) was observed. To facilitate coupling of the rf-only octopole to the ESI source, several design changes were made. First, to simplify the ion optics and obtain high ion transfer efficiencies, the second skimmer cone, lens L2 and lens L3 were removedfromthe electrospray head (seefigure3). An adaptor ring was then constructedfromstainless steel to extend the only remaining skimmer cone 0.250" forward. The adaptorringwas mounted between the base plate of the electrospray head and the skimmer cone, employing o-ring seals between the skimmer cone and base plate assemblies. The alignment tool used to determine the exact distancefromthe heated capillary exit to the skimmer cone was then modified to compensate for the stainless steel adaptor ring to maintain a constant distance between the heated capillary and the skimmer cone of 3.5 to 4.0 mm. The electrospray needle was also moved forward to compensate for the adjusted heated capillary position. Infigure3 is shown the modified electrospray source described above. The tube lens located at the end of the heated capillary (seefigure3) was used to gate ions into the rf-only octopole (via the skimmer cone). Control of the voltages applied to the tube/gate lens was accomplished by using the gate control circuitfromthe ITMS electronics. The circuit was modified so that both positive and negative ions could be gated efficiently. For the analysis of positive ions, a variable positive voltage is applied to the tube/gate lens (10-120 V) to focus the ion beam. To control the pulse width of the beam, a -180 V potential is applied to the tube/gate lens to stop ion transmission. For negative ions, a variable negative voltage (-10 to -100 V) is used for ion focusing and a +180 V signal is used to stop ion transmission (e.g., control the pulse width). All electrical connections (capillary heaters/temperature sensors, capillary offset voltage) for the ESI source were made through a 6" Confiâtflange(equipped with an Amphenol connector) located to the left of the ion source (seefigure5). High voltage for the electrospray needle and drying gas were controlled manually by an external power/gas distribution unh (Finnigan MAT, San Jose, CA). The electrospray source was pumped by two 500 L/min rotary pumps (model UNO 016B, Balzers Inc., Hudson, NH). A Harvard 11

>•

Heated Capillary

V////////////ZZÉ-

ESI Needle

Support Rod

y ESI Capillary

Gas Sheath Inlet

Figure 3. The modified Analydca electrospray ion source showing the elimination of the second skimmer cone, lens L2 and lens L3. Also shown is the stainless steel adaptor ring used to extend thefirstskimmer cone region 0.250" forward for coupling to the rf-onfy octopole.

First Differentially Pumped Vacuum Region

Couple For Octopole ^

(modified extension)

First Skimmer Cone

ESI Tube Lens

Vacuum Connection

in

25. STEPHENSON ET A L


521

Apparatus 22 syringe pump (South Narick, MA) was used for the direct infusion of samples into the electrospray source. All flow rates were 3 μΙ7πιΐη unless otherwise stated. All proteins were sprayed (positive ion mode) in a 50:50 methanol/water solution containing 0.1% acetic acid. Carbohydrate samples (positive ion mode) were also sprayed in a 50:50 methanol/water solution with 5 mM ammonium acetate. Oligonucleotides samples (negative ion mode) were prepared in a 70:30 methanol/water solution. The QITMS instrument employed in these studies was built and designed at the University of Florida. The system consists of a standard Finnigan MAT (San Jose, CA) ITMS ion trap analyzer mounted into a differentially pumped vacuum manifold (two 500 L/s turbo pumps). The electronics obtained from Finnigan MAT were modified to extend (and optimize) the mass range of the standard system (normally 650 u). Software used for integrated system control of the C0 laser and QITMS system (ICMS) was developed in our laboratory (60). The ion injection system utilized an rf-only octopole ion guide for the efficient transfer of the electrosprayed ions from the source region to the ion trap analyzer. This ion injection system is based on the design of Schwartz et al. (61). The major advantages of rf-only devices include the efficient transport of ionsfroma high pressure region (ESI source) to a region of lower pressure with minimal scattering losses, ease of use (e.g. no lenses to tune), and the ability to inject ions of different m/z ratios all at the same energy (41). The choice of an rf-only octopole over that of a corresponding hexapole or quadrupole can be explained by examining the effective trapping potential (equation 2) of any rf-only device: 2

(2)

where V^is the effective trapping potential, e the charge on the ion, the zero-to-peak rf voltage applied to the multipole, m the mass of the ion, ω the iffrequencyapplied to the multipole, r the inscribed radius of the multipole, r the displacement of an ionfromthe center axis of the multipole, and 2n the number of poles present. Infigure4 is shown a plot of effective trapping potential versus ion displacementfromthe central axis of three different rf-only devices (quadrupole n=2, hexapole n=3, and octopole n=4). The octopole parameters used are seen in table 1. These parameters are the actual design specifications of the rf-onry octopole developed in our laboratory. All parameters for the three multipole systems in table 1 are constant except for the value of η The plot shown infigure4 is for the +3 charge state of bovine insulin. The radial potential of the octopole has steep repulsive walls which approximate the ideal case of a square well. This means a large number of ions of differing m/z ratios can be transmitted to the ion trap at a constant translation^ energy (due to the large "flat bottom" portion of the well, where ion kinetic energies have only small perturbations), which yields higher transmission and trapping efficiencies. For the quadrupole and hexapole, the radial potential is more triangular in shape and, therefore, not as many ions can be transferred at constant energy, leading to a decrease in ion injection efficiency. This phenomenon can be explained by the dependence of the radial potential on the normalized ion displacement (r/r^ * . The effective radial 0

2

2

522


11111111111 » I l |

-3.0

-2.5 -2.0 -1.5

[ I ΓΊΤρ I I I 11 I I 1 ] M Ï l | l ΠΤ| I I I I 11 I I I 11 I I I ; -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0

Ion Displacement from the Central Axis (mm) Figure 4. Graph of the trapping potential function (radial potential energy versus ion displacement) for a quadrupole (n=2), hexapole (n=3), and octopole (n=4). The curves represent the +3 charge state of bovine bisulin (average molecular weight 5733 g/mol) where V is 100 V, ω is 1.659 MHz, and r is 2.94 mm for each multipole device. 0

0



523

potential in an octopole is proportional to i*, which provides a large trapping volume for the ions of interest (41,52). In die case of the other extreme where n=2 for the quadrupole, the radial potential is proportional to r with a maximum trapping energy one-fourth that of the octopole. Other advantages of the rf-only octopole include the ability to shield low energy ionsfromstray electric fields (or contact potentials) and reduced effectsfromspace charging (41,52). 2

Table 1. Parameters for the radial potential energy equation. Device

η

e

ω (MHz)

Quadrupole

2

+3

1.659

2.94

100

5733

Hexapole

3

+3

1.659

2.94

100

5733

Octopole

4

+3

1.659

2.94

100

5733

το

(mm)

V (V) n

m (g/mol)

For our instrument the inscribed radius, Γο, is 2.94 mm, with a corresponding rod radius (aj of 1 mm. This gives an a DNA (phosphodiester linkage) > peptides/proteins (amide linkage). Future studies will focus not only on the fundamental aspects of photodissociation (e.g. quantitative measurements of photoabsorption cross-sections for multiply charged electrospray ions), but also on the extension of this technique to solve real-world problems (e.g. structural elucidation of glycopeptide antibiotics). Future PID studies will be directed towards the preferred cleavage at glycosidic bond linkages (C—Ο—C groups), using more appropriate laser wavelengths to achieve higher photoabsorption cross sections. These PID studies have the potential to provide significant structural information for oligosaccharide composition/heterogeneity, linkage analysis, and possibly identification of glycosylation sites on peptides and proteins in the gas phase. Acknowledgements The authors wish to acknowledge the Office of Naval Research, an ACS Analytical Division Fellowship (to JLS) funded by Procter & Gamble, and the University of Florida

560


Division of Sponsored Research forfinancialassistance with this project. Special thanks also go to Mr. Joseph A. Shalosky for the machine work done on this project, and to Mr. Scott T. Quarmby for his assistance with the rf circuitry. Literature Cited 1.

2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

Busch, K.L.; Glish, G.L.; McLuckey, S.A. Reactions in MS/MS, in Mass Spectrometry/Mass Spectrometry: Techniques and Applications of Tandem Mass Spectrometry; VCH: New York, 1988; pp 87-90. Johnson, J.V.; Yost, R.A.; KeUey, P.E.; Bradford, D.C. Anal. Chem. 1990, 62, 2162-2172. McLuckey, S.A.; Van Berkel, G.J.; Goeringer, D.E.; Glish, G.L.; Anal. Chem. 1994, 66, 689A-696A. Dunbar, R.C. in Gas Phase Ion Chemistry,Vol.2; M.T. Bowers ed.; Academic Press: London, 1979. Dunbar, R.C. in Gas Phase Ion Chemistry,Vol.3; M.T. Bowers ed.; Academic Press: London, 1984. van der Hart, W. J. MassSpectrom.Reviews 1989, 8, 237-268. van der Hart, W.J. Int. J. Mass Spectrom. Ion Processes 1991, 118/119, 617-633. Louris, J.N.; Brodbelt, J.S.; Cooks, R.G. Int. J. Mass Spectrom Ion Processes 1987, 75, 345-352. Dunbar, R.C.; Weddle, G.H. J. Phys. Chem. 1988, 92, 5706. Hemberger, P.H.; Nogar, N.S.; Williams, J.D.; Cooks, R.G.; Syka, J.E.P. Chem. Phys. Lett. 1992, 191, 405-410. Williams, J.D.; Cooks, R.G.; Syka, J.E.P.; Hemberger, P.H.; Nogar, N.S. J. Am. Soc. Mass Spectrom. 1993, 4, 792-797. Lammert, S.A.; Cleven, C.D.; Cooks, R.G. J. Am. Soc. Mass Spectrom. 1994, 5, 29-36. Little, D.P.; Speir, P.J.; Senko, M.W.; O'Connor, P.B.; McLafferty, F.W. Anal. Chem. 1994, 66, 2809-2815. Castro, J.A.; Nuwaysir, L.M.; Ijames, C.F.; Wilkins, C.L. Anal. Chem. 1992, 64, 2238-2243. Williams, E.R.; Fulong, J.J.P.; McLafferty, F.W. J. Am. Soc. Mass Spectrom. 1990,1,288-294. Louris, J.N.; Amy, J.W.; Ridley, T.Y.; Cooks, R.G. Int. J. Mass Spectrom. Ion Processes 1989, 88, 97-111. Pedder, R.E.; Yost, R.A; Weber-Grabau, M. Proceedings of the 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami, FL, 1989, 468-469. Schwartz, J.C.; Cooks, R.G. Proceedings of the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, 1988, 634-635. Soni, M.; Cooks, R.G. Anal. Chem. 1994, 66, 2488-2496. Bier, M.E.; Hartford, R.E.; Herron, J.R.; Stafford, G.C. Proceedings of the 39th ASMS Conference on Mass Spectrometry and Allied Topics, Nashville, TN, 1991, 538-539. Kaiser, R.E.; Williams, J.D.; Schwartz, J.C.; Lammert, S.A.; Cooks, R.G. Proceedings of the 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami, FL, 1989, 369-370.

25. STEPHENSON ET AL Analysis of Biomolecules 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.

561

Van Berkel, F.J.; Glish, G.L.; McLuckey, S.A. Anal. Chem. 1990, 62, 1284-1295. Mordehai, A.V.; Hopfgartner, G.; Huggins, T.G.; Henion, J.D. Rapid Commun. Mass Spectrom. 1992, 6, 508-516. Boué, S.M; Stephenson, J.L.; Yost, R.A. Presented at the 43rd ASMS Conference on Mass Spectrometry and Allied Topics, Atlanta, GA, 1995. Doktycz, M.J.; Habibigoudarz, S.; McLuckey, S.A. Anal. Chem 1994, 66, 34163422. Boué, S.M; Jones, J.A.; Yost, R.A. Proceedings of the 42nd ASMS Conference on Mass Spectrometry and Allied Topics, Chicago, IL, 1994, 218. Asano, K.G.; Glish, G.L.; McLuckey, S.A. Proceedings of the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, 1988, 636-637. McLuckey, S.A.; Glish, G.L.; Asano, K.G. Anal.Chem.Acta. 1989, 225, 25-35. Duckworth, D.C.; Barshick, C.M.; Smith, D.H.; McLuckey, S.A. Anal. Chem. 1994, 66, 92-98. McLuckey, S.A.; dish, G.L.; Van Berkel, G.J. Proceedings of the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, AZ, 1990, 512-513. Chien, B.M.; Michael, S.M.; Lubman, D.M. Anal. Chem. 1993, 65, 1916-1924. Koppenaal, D.W.; Barinaga, C.J.; Smith, M.R. J. Anal. Atomic Spectrom. 1994, 9, 1053-1058. Louris, J.N.; Brodbelt-Lustig, J.S.; Kaiser, R.E.; Cooks, R.G. Proceedings of the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, 1988, 968-969. Eiden, G.G.; Garrett, A.W.; Cisper, M.E.; Nogar, N.S.; Hemberger, P.H. Int. J. MassSpectrom.Ion Processes 1994, 136, 119-141. Booth, M.M.; Stephenson Jr., J.L.: Yost, R.A. Proceedings of the 42nd ASMS Conference on Mass Spectrometry and Allied Topics, Chicago, IL, 1994, 693. Yang, M.; Dale, J.M.; Whitten, W.B. Anal. Chem. 1995, 67, 1021-1025. Dale, J.M.; Yang, M.; Whitten, W.B. Anal. Chem. 1994, 66, 3431-3435. Pinkston, J.D.; Delaney, T.E.; Morand, K.L.Anal.Chem.1992, 64, 1571-1577. Yost, R.A.; Enke, C.G. Anal. Chem. 1979,51,1251A-1264A. Teloy, E.; Gerlich, D. Chem. Phys. 1974, 4, 417-427. Szabo, I. Int. J. Mass Spectrom. Ion Processes 1986, 73, 197-235. Guettler, R.D.; Jones, G.C.; Posey, LA.; Kirchner, N.J.; Keller, B.A. Zare, R.N. J. Chem. Phys. 1994, 101, 3763-3771. Ervin, K.M.; Armentrout, P.B. J. Chem. Phys.. 1985, 83, 166-189. Syka, J.E.P. Szabo, I. Proceedings of the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, 1988, 1328-1329. Hail, M.E. U.S. Patent Shao, J.D.; Ng, C.Y. Chem. Phys.Lett.1985, 118, 481-485. Gerlich, D.; Disch, R.; Scherbarth, S. J. Chem. Phys. 1987, 87, 350-359. Anderson, S.L.; Houle, F.A.; Gerlich, D.; Lee, Y.T. J. Chem. Phys. 1981, 75, 2153-2162. Posey, L.A.; Guettler, R.D.; Kirchner, N.J.; Zare, R.N. J. Chem. Phys.. 1994, 101, 3772-3786. Miller, P.E.; Denton, MB. Int. J. MassSpectrom.Ion Processes 1986, 72, 223-238 Everdij, J.J; Huijser, Α.; Verster, N.F. Rev. Sci. Instrum. 1973, 44, 721-725.

562 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80.


Hägg, Α.; Szabo, I. Int J. Mass Spectrom. Ion Processes 1986, 73, 237-275. Friedman, M.H.; Yergey, A.L.; Campana, J.E., Rev. Sci. Instrum. 1982, 15, 53-61. White, J.U. J. Opt.Soc.Am.1942, 32, 285-288. Watson, C.H.; Zimmerman, J.A.; Bruce, J.E.; Eyler, J.R. J.Phys.Chem. 1991, 95, 6081-6086. Peins, D.L.; Cheeseman, M.A.; Ramanathan, R.; Eyler, J.R. J.Phys.Chem.1993, 97, 7839-7843. Stephenson, Jr., J.L.; Booth, M.M.; Shalosky, J.A.; Eyler, J.R.; Yost, R.A. J. Am. Soc Mass Spectrom. 1994, 5, 886-893. Stephenson, Jr., J.L.; Booth, M.M.; Eyler, J.R.; Yost, R.A. submitted to Rapid Comm. Mass Spectrom. Yates, N.A. Methodsfor Gas Chromatography-Tandem Mass Spectrometry on the Quadrupole Ion Trap, Ph.D. Dissertation University of Florida, 1994. ICMS Software, developed by Nathan A. Yates, Department of Chemistry, University of Florida, 1993. Schwartz, J.C.; Bier, M.; Syka, J.E.P. personal communication. Cox, A.L.; Skipper, J.; Chen, Y.; Henderson, R.A.; Darrow, T.L.; Shabanowitz, J.; Englehard, V.H.; Hunt, D.F.; Slinluff; C.L. Science 1994, 264, 716-719. Hunt, D.F.; Michel, H.; Dickerson, T.A.; Shabanowitz, J.; Cox, A.L.; Sakaguchi, K.; Appella, E.; Grey, H.M.; Sette, A. Science 1992, 256, 1817-1820. Hunt, D.F.; Henderson, R.A.; Shabanowitz, J.; Sakaguchi, K.; Michel, H.; Sevilir, N.; Cox, A.L.; Appella, E.; Englehard, V.H. Science 1992, 255, 1261-1263. Henderson, R.A.; Michel, H.; Sakaguchi, K.; Shabanowitz, J.; Appella, E.; Hunt, D.F.; Englehard, V.H. Science 1992, 255, 1264-1266. Ishikawa, K.; Nishimura, T.; Koga, Y.; Niwa, Y. Rapid Comm. Mass Spectrom. 1994, 8, 933-938. Kilby, G.W.; Sheil, M.M. Org. Mass Spectrom. 1993, 28, 1417-1423. Senko, M.W.; McLafferty, F.W. Anrun. Rev. Biophys. Biomol. Struct. 1994, 23, 763-785. Cox, K.A.; Williams, J.D.; Kaiser, R.E.; Cooks, R.G. Biol MassSpectrom.1992, 21, 226-241. Huddleston, M.J.; Beam, M.F.; Carr, S.A. Anal. Chem. 1993, 65, 877-884. Johnson, R.S.; Martin, S.A.; Bieman, K.; Stults, J.T.; Watson, J.T.Anal.Chem.. 1987, 59, 2621-2625. Johnson, R.S.; Martin, S. A Bieman,Κ.Int.J. Mass Spectrom. Ion Processes 1988, 86, 137-154. Baldwin, M.A. Natural Products Reports, 1995, 33-44. Reopstorff; P.; Fohlman, J. Biomed and Environ. Mass Spectrom. 1984, 11, 601. Kaiser, R.E.; Cooks, R.G.; Syka, J.E.P.; Stafford, G.C. Rapid Commun. Mass Spectrom. 1990, 4, 30. Hunt, D.F.; Yates, J.R. ΙΠ; Shabonowitz, J.; Winston, S.; Hauer, C.R. Proc. Natl. Acad. Sci. U.S.A. 1986, 83, 6233-6237. Bieman, K.; Martin, S.A. Mass Spectrom. Rev. 1987, 6, 1-75. Tang, X. J.; Boyd, R.K. Rapid Commun. Mass Spectrom. 1992, 6, 651-657. Tang, X.J.; Thibault, P.; Boyd, R.K. Anal. Chem. 1993, 65, 2824-2834. Laine,R.Α.InMethods in Enzymology, Volume 193, Mass Spectrometry James A. McClosky ed., 1990, Academic Press: San Diego, CA, pp 539-553.

25. STEPHENSON ET AL. 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.


563

Hellerqvist, C.G.; Sweetman, B.J. "Mass Spectrometry of Carbohydrates" in Biomedical Applications of Mass Spectrometry, vol. 34, John Wiley & Sons: New York, 1990. Kent, P.W. Pestic. Sci 1994, 41, 209-238. Reinhold, V.; Reinhold, B.Anal.Chem. 1995, 67, 1722-1784. Kamerling, J.P.; Vleigenthart, J.F.G. in Clinical Biochemistry, Principles, Methods and Applications: Mass spectrometry A.M. Lawson, Ed., Walter de Gruyter: New York, 1989, 177-244. Horendo, M.H.; Despeyroux, D.; Jennings, K.R. Org. Mass Spectrom. 1994, 29, 483-490. McLaughlin, L.G.; Henion, J.D.; Kijak, P.J. Biol. Mass Spectrom. 1994, 23, 417429. Garozzo, D.; Guiffrida, M.; Impallomeni, G. Anal. Chem. 1990, 62, 279-286. Chen, Y.; Chen, N,; Li, H.; Zhao, F.; Chen, N .Biomed.Environ. Mass Spectrom. 1987, 14, 9-15. Schneider, R.P.; Lynch, M.J.; Ericson, J.F.; Fouda, H.G. Anal. Chem. 1991, 63, 1789-1794. Laine, R.A.; Pamidimukkala, K.M.; French, A.D.; Hall, R.W.; Abbas, S.A.; Jain, R.K.; Matta, K.L. J. Am. Chem. Soc. 1988, 110, 6931-6939. Gu, J.; Hiraga, T.; Wada,Y.Biol.Mass Spectrom. 1994, 23, 212-217. Domon, B.; Costello, C.E. Glycoconjugate J. 1988, 5, 397. Corcoran, J.W.; Hahn, F.E. eds; Antibiotics III: Mechanism of Action of Antimicrobal and Antitumor Agents, Springer-Verlag: New York, 1975, 396-479. Roberts, G.D.; Carr, S.A.; Christensen, S.B. in Proceedings of the 35th ASMS Conference on Mass Spectrometry and Allied Topics, Denver, CO, 1987, 933. David, L.; Scanzi, E.; Fraisse, D.; Tabet, J.C. Tetrahedron 1982, 38, 1619. Barbalas, M.P.; McLafferty, F.W. Occolowitz, J.L.Biomed.Mass Spectrom. 1982, 10, 258. Cooper, R.; Unger, S.E. J. Antibiot. 1985, 38, 24. Siegel, M . M ; McGahren, W.J.; Tomer, K.B.; Chang, T.T.Biomed.Environ. Mass Spectrom. 1987, 14, 29. Holzman, G.; Ostwald, U.; Nickel, P.; Haack, H.J.; Widjaja, H.; Arduny, U. Biomed. Mass Spectrom. 1985, 12, 659. Nelson, C.C.; McCloskey, J.A.; Isono, K. in Proceedings of the 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami, FL, 1989, 724. Curtis, J.M.; Bradley, B.; Derrick, P.J.; Sheil, M.M.; Org. Mass Spectrom. 1992, 27, 502. Vincenti, M.; Guglielmetti, G.; Andriollo, N.; Cassani, G.Biomed.Environ. Mass Spectrom. 1990, 19, 240. Edwards, D.M.F.; Selva, E.; Stella, S.; Zerilli, L.F.; Gallo, G.G. Biol. Mass Spectrom. 1992, 21, 51. Straub, R.; Linder, M.; Voyksner, R.D. Anal. Chem. 1994, 66, 3651-3658. Cenry, R.L.; MacMillan, D.K; Gross, M.L.; Mallams, A.K.; Pramanik, B.N. J. Am. Soc. Mass Spectrom. 1994, 5, 152-158. Karas, M.; Hillenkamp, F.Anal.Chem. 1988, 60, 2299. Fenn, J.B.; Mann, M.; Meng, C.K.; Wong, S.F.; Whitehouse, C.M. Science 1989, 264, 64.

564 108. 109. 110.


Smith,R.D.;Loo, J.A.; Edmonds, C.G.; Barinaga, C.J.; Udseth, H.R. Anal. Chem. 1990, 62, 882-899. McLuckey, S.A.; Van Berkel, G.J.; Glish, G.L. J. Am. Soc. Mass Spectrom. 1992, 3, 60-70. Edmonds, C.G.; Barinaga, C.J.; Loo, J.A.; Udseth, H.R.; Smith, R.D. in Proceedings of the 37th ASMS Conference on Mass Spectrometry and Allied Topics, Miami Beach, FL, 1989, 844.

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