Electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is ca... more Electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is capable of producing high mass resolving power and improved mass accuracy for large proteins and noncovalent complexes when coupled with collisionally induced dissociation (CID) of noncovalent adducts and consequent minimization of ion charge density in the ICR trap during measurements. This work demonstrates the application of in-trap cleanup to several biologically relevant systems, including carbonic anhydrase, 4-oxalocrotonate tautomerase (4OT) analogue, and SecB, a chaperone from Escherichia coli. In-trap cleanup yields improved mass measurements for these systems and is expected to further enable measurements for even more complex systems where adduction levels have precluded study of intact complexes.
This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incide... more This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incident proton energies near 1 Gev. At this energy, the dominant reaction mechanisms are (1) quasi-free knockout of one or more nucleons, and (2) pion production through the (DELTA) resonance. The cross section due to quasi-free knockout can be reasonably well understood theoretically in a multiple scattering picture, which uses measured NN amplitudes as input. Calculations of this sort were carried out in reference 10 using scalar NN amplitudes parametrized as Gaussians. I have extended this picture to include spin dependent NN amplitudes. This allows calculation of all the spin observables, Ay, DLL, DSS, DNN, DLS, and DSL, as well as the cross section d(sigma)/d(OMEGA)dp due to quasi-free knockout of one or more particles. The cross section and polarization Ay have been measured at the LAMPF High Resolution Spectometer at T(,L) = 800 Mev on ('12)C. The theoretical results agree well with the data in the quasi-free region. The results for the remaining spin observables provide predictions for experiments which can be performed at LAMPF. By comparing the calculations with the data, it may be possible to separate the contribution due to a quasi-free knockout, and see a signature of quasi -free (DELTA) production in the spin observables.
... dependency. Malcolm Smith's scheme was similar but lasted longer. ... Prevention... more ... dependency. Malcolm Smith's scheme was similar but lasted longer. ... Prevention in the North-east In a much less sinister session Anthony Thornley, a psy-chiatrist from Newcastle, looked back at the lessons to be learnt from ...
... Richard D. Smith,* Charles J. Barinaga, and Harold R. Udseth Chemical Methods and Separations... more ... Richard D. Smith,* Charles J. Barinaga, and Harold R. Udseth Chemical Methods and Separations Group, Chemical Sciences Department, Pacific Northwest ... RL; Giblin, ED In Mass Spectrometry in the Analysis of Large Molecules; McNeal, C. J.; Ed.; Wiley: Chichester, 1986, pp ...
Inefficient ionization and poor transmission of the charged species produced by an electrospray f... more Inefficient ionization and poor transmission of the charged species produced by an electrospray from the ambient pressure mass spectrometer source into the high vacuum region required for mass analysis significantly limits achievable sensitivity. Here, we present evidence that, when operated at flow rates of 50 nL/min, a new electrospray-based ion source operated at ∼20 Torr can deliver ∼50% of the analyte ions initially in the solution as charged desolvated species into the rough vacuum region of mass spectrometers. The ion source can be tuned to optimize the analyte signal for readily ionized species while reducing the background contribution.
New methods are described for the measurement of the solubilities of solids in supercritical flui... more New methods are described for the measurement of the solubilities of solids in supercritical fluids. These methods utilize instrumentation developed for capillary supercritical fluid chromatography consisting of deactivated, small diameter, fused silica tubing, coupled with detection methods based upon on flame ionization and mass spectrometric detectors. The methods involve (a) direct solubility determination where the fused silica capillary is used
Electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is ca... more Electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is capable of producing high mass resolving power and improved mass accuracy for large proteins and noncovalent complexes when coupled with collisionally induced dissociation (CID) of noncovalent adducts and consequent minimization of ion charge density in the ICR trap during measurements. This work demonstrates the application of in-trap cleanup to several biologically relevant systems, including carbonic anhydrase, 4-oxalocrotonate tautomerase (4OT) analogue, and SecB, a chaperone from Escherichia coli. In-trap cleanup yields improved mass measurements for these systems and is expected to further enable measurements for even more complex systems where adduction levels have precluded study of intact complexes.
This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incide... more This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incident proton energies near 1 Gev. At this energy, the dominant reaction mechanisms are (1) quasi-free knockout of one or more nucleons, and (2) pion production through the (DELTA) resonance. The cross section due to quasi-free knockout can be reasonably well understood theoretically in a multiple scattering picture, which uses measured NN amplitudes as input. Calculations of this sort were carried out in reference 10 using scalar NN amplitudes parametrized as Gaussians. I have extended this picture to include spin dependent NN amplitudes. This allows calculation of all the spin observables, Ay, DLL, DSS, DNN, DLS, and DSL, as well as the cross section d(sigma)/d(OMEGA)dp due to quasi-free knockout of one or more particles. The cross section and polarization Ay have been measured at the LAMPF High Resolution Spectometer at T(,L) = 800 Mev on ('12)C. The theoretical results agree well with the data in the quasi-free region. The results for the remaining spin observables provide predictions for experiments which can be performed at LAMPF. By comparing the calculations with the data, it may be possible to separate the contribution due to a quasi-free knockout, and see a signature of quasi -free (DELTA) production in the spin observables.
... dependency. Malcolm Smith's scheme was similar but lasted longer. ... Prevention... more ... dependency. Malcolm Smith's scheme was similar but lasted longer. ... Prevention in the North-east In a much less sinister session Anthony Thornley, a psy-chiatrist from Newcastle, looked back at the lessons to be learnt from ...
... Richard D. Smith,* Charles J. Barinaga, and Harold R. Udseth Chemical Methods and Separations... more ... Richard D. Smith,* Charles J. Barinaga, and Harold R. Udseth Chemical Methods and Separations Group, Chemical Sciences Department, Pacific Northwest ... RL; Giblin, ED In Mass Spectrometry in the Analysis of Large Molecules; McNeal, C. J.; Ed.; Wiley: Chichester, 1986, pp ...
Inefficient ionization and poor transmission of the charged species produced by an electrospray f... more Inefficient ionization and poor transmission of the charged species produced by an electrospray from the ambient pressure mass spectrometer source into the high vacuum region required for mass analysis significantly limits achievable sensitivity. Here, we present evidence that, when operated at flow rates of 50 nL/min, a new electrospray-based ion source operated at ∼20 Torr can deliver ∼50% of the analyte ions initially in the solution as charged desolvated species into the rough vacuum region of mass spectrometers. The ion source can be tuned to optimize the analyte signal for readily ionized species while reducing the background contribution.
New methods are described for the measurement of the solubilities of solids in supercritical flui... more New methods are described for the measurement of the solubilities of solids in supercritical fluids. These methods utilize instrumentation developed for capillary supercritical fluid chromatography consisting of deactivated, small diameter, fused silica tubing, coupled with detection methods based upon on flame ionization and mass spectrometric detectors. The methods involve (a) direct solubility determination where the fused silica capillary is used
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