Size, weight and position are three of the most important parameters that describe a molecule in a biological system. Ion mobility spectrometry is capable of separating molecules on the basis of their size or shape, whereas imaging mass spectrometry is an effective tool to measure the molecular weight and spatial distribution of molecules. Recent developments in both fields enabled the combinat...

Heating rates of 20-30 "C gave satisfactory results for several additives, but no effort was made to establish an optimum heating rate. Extraction of polypropylene pellets with acetonitrile a t room temperature overnight gave clear evidence for the additives, but the extraction was approximately 2% efficient. Extraction with boiling decalin (4, 5) gave 0.053 wt 70 UV-531 in this sample. The sam...

A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circuit, and a low noise ion detector. The ion filter electronics are capable to generate square waveforms with peak-to-peak voltages up to 1000 ...

This Report describes biomolecular structural studies using the injected-ion mobility/MS approach. Several examples will illustrate how these methods can be used to resolve and characterize conformations, examine the dynamics of protein unfolding and folding in the gas phase, and complement MS methods for characterizing oligosaccharide isomers. [The development and application of these methods ...

The combination of mass spectrometry and ion mobility spectrometry (IMS) employing a temperature-variable drift cell or a drift tube divided into sections to make IMS-IMS experiments possible allows information to be obtained about the molecular dynamics of polyatomic ions in the absence of a solvent. The experiments allow the investigation of structural changes of both activated and native ion...

A model is presented of the A transition in superfluid helium in which fluctuations near the transition are approximated by distinct regions of normal fluid and superfluid. The macroscopic viscosity of such a medium is computed. The ion mobility is also computed, taking into account a region of normal fluid around the ion induced by electrostriction. The results are, for the viscosity, TJ, TJ t...

An ion mobility spectrometer that has its mobility cell as a 20-segment quadrupole and functionally the q2 of a triple-quadrupole mass spectrometer has been assembled and tested. The combination of high cell pressure (maximum of 4 Torr of helium) and low axial field (20-160 V per 20.2 cm) results in negligible internal excitation of the ions despite applications of rf and axial fields. The pres...

1. Many measurements were made with the two systems H(2)/NaOH C/NaOH C + x gm. gelatin/H(2) H(2)/NaOH C/KCl (sat.)/NaOH C + x gm. gelatin/H(2) in which x was varied from zero to more than enough for complete combination. 2. From these measurements the change in boundary potential with quantity of gelatin present was determined. 3. The boundary potentials were calculated by means of a modified f...

Johnson , J. L. Beauchamp, and I. Kanik, 1 Noyes Laboratory of Chemical Physics, California Institute of Technology, 1200 E. California Blvd, MC 127-72, Pasadena , CA 91125 ([email protected]; [email protected]), Material and Process Simulation Center, Beckman Institute, California Institute of Technology, 1200 E. California Bvd, MC 13974, Pasadena, CA 91125 ([email protected]), an...