California Institute of Technology

Jesse L Beauchamp

Evan L Neidholdt

John D Baldeschwieler

Chang Ho Sohn

Dmitri A Kossakovski

Stephen D O'Connor

Brian M Stoltz

Richard C Flagan

Konstantinos P Giapis

Nicholas A Brunelli

Patricia M George

Jeremy A May

Ronald L Grimm, Ii

Ryan R Julian

Marcel Widmer

Thomas Schindler

Sang-Won Lee

A continuous flow mobility classifier provide the ability to perform two-dimensional separation in mass spectrometry. An ionization system is used to ionize a sample. A differential mobility analyzer (DMA) (e.g., a nano-radial DMA) is coupled to the ionization system and to a mass spectrometer. The nano-RDMA is configured to separate the ionized sample by mobility for subsequent mass analysis by the mass spectrometer.

Continuous flow mobility classifier interface with mass spectrometer

A clickable cross-linker compound provides an easily scanned reporter ion for effective and efficient cross-linking and identification of intermolecular and intramolecular interactions of proteins and peptides.

Clickable cross-linker

Isobaric reagents for labeling analytes are provided. The isobaric reagents have facile design and synthesis that allows for differential labeling of an unlimited number of analyte samples.

Isobaric tags for analyte detection and quantification

A novel ion source for ambient mass spectrometry (switched ferroelectric plasma ionizer or 'SwiFerr'), which utilizes the ambient pressure plasma resulting from a sample of barium titanate [001] whose polarization is switched by an audio frequency electric field. High yields of both anions and cations are produced by the source and detected using an ion trap mass spectrometer. Protonated amines and deprotonated volatile acid species, respectively, are detected in the observed mass spectra. Aerodynamic sampling is employed to analyze powders of drug tablets of loperamide and ibuprofen. A peak corresponding to the active pharmaceutical ingredient for each drug is observed in the mass spectra. Pyridine is detected at concentrations in the low part-per-million range in air. The low power consumption of the source is consistent with incorporation into field portable instrumentation for detection of hazardous materials and trace substances in a variety of different applications.

Switched ferroelectric plasma ionizer

A compact, low power ambient pressure pyroelectric ionization source. The source can be constructed using a z-cut lithium niobate or lithium tantalate crystal with an attached resistive heater mounted in front of the atmospheric pressure inlet of an ion trap mass spectrometer. Positive and negative ion formation alternately results from thermally cycling the crystal over a narrow temperature range. Ionization of molecules such as 1,1,1,3,3,3-hexafluoroisopropanol or benzoic acid results in the observation of the singly deprotonated species and their clusters in the negative ion mass spectrum. Ionization of molecules such as triethylamine or triphenylamine with the source results in observation of the corresponding singly protonated species of each in the positive ion mass spectrum. The pyroelectric crystals are thermally cycled by as little as 30 K from ambient temperature. Ion formation is largely unaffected by contamination of the crystal faces. This ion source is robust.

Ambient pressure pyroelectric ion source for mass spectrometry

Biomimetic reagents capable of selectively forming non-covalent complexes and initiating intermolecular reactions with peptides in the gas phase are described. The reagents are particularly useful in gas phase peptides chemistry.

Chemical reagents capable of selective attachment to and reaction with peptides and proteins

A method and apparatus for probing the chemistry of a single droplet are provided. The technique uses a variation of the field-induced droplet ionization (FIDI) method, in which isolated droplets undergo heterogeneous reactions between solution phase analytes and gas-phase species. Following a specified reaction time, the application of a high electric field induces FIDI in the droplet, generating fine jets of highly charged progeny droplets that can then be characterized. Sampling over a range of delay times following exposure of the droplet to gas phase reactants, the spectra yield the temporal variation of reactant and product concentrations. Following the initial mass spectrometry studies, we developed an experiment to explore the parameter space associated with FIDI in an attempt to better understand and control the technique. In an alternative embodiment of the invention switched electric fields are integrated with the technique to allow for time-resolved studies of the droplet distortion, jetting, and charged progeny droplet formation associated with FIDI.

Chemical probe using field-induced droplet ionization mass spectrometry

A scanning probe microscope is combined with a laser induced breakdown spectrometer to provide spatially resolved chemical analysis of the surface correlated with the surface topography. Topographical analysis is achieved by scanning a sharp probe across the sample at constant distance from the surface. Chemical analysis is achieved by the means of laser induced breakdown spectroscopy by delivering pulsed laser radiation to the sample surface through the same sharp probe, and consequent collection and analysis of emission spectra from plasma generated on the sample by the laser radiation. The method comprises performing microtopographical analysis of the sample with a scanning probe, selecting a scanned topological site on the sample, generating a plasma plume at the selected scanned topological site, and measuring a spectrum of optical emission from the plasma at the selected scanned topological site. The apparatus comprises a scanning probe, a pulsed laser optically coupled to the probe, an optical spectrometer, and a controller coupled to the scanner, laser and spectrometer for controlling the operation of the scanner, laser and spectrometer. The probe and scanner are used for topographical profiling the sample. The probe is also used for laser radiation delivery to the sample for generating a plasma plume from the sample. Optical emission from the plasma plume is collected and delivered to the optical spectrometer so that analysis of emission spectrum by the optical spectrometer allows for identification of chemical composition of the sample at user selected sites.

Method and apparatus for chemical and topographical microanalysis

The present invention discloses an improved method and apparatus for analyzing the surface of materials using sub-micron laser desorption gas phase analysis. The method uses a combination of Near-field Optical Microscopy and Time-of Flight Mass Spectroscopy.

Sub-micron chemical imaging with near-field laser desorption

A capillary for use with an electrospray ion source includes a concentric outer capillary sleeve and inner capillary tube. An outer surface of the tube engages an inner surface of the sleeve. Conductors are formed at respective upstream and downstream ends of the capillary.

Capillary for electrospray ion source

A thin film of material such as metal is deposited on the surface of a substrate by placing a substrate (22) into a chamber (10) containing holder (12) cooled by heat exchanger 18. A beam (56) of U.V. light from the illumination source (42) is projected through monochromator (43), mask (46) and lens (16) onto a selected area (58) of the substrate at an energy level exceeding the photoemission threshold of the surface. A slow electron (60) is ejected from the surface into the capture zone (62). A compound AB such as iron pentacarbonyl from supply (30) is leaked into the chamber (10), enters the capture zone (60) to form a highly reactive deposition fragment A.sup.- which attaches to the surface and a dissociation fragment which is evacuated through outlet (14). The deposited fragment may further dissociate to form metal deposit.

Growing community of inventors

La Canada Flintridge, CA, United States of America

Jesse L Beauchamp