Other

Yale University

Analytica of Branford, Inc.

Fernandez De La Mora, Juan

Labowsky, Michael J.

De La Mora, Juan Fernandez

Michael J Labowsky

Juan Fernandez De La Mora

John Bennett Fenn

Jerome J Schmitt, Iii

Masamichi Yamashita

G Wayne Neilson

The invention describes a system and method to separate ions (and charged particles) suspended in gas based on their ion electrical mobility. Most common ion mobility analyzers involve two parallel plate (or concentric cylinder) elements (electrodes) between which is imposed an electrical field perpendicular to a sheath gas flow field between the cylinders. Separation occurs because high mobility ions tend to follow the electrical field while low mobility ions tend to follow the flow field. This invention describes various configurations of electrical elements and sheath gas flow fields for ion mobility separation devices with unique performance characteristics. These characteristics include devices in which: the ion inlet and outlet are on the same element; the inlet and outlet are at the same voltage; the outlet is upstream from the inlet; the outlet is on the axis; the inlet is on the axis; and the ions are focused on the outlet.

Ion mobility separation devices

A differential mobility analyzer (DMA) for separating charged particles or ions suspended in a gas and a method of using the DMA for separating such particles. The invention includes various means for increasing the resolution of the DMA by stabilizing the laminar flow within the DMA and by allowing unusually large flow velocities.

Method and apparatus to increase the resolution and widen the range of differential mobility analyzers (DMAs)

A method for analyzing chemical species and determining the molecular weight of a parent molecule. Multiply charged ions are produced from the parent molecule by adding adduct ions thereto. A mass analysis is conducted of the multiply charged ions to generate mass/charge data. The molecular weight is calculated by using a deconvolution procedure in which the adduct ion mass and the molecular weight of the parent molecule are both treated as unknowns. Alternatively, a modified deconvolution procedure in which the adduct ion mass is treated as a known value is used.

Method for eliminating noise and artifact the deconvolution of multiply

The invention comprises a method of analyzing the results obtained from the mass analysis of an ensemble or population of multiply charged ions comprising large polyatomic molecules of which is attached a plurality of charges. These molecules can be charged either by the attachment of charged mass or by the loss of charged mass. The charged mass is referred to as the 'adduct' ion mass. The measured mass spectrum for such a population of ions generally comprises a sequence of peaks for each distinct polyatomic molecular species, the ions of each peak differing from those of adjacent peaks in the sequence by only a single charge. The method of analysis taught by the invention produces a deconvoluted spectrum in which there is only one peak for each distinct molecular species, the magnitude of that single peak containing contributions from each of the multiplicity of peaks for that species in the measured spectrum. A unique feature of the method taught by the invention is the use of special signal filters and enhancer and averaging techniques which eliminate noise and artifact peaks and make the final spectrum easier to understand and to interpret.

Method for eliminating noise and artifact peaks in the deconvolution of

The invention comprises a method of analyzing the results obtained from the mass analysis of an ensemble or population of multiply charged ions comprising large polyatomic molecules to each of which is attached a plurality of charges. These molecules can be charged either by the attachment of charged mass or by the loss of charged mass. The charged mass is referred to as the 'adduct' ion mass. The measured mass spectrum for such a population of ions generally comprises a sequence of peaks for each distinct polyatomic molecular species, the ions of each peak differing from those of adjacent peaks in the sequence by only a single charge. The method of analysis taught by the invention produces a deconvoluted spectrum in which there is only one peak for each distinct molecular species, the magnitude of that single peak containing contributions from each of the multiplicity of peaks for that species in the measured spectrum. A unique feature of the method taught by the invention is that the deconvoluted spectrum becomes a three dimensional surface in which the three coordinates of the single peak for a particular species represent respectively the molecular weight Mr of the parent polyatomic molecular species, the effective mass ma of the adduct ion charges, and the relative abundance of the ions of the polyatomic molecular species in the population of ions that gave rise to the measured spectrum. Consequently, there is no need to assume a priori a particular value for the mass of the adduct ion.

Method for determining the molecular weights of polyatomic molecules by

An electrospray ion source for a mass spectrometer capable of generating ions from samples dissolved in a solution comprises a capillary tube through which the said solution is pumped into a first chamber maintained substantially at atmospheric pressure and in which an inert gas is flowing in a direction counter to the flow of the solution, and a small orifice in the end wall of the chamber opposite to and aligned with the capillary. A high potential difference is applied between the capillary and the end wall so that the solution is electrosprayed into the chamber and ions characteristic of the sample are formed. These ions are desolvated to a controllable extent by the inert gas, which may also be heated to improve the efficiency of the process and increase the maximum permissible flow rate of solution. The ions so formed pass through the small orifice into a second chamber maintained at a reduced pressure, and into a mass spectrometer. Alternatively an additional pressure reduction stage can be included, so that the ions pass into a third chamber maintained at a still lower pressure in which the mass spectrometer is situated through a conventional nozzle and skimmer arrangement. The ion source is particularly effective for the production of unfragmented and unsolvated ions from thermally unstable or involatile samples, and may be used as a liquid chromatograph--mass spectrometer interface.

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Wayne, NJ, United States of America

Michael J Labowsky