Jeol Ltd.

Neogenesis Drug Discovery, Inc.

Neogenesis, Inc.

Neogenesis Pharmaceuticals, Inc.

Andrew N Tyler

Seth N Birnbaum

D Allen Annis

Mark Birnbaum

Robert B Cody

A method and apparatus are provided for identifying unknown chemical structures that are related to one or more known structures. Measured masses of the unknown structures (US members) are compared with the expected masses of the known structures (DS members). The mass differences between US members and DS members are compared with changes in mass (&Dgr;M) between molecules analyzed as a function dependent upon structure (&Dgr;S). The mass difference is considered as a differential function, &Dgr;M/&Dgr;S, the result of which is calculated for each ion in the US when compared with each ion in the DS. These values are then correlated with values that would be expected based on assumed possible structural modifications. In addition, higher order differential functions, such as &Dgr; M/&Dgr;S , can be used as needed to allow for correlation of structures in which more than one structural motif has changed.

Method and apparatus for identifying unknown compounds in complex chemical mixtures using mass spectrometry and mass differential analysis

A technique for automatically analyzing mass spectrographic data from mixtures of chemical compounds has a series of screens designed to eliminate or reduce incorrect peak identifications due to background noise, system resolution, system contamination, multiply charged ions and isotope substitutions. With such a technique, mass spectrograph data analysis may be greatly simplified by the identification of probable spurious signals, and analysis will become simpler and more accurate.

Method for identifying compounds in a chemical mixture

A technique for automatically analyzing mass spectrographic data from mixtures of chemical compounds is described consisting a series of screens designed to eliminate or reduce incorrect peak identifications due to background noise, system resolution, system contamination, multiply charged ions and isotope substitutions. The technique performs a mass spectrum operation on a control sample, producing a first group of output values. Next, perform a mass spectrographic operation on a sample to be analyzed, producing a second group of output values. Select a first m/z ratio for a material expected to be present in the mixture from a predetermined library of calculated mass spectrometer output spectrums and subtract the value of the control sample at the expected output value from the value of the analyzed sample, and compare the difference to a predetermined value. If the value is greater than the predetermined value thus indicating that the signal is above the background noise level, generating a record at that m/z value for an expected material. Performing the same mass spectrum operation several times to eliminate random noise and background contamination. Next, identify peak values that don't have the expected peak width or proper retention time for the separation method. Identify multiply charged ions by examining peak separation. Examine the m/z location of the expected material and compare intensity at the expected m/z location with the intensity at the next lower m/z recorded peak to identify peaks related to atomic isotope substitution. With such a technique, mass spectrograph data analysis may be greatly simplified by the identification of probable spurious signals, and analysis will become simpler and more accurate.

A method of mass spectrometry comprises the steps of ionizing the mixture of the sample and the matrix by repeated irradiation with primary particle beam pulses; introducing the produced ions into a mass analyzer and separating the ions with the mass analyzer according to their mass/charge ratios; detecting signals indicative of the number of the separated ions with an array detector; and integrating the detected signals during data collection periods in synchrony with the irradiation pulses of the primary particle beam. The data collection periods have a predetermined duration and predetermined start times relative to the primary particle beam pulses.

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Reading, MA, United States of America

Andrew N Tyler