Perseptive Biosystems Inc.

Mds Inc.

Applied Biosystems, LLC

Dh Technologies Development Pte. Ltd.

Igor P Smirnov

Lawrence A Haff

Marvin L Vestal

Jennifer M Campbell

Andrew J Tomlinson

Anatoli Verentchikov

Cheryl E Murphy

Anatoli N Verentchikov

A sample plate for a MALDI process is provided which comprises an electrically conductive substrate having a hydrophobic coating whose thickness and hydrophobic character can be modified by changing the coating substrate and/or the concentration of the substrate. Different coating substances that have provided optimal performance of the sample plate for reproducible deposition and analysis by MALDI-MS and MALDI-MS/MS processes of analyte mixtures include synthetic waxes such as paraffin compositions, lipids, organic acids, silicon-containing compounds, silica polymers and natural waxes. Metal polishes that have been used to clean and regenerate plate surfaces have also provided a sample plate that has optimal performance for reproducible deposition and analysis by MALDI-MS and MALDI-MS/MS processes of analyte mixtures.

MALDI plate and process for making a MALDI plate

A mass spectrometer instrument for determining the molecular weight of labile molecules of biological importance, in particular heavy molecules, such as proteins, peptides or DNA oligomers, is disclosed. The instrument includes a MALDI ion source that is enclosed in a chamber with an inlet for admitting a gas and an ion sampling aperture for limiting gas flow from the chamber. The elevated pressure of the source in the range from 0.1 to 10 torr causes low energy collisions between the gas and the ions that can cause rapid collisional cooling of the excited ions, thereby improving the stability of the produced ions. The formation of clusters of ions (e.g., protein ions) with matrix materials is broken without fragmenting the ions by increasing the downstream gas temperature to between 150 and 250&deg; C. Operating the source at laser energy at least two times higher than the threshold value of ion formation and using a high repetition rate laser significantly improves sensitivity of analysis and speed of data acquisition.

Method and apparatus for determining molecular weight of labile molecules

The invention relates to methods for determining sequence information in polynucleotides by combining the recent disparate technologies of mass spectrometry and polynucleotide hybridization, amplification, extension and/or ligation techniques. Broadly, in a first step, the method for determining sequence information in a sample polynucleotide includes hybridizing with a sample nucleotide one or a mixture of oligonucleotide probes having a nucleotide sequence complementary to a portion of the sample polynucleotide, thereby forming a complex. Then, in a second step, the complex is contacted with at least a member selected from the group consisting of nucleosides, dideoxynucleosides, polymerases, nucleases, transcriptases, ligases and restriction enzymes to alter at least a subset of said oligonucleotide probes. In a third step, the method provides for determining the molecular weight of at least the subset of altered probes by mass spectrometry and infering the sequence information of the sample polynucleotide therefrom.

Methods for determining sequences information in polynucleotides using

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Brookline, MA, United States of America

Igor P Smirnov