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Displaying 26 - 50 of 86

An Operator-Independent Approach to Mass Spectral Peak Identification and Integration

May 1, 2004
Author(s)
William E. Wallace, Anthony J. Kearsley, Charles M. Guttman
A mathematical algorithm is presented that accurately locates and calculates the area beneath mass spectral peaks using only reproducible mathematical operations and a NO user-selected sensitivity parameters. This represents a major refinement of last year

Investigations of Electrospray Sample Deposition for Polymer MALDI Mass Spectrometry

February 1, 2004
Author(s)
S D. Hanton, I Z. Hyder, J R. Stets, K G. Owens, William R. Blair, Charles M. Guttman, Anthony A. Giuseppetti
In the interest of more thoroughly understanding the relationship between sample preparation technique and spectra quality produced in Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry, we have investigated details of the Electrospray

International Interlaboratory Comparison of Mixtures of Polystyrenes With Different End Groups Obtained by Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS): Preliminary Results

January 1, 2004
Author(s)
Charles M. Guttman, S Wetzel, Kathleen M. Flynn, B M. Fanconi, William E. Wallace, David L. VanderHart
NIST has sponsored a MALDI-TOF-MS interlaboratory comparison of mixtures of polymers of the same repeat unit with closely matching molecular masses but with different end groups. This interlaboratory comparison was designed to see how well a group of labs

Recent Advances in Quantitative Synthetic-Polymer Mass Spectrometry at NIST

January 1, 2004
Author(s)
William E. Wallace, Charles M. Guttman
Commensurate with NIST s mission to advance the state of quantitative measurement science we have worked to develop a method to determine absolute molecular mass distribution of synthetic polymers by mass spectrometry. Work has centered on using matrix

Certification of Standard Reference Material 1474a, A Polyethylene Resin

November 14, 2003
Author(s)
J R. Maurey, Kathleen M. Flynn, Charles M. Guttman
The melt flow rate of Standard Reference Material (SRM) 1474a, a linear polyethylene (narrow MWD ethylene-hexene copolymer) resin, was determined to be 5.10 g/10 min at 190 OC under a load of 2.16 kg using the ASTM Method D 1238-00. The average results

Certification of a Polystyrene Synthetic Polymer, SRM 2888

November 1, 2003
Author(s)
Charles M. Guttman, William R. Blair, B M. Fanconi, R J. Goldschmidt, William E. Wallace, S Wetzel, David L. VanderHart
The certification of a polystyrene standard reference material, SRM 2888, is described. The M w of SRM 2888 was determined by light scattering to be 7.19 x 10 +3 g/mol with a sample standard deviation of 0.14 x 10 +3 g/mol. A combined expanded uncertainty

Quantitative Synthetic Polymer Mass Spectrometry Workshop

February 1, 2003
Author(s)
William E. Wallace, Charles M. Guttman, S D. Hanton
Mass spectrometry is a rapidly evolving measurement technique for synthetic polymers. It holds the promise of providing not only absolute molecular mass distributions but also quantitative end-group and repeat-unit composition, and structural information

Optimizing the Covalent Cationization Method for the Mass Spectrometry of Polyolefins

August 1, 2002
Author(s)
Sheng Lin-Gibson, L Brunner, David L. VanderHart, Barry J. Bauer, B M. Fanconi, Charles M. Guttman, William E. Wallace
Previously a new method was introduced for the mass spectrometry of polyolefins whereby an organic cation is covalently bonded to the polymer to produce the necessary ionization for the creation of intact gas?phase macromolecules by matrix-assisted laser

Advanced Numerical Methods for Polymer Mass Spectral Data Analysis

July 1, 2002
Author(s)
William E. Wallace, Charles M. Guttman, Anthony J. Kearsley, Javier Bernal
A mathematical algorithm is presented that accurately locates and calculates the area beneath peaks using only reproducible mathematical operations and a single user-selected sensitivity parameter.