INTERNATIONAL INTERLABORATORY TESTING ADVANCES MASS DISTRIBUTION MEASUREMENT METHOD FOR SYNTHETIC POLYMERS.
Participants of the interlaboratory comparison reported the mass spectrum of the polystyrene and moments of the distribution calculated from mass spectrometric data. NIST staff calculated the moments from the submitted data as well. In some cases, the moments calculated by NIST using the participants data differed significantly from moments reported by the participants. The distribution in values of moments calculated by NIST was very narrow, with a standard deviation of one polystyrene repeat unit, approximately. Furthermore, analysis of these data yielded moments of the mass distribution lower than those obtained from current methods but within the measurement uncertainty. Nonetheless, it was found that calibration of mass spectrometers was not performed correctly by several participants and that methods of data analysis differed widely with some participants reporting moments of the distribution that differed significantly from the mean. The findings of the report will be used to improve the quantifica tion of the new mass spectrometric method for the determination of synthetic polymer mass distributions.
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|Publication:||Journal of Research of the National Institute of Standards and Technology|
|Article Type:||Brief Article|
|Date:||Nov 1, 2000|
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