NIST-Sponsored Interlaboratory Comparison of Polystyrene Molecular Mass Distribution Obtained by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry: Statistical Analysis

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• 作者：Charles M. Guttman ; Stephanie J. Wetzel ; William R. Blair ; Bruno M. Fanconi ; James E. Girard ; Robert J. Goldschmidt ; William E. Wallace ; and David L. VanderHart
• 刊名：Analytical Chemistry
• 出版年：2001
• 出版时间：March 15, 2001
• 年：2001
• 卷：73
• 期：6
• 页码：1252 - 1262
• 全文大小：175K
• 年卷期：v.73,no.6(March 15, 2001)
• ISSN：1520-6882

文摘

The method of preparation and methods of analysis of anarrow distribution polystyrene of ~7 ku used in aninterlaboratory comparison of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) of synthetic polymers is described. Sizeexclusion chromatography was used to measure thepolystyrene sample variability. Fourier transform infraredspectroscopy and MALDI-TOF-MS were used to analyzeend groups on the polymer. The polystyrene was analyzedby MALDI-TOF-MS and classical methods of polymercharacterization. The number (M_n) and mass (M_w) averageof the molecular mass distribution (MMD) determined bythe classical methods (light scattering and NMR) werecompared with those obtained by MALDI-TOF-MS. Agreement between classical methods to obtain the momentsof the MMD and the MALDI is found to be good overall.However, all the experimental values obtained by MALDIfell below the classical values. A discussion of why thesevalues are lower is included. We discuss the statisticalanalysis of the data from the interlaboratory comparisonconducted by NIST, which includes data from 23 differentlaboratories. Analysis of variance is used to examine theinfluences of the independent parameters (laboratory,matrix, instrument manufacturer, instrument mode) onthe data. The parameters, laboratory and instrumentmanufacturer, were determined to have an influence onthe MMD, where matrix and instrument mode were foundnot to have a significant influence.