title: Quantitative measurement of the polydispersity in the extent of functionalization of glass-forming calix[4]resorcinarenes.
abstract: The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring quantitatively their molecular mass distribution with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A mathematical method for polydisperse materials is described that creates a calibration curve to correct the ion signal intensities in the mass spectrum to give a more reliable molecular mass distribution. Correction is required due to various sample preparation and instrumental effects that may produce a systematic mass bias in the number of oligomers measured. This method employs gravimetric mixtures of analytes with different degrees of functionalization. One calix[4]resorcinarene was found to give accurate molecular mass distributions with little correction, while another, having a very similar molecular structure, was found to exhibit strong over-counting of the oligomers having a high degree of functionalization.
authors.affiliation: Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8541, USA. William.Wallace@nist.gov
authors.forename: W E
authors.initials: WE
authors.lastname: Wallace
authors.forename: K M
authors.initials: KM
authors.lastname: Flynn
authors.forename: C M
authors.initials: CM
authors.lastname: Guttman
authors.forename: D L
authors.initials: DL
authors.lastname: VanderHart
authors.forename: V M
authors.initials: VM
authors.lastname: Prabhu
authors.forename: A
authors.initials: A
authors.lastname: De Silva
authors.forename: N M
authors.initials: NM
authors.lastname: Felix
authors.forename: C K
authors.initials: CK
authors.lastname: Ober