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A rapid method for analyzing lignin in paper using IR reflectance spectra from its surface was developed. IR absorption and reflectance spectra of model paper samples prepared from cellulose fibers obtained from deciduous and coniferous woods with various lignin contents were analyzed. The intensity of the lignin absorption band at 1510 cm after Kubelka-Munk transformation of the paper reflectance spectra and chemical data on the fiber lignin content were well correlated. The analytical relationship between the lignin content in the paper fibers and the intensity of the lignin absorption band was used to estimate the lignin concentration in samples of Russian stamping paper from the 19th century using their IR reflectance spectra. The cellulose structure parameter estimated from the paper reflectance spectra showed that sheets containing lignin (5-16%) consisted entirely of wood fibers and were supplemented with kaolin. [ABSTRACT FROM AUTHOR]

We study the bulk pore structure of bioactive paper impregnated with an enzyme, alkaline phosphatase (ALP), retained with a cationic polyacrylamide (CPAM) with synchrotron small-angle x-ray scattering and examine the translational dynamics of water in the porous material using H pulsed field gradient NMR. The aim of this study is to understand the perturbation of enzyme kinetics from the bulk behavior through the localization of the enzyme within the pore structure. We interpret the small-angle x-ray scattering data where the range of length scales examined in the scattering experiment corresponds to the packing of the unitary crystallites, or microfibrils, and aggregates of these cellulosic microfibrils. Pulsed field gradient NMR measurement of HO diffusion in the pores between these aggregates indicates that some of these pores are strongly connected allowing convective mass transport, while others exhibit strongly restricted diffusion. Diffusion is also strongly anisotropic. We conclude that the CPAM retention polymer and the protein coat interior surfaces inside the pores of a particular size and that there is no major modification of the pore structure of paper by the CPAM or the ALP. The transport properties of this porous matrix are discussed in terms of the mechanisms by which sorption of ALP may perturb enzyme kinetics. [ABSTRACT FROM AUTHOR]

A rapid and non-destructive method for analyzing the structure of cellulose fibers using IR reflectance spectroscopy from a paper surface was developed and verified for correctness. IR absorption and reflectance spectra of standard paper samples of known composition (sheets made of four fibers of different origin without additives and with additives of kaolin and chalk) were analyzed. Good correlations between these two spectral methods were found for the studied samples. Calibration curves were useful for assessing the structure of cellulose samples from XVIth century historical paper. Data on the degree of cellulose ordering that were obtained from the paper reflectance spectra indicated that the studied sheets consisted mainly of flax fibers with added cotton. This agreed fully with the historical fact that the studied samples were rag papers. [ABSTRACT FROM AUTHOR]