Separation and concentration of azo compounds with crosslinked poly(vinylpyrrolidone)

High performance liquid chromatographic separation of polycyclic aromatic hydrocarbons on microparticulate pyrrolidone and application to the analysis of shale oil

“…This evidence supports interaction between lone pair electrons of the pyrrolidone amide linkage and the aromatic ring system of the PAHs in a charge transfer-like mode. Similar electronic interactions between pyrrolidone polymers and elemental iodine acting as an electron acceptor have been previously investigated (29, 30) and have been inferred from equilibrium studies of Polyclar AT and azo dyes (11). Electronic interactions theories rather than adsorption phenomena help to explain the normal mode retention behavior of higher ring systems.…”

“…In spite of the high sensitivity and the universal detection mechanism of the helium detector, it remains an un-popular detector, and in most cases its use has been limited to the analysis of high purity gases, with a few other applications (6-10). The reluctance to use the helium detector is based on several factors including (a) the belief that extreme care has to be taken in using ultrapure helium as carrier gas (11,12), and (b) the belief that the extreme sensitivity of this detector requires an excessively clean chromatographic system with the use of adsorbtion columns that produce minimal or no bleed (11,12). Other factors which have added to the reluctance to use this detector are: (c) the failure of the current detector mechanism to explain the negative and the bipolar detector responses to selected gases (13-15), (d) conflicting reports in the literature concerning the polarity of the detector signal with the purity of the helium carrier gas, and (e) lack of adequate experimental data with varying experimental conditions (16).…”

Molecular Interaction between E-Prostaglandins and Selected Polymers and Its Potential Utilization in Oral Dosage Form Design

“…The numerical values of K and m were 9.01 X lo5 and 1.11 X for tannic acid and 1.58 X lo4 and 2.34 X for I, respectively. Mourey et al (22) recently showed that the molecular interaction between azo compounds and I11 in aqueous solutions is structure dependent. The presence of polar functional groups (e.g., hydroxyl, amino, carboxylic, and sulfonic groups) in unionized forms facilitates interaction with the polymer.…”

Surface-enhanced Raman detection of chemical vapors with the use of personal dosimeters

“…They can also make the substrate surface more scratch resistant and thus amenable as a practical, rugged dosimeter. Finally, a polymer coating can enhance chemical selectivity 31,24 which not only may simplify spectral analysis, but also may increase the loading capacity of the dosimeter for the analyte molecules of interest. Figure 2, the higher concentration is defined by the ambient analyte vapor molecules at the open end of the tube (C 0 ), whereas the lower concentration corresponds to the concentration of analyte molecules very near, but not adsorbed to the SERS substrate surface (C s ) (kg · m Ϫ3 ).…”