Simultaneous determination of phosphonate, phosphate, and diphosphate by capillary electrophoresis using in-capillary complexation with Mo(VI)

This study describes the simultaneous determination of phosphonate, phosphate, and diphosphate by CE with direct UV detection, based on in-capillary complexation with Mo(VI). When a mixture of phosphonate, phosphate, and diphosphate was injected into a capillary containing 3.0 mM Mo(VI), 0.05 M malonate buffer (pH 3.0) and 45% v/v CH3CN, three well-defined peaks, due to the migration of the corresponding polyoxomolybdate anions, were separated. The respective calibration graphs were linear in the concentration range of 2 x 10(-6)-2 x 10(-4) M for phosphonate, 1 x 10(-6)-5 x 10(-5) M for phosphate, and 1 x 10(-6)-2 x 10(-4) M for diphosphate; the correlation coefficients were better than 0.9990. The present CE method is successfully applied to the simultaneous determination of phosphonate, phosphate, and diphosphate in tap water.     

Effects of external fields on a two-dimensional Klein-Gordon particle under pseudo-harmonic oscillator interaction

We study the effects of the perpendicular magnetic and Aharonov-Bohm(AB) flux fields on the energy levels of a two-dimensional(2D) Klein-Gordon(KG) particle subjected to an equal scalar and vector pseudo-harmonic oscillator(PHO).We calculate the exact energy eigenvalues and normalized wave functions in terms of chemical potential parameter,magnetic field strength,AB flux field,and magnetic quantum number by means of the Nikiforov-Uvarov(NU) method.The non-relativistic limit,PHO,and harmonic oscillator solutions in the existence and absence of external fields are also obtained.     

Local chain motions of poly(β-hydroxyoctanoate) in the bulk. 13C NMR relaxation study

Variable-temperature ¹³C NMR spin-lattice relaxation times (T₁) and Nuclear Overhauser Enhancements (NOE) at two magnetic fields have been used to study the dynamics of the amorphous part of a semicrystalline sample (33% of crystallinity) of poly(β-hydroxyoctanoate) (PHO). The interpretation of the relaxation data of the backbone carbons was made by employing a number of motional models. Among these, the DLM model offered the best interpretation of the relaxation data in terms of conformational transitions and librational motions of the backbone C? H vectors, and proved to be superior to unimodal distribution functions. The interpretation of temperature- and frequency-dependent T₁ and NOE data of the carbon nuclei in the n-pentyl side chain was made by employing a newly developed composite spectral density function for multiple internal C? C bond rotations of restricted amplitude and chain segmental motion. The temperature dependence of the linewidths of the various protonated carbon resonances of PHO has been discussed in terms of the semicrystalline character of this polymer. © 1995 John Wiley & Sons, Inc.     

低温解除龙牙百合休眠过程中糖类物质的转化

通过聚丙烯酰胺凝胶电泳技术与石蜡切片等技术研究了低温解除龙牙百合休眠过程中糖类物质的转化。结果表明：淀粉转化为还原糖的关键酶在不同时期表达有显著的差异,还原糖含量在低温处理的中期含量较高,淀粉粒的含量随低温处理的时间延长而减少。