猪肉中四种磺胺类药物残留的快速HPLC测定法

本文研究了一种快速、方便的测定猪肉中四种磺胺类药物;磺胺嘧啶(SDZ)、磺胺甲基噻啶(SMR)、磺胺二甲嘧啶(SMZ)、磺胺噬啶(STH)的高效液相色谱法。采用乙腈、氯仿提取样品,液液分配净化,再以RP-HPLC分离,紫外检测器254nm波长下检测定量、空白样品添加0.05～0.2mg/kg四种磺胺药物,回收率在74～85%的范围内;变异系数为2～7%;可检测出样品中低至5μg/kg的磺胺药物残留。     

A New Compound Isolated from a Bioactive Streptomycete

A new compound, named (S)-α-acetylamino-β-(3-indole)propano1 (1) was isolated, along with two known compounds teleocidin B 1 and emycin B from culture broth of a streptomycete strain YIM33176 (streptomyces pleomorphus). The structure of 1 was determined by detailed spectroscopic investigation.     

Modelling of particle layer detachment—Role of transient kinetic effects

Particle layers tend to build up on walls in many filtration and separation processes, calling for periodic removal in order to keep the apparatus running. Important factors are the adhesion of the layer on the substrate and the cohesion of the particles in the layer. Models describing such layer detachment generally assume constant and homogeneous conditions for the forces acting on the layer. But in reality detachment is extremely non-stationary concerning place and time, primarily due to changing conditi...     

Umbrella structure in Ho substituted YIG - NMR study

The NMR of ⁵⁷Fe in Ho: YIG and Gd: YIG was measured on polycrystalline samples at 4.2 and 77K. In spectra of both tetrahedral and octahedral Fe³⁺ ions satellite lines appear which were ascribed to Fe³⁺ with a rare earth ion in their vicinity. From the position of the satellites the magnitude and direction of the Ho³⁺ magnetic moment were deduced. The results for Ho³⁺ ion are in good agreement with the crystal field calculations and with other magnetic data, but disagree with the neutron scattering results in HoIG garnet. The results on Gd: YIG were used to check the correctness of the analysis.