A micellar electrokinetic chromatography (MEKC) method was developed for the determination of nateglinide in animal plasma by on-line sweeping technique, in which plasma samples were simply deproteinized with acetonitrile, and analyzed with 16 mmol/L NaH2PO4+6mmol/L Na2B4O7+60mmol/L sodium dodecyl sulfate (SDS) (pH 7.14) as the running buffer, a fused-silica capillary as the separation tube, 21 kV as the running voltage and UV detection at 214nm. Under these conditions, more than 100-fold enrichment of nateglinide was obtained with the good linear relation in the range of nateglinide plasma concentration 0.2-7mg/L (R=0.998). The method could be applied successfully to determine trace drugs in clinical analysis.

A high-performance liquid chromatographic (HPLC) method was developed for the chiral separation of an antagonist of alpha1A adrenoceptors, tamsulosin and its S-isomer. Baseline separation of the isomers was achieved within 35 min on a CHIRALCEL OD-RH column with a binary solvent mixture of 50 mmol l−1 KPF6-acetonitrile (v/v (70∶30), pH 5.0) as the optimized mobile phase. The detection limits and quantification limits of both R-isomer and S-isomer were 0.11 and 0.44 ng,respectively. The R.S.D. values of peak-area for the two isomer were 0.42% (of peak-height∶0.77%) for R-isomer and 0.64%(of peak-height∶0.92%) for S-isomer (n=5).

研究了一种制备硅胶整体柱的新方法。该工艺以四甲氧基硅烷和聚乙二醇为原料，采用改进的溶胶-凝胶技术，建立了消除柱体开裂和变形弯曲的方法及中孔的构建方法，考察了流速对柱压降的影响，并在正相色谱模式下应用制备的硅胶整体柱对苯取代化合物进行了分离。结果表明采用新工艺所制备的硅胶整体柱不开裂，不变形，并具有通孔和中孔双孔结构，渗透性强，柱压降低，机械强度高，柱效高等特点。这些特性尤其适合化合物的高效快速分离。

A new chiral stationary phase for nateglinide (N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine) based on a molecularly imprinted polymer has been prepared by non-covalent imprinting. For chromatographic analysis the effects on the separation of mobile phase composition, flow rate, and temperature were investigated, and the optimum conditions for HPLC were shown to be: mobile phase, acetonitrile; flow rate, 0.5mL min-1; temperature, 25℃. It was shown that the nateglinide-imprinted polymer was capable of recognizing the enantiomeric difference between nateglinide and its L enantiomer, whereas the non-imprinted polymer had no such ability. Scatchard analysis was used to investigate the binding characteristics of the nateglinide-imprinted stationary phase; this indicated that two classes of binding site were present in the imprinted polymer. The equilibrium dissociation constant (KD) and the apparent maximum number (Qmax) of high-and low-affinity binding sites were 3.7×10-4mol L-1 and 11.38µmol g-1, and 1.81×10-3mol L-1 and 27.73µmol g-1,respectively.

A new approach of preparingmonolithic silica column was founded by adopting an improved solgel technology with tetramethoxy silane and polyethylene glycol as the matrix materials. The reason of resulting in crack and deformation of monolith ic column was explained. By using N, N-dimethylformam ide and a heat treatment procedure, the problems of crack and deformation in preparing the column were solved and the drying time was shortened greatly. In addition, the methods of fabricating mesopore and the effects of porogen solvent of different concentrations on monolith ic silica column were investigated. The results show that the column prepared possessed bimodal pores structuresw ith micrometer-size co-continu-ous through-pores and silica skeletons which have nanometer-size mesopores, straight appearance, high porosity, good chemical and mechanical stability. The characteristics would favour the separation with a rapid speed and high efficiency for both smallmolecules and macromolecules.