Atomic layer deposition has been employed for postsynthesis treatment of octadecyl bonded silica (ODS) as a typical reversed-phase stationary phase for high performance liquid chromatography (HPLC) ,in an effort to alleviate peak tailing for basic compounds. With hexamethyldisilazane( HMDS) as an endcapping agent,the ODS packing materials were heated to 250℃,and maintained at that temperature for 6 h,affording packing materials which are highly inert to basic compounds. Chromatographic performance in terms of retention factor and tailing factor of the resulting phases was evaluated using phenol/pyridine and naphthalene/ami-triptyline pairs as probes. The results were compared with those for the same packing treated by liquid phase method and for the commercial products including Zorbax SB-C_(18) and Kromasil C_(18). The separation characteristics of the ODS phase obtained by atomic layer deposition appear to be superior to that by liquid phase method and,comparable with or even better than the commercial products studied. Being solvent-free process amenable to mass production,the described method provides an economical and eco-friendly approach to manufacturing HPLC packing materials on industrial scale.

Objective To explore the effects of ultraviolet irradiation on platelet. Methods Three assays were been developed.These include platelet count,release of alpha granule membrane protein 140(GMP-140)and morphology of platelet by electron micrograph in those samples before and after ultraviolet irradiation.Results Compared with the nonirradiated controls,the irradiated units showed significant changes including decrease of platelet count,increase of release of GMP-140 and platelet lesion in morphology.Conclusion Ultraviolet irradiation may have activation and lesion effect in platelet.