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以带正电的聚苯乙烯(PS)微球为模板分别制备出表面层为二氧化硅的杂化微球(PS@Si O2)及空心二氧化硅微球(HSSi,hollow spheres of Si O2).利用巯基硅烷偶联剂的桥联作用将金或银纳米粒子修饰到二氧化硅壳层的外表面,制备出4种结构均匀、体积窄分布的复合粒子:(1)纳米金修饰在空心二氧化硅微球的外表面(HSSi-Au NPs);(2)纳米金修饰在实心的PS/二氧化硅杂化微球(PS为核、二氧化硅为壳层)的外表面(PS@Si O2-Au NPs);(3)纳米银修饰在空心二氧化硅微球的外表面(HSSi-Ag NPs)以及(4)纳米银修饰在实心的PS/二氧化硅杂化微球的外表面(PS@Si O2-Ag NPs).分别利用上述4种复合粒子作为拉曼增强(SERS)基底,并以结晶紫(CV)为探针分子对各基底的拉曼增强效果进行了研究,其CV检测限依次为10-10、10-9、10-11和10-11mol/L,均具有较高的灵敏度.结果表明,以空心二氧化硅微球作为载体的增强效果优于以实心的杂化微球作为载体的增强效果(HSSi-Au NPs对CV的检测限比PS@Si O2-Au NPs对CV的检测限低1个数量级;虽然HSSi-Ag NPs和PS@Si O2-Ag NPs对CV的检测限相同,但对于相同浓度的CV,前者所获得的信号要明显强于后者).多次随机的重复测试表明,上述4种基底均具有优良的重复性.将上述4种基底在实验室放置3个月后用于CV的检测,各个基底仍具有相近的拉曼增强效果,即上述4种SERS基底的稳定性良好.
Polystyrene (PS) microspheres with positive charge were used as templates to prepare PS @ Si O2 and hollow spheres of Si O2 ). Four kinds of composite particles with uniform structure and narrow volume distribution were prepared by modifying the gold or silver nanoparticles onto the outer surface of the silica shell by the bridging effect of mercaptosilane coupling agent: (1) (HSSi-Au NPs); (2) nano-gold modified in solid PS / silica hybrid microspheres (PS for the core, silica shell) of the outer surface of the PS @ Si O2-Au NPs); (3) nanosilver modified on the outer surface of hollow silica microspheres (HSSi-Ag NPs); and (4) nanosilver modified on solid PS / silica hybrid microspheres (PS @ Si O2-Ag NPs). The Raman enhancement effect of each substrate was investigated by using the above four kinds of composite particles as Raman enhancement (SERS) substrates and crystal violet (VV) The detection limit of CV was 10-10, 10-9, 10-11 and 10-11mol / L, respectively, with high sensitivity.The results showed that the hollow silica microsphere as the carrier is better than the enhancement effect In fact The synergistic effect of HSS-Au NPs on the detection of CV is one order of magnitude lower than that of PS @ Si O2-Au NPs for CVs. Although HSSi-Au NPs and PS @ Si O2- The detection limits of CV for Ag NPs are the same, but for the same concentration of CV, the signal obtained by the former is significantly stronger than the latter.) Repeated randomized tests show that the above 4 kinds of substrates all have excellent repeatability. Four substrates were tested in the CV for 3 months after being placed in the laboratory, and each substrate still had a similar Raman enhancement effect, ie, the stability of the four SERS substrates was good.