巯基功能化有机硅纳米颗粒修饰金电极的制备及对痕量铅的测定
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摘要
以3-巯丙基三甲氧基硅烷(MPTS)为单一硅源,十六烷基三甲基溴化铵(CTMAB)存在下,采用一步简单混合,较方便地制得均匀、小粒径的有机硅纳米颗粒。采用原子力显微镜(AFM)、透射电子显微镜(TEM)对有机硅纳米进行表征,测得粒径约为2.5 nm。通过自组装法将其固定在金电极表面,得到均匀、高巯基含量的有机硅纳米修饰电极。采用方波溶出伏安法(SWV),考察了CTMAB浓度、Bi3+浓度、支持电解质、pH值富集电位及富集时间等参数对铅溶出信号的影响。结果表明:在0.2 mol/L HAc-NaAc(pH 5.0)缓冲溶液中,-1.0V电位下富集10 min,Pb2+溶出峰电流与浓度分别在5.0～500×10-12mol/L;2.5～250×10-9 mol/L和250～1250×10-9 mol/L范围内呈线性关系,最低检出浓度为5.0×10-12mol/L。利用本方法测定了实际水样中铅的含量,并与原子荧光光谱法进行对比,结果一致。
By a facile one-step synthesis route,the uniform organosilica nanoparticles with small sizes were fabricated using(3-mercaptopropyl)-trimethoxysilane(MPTS) as a single silica source and cetyltrimethylammonium bromide(CTAB) as a template.The morphology of the organosilica nanoparticles was characterized by atomic force microscope(AFM).The particle size was about 2.5 nm as measured by transmission electron microscope(TEM).By simple self-assembling,the uniform and stable organosilica-nanoparticle film modified Au electrode with high density of thiol group was obtained.Several experimental parameters such as CTAB content,Bi3+ concentration,supporting electrolyte,pH values,accumulation potential and accumulation time were studied by square wave stripping voltammetry(SWV).Under the optimized experimental conditions,the three linear ranges of 5.0~500×10-12 mol/L,2.5~250×10-9 mol/L and 250~1250×10-9 mol/L were achieved with 10 min preconcentration at1.0 V in 0.2 mol/L acetic acid-sodium acetate buffer(pH 5).The lowest detectable concentration was as low as 5.0×10-12 mol/L.The developed sensor was applied to the detection of lead in actual water,and the results were concordant with those by atomic fluorescence spectrometry(AFS).
By a facile one-step synthesis route,the uniform organosilica nanoparticles with small sizes were fabricated using(3-mercaptopropyl)-trimethoxysilane(MPTS) as a single silica source and cetyltrimethylammonium bromide(CTAB) as a template.The morphology of the organosilica nanoparticles was characterized by atomic force microscope(AFM).The particle size was about 2.5 nm as measured by transmission electron microscope(TEM).By simple self-assembling,the uniform and stable organosilica-nanoparticle film modified Au electrode with high density of thiol group was obtained.Several experimental parameters such as CTAB content,Bi3+ concentration,supporting electrolyte,pH values,accumulation potential and accumulation time were studied by square wave stripping voltammetry(SWV).Under the optimized experimental conditions,the three linear ranges of 5.0~500×10-12 mol/L,2.5~250×10-9 mol/L and 250~1250×10-9 mol/L were achieved with 10 min preconcentration at1.0 V in 0.2 mol/L acetic acid-sodium acetate buffer(pH 5).The lowest detectable concentration was as low as 5.0×10-12 mol/L.The developed sensor was applied to the detection of lead in actual water,and the results were concordant with those by atomic fluorescence spectrometry(AFS).
引文
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