采用化学还原法合成牛血清白蛋白(BSA)修饰的金纳米簇(AuNCs),基于Co^(2+)对AuNCs的荧光猝灭作用,提出了一种快速、简便、灵敏测定Co^(2+)含量的方法。以柠檬酸为还原剂、BSA为保护剂、氯金酸为原料合成AuNCs。分取0.20 mL AuNCs溶液,加...采用化学还原法合成牛血清白蛋白(BSA)修饰的金纳米簇(AuNCs),基于Co^(2+)对AuNCs的荧光猝灭作用,提出了一种快速、简便、灵敏测定Co^(2+)含量的方法。以柠檬酸为还原剂、BSA为保护剂、氯金酸为原料合成AuNCs。分取0.20 mL AuNCs溶液,加入0.6 mL pH 9.0碳酸钠-碳酸氢钠缓冲溶液,用水稀释至1.00 mL,在发射波长630 nm处测量上述体系(空白体系)的荧光强度F0。取10片维生素B12药片,研磨后,分取0.1270 g,用水溶解并稀释至100 mL,分取10μL于空白体系中,混匀后静置反应5 min,测量荧光强度F,利用荧光强度的差值ΔF(ΔF=F0-F)进行定量。结果显示:合成的AuNCs分布均匀,Co^(2+)对AuNCs体系有荧光猝灭作用,属于动态猝灭过程。添加10倍Co^(2+)浓度的干扰离子,Fe^(2+)、Pb^(2+)、Al^(3+)、Zn^(2+)、Mg^(2+)、Cr^(3+)、Cu^(2+)、Sr^(2+)、Mn^(2+)、Ca^(2+)不产生干扰,Fe3+、Ni2+的干扰可通过添加三乙醇胺和邻二氮菲掩蔽,Hg2+的干扰严重。Co^(2+)浓度分别在2.0×10^(-11)~1.5×10^(-10)mol·L^(-1)和1.5×10^(-10)~9.9×10^(-10)mol·L^(-1)内与对应的ΔF呈线性关系,检出限(3s/k)为1.7×10^(-12)mol·L^(-1)。按照标准加入法对两个厂家的实际样品进行回收试验,所得测定值和标签值较为接近,Co^(2+)回收率均接近100%,测定值的相对标准偏差(n=5)均小于5.0%。展开更多
Prepare multi-wall carbon nanotubes modifying gold electrode(MWCNT/Au) and study this electrode electrocatalytic action to vitamin B12(VB12) and determining analytic condition of VB12 in the solution.In the mixture of...Prepare multi-wall carbon nanotubes modifying gold electrode(MWCNT/Au) and study this electrode electrocatalytic action to vitamin B12(VB12) and determining analytic condition of VB12 in the solution.In the mixture of 0.1 mol/L KCl as supporting electrolyte and phosphatic buffer solution(pH 7.0),a sensitive reduction peak of VB12 on MWCNT/Au was obtained by cyclic voltammetry.The potential peak for VB12 is-0.120V(vs.SCE).And the reduction peak currents of linear sweep voltammetry are linearly related to the concentration of VB12 in the range of 5×10-5mol/L～5×10-6 mol/L and 1×10-6mol/L～5×10-8 mol/L and the detect limit can reach 1.0×10-8 mol/L.This electrode has been applied to the direct determination of VB12 in sample with a recovery of 95.5%～108.5%.展开更多
文摘Prepare multi-wall carbon nanotubes modifying gold electrode(MWCNT/Au) and study this electrode electrocatalytic action to vitamin B12(VB12) and determining analytic condition of VB12 in the solution.In the mixture of 0.1 mol/L KCl as supporting electrolyte and phosphatic buffer solution(pH 7.0),a sensitive reduction peak of VB12 on MWCNT/Au was obtained by cyclic voltammetry.The potential peak for VB12 is-0.120V(vs.SCE).And the reduction peak currents of linear sweep voltammetry are linearly related to the concentration of VB12 in the range of 5×10-5mol/L～5×10-6 mol/L and 1×10-6mol/L～5×10-8 mol/L and the detect limit can reach 1.0×10-8 mol/L.This electrode has been applied to the direct determination of VB12 in sample with a recovery of 95.5%～108.5%.
