血液中血红蛋白含量的测定

利用电合成方法在玻碳电极表面制备聚硫堇薄膜,并用电化学及石英电子微天平方法研究其对血红蛋白的吸附作用.吸附态血红蛋白具有直接的电化学行为,且其氧化-还原电流与血红蛋白(Hb)的含量成正比关系,可用于血液中血红蛋白含量的测定.     

聚硫堇/石墨烯修饰玻碳电极测定壬基酚

用电化学聚合法在玻碳电极上形成聚硫堇,再修饰石墨烯,制备出聚硫堇/石墨烯修饰电极。并采用循环伏安法和差分脉冲伏安法对壬基酚在此修饰电极上的电化学行为进行测定,对实验条件进行了优化,结果表明,在p H值为4.0的B-R缓冲溶液中,壬基酚在3.0×10-8~2.4×10-7mol/L的浓度范围内与其氧化峰电流值呈现良好的线性关系,线性系数为0.9916,最低检测限为2.0×10-8mol/L(S/N=3),可用于实际样品的检测。     

A new amperometric biosensor for hydrogen peroxide determination based on HRP-nanogold-PTH-nanogold-modified carbon paste electrodes

A new strategy for immobilization of horseradish peroxidase (HRP) has been developed by self-assembling gold nanoparticles to multiporous polythionine (PTH) film modified carbon paste interface. A thionine film was initially electropolymerized onto carbon paste interface in a mildly acidic thionine solution at a bias voltage of −1.0 to 1.5 V. This process is accompanied by the hydrogen evolution reaction, and the released hydrogen gas made the PTH film with multiporous structure. The multiporous PTH film provided a biocompatible microenvironment for gold nanoparticles and enzyme molecules, and greatly amplified the coverage of HRP molecules on the electrode surface. Voltammetric and time-based amperometric techniques were employed to characterize the properties of the derived biosensor. The performance and factors influencing the performance of the biosensor were also proposed. The immobilized HRP displayed a catalytic property to the reduction of H₂O₂. The H₂O₂ biosensor achieved 95% of the steady-state current within 2 s, and exhibited a linear range of 9.6×10⁻⁶ to 1.2×10⁻³ M H₂O₂ with a detection limit of 7.5×10⁻⁷ M (S/N = 3). Furthermore, the biosensor remained at about 90% of its original sensitivity after 2 weeks’ storage.     

双波长双指示剂褪色光度法测定大米中的痕量镉

在盐酸介质中,痕量镉离子对双氧水氧化茜素红S和硫堇具有较强烈的催化作用,因此建立了一种测定痕量镉离子的双波长双指示剂褪色光度法.实验结果表明,溶液的最大吸收波长分别出现在420 nm和610 nm.6次空白实验的标准偏差S=6.31×10-4,相对标准偏差为0.01％,检出限为4.878×10-2μg/mL.该方法用于大米样品中痕量镉的测定,结果令人满意.     

基于纳米金/硫堇修饰金电极的脱落酸安培免疫传感器的研制

提出了一种基于纳米金/硫堇修饰金电极的ABA安培免疫传感器。该传感器基于H2O2-HRP-硫堇催化波体系构建,其中硫堇为传感介质。当HRP存在时,通过加入H2O2,硫堇的还原电流大幅增加,并且电流的增加依赖于HRP活性。HRP活性又由ABA与HRP酶标抗体结合物调控,产生一个减小的催化波。用BSA封闭硫堇单分子层修饰后可能存在的活性位点以避免非特异性吸附。优化了测定条件,包括酶标抗体和硫堇的最佳比例、培育时间、缓冲液的pH值和H2O2浓度。此传感器的还原电流在ABA浓度0.5~1000ng/mL范围内呈线性下降,回归方程为y=0.0209x 17.071,相关系数为0.9922,检测限为0.2ng/mL。     

基于聚硫堇的一次性O型口蹄疫抗原酶免疫传感器的研制

将O型口蹄疫酶标抗体掺杂于有机-无机溶胶凝胶中,并修饰于聚硫菫的丝网印刷碳电极表面,从而制备一次性口蹄疫病毒抗原(FMDV-Ag)酶免疫传感器。试验中采用直接免疫分析法检测口蹄疫病毒抗原。根据免疫反应前后还原峰电流下降的百分率K值的大小实现对抗原的检测。在优化条件下,免疫传感器检测抗原的线性范围为77～388ng/mL,最低检出限为32ng/mL。免疫电极具有较好的特异性、重现性(RSD=5.6%)、稳定性(10d后电流响应为初始值的89.5%)和准确性(与AGP符合率为95%)。因此,该免疫传感器有望用于O型口蹄疫抗原的快速检测。     

光谱法研究硫堇与人血清白蛋白的相互作用

用荧光光谱、紫外-可见吸收光谱和圆二色谱等光谱方法研究了生理条件下硫堇(TH)与人血清白蛋白(HSA)的作用机理.测得不同温度下,硫堇与人血清白蛋白的结合常数和结合位点数,确定硫堇对人血清白蛋白荧光的猝灭是静态猝灭过程,并依据Forster无辐射能量转移理论获得了TH与HSA的结合距离4.604 nm,热力学参数Δ H =-9.024 kJ/mol,Δ S =40.63 J·mol-1·K-1,表明TH与HSA主要为静电力相互作用,同步荧光光谱和圆二色谱显示了TH对HSA的二级结构构象产生影响.     

光谱技术研究硫堇与牛血清白蛋白的结合反应

用荧光光谱、紫外可见吸收光谱和圆二色光谱技术研究了生理条件下硫堇(TH)与牛血清白蛋白(BSA)的结合反应.结果表明,硫堇借静电力与牛血清白蛋白发生相互作用并对牛血清白蛋白的荧光以静态方式猝灭,其结合常数为1.155×105L·mol-1、结合位点数为1.835、结合距离2.865 nm.同步荧光和圆二色技术证实TH对BSA的构像有影响.     

Highly sensitive and simultaneous determination of hydroquinone and catechol at poly(thionine) modified glassy carbon electrode

A simple and highly sensitive electrochemical method for the simultaneous and quantitative detection of hydroquinone (HQ) and catechol (CT) was developed, based on a poly(thionine)-modified glassy carbon electrode (GCE). The modified electrode showed excellent electrocatalytic activity and reversibility towards the oxidation of both HQ and CT in 0.1 M phosphate buffer solution (PBS, pH 7.0). The peak-to-peak separations (ΔE_p) between oxidation and reduction waves in CV were decreased significantly from 262 and 204 mV at the bare GCE, to 63 and 56 mV, respectively for HQ and CT at the poly(thionine) modified GCE. Furthermore, the redox responses from the mixture of HQ and CT were easily resolved in both CV and DPV due to a difference in the catalytic activity of the modified GCE to each component. The peak potential separation of ca. 0.1 V was large enough for the simultaneous determination of HQ and CT electrochemically. The oxidation peak currents of HQ and CT were linear over the range from 1 to 120 μM in the presence of 100 and 200 μM of HQ and CT, respectively. The modified electrode showed very high sensitivity of 1.8 and 1.2 μA μM⁻¹ cm⁻² for HQ and CT, respectively. The detection limits (S/N = 3) for HQ and CT were 30 and 25 nM, respectively. The developed sensor was successfully examined for real sample analysis with tap water and revealed stable and reliable recovery data.     

Electrocatalysis and determination of uracil on polythionine/multiwall carbon nanotubes modified electrode

A new type of poly (thionine)/multiwall carbon nanotube/glassy carbon (PTH/MWNTs/GC) electrode was fabricated by electropolymerization thionine onto the surface of MWNTs modified GC electrode. The properties and behaviors of the modified electrode were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The results show that the high sensitivity and selectivity are mainly caused by the unique carbon surface of the carbon nanotubes and the catalytic activity of thionine. The modified electrode exhibited excellent electrocatalytic behavior to the oxidation of uracil, and was firstly applied to determinate the concentration of uracil for the differential pulse voltammograms. Under the optimum conditions, linear calibration equation was obtained over the uracil concentration range from 1.0 × 10^?5 to 5.5 × 10^?2M with a correlation coefficient of 0.9978 and a detection limit 2.0 × 10^?7M (based on S/N = 3) was also gained. The good electrocatalytic response of uracil at PTH/MWNTs/GC electrode suggests that the PTH/MWNTs are an excellent platform for electrochemical biosensing. The modified electrode displays excellent repeatability, stability, and high sensitivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008