氧化苏木精复合电极测定牛奶中残留青霉素

氧化苏木精复合电极测定牛奶中残留青霉素;电流型电化学生物传感器;氧化苏木精;青霉素     

铂黑修饰酶电极测定胆碱

利用电化学方法在玻碳电极上均匀沉积亚微米粒度铂黑并进而修饰一层胆碱氧化酶膜,制成了胆碱酶电极。以计时电流法测定氯化胆碱,检测下限为 ７．４ μｍｏｌ／Ｌ,线性范围２．４×１０－２～ １．０ ｍｍｏｌ／Ｌ,重现性好,使用寿命较长。     

利用SPR生物传感器检测牛奶中的氨苄青霉素残留

近年来,在食品安全检测领域,利用表面等离子体共振(surface plasmon resonance,SPR)传感器结合免疫测定方法进行痕量物质检测的技术得到了迅速发展。本文采用表面等离子共振生物传感器检测牛奶中的氨苄青霉素残留。从pH值、离子浓度和配体浓度三个方面讨论了实验条件对配体在传感器表面固定的影响,实验结果表明pH值为4.5、离子浓度为10mM以及配体浓度为400μg.mL-1为较佳实验条件。在此实验条件下对BSA-氨苄青霉素偶联物进行了固定,并采用该传感器对不同浓度的氨苄青霉素的水溶液和牛奶溶液进行了检测,最低检测限LOD分别为1.7ng.mL-1和1.8ng.mL-1,均低于氨苄青霉素的最大残留检测限(maximum residue limit,MRL)4.1ng.mL-1,验证了检测方法的可行性。     

可检测有机磷农药残留的丝网印刷酶电极

制备了用于有机磷农药检测的电化学生物酶电极, 并从工作电极上修饰物的选择、测定电压的确定、生物酶电极预活化时间的选定、测定时间的选定、温度的影响、pH值的影响、底物浓度的影响、固定方法的选择、固定酶时温度和时间的影响等多方面对丝网印刷的生物酶电极进行了较为全面的研究, 应用经过优化的生物酶电极对有机磷农药乙基对氧磷进行了检测. 结果表明: 抑制率与乙基对氧磷浓度的常用对数在1.00×10^－7～1.00×10^－5 g•mL^－1范围内成线性关系, 线性回归方程为A/%＝267.2＋37.20lg[c/(g•mL^－1)], 相关系数r＝0.9882. 当信噪比为3时, 检出限为2.10 ng•mL^－1, 低于国家标准所要求的最低残留量.     

测定牛奶中5种青霉素残留量的高效液相色谱柱前衍生法

样品采用乙腈直接提取,离心分离及固相（Ｃ１８柱）净化方式,经衍生后,用液相色谱紫外检测器测定牛奶中５种青霉素残留,方法最小检测质量 度０．００５ｍｇ／Ｌ,回收率范围在６８．９％－１０１．３％之间,相对标准偏差为３．２１％－６．１８％。     

牛奶中2种青霉素残留的高效液相色谱柱前衍生法检测

利用金属铜离子和青霉素G、氨苄西林可在一定条件下形成稳定络合物,建立了一种高效液相色谱快速测定牛奶中2种青霉素残留的方法.样品经酸化乙腈沉淀蛋白,离心处理.色谱柱为Agilent TC C18(150 mm×4.6 mm I.d., 5 μm),甲醇-水为流动相,流速1.5 mL/min,检测波长320 nm,样品在5 min内完成分离检测.青霉素G和氨苄西林的质量浓度分别在0.05 ～1.0 mg/L、0.08 ～2.1 mg/L范围内呈良好的线性关系,相关系数分别为0.995 6、0.998 4.方法的检出限分别为1.5×10-5、2.4×10-5g/L,相对标准偏差分别为2.4%、1.8%(n=5).方法显示出较好的选择性和较高灵敏度,适于牛奶中青霉素G和氨苄西林残留的检测.     

高载酶量酶/酶免疫电极的制备及其电化学机理研究

本文利用扫描电镜和电化学方法确定了最佳镀铂电位,并进一步研究了酶电极和酶免疫电极在基体电极镀铂和未镀铂条件下的米氏常数、电化学反应速率常数和反应速度控制步骤。比较分析了生物电极的最佳实验条件。     

导电聚合物酶电极的研究概况

简述导电聚合物酶电极的制备及其在生物传感器领域的应用，主要包括导电聚合物固定酶的方法、反应机理、以及导电聚合物酶电极的最近进展等。     

L-Glutamine Enzyme Electrode for On-Line Mammalian Cell Culture Process Control

Abstract

Glutaminase and glutamate oxidase were immobillzed into a gelatin support fixed on a pO₂ sensor. The overall activity (0₂ consumption) was correlated to glutamine concentrations range from 0.2 to 2mM. The sample oxygen content dependence of the signal was minimized by the support properties. Measuring time for each sample was 2 minutes including response data treatment and rinsing steps. On repeated use, the electrode signal for 0.5mM was stable for 300 assays at least. This technique has been applied in different mammalian cell cultures.     

聚合物／石墨复合材料电极及其在银离子测定中的应用

用石墨粉填充苯乙烯－丙烯腈共聚树脂（ＡＳ树脂），挤出成型，制取ＡＳ树脂／石墨复合导电材料电极．用红外光谱、循环伏安等手段表征了电极的结构及特性．电极对测定Ａｇ＋有较好的选择性、稳定性和再现性，并较一般玻碳电极更易化学修饰     

A Model of Oximeter - Based Enzyme Electrode

Abstract

A model of an oximeter-based two-substrate enzyme electrode is presented. The simplifications of the general model lead to a solution to differential equations describing the influence of the rate of the enzyme reaction in combination with the diffusion phenomena on measurable oxygen flux. Both transient phase and steady state conditions for experimental data can be considered within the frames of the model and provide possibilities for the calibration of the biosensor. The optimal parameters for the biosensor calibration can be used in practical design of enzyme electrodes.     

Study on the United Glucose Oxidase Electrode Constructed by Composite Electrode

A novel type of united glucose oxidase (GOD) electrode was designed. Glucose oxidase and ferrocene (Fc), which was a mediator, were added into the composite electrode that was constructed by graphite powder, acetylene black, and epoxy resin. These three materials in composite electrode kept constant proportion in weight. And the optimum amounts of GOD and Fc among united enzyme electrode were 5% and 2%, respectively. The glucose was detected linearly in the concentration range 0.01–9.0 mM with a 20-s steady-state response time and 36 nA/mM of the sensitivity at 0.15 V applied potential. And electrode fouling problem and the response current from the interferents were avoided. The response current of the united GOD electrode had no obvious deterioration within 80 days when stored at 4°C in a refrigerator. The detecting results of human serum by the united GOD electrode had good consistency with that by standard enzyme method. The maximum deviation between these two detecting values was 5%. It might be used for detecting the blood sugar in clinical assay.     

电位型痕量硫氢根模拟酶生物传感器研究

以恒电位法在pH=9.0碱性水溶液中碳纤维簇电极上镀单层锌,在含有组氨酸和电解氧化锌镀层下原位合成了锌-组氨酸-羟基络合物修饰碳纤维电极,模拟了生物酶识别痕量的硫氢酸根离子,优化了电极制备的条件。建立了开路电位测定硫氢酸根离子的方法,在中性水溶液中,该电极以开路电位变化响应注入溶液中的硫离子浓度,并可用能斯特方程描述开路电位变化的规律。方法的最低检出限为1.0×10~(-15)mol/L,检测范围为1.0×10~(-6)~1.0×10~(-15)mol/L,相对标准偏差为3.5%。对实际样品中硫氢酸根离子检测结果为1.12×10~(-13)mol/L,加标回收率为109.2%。研制的电化学传感器具有响应快速,灵敏度高,检出限低,检测范围宽,仪器简单方便等特点。     

硼掺杂金刚石电极及其电分析应用

一种新电极材料的发明往往会推动电分析测试的发展。硼掺杂金刚石(BDD)电极在电分析中具备宽电势窗口、低背景电流、 耐腐蚀稳定性高和低吸附的特点,因而在电分析化学中引起了广泛的兴趣。本文对BDD电极的制备、表征和基本电分析性质进行了介绍,并对其在毛细管电泳、生物传感电极、痕量金属离子检测、化学修饰电极及化学需氧量快速测定方面的应用进行了综述。     

Synthesis of Molecularly Imprinted Polymer for Sensitive Penicillin Determination in Milk

Abstract

Penicillin G (PG) in milk is unsafe for human and is a big problem for the foods industry. Hence, the better analytical and eliminative techniques are demanded. We investigated a PG molecular imprinted polymer (MIP), which can sensitively detect and extract the PG from milk and other samples. The MIP synthesis involved a β-lactam antibiotics PG, methacrylic acid (MAA) and dimethyl formamide (DMF). Its properties were analyzed with Scatchard plot, which showed that there were two affinity sites of the PG polymer. The first equilibrium dissociation constant of the high-affinity binding sites Kd₁ was 1.14 × 10^?4 mol/L and the binding capacity Q_max1 was 46.01 µmol/g; the second equilibrium dissociation constant of the low-affinity binding sites Kd₂ was 1.35 × 10^?3 mol/L and the binding capacity Q_max2 was 72.55 µmol/g. Furthermore, two PG determination methods using the polymer were developed. The first was carried out quantitatively with a spectrophotometer and the detection limit was 1 ppm. The other one was the combination of the MIP particles with milk fermentation for PG analysis and the sensitivity was 10 ppb.     

用碘离子选择性电极测定微量联氨

本文提出了用碘离子选择性电极间接测定联氨的方法,其检测下限为5×10~(-5)mol/L。对常见的干扰物质只需进行简单的酸化即可进行测定。