Amperometric immunosensor for nonylphenol determination based on peroxidase indicating reaction.
ABSTRACT Novel immunosensor for nonylphenol (NP) determination has been developed by immobilization of specific antibodies together with horseradish peroxidase on the surface of carbon screen-printed electrode. The signal of the immunosensor is generated by the involvement of NP accumulated in the peroxidase oxidation of mediator (Methylene Blue, hydroquinone or iodide). This results in the increase of the signal recorded by linear-sweep voltammetry. The sensitivity of the detection depends on the nature of mediator, its concentration and incubation period. Cross-selectivity of the response toward readily oxidized phenolic compounds has been determined. The immunosensor developed makes it possible to detect from 20 microgL(-1) to 44 mgL(-1) of NP with detection limit 10 microgL(-1) of NP.
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ABSTRACT: A facile electrochemical sensor for the determination of nonylphenol (NP) was fabricated in this work. Cetyltrimethylammonium bromide (CTAB), which formed a bilayer on the surface of the carbon paste (CP) electrode, displayed a remarkable enhancement effect for the electrochemical oxidation of NP. Moreover, the oxidation peak current of NP at the CTAB/CP electrode demonstrated a linear relationship with NP concentration, which could be applied in the direct determination of NP. Some experimental parameters were investigated, such as external solution pH, mode and time of accumulation, concentration and modification time of CTAB and so on. Under optimized conditions, a wide linear range from 1.0 × 10-7 mol·L-1 to 2.5 × 10-5 mol·L-1 was obtained for the sensor, with a low limit of detection at 1.0 × 10-8 mol·L-1. Several distinguishing advantages of the as-prepared sensor, including facile fabrication, easy operation, low cost and so on, suggest a great potential for its practical applications.Sensors 01/2013; 13(1):758-68. · 1.95 Impact Factor
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ABSTRACT: Biosensor technology is based on a specific biological recognition element in combination with a transducer for signal processing. Since their inception, biosensors have been expected to play a significant analytical role in environmental monitoring. The use of biological data to complement chemical analysis, as well as the development of biosensors and other biological approaches, has grown steadily in recent years. However, the commercialization of biosensor technology has significantly lagged behind their search output as reflected by a plethora of publications and patenting activities. The rationale behind the slow and limited technology transfer could be attributed to cost considerations and some key technical barriers. During the last 15 years a relevant support has been provided by public institutions for biosensor research in the USA, Japan and, especially, in Europe. In addition, biomonitoring is an essential tool for rapid and cost-effective environmental monitoring. For this reason, biosensor technology has been considered as a key tool for the complete implementation of the new European Union (EU) directives, such as the Water Framework Directive (WFD), and other related directives such as the recent Marine Strategy Framework Directive. Analytical chemistry has changed considerably, driven by automation, miniaturization and system integration with high throughput for multiple tasks. Such requirements pose a great challenge in biosensor technology where the biosensor is often designed to detect a single or a few target analytes. Successful biosensors must be versatile to support interchangeable biorecognition elements, and, in addition, miniaturization must be feasible to allow automation for parallel sensing with ease of operation at a competitive cost. A significant up front investment in research and development is a prerequisite in the commercialization of biosensors. The progress in such endeavours is incremented with limited success, thus, the market entry for a new venture is very difficult unless a niche product can be developed with a considerable market volume. Recent technological developments in the miniaturization of electronics and wireless communication technology have led to the emergence of Environmental Sensor Networks (ESN). These will greatly enhance monitoring of the natural environment and in some cases open up new techniques for taking measurements or allow previously impossible deployments of sensors. Herein we present the principles, advantages and limitations of biosensor technology for environmental diagnosis, with special emphasis on those based on nanomaterials and technologies for remote biosensing developed under the support provided by public institutions for research in USA, Japan and Europe.05/2009: pages 1-32;
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ABSTRACT: Interaction of the cationic surfactants benzalkonium chloride and 1-hexadecylpyridinium chloride, in the concentration range 0.1 microM to 1 mM with calf thymus DNA and with short 19-mer double-stranded DNA has been examined in solution using UV absorption and fluorescent spectroscopies and at the liquid-solution interface by thickness-shear mode acoustic wave sensor. Higher concentrations of surfactant resulted in an increase of UV absorption, and decrease of melting temperature and van't Hoff enthalpy of calf thymus DNA. Both surfactants induce fluorescence quenching of ethidium bromide which is also associated with intercalation of the molecules into the nucleic acid strand. The effect of the pyridinium compound is greater than for the other surfactant likely because of the lower size of polar head group in this molecule. With respect to acoustic wave detection at the device surface, for relatively low surfactant concentrations (below 100 microM), decreases of both series resonant frequency and motional resistance were observed. At higher surfactant concentration both parameters increased. These effects are attributed to acoustic coupling processes that occur at the device-film/liquid boundary.The Analyst 05/2010; 135(5):980-6. · 4.23 Impact Factor