Preparation Of Fiber Optical Chemical Sensor, Development Of Instrument System And Applied Techniques In Biologic Medicine And Environmental Monitoring

Fiber optical chemical sensor (FOCS) is a new growing point which combining the fiber optic techniques,spectrum analysis and computer-science technologies. Light can be guided into the fiber and transmitted to the remote end where a sensor inserted into sample was fixed. The on-line information can be obtained with the instrument constituted by electron conversion,analog-to-digital transform and data analysis system. A,continual,on-line and in-situ analysis technique for analyte in biologic medicine and environment is achieved. The study will develop a fiber optic chemical sensor based on multiple quenching and its instrument system. A applied techniques will be established for monitoring analyte in biologic medicine and environment.1,The preparation of Fiber optic chemical sensorThe preparation of various sensitive,stable and reversible sensors is the key for development of FOCS. After completing the methods of embedding with organic polymer and chemical bonding,the present paper mainly describes the method of Sol-Gel technique technique. The results show different methods each has the characteristics.Organic polymer embedding:The process of embedding with;organic polymer is simple,convenient and easily to operate. The member sensor is soft and suitable for detecting the hydrophilic sample. A multiple sensor developed by integrating Pyrenebutyric acid (PBA) membrane with cation exchange resinor cellulose acetate can eliminate the interference of Fe (III). The Cr(Vl) in waste water has detected with the detect limit of 0.2mg L" and the reversibility of 105.1 +4. 05% But the membrane can swell in hydrophobic circumstance and the stability of this kind sensor decreased. Chemical covalent immobilization:The life sensor is improved greatly when molecular is chemical bonding to the solid reagent. No probe leakage was found when the sensor dipped in ethanol and n-hexane for 15 days. This technique is limited for its prolix procession and request of special active function in the structure of molecular probe,Sol-gel:The development of Sol-Gel technique provides a convenient way to incorporate molecular probe in porous inorganic material. The porous structure is proved by observation with scan electron microscope. The aperture is 0.13-2.0 u m which can block off the solid particulate and suspension impurity. The thickness of coating is 1 .30 i* m. For biosensor the porous structure providing essentially the same local aqueous mieroenvironment as in biological media.A biosensor is presented for encapsulation of lactate dehydrogenase(LDH) by Sol-Gel method. The pyruvate and nicotinamide adenine dinucleotide (NADH) can enter into porous freely and react with enzyme. The linearity for the concentration of pyruvate ranging from 1.14 to 34.2 X 10"3mol L"1 when the concentration of NADH is 5.58 X 10"2mol L"1 The optimum reaction temperature and pH are 35C and 7.4 for LDH biosensor,respectively. And the biosensor can be used for almost 70times. The study has offered a feasible method for immobilization of biological active substance.2 The design and manufacture of FOCS instrument systemThe foundation of commercial fiber optical chemical technique is to manufacture a fiber optical chemical instrument system. An instrument is assembled with Xenon light as the source,bifurcate quartz fiber as the carrier for light,high precision photomultiplier tube for the conversion of light signal to electron signal and the 16-digit multi-channels analog-to-digital card for collection of data. The applications software of real-time monitoring system is written by Visual Basic 6.0 with a confront object according to the principle of multiple quenching of fluorescence. It is easily operated under Window's98 with menu suggestion. System error can be eliminated by standard curve preparation and revising. The processing control in on-line monitoring thedissolution of drug preparation and in-situ detecting Cr(VI) in waste water have been achieved with the instrument and software. There will be extensive application wh...